2023-12-26 20:02:32

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 00/10] IOMMU memory observability

----------------------------------------------------------------------
Changelog
----------------------------------------------------------------------
v3:
- Sync with v6.7-rc7
- Addressed comments from David Rientjes: s/pages/page/, added unlikely() into
the branches, expanded comment for iommu_free_pages_list().
- Added Acked-bys: David Rientjes

v2:
- Added Reviewed-by Janne Grunau
- Sync with 6.7.0-rc3, 3b47bc037bd44f142ac09848e8d3ecccc726be99
- Separated form the series patches:
vhost-vdpa: account iommu allocations
https://lore.kernel.org/all/[email protected]
vfio: account iommu allocations
https://lore.kernel.org/all/[email protected]
as suggested by Jason Gunthorpe
- Fixed SPARC build issue detected by kernel test robot
- Drop the following patches as they do account iommu page tables:
iommu/dma: use page allocation function provided by iommu-pages.h
iommu/fsl: use page allocation function provided by iommu-pages.h
iommu/iommufd: use page allocation function provided by iommu-pages.h
as suggested by Robin Murphy. These patches are not related to IOMMU
page tables. We might need to do a separate work to support DMA
observability.
- Remove support iommu/io-pgtable-arm-v7s as the 2nd level pages are
under a page size, thanks Robin Murphy for pointing this out.

----------------------------------------------------------------------
Description
----------------------------------------------------------------------
IOMMU subsystem may contain state that is in gigabytes. Majority of that
state is iommu page tables. Yet, there is currently, no way to observe
how much memory is actually used by the iommu subsystem.

This patch series solves this problem by adding both observability to
all pages that are allocated by IOMMU, and also accountability, so
admins can limit the amount if via cgroups.

The system-wide observability is using /proc/meminfo:
SecPageTables: 438176 kB

Contains IOMMU and KVM memory.

Per-node observability:
/sys/devices/system/node/nodeN/meminfo
Node N SecPageTables: 422204 kB

Contains IOMMU and KVM memory memory in the given NUMA node.

Per-node IOMMU only observability:
/sys/devices/system/node/nodeN/vmstat
nr_iommu_pages 105555

Contains number of pages IOMMU allocated in the given node.

Accountability: using sec_pagetables cgroup-v2 memory.stat entry.

With the change, iova_stress[1] stops as limit is reached:

# ./iova_stress
iova space: 0T free memory: 497G
iova space: 1T free memory: 495G
iova space: 2T free memory: 493G
iova space: 3T free memory: 491G

stops as limit is reached.

This series encorporates suggestions that came from the discussion
at LPC [2].
----------------------------------------------------------------------
[1] https://github.com/soleen/iova_stress
[2] https://lpc.events/event/17/contributions/1466
----------------------------------------------------------------------
Previous versions
v1: https://lore.kernel.org/all/[email protected]
v2: https://lore.kernel.org/linux-mm/[email protected]
----------------------------------------------------------------------

Pasha Tatashin (10):
iommu/vt-d: add wrapper functions for page allocations
iommu/amd: use page allocation function provided by iommu-pages.h
iommu/io-pgtable-arm: use page allocation function provided by
iommu-pages.h
iommu/io-pgtable-dart: use page allocation function provided by
iommu-pages.h
iommu/exynos: use page allocation function provided by iommu-pages.h
iommu/rockchip: use page allocation function provided by iommu-pages.h
iommu/sun50i: use page allocation function provided by iommu-pages.h
iommu/tegra-smmu: use page allocation function provided by
iommu-pages.h
iommu: observability of the IOMMU allocations
iommu: account IOMMU allocated memory

Documentation/admin-guide/cgroup-v2.rst | 2 +-
Documentation/filesystems/proc.rst | 4 +-
drivers/iommu/amd/amd_iommu.h | 8 -
drivers/iommu/amd/init.c | 91 +++++----
drivers/iommu/amd/io_pgtable.c | 13 +-
drivers/iommu/amd/io_pgtable_v2.c | 20 +-
drivers/iommu/amd/iommu.c | 13 +-
drivers/iommu/exynos-iommu.c | 14 +-
drivers/iommu/intel/dmar.c | 10 +-
drivers/iommu/intel/iommu.c | 47 ++---
drivers/iommu/intel/iommu.h | 2 -
drivers/iommu/intel/irq_remapping.c | 10 +-
drivers/iommu/intel/pasid.c | 12 +-
drivers/iommu/intel/svm.c | 7 +-
drivers/iommu/io-pgtable-arm.c | 7 +-
drivers/iommu/io-pgtable-dart.c | 37 ++--
drivers/iommu/iommu-pages.h | 236 ++++++++++++++++++++++++
drivers/iommu/rockchip-iommu.c | 14 +-
drivers/iommu/sun50i-iommu.c | 7 +-
drivers/iommu/tegra-smmu.c | 18 +-
include/linux/mmzone.h | 5 +-
mm/vmstat.c | 3 +
22 files changed, 395 insertions(+), 185 deletions(-)
create mode 100644 drivers/iommu/iommu-pages.h

--
2.43.0.472.g3155946c3a-goog



2023-12-26 20:03:36

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 01/10] iommu/vt-d: add wrapper functions for page allocations

In order to improve observability and accountability of IOMMU layer, we
must account the number of pages that are allocated by functions that
are calling directly into buddy allocator.

This is achieved by first wrapping the allocation related functions into a
separate inline functions in new file:

drivers/iommu/iommu-pages.h

Convert all page allocation calls under iommu/intel to use these new
functions.

Signed-off-by: Pasha Tatashin <[email protected]>
---
drivers/iommu/intel/dmar.c | 10 +-
drivers/iommu/intel/iommu.c | 47 +++----
drivers/iommu/intel/iommu.h | 2 -
drivers/iommu/intel/irq_remapping.c | 10 +-
drivers/iommu/intel/pasid.c | 12 +-
drivers/iommu/intel/svm.c | 7 +-
drivers/iommu/iommu-pages.h | 204 ++++++++++++++++++++++++++++
7 files changed, 241 insertions(+), 51 deletions(-)
create mode 100644 drivers/iommu/iommu-pages.h

diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 23cb80d62a9a..f72b1e4334b1 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -32,6 +32,7 @@

#include "iommu.h"
#include "../irq_remapping.h"
+#include "../iommu-pages.h"
#include "perf.h"
#include "trace.h"
#include "perfmon.h"
@@ -1185,7 +1186,7 @@ static void free_iommu(struct intel_iommu *iommu)
}

if (iommu->qi) {
- free_page((unsigned long)iommu->qi->desc);
+ iommu_free_page(iommu->qi->desc);
kfree(iommu->qi->desc_status);
kfree(iommu->qi);
}
@@ -1732,6 +1733,7 @@ int dmar_enable_qi(struct intel_iommu *iommu)
{
struct q_inval *qi;
struct page *desc_page;
+ int order;

if (!ecap_qis(iommu->ecap))
return -ENOENT;
@@ -1752,8 +1754,8 @@ int dmar_enable_qi(struct intel_iommu *iommu)
* Need two pages to accommodate 256 descriptors of 256 bits each
* if the remapping hardware supports scalable mode translation.
*/
- desc_page = alloc_pages_node(iommu->node, GFP_ATOMIC | __GFP_ZERO,
- !!ecap_smts(iommu->ecap));
+ order = ecap_smts(iommu->ecap) ? 1 : 0;
+ desc_page = __iommu_alloc_pages_node(iommu->node, GFP_ATOMIC, order);
if (!desc_page) {
kfree(qi);
iommu->qi = NULL;
@@ -1764,7 +1766,7 @@ int dmar_enable_qi(struct intel_iommu *iommu)

qi->desc_status = kcalloc(QI_LENGTH, sizeof(int), GFP_ATOMIC);
if (!qi->desc_status) {
- free_page((unsigned long) qi->desc);
+ iommu_free_page(qi->desc);
kfree(qi);
iommu->qi = NULL;
return -ENOMEM;
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 897159dba47d..4ae52569ab4a 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -28,6 +28,7 @@
#include "../dma-iommu.h"
#include "../irq_remapping.h"
#include "../iommu-sva.h"
+#include "../iommu-pages.h"
#include "pasid.h"
#include "cap_audit.h"
#include "perfmon.h"
@@ -367,22 +368,6 @@ static int __init intel_iommu_setup(char *str)
}
__setup("intel_iommu=", intel_iommu_setup);

-void *alloc_pgtable_page(int node, gfp_t gfp)
-{
- struct page *page;
- void *vaddr = NULL;
-
- page = alloc_pages_node(node, gfp | __GFP_ZERO, 0);
- if (page)
- vaddr = page_address(page);
- return vaddr;
-}
-
-void free_pgtable_page(void *vaddr)
-{
- free_page((unsigned long)vaddr);
-}
-
static inline int domain_type_is_si(struct dmar_domain *domain)
{
return domain->domain.type == IOMMU_DOMAIN_IDENTITY;
@@ -617,7 +602,7 @@ struct context_entry *iommu_context_addr(struct intel_iommu *iommu, u8 bus,
if (!alloc)
return NULL;

- context = alloc_pgtable_page(iommu->node, GFP_ATOMIC);
+ context = iommu_alloc_page_node(iommu->node, GFP_ATOMIC);
if (!context)
return NULL;

@@ -791,17 +776,17 @@ static void free_context_table(struct intel_iommu *iommu)
for (i = 0; i < ROOT_ENTRY_NR; i++) {
context = iommu_context_addr(iommu, i, 0, 0);
if (context)
- free_pgtable_page(context);
+ iommu_free_page(context);

if (!sm_supported(iommu))
continue;

context = iommu_context_addr(iommu, i, 0x80, 0);
if (context)
- free_pgtable_page(context);
+ iommu_free_page(context);
}

- free_pgtable_page(iommu->root_entry);
+ iommu_free_page(iommu->root_entry);
iommu->root_entry = NULL;
}

@@ -939,7 +924,7 @@ static struct dma_pte *pfn_to_dma_pte(struct dmar_domain *domain,
if (!dma_pte_present(pte)) {
uint64_t pteval;

- tmp_page = alloc_pgtable_page(domain->nid, gfp);
+ tmp_page = iommu_alloc_page_node(domain->nid, gfp);

if (!tmp_page)
return NULL;
@@ -951,7 +936,7 @@ static struct dma_pte *pfn_to_dma_pte(struct dmar_domain *domain,

if (cmpxchg64(&pte->val, 0ULL, pteval))
/* Someone else set it while we were thinking; use theirs. */
- free_pgtable_page(tmp_page);
+ iommu_free_page(tmp_page);
else
domain_flush_cache(domain, pte, sizeof(*pte));
}
@@ -1064,7 +1049,7 @@ static void dma_pte_free_level(struct dmar_domain *domain, int level,
last_pfn < level_pfn + level_size(level) - 1)) {
dma_clear_pte(pte);
domain_flush_cache(domain, pte, sizeof(*pte));
- free_pgtable_page(level_pte);
+ iommu_free_page(level_pte);
}
next:
pfn += level_size(level);
@@ -1088,7 +1073,7 @@ static void dma_pte_free_pagetable(struct dmar_domain *domain,

/* free pgd */
if (start_pfn == 0 && last_pfn == DOMAIN_MAX_PFN(domain->gaw)) {
- free_pgtable_page(domain->pgd);
+ iommu_free_page(domain->pgd);
domain->pgd = NULL;
}
}
@@ -1190,7 +1175,7 @@ static int iommu_alloc_root_entry(struct intel_iommu *iommu)
{
struct root_entry *root;

- root = alloc_pgtable_page(iommu->node, GFP_ATOMIC);
+ root = iommu_alloc_page_node(iommu->node, GFP_ATOMIC);
if (!root) {
pr_err("Allocating root entry for %s failed\n",
iommu->name);
@@ -1863,7 +1848,7 @@ static void domain_exit(struct dmar_domain *domain)
LIST_HEAD(freelist);

domain_unmap(domain, 0, DOMAIN_MAX_PFN(domain->gaw), &freelist);
- put_pages_list(&freelist);
+ iommu_free_pages_list(&freelist);
}

if (WARN_ON(!list_empty(&domain->devices)))
@@ -2640,7 +2625,7 @@ static int copy_context_table(struct intel_iommu *iommu,
if (!old_ce)
goto out;

- new_ce = alloc_pgtable_page(iommu->node, GFP_KERNEL);
+ new_ce = iommu_alloc_page_node(iommu->node, GFP_KERNEL);
if (!new_ce)
goto out_unmap;

@@ -3573,7 +3558,7 @@ static int intel_iommu_memory_notifier(struct notifier_block *nb,
start_vpfn, mhp->nr_pages,
list_empty(&freelist), 0);
rcu_read_unlock();
- put_pages_list(&freelist);
+ iommu_free_pages_list(&freelist);
}
break;
}
@@ -4004,7 +3989,7 @@ static int md_domain_init(struct dmar_domain *domain, int guest_width)
domain->max_addr = 0;

/* always allocate the top pgd */
- domain->pgd = alloc_pgtable_page(domain->nid, GFP_ATOMIC);
+ domain->pgd = iommu_alloc_page_node(domain->nid, GFP_ATOMIC);
if (!domain->pgd)
return -ENOMEM;
domain_flush_cache(domain, domain->pgd, PAGE_SIZE);
@@ -4151,7 +4136,7 @@ int prepare_domain_attach_device(struct iommu_domain *domain,
pte = dmar_domain->pgd;
if (dma_pte_present(pte)) {
dmar_domain->pgd = phys_to_virt(dma_pte_addr(pte));
- free_pgtable_page(pte);
+ iommu_free_page(pte);
}
dmar_domain->agaw--;
}
@@ -4298,7 +4283,7 @@ static void intel_iommu_tlb_sync(struct iommu_domain *domain,
start_pfn, nrpages,
list_empty(&gather->freelist), 0);

- put_pages_list(&gather->freelist);
+ iommu_free_pages_list(&gather->freelist);
}

static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index ce030c5b5772..453e5d84f6a6 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -897,8 +897,6 @@ void domain_update_iommu_cap(struct dmar_domain *domain);

int dmar_ir_support(void);

-void *alloc_pgtable_page(int node, gfp_t gfp);
-void free_pgtable_page(void *vaddr);
void iommu_flush_write_buffer(struct intel_iommu *iommu);
struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn);
struct iommu_domain *intel_nested_domain_alloc(struct iommu_domain *parent,
diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c
index 29b9e55dcf26..72e1c1342c13 100644
--- a/drivers/iommu/intel/irq_remapping.c
+++ b/drivers/iommu/intel/irq_remapping.c
@@ -22,6 +22,7 @@

#include "iommu.h"
#include "../irq_remapping.h"
+#include "../iommu-pages.h"
#include "cap_audit.h"

enum irq_mode {
@@ -536,8 +537,8 @@ static int intel_setup_irq_remapping(struct intel_iommu *iommu)
if (!ir_table)
return -ENOMEM;

- pages = alloc_pages_node(iommu->node, GFP_KERNEL | __GFP_ZERO,
- INTR_REMAP_PAGE_ORDER);
+ pages = __iommu_alloc_pages_node(iommu->node, GFP_KERNEL,
+ INTR_REMAP_PAGE_ORDER);
if (!pages) {
pr_err("IR%d: failed to allocate pages of order %d\n",
iommu->seq_id, INTR_REMAP_PAGE_ORDER);
@@ -622,7 +623,7 @@ static int intel_setup_irq_remapping(struct intel_iommu *iommu)
out_free_bitmap:
bitmap_free(bitmap);
out_free_pages:
- __free_pages(pages, INTR_REMAP_PAGE_ORDER);
+ __iommu_free_pages(pages, INTR_REMAP_PAGE_ORDER);
out_free_table:
kfree(ir_table);

@@ -643,8 +644,7 @@ static void intel_teardown_irq_remapping(struct intel_iommu *iommu)
irq_domain_free_fwnode(fn);
iommu->ir_domain = NULL;
}
- free_pages((unsigned long)iommu->ir_table->base,
- INTR_REMAP_PAGE_ORDER);
+ iommu_free_pages(iommu->ir_table->base, INTR_REMAP_PAGE_ORDER);
bitmap_free(iommu->ir_table->bitmap);
kfree(iommu->ir_table);
iommu->ir_table = NULL;
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 74e8e4c17e81..1856e74bba78 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -20,6 +20,7 @@

#include "iommu.h"
#include "pasid.h"
+#include "../iommu-pages.h"

/*
* Intel IOMMU system wide PASID name space:
@@ -116,8 +117,7 @@ int intel_pasid_alloc_table(struct device *dev)

size = max_pasid >> (PASID_PDE_SHIFT - 3);
order = size ? get_order(size) : 0;
- pages = alloc_pages_node(info->iommu->node,
- GFP_KERNEL | __GFP_ZERO, order);
+ pages = __iommu_alloc_pages_node(info->iommu->node, GFP_KERNEL, order);
if (!pages) {
kfree(pasid_table);
return -ENOMEM;
@@ -154,10 +154,10 @@ void intel_pasid_free_table(struct device *dev)
max_pde = pasid_table->max_pasid >> PASID_PDE_SHIFT;
for (i = 0; i < max_pde; i++) {
table = get_pasid_table_from_pde(&dir[i]);
- free_pgtable_page(table);
+ iommu_free_page(table);
}

- free_pages((unsigned long)pasid_table->table, pasid_table->order);
+ iommu_free_pages(pasid_table->table, pasid_table->order);
kfree(pasid_table);
}

@@ -203,7 +203,7 @@ static struct pasid_entry *intel_pasid_get_entry(struct device *dev, u32 pasid)
retry:
entries = get_pasid_table_from_pde(&dir[dir_index]);
if (!entries) {
- entries = alloc_pgtable_page(info->iommu->node, GFP_ATOMIC);
+ entries = iommu_alloc_page_node(info->iommu->node, GFP_ATOMIC);
if (!entries)
return NULL;

@@ -215,7 +215,7 @@ static struct pasid_entry *intel_pasid_get_entry(struct device *dev, u32 pasid)
*/
if (cmpxchg64(&dir[dir_index].val, 0ULL,
(u64)virt_to_phys(entries) | PASID_PTE_PRESENT)) {
- free_pgtable_page(entries);
+ iommu_free_page(entries);
goto retry;
}
if (!ecap_coherent(info->iommu->ecap)) {
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index ac12f76c1212..e97f68427b54 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -23,6 +23,7 @@
#include "pasid.h"
#include "perf.h"
#include "../iommu-sva.h"
+#include "../iommu-pages.h"
#include "trace.h"

static irqreturn_t prq_event_thread(int irq, void *d);
@@ -67,7 +68,7 @@ int intel_svm_enable_prq(struct intel_iommu *iommu)
struct page *pages;
int irq, ret;

- pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, PRQ_ORDER);
+ pages = __iommu_alloc_pages(GFP_KERNEL, PRQ_ORDER);
if (!pages) {
pr_warn("IOMMU: %s: Failed to allocate page request queue\n",
iommu->name);
@@ -118,7 +119,7 @@ int intel_svm_enable_prq(struct intel_iommu *iommu)
dmar_free_hwirq(irq);
iommu->pr_irq = 0;
free_prq:
- free_pages((unsigned long)iommu->prq, PRQ_ORDER);
+ iommu_free_pages(iommu->prq, PRQ_ORDER);
iommu->prq = NULL;

return ret;
@@ -141,7 +142,7 @@ int intel_svm_finish_prq(struct intel_iommu *iommu)
iommu->iopf_queue = NULL;
}

- free_pages((unsigned long)iommu->prq, PRQ_ORDER);
+ iommu_free_pages(iommu->prq, PRQ_ORDER);
iommu->prq = NULL;

return 0;
diff --git a/drivers/iommu/iommu-pages.h b/drivers/iommu/iommu-pages.h
new file mode 100644
index 000000000000..99105503b771
--- /dev/null
+++ b/drivers/iommu/iommu-pages.h
@@ -0,0 +1,204 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2023, Google LLC.
+ * Pasha Tatashin <[email protected]>
+ */
+
+#ifndef __IOMMU_PAGES_H
+#define __IOMMU_PAGES_H
+
+#include <linux/vmstat.h>
+#include <linux/gfp.h>
+#include <linux/mm.h>
+
+/*
+ * All page allocation that are performed in the IOMMU subsystem must use one of
+ * the functions below. This is necessary for the proper accounting as IOMMU
+ * state can be rather large, i.e. multiple gigabytes in size.
+ */
+
+/**
+ * __iommu_alloc_pages_node - allocate a zeroed page of a given order from
+ * specific NUMA node.
+ * @nid: memory NUMA node id
+ * @gfp: buddy allocator flags
+ * @order: page order
+ *
+ * returns the head struct page of the allocated page.
+ */
+static inline struct page *__iommu_alloc_pages_node(int nid, gfp_t gfp,
+ int order)
+{
+ struct page *page;
+
+ page = alloc_pages_node(nid, gfp | __GFP_ZERO, order);
+ if (unlikely(!page))
+ return NULL;
+
+ return page;
+}
+
+/**
+ * __iommu_alloc_pages - allocate a zeroed page of a given order.
+ * @gfp: buddy allocator flags
+ * @order: page order
+ *
+ * returns the head struct page of the allocated page.
+ */
+static inline struct page *__iommu_alloc_pages(gfp_t gfp, int order)
+{
+ struct page *page;
+
+ page = alloc_pages(gfp | __GFP_ZERO, order);
+ if (unlikely(!page))
+ return NULL;
+
+ return page;
+}
+
+/**
+ * __iommu_alloc_page_node - allocate a zeroed page at specific NUMA node.
+ * @nid: memory NUMA node id
+ * @gfp: buddy allocator flags
+ *
+ * returns the struct page of the allocated page.
+ */
+static inline struct page *__iommu_alloc_page_node(int nid, gfp_t gfp)
+{
+ return __iommu_alloc_pages_node(nid, gfp, 0);
+}
+
+/**
+ * __iommu_alloc_page - allocate a zeroed page
+ * @gfp: buddy allocator flags
+ *
+ * returns the struct page of the allocated page.
+ */
+static inline struct page *__iommu_alloc_page(gfp_t gfp)
+{
+ return __iommu_alloc_pages(gfp, 0);
+}
+
+/**
+ * __iommu_free_pages - free page of a given order
+ * @page: head struct page of the page
+ * @order: page order
+ */
+static inline void __iommu_free_pages(struct page *page, int order)
+{
+ if (!page)
+ return;
+
+ __free_pages(page, order);
+}
+
+/**
+ * __iommu_free_page - free page
+ * @page: struct page of the page
+ */
+static inline void __iommu_free_page(struct page *page)
+{
+ __iommu_free_pages(page, 0);
+}
+
+/**
+ * iommu_alloc_pages_node - allocate a zeroed page of a given order from
+ * specific NUMA node.
+ * @nid: memory NUMA node id
+ * @gfp: buddy allocator flags
+ * @order: page order
+ *
+ * returns the virtual address of the allocated page
+ */
+static inline void *iommu_alloc_pages_node(int nid, gfp_t gfp, int order)
+{
+ struct page *page = __iommu_alloc_pages_node(nid, gfp, order);
+
+ if (unlikely(!page))
+ return NULL;
+
+ return page_address(page);
+}
+
+/**
+ * iommu_alloc_pages - allocate a zeroed page of a given order
+ * @gfp: buddy allocator flags
+ * @order: page order
+ *
+ * returns the virtual address of the allocated page
+ */
+static inline void *iommu_alloc_pages(gfp_t gfp, int order)
+{
+ struct page *page = __iommu_alloc_pages(gfp, order);
+
+ if (unlikely(!page))
+ return NULL;
+
+ return page_address(page);
+}
+
+/**
+ * iommu_alloc_page_node - allocate a zeroed page at specific NUMA node.
+ * @nid: memory NUMA node id
+ * @gfp: buddy allocator flags
+ *
+ * returns the virtual address of the allocated page
+ */
+static inline void *iommu_alloc_page_node(int nid, gfp_t gfp)
+{
+ return iommu_alloc_pages_node(nid, gfp, 0);
+}
+
+/**
+ * iommu_alloc_page - allocate a zeroed page
+ * @gfp: buddy allocator flags
+ *
+ * returns the virtual address of the allocated page
+ */
+static inline void *iommu_alloc_page(gfp_t gfp)
+{
+ return iommu_alloc_pages(gfp, 0);
+}
+
+/**
+ * iommu_free_pages - free page of a given order
+ * @virt: virtual address of the page to be freed.
+ * @order: page order
+ */
+static inline void iommu_free_pages(void *virt, int order)
+{
+ if (!virt)
+ return;
+
+ __iommu_free_pages(virt_to_page(virt), order);
+}
+
+/**
+ * iommu_free_page - free page
+ * @virt: virtual address of the page to be freed.
+ */
+static inline void iommu_free_page(void *virt)
+{
+ iommu_free_pages(virt, 0);
+}
+
+/**
+ * iommu_free_pages_list - free a list of pages.
+ * @page: the head of the lru list to be freed.
+ *
+ * There are no locking requirement for these pages, as they are going to be
+ * put on a free list as soon as refcount reaches 0. Pages are put on this LRU
+ * list once they are removed from the IOMMU page tables. However, they can
+ * still be access through debugfs.
+ */
+static inline void iommu_free_pages_list(struct list_head *page)
+{
+ while (!list_empty(page)) {
+ struct page *p = list_entry(page->prev, struct page, lru);
+
+ list_del(&p->lru);
+ put_page(p);
+ }
+}
+
+#endif /* __IOMMU_PAGES_H */
--
2.43.0.472.g3155946c3a-goog


2023-12-26 20:03:50

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 03/10] iommu/io-pgtable-arm: use page allocation function provided by iommu-pages.h

Convert iommu/io-pgtable-arm.c to use the new page allocation functions
provided in iommu-pages.h.

Signed-off-by: Pasha Tatashin <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
drivers/iommu/io-pgtable-arm.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 72dcdd468cf3..21d315151ad6 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -21,6 +21,7 @@
#include <asm/barrier.h>

#include "io-pgtable-arm.h"
+#include "iommu-pages.h"

#define ARM_LPAE_MAX_ADDR_BITS 52
#define ARM_LPAE_S2_MAX_CONCAT_PAGES 16
@@ -197,7 +198,7 @@ static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
void *pages;

VM_BUG_ON((gfp & __GFP_HIGHMEM));
- p = alloc_pages_node(dev_to_node(dev), gfp | __GFP_ZERO, order);
+ p = __iommu_alloc_pages_node(dev_to_node(dev), gfp, order);
if (!p)
return NULL;

@@ -221,7 +222,7 @@ static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
dev_err(dev, "Cannot accommodate DMA translation for IOMMU page tables\n");
dma_unmap_single(dev, dma, size, DMA_TO_DEVICE);
out_free:
- __free_pages(p, order);
+ __iommu_free_pages(p, order);
return NULL;
}

@@ -231,7 +232,7 @@ static void __arm_lpae_free_pages(void *pages, size_t size,
if (!cfg->coherent_walk)
dma_unmap_single(cfg->iommu_dev, __arm_lpae_dma_addr(pages),
size, DMA_TO_DEVICE);
- free_pages((unsigned long)pages, get_order(size));
+ iommu_free_pages(pages, get_order(size));
}

static void __arm_lpae_sync_pte(arm_lpae_iopte *ptep, int num_entries,
--
2.43.0.472.g3155946c3a-goog


2023-12-26 20:03:59

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 02/10] iommu/amd: use page allocation function provided by iommu-pages.h

Convert iommu/amd/* files to use the new page allocation functions
provided in iommu-pages.h.

Signed-off-by: Pasha Tatashin <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
drivers/iommu/amd/amd_iommu.h | 8 ---
drivers/iommu/amd/init.c | 91 ++++++++++++++-----------------
drivers/iommu/amd/io_pgtable.c | 13 +++--
drivers/iommu/amd/io_pgtable_v2.c | 20 +++----
drivers/iommu/amd/iommu.c | 13 +++--
5 files changed, 64 insertions(+), 81 deletions(-)

diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
index 86be1edd50ee..bf697d566e0b 100644
--- a/drivers/iommu/amd/amd_iommu.h
+++ b/drivers/iommu/amd/amd_iommu.h
@@ -136,14 +136,6 @@ static inline int get_pci_sbdf_id(struct pci_dev *pdev)
return PCI_SEG_DEVID_TO_SBDF(seg, devid);
}

-static inline void *alloc_pgtable_page(int nid, gfp_t gfp)
-{
- struct page *page;
-
- page = alloc_pages_node(nid, gfp | __GFP_ZERO, 0);
- return page ? page_address(page) : NULL;
-}
-
bool translation_pre_enabled(struct amd_iommu *iommu);
bool amd_iommu_is_attach_deferred(struct device *dev);
int __init add_special_device(u8 type, u8 id, u32 *devid, bool cmd_line);
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 64bcf3df37ee..5b8a80fc7e50 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -35,6 +35,7 @@

#include "amd_iommu.h"
#include "../irq_remapping.h"
+#include "../iommu-pages.h"

/*
* definitions for the ACPI scanning code
@@ -648,8 +649,8 @@ static int __init find_last_devid_acpi(struct acpi_table_header *table, u16 pci_
/* Allocate per PCI segment device table */
static inline int __init alloc_dev_table(struct amd_iommu_pci_seg *pci_seg)
{
- pci_seg->dev_table = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO | GFP_DMA32,
- get_order(pci_seg->dev_table_size));
+ pci_seg->dev_table = iommu_alloc_pages(GFP_KERNEL | GFP_DMA32,
+ get_order(pci_seg->dev_table_size));
if (!pci_seg->dev_table)
return -ENOMEM;

@@ -658,17 +659,16 @@ static inline int __init alloc_dev_table(struct amd_iommu_pci_seg *pci_seg)

static inline void free_dev_table(struct amd_iommu_pci_seg *pci_seg)
{
- free_pages((unsigned long)pci_seg->dev_table,
- get_order(pci_seg->dev_table_size));
+ iommu_free_pages(pci_seg->dev_table,
+ get_order(pci_seg->dev_table_size));
pci_seg->dev_table = NULL;
}

/* Allocate per PCI segment IOMMU rlookup table. */
static inline int __init alloc_rlookup_table(struct amd_iommu_pci_seg *pci_seg)
{
- pci_seg->rlookup_table = (void *)__get_free_pages(
- GFP_KERNEL | __GFP_ZERO,
- get_order(pci_seg->rlookup_table_size));
+ pci_seg->rlookup_table = iommu_alloc_pages(GFP_KERNEL,
+ get_order(pci_seg->rlookup_table_size));
if (pci_seg->rlookup_table == NULL)
return -ENOMEM;

@@ -677,16 +677,15 @@ static inline int __init alloc_rlookup_table(struct amd_iommu_pci_seg *pci_seg)

static inline void free_rlookup_table(struct amd_iommu_pci_seg *pci_seg)
{
- free_pages((unsigned long)pci_seg->rlookup_table,
- get_order(pci_seg->rlookup_table_size));
+ iommu_free_pages(pci_seg->rlookup_table,
+ get_order(pci_seg->rlookup_table_size));
pci_seg->rlookup_table = NULL;
}

static inline int __init alloc_irq_lookup_table(struct amd_iommu_pci_seg *pci_seg)
{
- pci_seg->irq_lookup_table = (void *)__get_free_pages(
- GFP_KERNEL | __GFP_ZERO,
- get_order(pci_seg->rlookup_table_size));
+ pci_seg->irq_lookup_table = iommu_alloc_pages(GFP_KERNEL,
+ get_order(pci_seg->rlookup_table_size));
kmemleak_alloc(pci_seg->irq_lookup_table,
pci_seg->rlookup_table_size, 1, GFP_KERNEL);
if (pci_seg->irq_lookup_table == NULL)
@@ -698,8 +697,8 @@ static inline int __init alloc_irq_lookup_table(struct amd_iommu_pci_seg *pci_se
static inline void free_irq_lookup_table(struct amd_iommu_pci_seg *pci_seg)
{
kmemleak_free(pci_seg->irq_lookup_table);
- free_pages((unsigned long)pci_seg->irq_lookup_table,
- get_order(pci_seg->rlookup_table_size));
+ iommu_free_pages(pci_seg->irq_lookup_table,
+ get_order(pci_seg->rlookup_table_size));
pci_seg->irq_lookup_table = NULL;
}

@@ -707,8 +706,8 @@ static int __init alloc_alias_table(struct amd_iommu_pci_seg *pci_seg)
{
int i;

- pci_seg->alias_table = (void *)__get_free_pages(GFP_KERNEL,
- get_order(pci_seg->alias_table_size));
+ pci_seg->alias_table = iommu_alloc_pages(GFP_KERNEL,
+ get_order(pci_seg->alias_table_size));
if (!pci_seg->alias_table)
return -ENOMEM;

@@ -723,8 +722,8 @@ static int __init alloc_alias_table(struct amd_iommu_pci_seg *pci_seg)

static void __init free_alias_table(struct amd_iommu_pci_seg *pci_seg)
{
- free_pages((unsigned long)pci_seg->alias_table,
- get_order(pci_seg->alias_table_size));
+ iommu_free_pages(pci_seg->alias_table,
+ get_order(pci_seg->alias_table_size));
pci_seg->alias_table = NULL;
}

@@ -735,8 +734,8 @@ static void __init free_alias_table(struct amd_iommu_pci_seg *pci_seg)
*/
static int __init alloc_command_buffer(struct amd_iommu *iommu)
{
- iommu->cmd_buf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
- get_order(CMD_BUFFER_SIZE));
+ iommu->cmd_buf = iommu_alloc_pages(GFP_KERNEL,
+ get_order(CMD_BUFFER_SIZE));

return iommu->cmd_buf ? 0 : -ENOMEM;
}
@@ -844,19 +843,19 @@ static void iommu_disable_command_buffer(struct amd_iommu *iommu)

static void __init free_command_buffer(struct amd_iommu *iommu)
{
- free_pages((unsigned long)iommu->cmd_buf, get_order(CMD_BUFFER_SIZE));
+ iommu_free_pages(iommu->cmd_buf, get_order(CMD_BUFFER_SIZE));
}

static void *__init iommu_alloc_4k_pages(struct amd_iommu *iommu,
gfp_t gfp, size_t size)
{
int order = get_order(size);
- void *buf = (void *)__get_free_pages(gfp, order);
+ void *buf = iommu_alloc_pages(gfp, order);

if (buf &&
check_feature(FEATURE_SNP) &&
set_memory_4k((unsigned long)buf, (1 << order))) {
- free_pages((unsigned long)buf, order);
+ iommu_free_pages(buf, order);
buf = NULL;
}

@@ -866,7 +865,7 @@ static void *__init iommu_alloc_4k_pages(struct amd_iommu *iommu,
/* allocates the memory where the IOMMU will log its events to */
static int __init alloc_event_buffer(struct amd_iommu *iommu)
{
- iommu->evt_buf = iommu_alloc_4k_pages(iommu, GFP_KERNEL | __GFP_ZERO,
+ iommu->evt_buf = iommu_alloc_4k_pages(iommu, GFP_KERNEL,
EVT_BUFFER_SIZE);

return iommu->evt_buf ? 0 : -ENOMEM;
@@ -900,14 +899,13 @@ static void iommu_disable_event_buffer(struct amd_iommu *iommu)

static void __init free_event_buffer(struct amd_iommu *iommu)
{
- free_pages((unsigned long)iommu->evt_buf, get_order(EVT_BUFFER_SIZE));
+ iommu_free_pages(iommu->evt_buf, get_order(EVT_BUFFER_SIZE));
}

/* allocates the memory where the IOMMU will log its events to */
static int __init alloc_ppr_log(struct amd_iommu *iommu)
{
- iommu->ppr_log = iommu_alloc_4k_pages(iommu, GFP_KERNEL | __GFP_ZERO,
- PPR_LOG_SIZE);
+ iommu->ppr_log = iommu_alloc_4k_pages(iommu, GFP_KERNEL, PPR_LOG_SIZE);

return iommu->ppr_log ? 0 : -ENOMEM;
}
@@ -936,14 +934,14 @@ static void iommu_enable_ppr_log(struct amd_iommu *iommu)

static void __init free_ppr_log(struct amd_iommu *iommu)
{
- free_pages((unsigned long)iommu->ppr_log, get_order(PPR_LOG_SIZE));
+ iommu_free_pages(iommu->ppr_log, get_order(PPR_LOG_SIZE));
}

static void free_ga_log(struct amd_iommu *iommu)
{
#ifdef CONFIG_IRQ_REMAP
- free_pages((unsigned long)iommu->ga_log, get_order(GA_LOG_SIZE));
- free_pages((unsigned long)iommu->ga_log_tail, get_order(8));
+ iommu_free_pages(iommu->ga_log, get_order(GA_LOG_SIZE));
+ iommu_free_pages(iommu->ga_log_tail, get_order(8));
#endif
}

@@ -988,13 +986,11 @@ static int iommu_init_ga_log(struct amd_iommu *iommu)
if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir))
return 0;

- iommu->ga_log = (u8 *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
- get_order(GA_LOG_SIZE));
+ iommu->ga_log = iommu_alloc_pages(GFP_KERNEL, get_order(GA_LOG_SIZE));
if (!iommu->ga_log)
goto err_out;

- iommu->ga_log_tail = (u8 *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
- get_order(8));
+ iommu->ga_log_tail = iommu_alloc_pages(GFP_KERNEL, get_order(8));
if (!iommu->ga_log_tail)
goto err_out;

@@ -1007,7 +1003,7 @@ static int iommu_init_ga_log(struct amd_iommu *iommu)

static int __init alloc_cwwb_sem(struct amd_iommu *iommu)
{
- iommu->cmd_sem = iommu_alloc_4k_pages(iommu, GFP_KERNEL | __GFP_ZERO, 1);
+ iommu->cmd_sem = iommu_alloc_4k_pages(iommu, GFP_KERNEL, 1);

return iommu->cmd_sem ? 0 : -ENOMEM;
}
@@ -1015,7 +1011,7 @@ static int __init alloc_cwwb_sem(struct amd_iommu *iommu)
static void __init free_cwwb_sem(struct amd_iommu *iommu)
{
if (iommu->cmd_sem)
- free_page((unsigned long)iommu->cmd_sem);
+ iommu_free_page((void *)iommu->cmd_sem);
}

static void iommu_enable_xt(struct amd_iommu *iommu)
@@ -1080,7 +1076,6 @@ static bool __copy_device_table(struct amd_iommu *iommu)
u32 lo, hi, devid, old_devtb_size;
phys_addr_t old_devtb_phys;
u16 dom_id, dte_v, irq_v;
- gfp_t gfp_flag;
u64 tmp;

/* Each IOMMU use separate device table with the same size */
@@ -1114,9 +1109,8 @@ static bool __copy_device_table(struct amd_iommu *iommu)
if (!old_devtb)
return false;

- gfp_flag = GFP_KERNEL | __GFP_ZERO | GFP_DMA32;
- pci_seg->old_dev_tbl_cpy = (void *)__get_free_pages(gfp_flag,
- get_order(pci_seg->dev_table_size));
+ pci_seg->old_dev_tbl_cpy = iommu_alloc_pages(GFP_KERNEL | GFP_DMA32,
+ get_order(pci_seg->dev_table_size));
if (pci_seg->old_dev_tbl_cpy == NULL) {
pr_err("Failed to allocate memory for copying old device table!\n");
memunmap(old_devtb);
@@ -2800,8 +2794,8 @@ static void early_enable_iommus(void)

for_each_pci_segment(pci_seg) {
if (pci_seg->old_dev_tbl_cpy != NULL) {
- free_pages((unsigned long)pci_seg->old_dev_tbl_cpy,
- get_order(pci_seg->dev_table_size));
+ iommu_free_pages(pci_seg->old_dev_tbl_cpy,
+ get_order(pci_seg->dev_table_size));
pci_seg->old_dev_tbl_cpy = NULL;
}
}
@@ -2814,8 +2808,8 @@ static void early_enable_iommus(void)
pr_info("Copied DEV table from previous kernel.\n");

for_each_pci_segment(pci_seg) {
- free_pages((unsigned long)pci_seg->dev_table,
- get_order(pci_seg->dev_table_size));
+ iommu_free_pages(pci_seg->dev_table,
+ get_order(pci_seg->dev_table_size));
pci_seg->dev_table = pci_seg->old_dev_tbl_cpy;
}

@@ -3018,8 +3012,8 @@ static bool __init check_ioapic_information(void)

static void __init free_dma_resources(void)
{
- free_pages((unsigned long)amd_iommu_pd_alloc_bitmap,
- get_order(MAX_DOMAIN_ID/8));
+ iommu_free_pages(amd_iommu_pd_alloc_bitmap,
+ get_order(MAX_DOMAIN_ID / 8));
amd_iommu_pd_alloc_bitmap = NULL;

free_unity_maps();
@@ -3091,9 +3085,8 @@ static int __init early_amd_iommu_init(void)
/* Device table - directly used by all IOMMUs */
ret = -ENOMEM;

- amd_iommu_pd_alloc_bitmap = (void *)__get_free_pages(
- GFP_KERNEL | __GFP_ZERO,
- get_order(MAX_DOMAIN_ID/8));
+ amd_iommu_pd_alloc_bitmap = iommu_alloc_pages(GFP_KERNEL,
+ get_order(MAX_DOMAIN_ID / 8));
if (amd_iommu_pd_alloc_bitmap == NULL)
goto out;

diff --git a/drivers/iommu/amd/io_pgtable.c b/drivers/iommu/amd/io_pgtable.c
index 6c0621f6f572..f8b7d4c39a9f 100644
--- a/drivers/iommu/amd/io_pgtable.c
+++ b/drivers/iommu/amd/io_pgtable.c
@@ -22,6 +22,7 @@

#include "amd_iommu_types.h"
#include "amd_iommu.h"
+#include "../iommu-pages.h"

static void v1_tlb_flush_all(void *cookie)
{
@@ -156,7 +157,7 @@ static bool increase_address_space(struct protection_domain *domain,
bool ret = true;
u64 *pte;

- pte = alloc_pgtable_page(domain->nid, gfp);
+ pte = iommu_alloc_page_node(domain->nid, gfp);
if (!pte)
return false;

@@ -187,7 +188,7 @@ static bool increase_address_space(struct protection_domain *domain,

out:
spin_unlock_irqrestore(&domain->lock, flags);
- free_page((unsigned long)pte);
+ iommu_free_page(pte);

return ret;
}
@@ -250,7 +251,7 @@ static u64 *alloc_pte(struct protection_domain *domain,

if (!IOMMU_PTE_PRESENT(__pte) ||
pte_level == PAGE_MODE_NONE) {
- page = alloc_pgtable_page(domain->nid, gfp);
+ page = iommu_alloc_page_node(domain->nid, gfp);

if (!page)
return NULL;
@@ -259,7 +260,7 @@ static u64 *alloc_pte(struct protection_domain *domain,

/* pte could have been changed somewhere. */
if (!try_cmpxchg64(pte, &__pte, __npte))
- free_page((unsigned long)page);
+ iommu_free_page(page);
else if (IOMMU_PTE_PRESENT(__pte))
*updated = true;

@@ -430,7 +431,7 @@ static int iommu_v1_map_pages(struct io_pgtable_ops *ops, unsigned long iova,
}

/* Everything flushed out, free pages now */
- put_pages_list(&freelist);
+ iommu_free_pages_list(&freelist);

return ret;
}
@@ -579,7 +580,7 @@ static void v1_free_pgtable(struct io_pgtable *iop)
/* Make changes visible to IOMMUs */
amd_iommu_domain_update(dom);

- put_pages_list(&freelist);
+ iommu_free_pages_list(&freelist);
}

static struct io_pgtable *v1_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
diff --git a/drivers/iommu/amd/io_pgtable_v2.c b/drivers/iommu/amd/io_pgtable_v2.c
index f818a7e254d4..1e08dab93686 100644
--- a/drivers/iommu/amd/io_pgtable_v2.c
+++ b/drivers/iommu/amd/io_pgtable_v2.c
@@ -18,6 +18,7 @@

#include "amd_iommu_types.h"
#include "amd_iommu.h"
+#include "../iommu-pages.h"

#define IOMMU_PAGE_PRESENT BIT_ULL(0) /* Is present */
#define IOMMU_PAGE_RW BIT_ULL(1) /* Writeable */
@@ -99,11 +100,6 @@ static inline int page_size_to_level(u64 pg_size)
return PAGE_MODE_1_LEVEL;
}

-static inline void free_pgtable_page(u64 *pt)
-{
- free_page((unsigned long)pt);
-}
-
static void free_pgtable(u64 *pt, int level)
{
u64 *p;
@@ -125,10 +121,10 @@ static void free_pgtable(u64 *pt, int level)
if (level > 2)
free_pgtable(p, level - 1);
else
- free_pgtable_page(p);
+ iommu_free_page(p);
}

- free_pgtable_page(pt);
+ iommu_free_page(pt);
}

/* Allocate page table */
@@ -156,14 +152,14 @@ static u64 *v2_alloc_pte(int nid, u64 *pgd, unsigned long iova,
}

if (!IOMMU_PTE_PRESENT(__pte)) {
- page = alloc_pgtable_page(nid, gfp);
+ page = iommu_alloc_page_node(nid, gfp);
if (!page)
return NULL;

__npte = set_pgtable_attr(page);
/* pte could have been changed somewhere. */
if (cmpxchg64(pte, __pte, __npte) != __pte)
- free_pgtable_page(page);
+ iommu_free_page(page);
else if (IOMMU_PTE_PRESENT(__pte))
*updated = true;

@@ -185,7 +181,7 @@ static u64 *v2_alloc_pte(int nid, u64 *pgd, unsigned long iova,
if (pg_size == IOMMU_PAGE_SIZE_1G)
free_pgtable(__pte, end_level - 1);
else if (pg_size == IOMMU_PAGE_SIZE_2M)
- free_pgtable_page(__pte);
+ iommu_free_page(__pte);
}

return pte;
@@ -380,7 +376,7 @@ static struct io_pgtable *v2_alloc_pgtable(struct io_pgtable_cfg *cfg, void *coo
int ret;
int ias = IOMMU_IN_ADDR_BIT_SIZE;

- pgtable->pgd = alloc_pgtable_page(pdom->nid, GFP_ATOMIC);
+ pgtable->pgd = iommu_alloc_page_node(pdom->nid, GFP_ATOMIC);
if (!pgtable->pgd)
return NULL;

@@ -403,7 +399,7 @@ static struct io_pgtable *v2_alloc_pgtable(struct io_pgtable_cfg *cfg, void *coo
return &pgtable->iop;

err_free_pgd:
- free_pgtable_page(pgtable->pgd);
+ iommu_free_page(pgtable->pgd);

return NULL;
}
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index fcc987f5d4ed..9a228a95da0e 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -42,6 +42,7 @@
#include "amd_iommu.h"
#include "../dma-iommu.h"
#include "../irq_remapping.h"
+#include "../iommu-pages.h"

#define CMD_SET_TYPE(cmd, t) ((cmd)->data[1] |= ((t) << 28))

@@ -1642,7 +1643,7 @@ static void free_gcr3_tbl_level1(u64 *tbl)

ptr = iommu_phys_to_virt(tbl[i] & PAGE_MASK);

- free_page((unsigned long)ptr);
+ iommu_free_page(ptr);
}
}

@@ -1670,7 +1671,7 @@ static void free_gcr3_table(struct protection_domain *domain)
else
BUG_ON(domain->glx != 0);

- free_page((unsigned long)domain->gcr3_tbl);
+ iommu_free_page(domain->gcr3_tbl);
}

/*
@@ -1697,7 +1698,7 @@ static int setup_gcr3_table(struct protection_domain *domain, int pasids)
if (levels > amd_iommu_max_glx_val)
return -EINVAL;

- domain->gcr3_tbl = alloc_pgtable_page(domain->nid, GFP_ATOMIC);
+ domain->gcr3_tbl = iommu_alloc_page_node(domain->nid, GFP_ATOMIC);
if (domain->gcr3_tbl == NULL)
return -ENOMEM;

@@ -2092,7 +2093,7 @@ static void protection_domain_free(struct protection_domain *domain)
free_gcr3_table(domain);

if (domain->iop.root)
- free_page((unsigned long)domain->iop.root);
+ iommu_free_page(domain->iop.root);

if (domain->id)
domain_id_free(domain->id);
@@ -2107,7 +2108,7 @@ static int protection_domain_init_v1(struct protection_domain *domain, int mode)
BUG_ON(mode < PAGE_MODE_NONE || mode > PAGE_MODE_6_LEVEL);

if (mode != PAGE_MODE_NONE) {
- pt_root = (void *)get_zeroed_page(GFP_KERNEL);
+ pt_root = iommu_alloc_page(GFP_KERNEL);
if (!pt_root)
return -ENOMEM;
}
@@ -2783,7 +2784,7 @@ static u64 *__get_gcr3_pte(u64 *root, int level, u32 pasid, bool alloc)
if (!alloc)
return NULL;

- root = (void *)get_zeroed_page(GFP_ATOMIC);
+ root = iommu_alloc_page(GFP_ATOMIC);
if (root == NULL)
return NULL;

--
2.43.0.472.g3155946c3a-goog


2023-12-26 20:04:04

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 04/10] iommu/io-pgtable-dart: use page allocation function provided by iommu-pages.h

Convert iommu/io-pgtable-dart.c to use the new page allocation functions
provided in iommu-pages.h., and remove unnecessary struct io_pgtable_cfg
argument from __dart_alloc_pages().

Signed-off-by: Pasha Tatashin <[email protected]>
Reviewed-by: Janne Grunau <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
drivers/iommu/io-pgtable-dart.c | 37 +++++++++++++--------------------
1 file changed, 14 insertions(+), 23 deletions(-)

diff --git a/drivers/iommu/io-pgtable-dart.c b/drivers/iommu/io-pgtable-dart.c
index 74b1ef2b96be..ad28031e1e93 100644
--- a/drivers/iommu/io-pgtable-dart.c
+++ b/drivers/iommu/io-pgtable-dart.c
@@ -23,6 +23,7 @@
#include <linux/types.h>

#include <asm/barrier.h>
+#include "iommu-pages.h"

#define DART1_MAX_ADDR_BITS 36

@@ -106,18 +107,12 @@ static phys_addr_t iopte_to_paddr(dart_iopte pte,
return paddr;
}

-static void *__dart_alloc_pages(size_t size, gfp_t gfp,
- struct io_pgtable_cfg *cfg)
+static void *__dart_alloc_pages(size_t size, gfp_t gfp)
{
int order = get_order(size);
- struct page *p;

VM_BUG_ON((gfp & __GFP_HIGHMEM));
- p = alloc_pages(gfp | __GFP_ZERO, order);
- if (!p)
- return NULL;
-
- return page_address(p);
+ return iommu_alloc_pages(gfp, order);
}

static int dart_init_pte(struct dart_io_pgtable *data,
@@ -262,13 +257,13 @@ static int dart_map_pages(struct io_pgtable_ops *ops, unsigned long iova,

/* no L2 table present */
if (!pte) {
- cptep = __dart_alloc_pages(tblsz, gfp, cfg);
+ cptep = __dart_alloc_pages(tblsz, gfp);
if (!cptep)
return -ENOMEM;

pte = dart_install_table(cptep, ptep, 0, data);
if (pte)
- free_pages((unsigned long)cptep, get_order(tblsz));
+ iommu_free_pages(cptep, get_order(tblsz));

/* L2 table is present (now) */
pte = READ_ONCE(*ptep);
@@ -419,8 +414,7 @@ apple_dart_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
cfg->apple_dart_cfg.n_ttbrs = 1 << data->tbl_bits;

for (i = 0; i < cfg->apple_dart_cfg.n_ttbrs; ++i) {
- data->pgd[i] = __dart_alloc_pages(DART_GRANULE(data), GFP_KERNEL,
- cfg);
+ data->pgd[i] = __dart_alloc_pages(DART_GRANULE(data), GFP_KERNEL);
if (!data->pgd[i])
goto out_free_data;
cfg->apple_dart_cfg.ttbr[i] = virt_to_phys(data->pgd[i]);
@@ -429,9 +423,10 @@ apple_dart_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
return &data->iop;

out_free_data:
- while (--i >= 0)
- free_pages((unsigned long)data->pgd[i],
- get_order(DART_GRANULE(data)));
+ while (--i >= 0) {
+ iommu_free_pages(data->pgd[i],
+ get_order(DART_GRANULE(data)));
+ }
kfree(data);
return NULL;
}
@@ -439,6 +434,7 @@ apple_dart_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
static void apple_dart_free_pgtable(struct io_pgtable *iop)
{
struct dart_io_pgtable *data = io_pgtable_to_data(iop);
+ int order = get_order(DART_GRANULE(data));
dart_iopte *ptep, *end;
int i;

@@ -449,15 +445,10 @@ static void apple_dart_free_pgtable(struct io_pgtable *iop)
while (ptep != end) {
dart_iopte pte = *ptep++;

- if (pte) {
- unsigned long page =
- (unsigned long)iopte_deref(pte, data);
-
- free_pages(page, get_order(DART_GRANULE(data)));
- }
+ if (pte)
+ iommu_free_pages(iopte_deref(pte, data), order);
}
- free_pages((unsigned long)data->pgd[i],
- get_order(DART_GRANULE(data)));
+ iommu_free_pages(data->pgd[i], order);
}

kfree(data);
--
2.43.0.472.g3155946c3a-goog


2023-12-26 20:04:59

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 07/10] iommu/sun50i: use page allocation function provided by iommu-pages.h

Convert iommu/sun50i-iommu.c to use the new page allocation functions
provided in iommu-pages.h.

Signed-off-by: Pasha Tatashin <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
drivers/iommu/sun50i-iommu.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
index 41484a5a399b..172ddb717eb5 100644
--- a/drivers/iommu/sun50i-iommu.c
+++ b/drivers/iommu/sun50i-iommu.c
@@ -26,6 +26,8 @@
#include <linux/spinlock.h>
#include <linux/types.h>

+#include "iommu-pages.h"
+
#define IOMMU_RESET_REG 0x010
#define IOMMU_RESET_RELEASE_ALL 0xffffffff
#define IOMMU_ENABLE_REG 0x020
@@ -679,8 +681,7 @@ sun50i_iommu_domain_alloc_paging(struct device *dev)
if (!sun50i_domain)
return NULL;

- sun50i_domain->dt = (u32 *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
- get_order(DT_SIZE));
+ sun50i_domain->dt = iommu_alloc_pages(GFP_KERNEL, get_order(DT_SIZE));
if (!sun50i_domain->dt)
goto err_free_domain;

@@ -702,7 +703,7 @@ static void sun50i_iommu_domain_free(struct iommu_domain *domain)
{
struct sun50i_iommu_domain *sun50i_domain = to_sun50i_domain(domain);

- free_pages((unsigned long)sun50i_domain->dt, get_order(DT_SIZE));
+ iommu_free_pages(sun50i_domain->dt, get_order(DT_SIZE));
sun50i_domain->dt = NULL;

kfree(sun50i_domain);
--
2.43.0.472.g3155946c3a-goog


2023-12-26 20:06:03

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 08/10] iommu/tegra-smmu: use page allocation function provided by iommu-pages.h

Convert iommu/tegra-smmu.c to use the new page allocation functions
provided in iommu-pages.h.

Signed-off-by: Pasha Tatashin <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
drivers/iommu/tegra-smmu.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 310871728ab4..5e0730dc1b0e 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -19,6 +19,8 @@
#include <soc/tegra/ahb.h>
#include <soc/tegra/mc.h>

+#include "iommu-pages.h"
+
struct tegra_smmu_group {
struct list_head list;
struct tegra_smmu *smmu;
@@ -282,7 +284,7 @@ static struct iommu_domain *tegra_smmu_domain_alloc_paging(struct device *dev)

as->attr = SMMU_PD_READABLE | SMMU_PD_WRITABLE | SMMU_PD_NONSECURE;

- as->pd = alloc_page(GFP_KERNEL | __GFP_DMA | __GFP_ZERO);
+ as->pd = __iommu_alloc_page(GFP_KERNEL | __GFP_DMA);
if (!as->pd) {
kfree(as);
return NULL;
@@ -290,7 +292,7 @@ static struct iommu_domain *tegra_smmu_domain_alloc_paging(struct device *dev)

as->count = kcalloc(SMMU_NUM_PDE, sizeof(u32), GFP_KERNEL);
if (!as->count) {
- __free_page(as->pd);
+ __iommu_free_page(as->pd);
kfree(as);
return NULL;
}
@@ -298,7 +300,7 @@ static struct iommu_domain *tegra_smmu_domain_alloc_paging(struct device *dev)
as->pts = kcalloc(SMMU_NUM_PDE, sizeof(*as->pts), GFP_KERNEL);
if (!as->pts) {
kfree(as->count);
- __free_page(as->pd);
+ __iommu_free_page(as->pd);
kfree(as);
return NULL;
}
@@ -599,14 +601,14 @@ static u32 *as_get_pte(struct tegra_smmu_as *as, dma_addr_t iova,
dma = dma_map_page(smmu->dev, page, 0, SMMU_SIZE_PT,
DMA_TO_DEVICE);
if (dma_mapping_error(smmu->dev, dma)) {
- __free_page(page);
+ __iommu_free_page(page);
return NULL;
}

if (!smmu_dma_addr_valid(smmu, dma)) {
dma_unmap_page(smmu->dev, dma, SMMU_SIZE_PT,
DMA_TO_DEVICE);
- __free_page(page);
+ __iommu_free_page(page);
return NULL;
}

@@ -649,7 +651,7 @@ static void tegra_smmu_pte_put_use(struct tegra_smmu_as *as, unsigned long iova)
tegra_smmu_set_pde(as, iova, 0);

dma_unmap_page(smmu->dev, pte_dma, SMMU_SIZE_PT, DMA_TO_DEVICE);
- __free_page(page);
+ __iommu_free_page(page);
as->pts[pde] = NULL;
}
}
@@ -688,7 +690,7 @@ static struct page *as_get_pde_page(struct tegra_smmu_as *as,
if (gfpflags_allow_blocking(gfp))
spin_unlock_irqrestore(&as->lock, *flags);

- page = alloc_page(gfp | __GFP_DMA | __GFP_ZERO);
+ page = __iommu_alloc_page(gfp | __GFP_DMA);

if (gfpflags_allow_blocking(gfp))
spin_lock_irqsave(&as->lock, *flags);
@@ -700,7 +702,7 @@ static struct page *as_get_pde_page(struct tegra_smmu_as *as,
*/
if (as->pts[pde]) {
if (page)
- __free_page(page);
+ __iommu_free_page(page);

page = as->pts[pde];
}
--
2.43.0.472.g3155946c3a-goog


2023-12-26 20:06:11

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 09/10] iommu: observability of the IOMMU allocations

Add NR_IOMMU_PAGES into node_stat_item that counts number of pages
that are allocated by the IOMMU subsystem.

The allocations can be view per-node via:
/sys/devices/system/node/nodeN/vmstat.

For example:

$ grep iommu /sys/devices/system/node/node*/vmstat
/sys/devices/system/node/node0/vmstat:nr_iommu_pages 106025
/sys/devices/system/node/node1/vmstat:nr_iommu_pages 3464

The value is in page-count, therefore, in the above example
the iommu allocations amount to ~428M.

Signed-off-by: Pasha Tatashin <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
drivers/iommu/iommu-pages.h | 30 ++++++++++++++++++++++++++++++
include/linux/mmzone.h | 3 +++
mm/vmstat.c | 3 +++
3 files changed, 36 insertions(+)

diff --git a/drivers/iommu/iommu-pages.h b/drivers/iommu/iommu-pages.h
index 99105503b771..4e70cdf7acac 100644
--- a/drivers/iommu/iommu-pages.h
+++ b/drivers/iommu/iommu-pages.h
@@ -17,6 +17,30 @@
* state can be rather large, i.e. multiple gigabytes in size.
*/

+/**
+ * __iommu_alloc_account - account for newly allocated page.
+ * @page: head struct page of the page.
+ * @order: order of the page
+ */
+static inline void __iommu_alloc_account(struct page *page, int order)
+{
+ const long pgcnt = 1l << order;
+
+ mod_node_page_state(page_pgdat(page), NR_IOMMU_PAGES, pgcnt);
+}
+
+/**
+ * __iommu_free_account - account a page that is about to be freed.
+ * @page: head struct page of the page.
+ * @order: order of the page
+ */
+static inline void __iommu_free_account(struct page *page, int order)
+{
+ const long pgcnt = 1l << order;
+
+ mod_node_page_state(page_pgdat(page), NR_IOMMU_PAGES, -pgcnt);
+}
+
/**
* __iommu_alloc_pages_node - allocate a zeroed page of a given order from
* specific NUMA node.
@@ -35,6 +59,8 @@ static inline struct page *__iommu_alloc_pages_node(int nid, gfp_t gfp,
if (unlikely(!page))
return NULL;

+ __iommu_alloc_account(page, order);
+
return page;
}

@@ -53,6 +79,8 @@ static inline struct page *__iommu_alloc_pages(gfp_t gfp, int order)
if (unlikely(!page))
return NULL;

+ __iommu_alloc_account(page, order);
+
return page;
}

@@ -89,6 +117,7 @@ static inline void __iommu_free_pages(struct page *page, int order)
if (!page)
return;

+ __iommu_free_account(page, order);
__free_pages(page, order);
}

@@ -197,6 +226,7 @@ static inline void iommu_free_pages_list(struct list_head *page)
struct page *p = list_entry(page->prev, struct page, lru);

list_del(&p->lru);
+ __iommu_free_account(p, 0);
put_page(p);
}
}
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 9db36e197712..f0b54c752e22 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -200,6 +200,9 @@ enum node_stat_item {
#endif
NR_PAGETABLE, /* used for pagetables */
NR_SECONDARY_PAGETABLE, /* secondary pagetables, e.g. KVM pagetables */
+#ifdef CONFIG_IOMMU_SUPPORT
+ NR_IOMMU_PAGES, /* # of pages allocated by IOMMU */
+#endif
#ifdef CONFIG_SWAP
NR_SWAPCACHE,
#endif
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 359460deb377..801b58890b6c 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1242,6 +1242,9 @@ const char * const vmstat_text[] = {
#endif
"nr_page_table_pages",
"nr_sec_page_table_pages",
+#ifdef CONFIG_IOMMU_SUPPORT
+ "nr_iommu_pages",
+#endif
#ifdef CONFIG_SWAP
"nr_swapcached",
#endif
--
2.43.0.472.g3155946c3a-goog


2023-12-26 20:07:16

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 06/10] iommu/rockchip: use page allocation function provided by iommu-pages.h

Convert iommu/rockchip-iommu.c to use the new page allocation functions
provided in iommu-pages.h.

Signed-off-by: Pasha Tatashin <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
drivers/iommu/rockchip-iommu.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 2685861c0a12..e04f22d481d0 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -26,6 +26,8 @@
#include <linux/slab.h>
#include <linux/spinlock.h>

+#include "iommu-pages.h"
+
/** MMU register offsets */
#define RK_MMU_DTE_ADDR 0x00 /* Directory table address */
#define RK_MMU_STATUS 0x04
@@ -727,14 +729,14 @@ static u32 *rk_dte_get_page_table(struct rk_iommu_domain *rk_domain,
if (rk_dte_is_pt_valid(dte))
goto done;

- page_table = (u32 *)get_zeroed_page(GFP_ATOMIC | rk_ops->gfp_flags);
+ page_table = iommu_alloc_page(GFP_ATOMIC | rk_ops->gfp_flags);
if (!page_table)
return ERR_PTR(-ENOMEM);

pt_dma = dma_map_single(dma_dev, page_table, SPAGE_SIZE, DMA_TO_DEVICE);
if (dma_mapping_error(dma_dev, pt_dma)) {
dev_err(dma_dev, "DMA mapping error while allocating page table\n");
- free_page((unsigned long)page_table);
+ iommu_free_page(page_table);
return ERR_PTR(-ENOMEM);
}

@@ -1061,7 +1063,7 @@ static struct iommu_domain *rk_iommu_domain_alloc_paging(struct device *dev)
* Each level1 (dt) and level2 (pt) table has 1024 4-byte entries.
* Allocate one 4 KiB page for each table.
*/
- rk_domain->dt = (u32 *)get_zeroed_page(GFP_KERNEL | rk_ops->gfp_flags);
+ rk_domain->dt = iommu_alloc_page(GFP_KERNEL | rk_ops->gfp_flags);
if (!rk_domain->dt)
goto err_free_domain;

@@ -1083,7 +1085,7 @@ static struct iommu_domain *rk_iommu_domain_alloc_paging(struct device *dev)
return &rk_domain->domain;

err_free_dt:
- free_page((unsigned long)rk_domain->dt);
+ iommu_free_page(rk_domain->dt);
err_free_domain:
kfree(rk_domain);

@@ -1104,13 +1106,13 @@ static void rk_iommu_domain_free(struct iommu_domain *domain)
u32 *page_table = phys_to_virt(pt_phys);
dma_unmap_single(dma_dev, pt_phys,
SPAGE_SIZE, DMA_TO_DEVICE);
- free_page((unsigned long)page_table);
+ iommu_free_page(page_table);
}
}

dma_unmap_single(dma_dev, rk_domain->dt_dma,
SPAGE_SIZE, DMA_TO_DEVICE);
- free_page((unsigned long)rk_domain->dt);
+ iommu_free_page(rk_domain->dt);

kfree(rk_domain);
}
--
2.43.0.472.g3155946c3a-goog


2023-12-26 20:07:29

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 10/10] iommu: account IOMMU allocated memory

In order to be able to limit the amount of memory that is allocated
by IOMMU subsystem, the memory must be accounted.

Account IOMMU as part of the secondary pagetables as it was discussed
at LPC.

The value of SecPageTables now contains mmeory allocation by IOMMU
and KVM.

Signed-off-by: Pasha Tatashin <[email protected]>
---
Documentation/admin-guide/cgroup-v2.rst | 2 +-
Documentation/filesystems/proc.rst | 4 ++--
drivers/iommu/iommu-pages.h | 2 ++
include/linux/mmzone.h | 2 +-
4 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 3f85254f3cef..e004e05a7cde 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1418,7 +1418,7 @@ PAGE_SIZE multiple when read back.
sec_pagetables
Amount of memory allocated for secondary page tables,
this currently includes KVM mmu allocations on x86
- and arm64.
+ and arm64 and IOMMU page tables.

percpu (npn)
Amount of memory used for storing per-cpu kernel
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 49ef12df631b..86f137a9b66b 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -1110,8 +1110,8 @@ KernelStack
PageTables
Memory consumed by userspace page tables
SecPageTables
- Memory consumed by secondary page tables, this currently
- currently includes KVM mmu allocations on x86 and arm64.
+ Memory consumed by secondary page tables, this currently includes
+ KVM mmu and IOMMU allocations on x86 and arm64.
NFS_Unstable
Always zero. Previous counted pages which had been written to
the server, but has not been committed to stable storage.
diff --git a/drivers/iommu/iommu-pages.h b/drivers/iommu/iommu-pages.h
index 4e70cdf7acac..b4289d577e2c 100644
--- a/drivers/iommu/iommu-pages.h
+++ b/drivers/iommu/iommu-pages.h
@@ -27,6 +27,7 @@ static inline void __iommu_alloc_account(struct page *page, int order)
const long pgcnt = 1l << order;

mod_node_page_state(page_pgdat(page), NR_IOMMU_PAGES, pgcnt);
+ mod_lruvec_page_state(page, NR_SECONDARY_PAGETABLE, pgcnt);
}

/**
@@ -39,6 +40,7 @@ static inline void __iommu_free_account(struct page *page, int order)
const long pgcnt = 1l << order;

mod_node_page_state(page_pgdat(page), NR_IOMMU_PAGES, -pgcnt);
+ mod_lruvec_page_state(page, NR_SECONDARY_PAGETABLE, -pgcnt);
}

/**
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f0b54c752e22..da68f9977206 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -199,7 +199,7 @@ enum node_stat_item {
NR_KERNEL_SCS_KB, /* measured in KiB */
#endif
NR_PAGETABLE, /* used for pagetables */
- NR_SECONDARY_PAGETABLE, /* secondary pagetables, e.g. KVM pagetables */
+ NR_SECONDARY_PAGETABLE, /* secondary pagetables, KVM & IOMMU */
#ifdef CONFIG_IOMMU_SUPPORT
NR_IOMMU_PAGES, /* # of pages allocated by IOMMU */
#endif
--
2.43.0.472.g3155946c3a-goog


2023-12-26 20:15:35

by Pasha Tatashin

[permalink] [raw]
Subject: [PATCH v3 05/10] iommu/exynos: use page allocation function provided by iommu-pages.h

Convert iommu/exynos-iommu.c to use the new page allocation functions
provided in iommu-pages.h.

Signed-off-by: Pasha Tatashin <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
drivers/iommu/exynos-iommu.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 2c6e9094f1e9..3eab0ae65a4f 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -22,6 +22,8 @@
#include <linux/pm_runtime.h>
#include <linux/slab.h>

+#include "iommu-pages.h"
+
typedef u32 sysmmu_iova_t;
typedef u32 sysmmu_pte_t;
static struct iommu_domain exynos_identity_domain;
@@ -900,11 +902,11 @@ static struct iommu_domain *exynos_iommu_domain_alloc_paging(struct device *dev)
if (!domain)
return NULL;

- domain->pgtable = (sysmmu_pte_t *)__get_free_pages(GFP_KERNEL, 2);
+ domain->pgtable = iommu_alloc_pages(GFP_KERNEL, 2);
if (!domain->pgtable)
goto err_pgtable;

- domain->lv2entcnt = (short *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
+ domain->lv2entcnt = iommu_alloc_pages(GFP_KERNEL, 1);
if (!domain->lv2entcnt)
goto err_counter;

@@ -930,9 +932,9 @@ static struct iommu_domain *exynos_iommu_domain_alloc_paging(struct device *dev)
return &domain->domain;

err_lv2ent:
- free_pages((unsigned long)domain->lv2entcnt, 1);
+ iommu_free_pages(domain->lv2entcnt, 1);
err_counter:
- free_pages((unsigned long)domain->pgtable, 2);
+ iommu_free_pages(domain->pgtable, 2);
err_pgtable:
kfree(domain);
return NULL;
@@ -973,8 +975,8 @@ static void exynos_iommu_domain_free(struct iommu_domain *iommu_domain)
phys_to_virt(base));
}

- free_pages((unsigned long)domain->pgtable, 2);
- free_pages((unsigned long)domain->lv2entcnt, 1);
+ iommu_free_pages(domain->pgtable, 2);
+ iommu_free_pages(domain->lv2entcnt, 1);
kfree(domain);
}

--
2.43.0.472.g3155946c3a-goog


2023-12-27 00:25:48

by David Rientjes

[permalink] [raw]
Subject: Re: [PATCH v3 10/10] iommu: account IOMMU allocated memory

On Tue, 26 Dec 2023, Pasha Tatashin wrote:

> In order to be able to limit the amount of memory that is allocated
> by IOMMU subsystem, the memory must be accounted.
>
> Account IOMMU as part of the secondary pagetables as it was discussed
> at LPC.
>
> The value of SecPageTables now contains mmeory allocation by IOMMU
> and KVM.
>
> Signed-off-by: Pasha Tatashin <[email protected]>

Acked-by: David Rientjes <[email protected]>

2023-12-27 00:27:59

by David Rientjes

[permalink] [raw]
Subject: Re: [PATCH v3 01/10] iommu/vt-d: add wrapper functions for page allocations

On Tue, 26 Dec 2023, Pasha Tatashin wrote:

> In order to improve observability and accountability of IOMMU layer, we
> must account the number of pages that are allocated by functions that
> are calling directly into buddy allocator.
>
> This is achieved by first wrapping the allocation related functions into a
> separate inline functions in new file:
>
> drivers/iommu/iommu-pages.h
>
> Convert all page allocation calls under iommu/intel to use these new
> functions.
>
> Signed-off-by: Pasha Tatashin <[email protected]>

Acked-by: David Rientjes <[email protected]>

2023-12-27 10:06:18

by Bagas Sanjaya

[permalink] [raw]
Subject: Re: [PATCH v3 00/10] IOMMU memory observability

On Tue, Dec 26, 2023 at 08:01:55PM +0000, Pasha Tatashin wrote:
> ----------------------------------------------------------------------
> Changelog
> ----------------------------------------------------------------------
> v3:
> - Sync with v6.7-rc7
> - Addressed comments from David Rientjes: s/pages/page/, added unlikely() into
> the branches, expanded comment for iommu_free_pages_list().
> - Added Acked-bys: David Rientjes
>
> v2:
> - Added Reviewed-by Janne Grunau
> - Sync with 6.7.0-rc3, 3b47bc037bd44f142ac09848e8d3ecccc726be99
> - Separated form the series patches:
> vhost-vdpa: account iommu allocations
> https://lore.kernel.org/all/[email protected]
> vfio: account iommu allocations
> https://lore.kernel.org/all/[email protected]
> as suggested by Jason Gunthorpe
> - Fixed SPARC build issue detected by kernel test robot
> - Drop the following patches as they do account iommu page tables:
> iommu/dma: use page allocation function provided by iommu-pages.h
> iommu/fsl: use page allocation function provided by iommu-pages.h
> iommu/iommufd: use page allocation function provided by iommu-pages.h
> as suggested by Robin Murphy. These patches are not related to IOMMU
> page tables. We might need to do a separate work to support DMA
> observability.
> - Remove support iommu/io-pgtable-arm-v7s as the 2nd level pages are
> under a page size, thanks Robin Murphy for pointing this out.
>
> ----------------------------------------------------------------------
> Description
> ----------------------------------------------------------------------
> IOMMU subsystem may contain state that is in gigabytes. Majority of that
> state is iommu page tables. Yet, there is currently, no way to observe
> how much memory is actually used by the iommu subsystem.
>
> This patch series solves this problem by adding both observability to
> all pages that are allocated by IOMMU, and also accountability, so
> admins can limit the amount if via cgroups.
>
> The system-wide observability is using /proc/meminfo:
> SecPageTables: 438176 kB
>
> Contains IOMMU and KVM memory.
>
> Per-node observability:
> /sys/devices/system/node/nodeN/meminfo
> Node N SecPageTables: 422204 kB
>
> Contains IOMMU and KVM memory memory in the given NUMA node.
>
> Per-node IOMMU only observability:
> /sys/devices/system/node/nodeN/vmstat
> nr_iommu_pages 105555
>
> Contains number of pages IOMMU allocated in the given node.
>
> Accountability: using sec_pagetables cgroup-v2 memory.stat entry.
>
> With the change, iova_stress[1] stops as limit is reached:
>
> # ./iova_stress
> iova space: 0T free memory: 497G
> iova space: 1T free memory: 495G
> iova space: 2T free memory: 493G
> iova space: 3T free memory: 491G
>
> stops as limit is reached.
>
> This series encorporates suggestions that came from the discussion
> at LPC [2].
> ----------------------------------------------------------------------
> [1] https://github.com/soleen/iova_stress
> [2] https://lpc.events/event/17/contributions/1466
> ----------------------------------------------------------------------
> Previous versions
> v1: https://lore.kernel.org/all/[email protected]
> v2: https://lore.kernel.org/linux-mm/[email protected]
> ----------------------------------------------------------------------
>

First of all, Merry Christmas and Happy New Year for all!

And for this series, no observable regressions when booting the kernel with
the series applied.

Tested-by: Bagas Sanjaya <[email protected]>

--
An old man doll... just what I always wanted! - Clara


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2023-12-28 14:37:36

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH v3 00/10] IOMMU memory observability

> > This series encorporates suggestions that came from the discussion
> > at LPC [2].
> > ----------------------------------------------------------------------
> > [1] https://github.com/soleen/iova_stress
> > [2] https://lpc.events/event/17/contributions/1466
> > ----------------------------------------------------------------------
> > Previous versions
> > v1: https://lore.kernel.org/all/[email protected]
> > v2: https://lore.kernel.org/linux-mm/[email protected]
> > ----------------------------------------------------------------------
> >
>
> First of all, Merry Christmas and Happy New Year for all!
>
> And for this series, no observable regressions when booting the kernel with
> the series applied.
>
> Tested-by: Bagas Sanjaya <[email protected]>

Thank you for testing.

Pasha

2024-01-04 15:41:26

by Michal Koutný

[permalink] [raw]
Subject: Re: [PATCH v3 00/10] IOMMU memory observability

Hello.

On Tue, Dec 26, 2023 at 08:01:55PM +0000, Pasha Tatashin <[email protected]> wrote:
> This patch series solves this problem by adding both observability to
> all pages that are allocated by IOMMU, and also accountability, so
> admins can limit the amount if via cgroups.

Maybe this is a mismatch in vocabulary what you mean by the verb
"limit". But I don't see in the patchset that the offending pages would
be allocated with GFP_ACCOUNT. So the result is that the pages are
accounted (you can view the amount in memory.stat) but they are not
subject to memcg limits.

Is that what you intend?


Regards,
Michal


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2024-01-04 16:30:48

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH v3 00/10] IOMMU memory observability

On Thu, Jan 4, 2024 at 10:31 AM Michal Koutný <[email protected]> wrote:
>
> Hello.
>
> On Tue, Dec 26, 2023 at 08:01:55PM +0000, Pasha Tatashin <[email protected]> wrote:
> > This patch series solves this problem by adding both observability to
> > all pages that are allocated by IOMMU, and also accountability, so
> > admins can limit the amount if via cgroups.
>
> Maybe this is a mismatch in vocabulary what you mean by the verb
> "limit". But I don't see in the patchset that the offending pages would
> be allocated with GFP_ACCOUNT. So the result is that the pages are
> accounted (you can view the amount in memory.stat) but they are not
> subject to memcg limits.
>
> Is that what you intend?

Hi Michal,

Thank you for taking a look at this. The two patches [1] [2] which add
GFP_KERNEL_ACCOUNT were sent separate from this series at request of
reviewers:

Pasha

[1] https://lore.kernel.org/linux-mm/[email protected]
[2] https://lore.kernel.org/linux-mm/[email protected]

>
>
> Regards,
> Michal

2024-01-04 17:04:49

by Michal Koutný

[permalink] [raw]
Subject: Re: [PATCH v3 00/10] IOMMU memory observability

On Thu, Jan 04, 2024 at 11:29:43AM -0500, Pasha Tatashin <[email protected]> wrote:
> Thank you for taking a look at this. The two patches [1] [2] which add
> GFP_KERNEL_ACCOUNT were sent separate from this series at request of
> reviewers:

Ah, I didn't catch that.

Though, I mean the patch 02/10 calls iommu_alloc_pages() with GFP_KERNEL
(and not a passed gfp from iommu_map).
Then patch 09/10 accounts all iommu_alloc_pages() under NR_IOMMU_PAGES.

I think there is a difference between what's shown NR_IOMMU_PAGES and
what will have __GFP_ACCOUNT because of that.

I.e. is it the intention that this difference is not subject to
limiting?

(Note: I'm not familiar with iommu code and moreover I'm only looking at
the two patch sets, not the complete code applied. So you may correct my
reasoning.)


Thanks,
Michal


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2024-01-04 19:13:26

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH v3 00/10] IOMMU memory observability

On Thu, Jan 4, 2024 at 12:04 PM Michal Koutný <[email protected]> wrote:
>
> On Thu, Jan 04, 2024 at 11:29:43AM -0500, Pasha Tatashin <[email protected]> wrote:
> > Thank you for taking a look at this. The two patches [1] [2] which add
> > GFP_KERNEL_ACCOUNT were sent separate from this series at request of
> > reviewers:
>
> Ah, I didn't catch that.
>
> Though, I mean the patch 02/10 calls iommu_alloc_pages() with GFP_KERNEL
> (and not a passed gfp from iommu_map).
> Then patch 09/10 accounts all iommu_alloc_pages() under NR_IOMMU_PAGES.
>
> I think there is a difference between what's shown NR_IOMMU_PAGES and
> what will have __GFP_ACCOUNT because of that.
>
> I.e. is it the intention that this difference is not subject to
> limiting?

Yes, we will have a difference between GFP_ACCOUNT and what
NR_IOMMU_PAGES shows. GFP_ACCOUNT is set only where it makes sense to
charge to user processes, i.e. IOMMU Page Tables, but there more IOMMU
shared data that should not really be charged to a specific process.
The charged and uncharged data will be visible via /proc/vmstat
nr_iommu_pages field.

Pasha

>
> (Note: I'm not familiar with iommu code and moreover I'm only looking at
> the two patch sets, not the complete code applied. So you may correct my
> reasoning.)
>
>
> Thanks,
> Michal

2024-01-05 08:20:46

by Thierry Reding

[permalink] [raw]
Subject: Re: [PATCH v3 08/10] iommu/tegra-smmu: use page allocation function provided by iommu-pages.h

On Tue, Dec 26, 2023 at 08:02:03PM +0000, Pasha Tatashin wrote:
> Convert iommu/tegra-smmu.c to use the new page allocation functions
> provided in iommu-pages.h.
>
> Signed-off-by: Pasha Tatashin <[email protected]>
> Acked-by: David Rientjes <[email protected]>
> ---
> drivers/iommu/tegra-smmu.c | 18 ++++++++++--------
> 1 file changed, 10 insertions(+), 8 deletions(-)

Acked-by: Thierry Reding <[email protected]>


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2024-01-05 09:03:09

by Michal Koutný

[permalink] [raw]
Subject: Re: [PATCH v3 00/10] IOMMU memory observability

On Thu, Jan 04, 2024 at 02:12:26PM -0500, Pasha Tatashin <[email protected]> wrote:
> Yes, we will have a difference between GFP_ACCOUNT and what
> NR_IOMMU_PAGES shows. GFP_ACCOUNT is set only where it makes sense to
> charge to user processes, i.e. IOMMU Page Tables, but there more IOMMU
> shared data that should not really be charged to a specific process.

I see. I'd suggest adding this explanation to commit 10/10 message
(perhaps with some ballpark numbers of pages). In order to have a
reference and understadning if someone decided to charge (and limit) all
in the future.

Thanks,
Michal


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2024-01-05 15:34:31

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH v3 00/10] IOMMU memory observability

On Fri, Jan 5, 2024 at 4:02 AM Michal Koutný <[email protected]> wrote:
>
> On Thu, Jan 04, 2024 at 02:12:26PM -0500, Pasha Tatashin <[email protected]> wrote:
> > Yes, we will have a difference between GFP_ACCOUNT and what
> > NR_IOMMU_PAGES shows. GFP_ACCOUNT is set only where it makes sense to
> > charge to user processes, i.e. IOMMU Page Tables, but there more IOMMU
> > shared data that should not really be charged to a specific process.
>
> I see. I'd suggest adding this explanation to commit 10/10 message
> (perhaps with some ballpark numbers of pages). In order to have a
> reference and understadning if someone decided to charge (and limit) all
> in the future.

Sure, I will update the commit log in 10/10 with this info if we will have v4.

Pasha

>
> Thanks,
> Michal

2024-02-13 13:13:02

by Will Deacon

[permalink] [raw]
Subject: Re: [PATCH v3 10/10] iommu: account IOMMU allocated memory

Hi Pasha,

On Tue, Dec 26, 2023 at 08:02:05PM +0000, Pasha Tatashin wrote:
> In order to be able to limit the amount of memory that is allocated
> by IOMMU subsystem, the memory must be accounted.
>
> Account IOMMU as part of the secondary pagetables as it was discussed
> at LPC.
>
> The value of SecPageTables now contains mmeory allocation by IOMMU
> and KVM.
>
> Signed-off-by: Pasha Tatashin <[email protected]>
> ---
> Documentation/admin-guide/cgroup-v2.rst | 2 +-
> Documentation/filesystems/proc.rst | 4 ++--
> drivers/iommu/iommu-pages.h | 2 ++
> include/linux/mmzone.h | 2 +-
> 4 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
> index 3f85254f3cef..e004e05a7cde 100644
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -1418,7 +1418,7 @@ PAGE_SIZE multiple when read back.
> sec_pagetables
> Amount of memory allocated for secondary page tables,
> this currently includes KVM mmu allocations on x86
> - and arm64.
> + and arm64 and IOMMU page tables.
>
> percpu (npn)
> Amount of memory used for storing per-cpu kernel
> diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
> index 49ef12df631b..86f137a9b66b 100644
> --- a/Documentation/filesystems/proc.rst
> +++ b/Documentation/filesystems/proc.rst
> @@ -1110,8 +1110,8 @@ KernelStack
> PageTables
> Memory consumed by userspace page tables
> SecPageTables
> - Memory consumed by secondary page tables, this currently
> - currently includes KVM mmu allocations on x86 and arm64.
> + Memory consumed by secondary page tables, this currently includes
> + KVM mmu and IOMMU allocations on x86 and arm64.

While I can see the value in this for IOMMU mappings managed by VFIO,
doesn't this end up conflating that with the normal case of DMA domains?
For systems that e.g. rely on an IOMMU for functional host DMA, it seems
wrong to subject that to accounting constraints.

Will

2024-02-16 17:58:18

by Will Deacon

[permalink] [raw]
Subject: Re: [PATCH v3 10/10] iommu: account IOMMU allocated memory

On Tue, Feb 13, 2024 at 10:44:53AM -0500, Pasha Tatashin wrote:
> > > SecPageTables
> > > - Memory consumed by secondary page tables, this currently
> > > - currently includes KVM mmu allocations on x86 and arm64.
> > > + Memory consumed by secondary page tables, this currently includes
> > > + KVM mmu and IOMMU allocations on x86 and arm64.
>
> Hi Will,
>
> > While I can see the value in this for IOMMU mappings managed by VFIO,
> > doesn't this end up conflating that with the normal case of DMA domains?
> > For systems that e.g. rely on an IOMMU for functional host DMA, it seems
> > wrong to subject that to accounting constraints.
>
> The accounting constraints are only applicable when GFP_KERNEL_ACCOUNT
> is passed to the iommu mapping functions. We do that from the vfio,
> iommufd, and vhost. Without this flag, the memory useage is reported
> in /proc/meminfo as part of SecPageTables field, but not constrained
> in cgroup.

Thanks, Pasha, that explanation makes sense. I still find it bizarre to
include IOMMU allocations from the DMA API in SecPageTables though, and
I worry that it will confuse people who are using that metric as a way
to get a feeling for how much memory is being used by KVM's secondary
page-tables. As an extreme example, having a non-zero SecPageTables count
without KVM even compiled in is pretty bizarre.

Will

2024-02-16 19:52:10

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH v3 10/10] iommu: account IOMMU allocated memory

On Fri, Feb 16, 2024 at 12:58 PM Will Deacon <[email protected]> wrote:
>
> On Tue, Feb 13, 2024 at 10:44:53AM -0500, Pasha Tatashin wrote:
> > > > SecPageTables
> > > > - Memory consumed by secondary page tables, this currently
> > > > - currently includes KVM mmu allocations on x86 and arm64.
> > > > + Memory consumed by secondary page tables, this currently includes
> > > > + KVM mmu and IOMMU allocations on x86 and arm64.
> >
> > Hi Will,
> >
> > > While I can see the value in this for IOMMU mappings managed by VFIO,
> > > doesn't this end up conflating that with the normal case of DMA domains?
> > > For systems that e.g. rely on an IOMMU for functional host DMA, it seems
> > > wrong to subject that to accounting constraints.
> >
> > The accounting constraints are only applicable when GFP_KERNEL_ACCOUNT
> > is passed to the iommu mapping functions. We do that from the vfio,
> > iommufd, and vhost. Without this flag, the memory useage is reported
> > in /proc/meminfo as part of SecPageTables field, but not constrained
> > in cgroup.
>
> Thanks, Pasha, that explanation makes sense. I still find it bizarre to
> include IOMMU allocations from the DMA API in SecPageTables though, and
> I worry that it will confuse people who are using that metric as a way
> to get a feeling for how much memory is being used by KVM's secondary
> page-tables. As an extreme example, having a non-zero SecPageTables count
> without KVM even compiled in is pretty bizarre.

I agree; I also prefer a new field in /proc/meminfo named
'IOMMUPageTables'. This is what I proposed at LPC, but I was asked to
reuse the existing 'SecPageTables' field instead. The rationale was
that 'secondary' implies not only KVM page tables, but any other
non-regular page tables.

I would appreciate the opinion of IOMMU maintainers on this: is it
preferable to bundle the information with 'SecPageTables' or maintain
a separate field?

Pasha

2024-02-21 13:33:39

by Will Deacon

[permalink] [raw]
Subject: Re: [PATCH v3 10/10] iommu: account IOMMU allocated memory

On Fri, Feb 16, 2024 at 02:48:00PM -0500, Pasha Tatashin wrote:
> On Fri, Feb 16, 2024 at 12:58 PM Will Deacon <[email protected]> wrote:
> >
> > On Tue, Feb 13, 2024 at 10:44:53AM -0500, Pasha Tatashin wrote:
> > > > > SecPageTables
> > > > > - Memory consumed by secondary page tables, this currently
> > > > > - currently includes KVM mmu allocations on x86 and arm64.
> > > > > + Memory consumed by secondary page tables, this currently includes
> > > > > + KVM mmu and IOMMU allocations on x86 and arm64.
> > >
> > > Hi Will,
> > >
> > > > While I can see the value in this for IOMMU mappings managed by VFIO,
> > > > doesn't this end up conflating that with the normal case of DMA domains?
> > > > For systems that e.g. rely on an IOMMU for functional host DMA, it seems
> > > > wrong to subject that to accounting constraints.
> > >
> > > The accounting constraints are only applicable when GFP_KERNEL_ACCOUNT
> > > is passed to the iommu mapping functions. We do that from the vfio,
> > > iommufd, and vhost. Without this flag, the memory useage is reported
> > > in /proc/meminfo as part of SecPageTables field, but not constrained
> > > in cgroup.
> >
> > Thanks, Pasha, that explanation makes sense. I still find it bizarre to
> > include IOMMU allocations from the DMA API in SecPageTables though, and
> > I worry that it will confuse people who are using that metric as a way
> > to get a feeling for how much memory is being used by KVM's secondary
> > page-tables. As an extreme example, having a non-zero SecPageTables count
> > without KVM even compiled in is pretty bizarre.
>
> I agree; I also prefer a new field in /proc/meminfo named
> 'IOMMUPageTables'. This is what I proposed at LPC, but I was asked to
> reuse the existing 'SecPageTables' field instead. The rationale was
> that 'secondary' implies not only KVM page tables, but any other
> non-regular page tables.
>
> I would appreciate the opinion of IOMMU maintainers on this: is it
> preferable to bundle the information with 'SecPageTables' or maintain
> a separate field?

I personally find it confusing to add all IOMMU page-table allocations
to SecPageTables, considering that userspace could be using that today
with a reasonable expectation that it's concerned only with virtual
machine overhead. However, if the opposite conclusion was reached at LPC,
then I really don't want to re-open the discussion and derail your
patchset.

Will

2024-02-22 00:22:12

by Jason Gunthorpe

[permalink] [raw]
Subject: Re: [PATCH v3 10/10] iommu: account IOMMU allocated memory

On Fri, Feb 16, 2024 at 02:48:00PM -0500, Pasha Tatashin wrote:
> On Fri, Feb 16, 2024 at 12:58 PM Will Deacon <[email protected]> wrote:
> >
> > On Tue, Feb 13, 2024 at 10:44:53AM -0500, Pasha Tatashin wrote:
> > > > > SecPageTables
> > > > > - Memory consumed by secondary page tables, this currently
> > > > > - currently includes KVM mmu allocations on x86 and arm64.
> > > > > + Memory consumed by secondary page tables, this currently includes
> > > > > + KVM mmu and IOMMU allocations on x86 and arm64.
> > >
> > > Hi Will,
> > >
> > > > While I can see the value in this for IOMMU mappings managed by VFIO,
> > > > doesn't this end up conflating that with the normal case of DMA domains?
> > > > For systems that e.g. rely on an IOMMU for functional host DMA, it seems
> > > > wrong to subject that to accounting constraints.
> > >
> > > The accounting constraints are only applicable when GFP_KERNEL_ACCOUNT
> > > is passed to the iommu mapping functions. We do that from the vfio,
> > > iommufd, and vhost. Without this flag, the memory useage is reported
> > > in /proc/meminfo as part of SecPageTables field, but not constrained
> > > in cgroup.
> >
> > Thanks, Pasha, that explanation makes sense. I still find it bizarre to
> > include IOMMU allocations from the DMA API in SecPageTables though, and
> > I worry that it will confuse people who are using that metric as a way
> > to get a feeling for how much memory is being used by KVM's secondary
> > page-tables. As an extreme example, having a non-zero SecPageTables count
> > without KVM even compiled in is pretty bizarre.
>
> I agree; I also prefer a new field in /proc/meminfo named
> 'IOMMUPageTables'. This is what I proposed at LPC, but I was asked to
> reuse the existing 'SecPageTables' field instead. The rationale was
> that 'secondary' implies not only KVM page tables, but any other
> non-regular page tables.

Right, SeanC mentioned that the purpose of SecPageTables was to
capture all non-mm page table radix allocations.

> I would appreciate the opinion of IOMMU maintainers on this: is it
> preferable to bundle the information with 'SecPageTables' or maintain
> a separate field?

I think you should keep them together. I don't think we should be
introducing new counters, in general.

Detailed memory profile should come from some kind of more dynamic and
universal scheme. Hopefully that other giant thread about profiling
will reach some conclusion.

Jason

2024-02-22 00:28:02

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH v3 10/10] iommu: account IOMMU allocated memory

> > > > > While I can see the value in this for IOMMU mappings managed by VFIO,
> > > > > doesn't this end up conflating that with the normal case of DMA domains?
> > > > > For systems that e.g. rely on an IOMMU for functional host DMA, it seems
> > > > > wrong to subject that to accounting constraints.
> > > >
> > > > The accounting constraints are only applicable when GFP_KERNEL_ACCOUNT
> > > > is passed to the iommu mapping functions. We do that from the vfio,
> > > > iommufd, and vhost. Without this flag, the memory useage is reported
> > > > in /proc/meminfo as part of SecPageTables field, but not constrained
> > > > in cgroup.
> > >
> > > Thanks, Pasha, that explanation makes sense. I still find it bizarre to
> > > include IOMMU allocations from the DMA API in SecPageTables though, and
> > > I worry that it will confuse people who are using that metric as a way
> > > to get a feeling for how much memory is being used by KVM's secondary
> > > page-tables. As an extreme example, having a non-zero SecPageTables count
> > > without KVM even compiled in is pretty bizarre.
> >
> > I agree; I also prefer a new field in /proc/meminfo named
> > 'IOMMUPageTables'. This is what I proposed at LPC, but I was asked to
> > reuse the existing 'SecPageTables' field instead. The rationale was
> > that 'secondary' implies not only KVM page tables, but any other
> > non-regular page tables.
>
> Right, SeanC mentioned that the purpose of SecPageTables was to
> capture all non-mm page table radix allocations.
>
> > I would appreciate the opinion of IOMMU maintainers on this: is it
> > preferable to bundle the information with 'SecPageTables' or maintain
> > a separate field?
>
> I think you should keep them together. I don't think we should be
> introducing new counters, in general.

Thanks Jason, I will keep it as-is. I will send a new version soon
with your comments addressed.

> Detailed memory profile should come from some kind of more dynamic and
> universal scheme. Hopefully that other giant thread about profiling
> will reach some conclusion.

+1! Memory profiling is going to be a very useful addition to the kernel.

Pasha