The Thunderbolt vulnerabilities are public and have a nice
name as Thunderclap [1] [3] nowadays. This patch series aims
to mitigate those concerns.
An external PCI device is a PCI peripheral device connected
to the system through an external bus, such as Thunderbolt.
What makes it different is that it can't be trusted to the
same degree as the devices build into the system. Generally,
a trusted PCIe device will DMA into the designated buffers
and not overrun or otherwise write outside the specified
bounds. But it's different for an external device.
The minimum IOMMU mapping granularity is one page (4k), so
for DMA transfers smaller than that a malicious PCIe device
can access the whole page of memory even if it does not
belong to the driver in question. This opens a possibility
for DMA attack. For more information about DMA attacks
imposed by an untrusted PCI/PCIe device, please refer to [2].
This implements bounce buffer for the untrusted external
devices. The transfers should be limited in isolated pages
so the IOMMU window does not cover memory outside of what
the driver expects. Previously (v3 and before), we proposed
an optimisation to only copy the head and tail of the buffer
if it spans multiple pages, and directly map the ones in the
middle. Figure 1 gives a big picture about this solution.
swiotlb System
IOVA bounce page Memory
.---------. .---------. .---------.
| | | | | |
| | | | | |
buffer_start .---------. .---------. .---------.
| |----->| |*******>| |
| | | | swiotlb| |
| | | | mapping| |
IOMMU Page '---------' '---------' '---------'
Boundary | | | |
| | | |
| | | |
| |------------------------>| |
| | IOMMU mapping | |
| | | |
IOMMU Page .---------. .---------.
Boundary | | | |
| | | |
| |------------------------>| |
| | IOMMU mapping | |
| | | |
| | | |
IOMMU Page .---------. .---------. .---------.
Boundary | | | | | |
| | | | | |
| |----->| |*******>| |
buffer_end '---------' '---------' swiotlb'---------'
| | | | mapping| |
| | | | | |
'---------' '---------' '---------'
Figure 1: A big view of iommu bounce page
As Robin Murphy pointed out, this ties us to using strict mode for
TLB maintenance, which may not be an overall win depending on the
balance between invalidation bandwidth vs. memcpy bandwidth. If we
use standard SWIOTLB logic to always copy the whole thing, we should
be able to release the bounce pages via the flush queue to allow
'safe' lazy unmaps. So since v4 we start to use the standard swiotlb
logic.
swiotlb System
IOVA bounce page Memory
buffer_start .---------. .---------. .---------.
| | | | | |
| | | | | |
| | | | .---------.physical
| |----->| | ------>| |_start
| |iommu | | swiotlb| |
| | map | | map | |
IOMMU Page .---------. .---------. '---------'
Boundary | | | | | |
| | | | | |
| |----->| | | |
| |iommu | | | |
| | map | | | |
| | | | | |
IOMMU Page .---------. .---------. .---------.
Boundary | | | | | |
| |----->| | | |
| |iommu | | | |
| | map | | | |
| | | | | |
IOMMU Page | | | | | |
Boundary .---------. .---------. .---------.
| | | |------->| |
buffer_end '---------' '---------' swiotlb| |
| |----->| | map | |
| |iommu | | | |
| | map | | '---------' physical
| | | | | | _end
'---------' '---------' '---------'
Figure 2: A big view of simplified iommu bounce page
The implementation of bounce buffers for untrusted devices
will cause a little performance overhead, but we didn't see
any user experience problems. The users could use the kernel
parameter defined in the IOMMU driver to remove the performance
overhead if they trust their devices enough.
This series introduces below APIs for bounce page:
* iommu_bounce_map(dev, addr, paddr, size, dir, attrs)
- Map a buffer start at DMA address @addr in bounce page
manner. For buffer that doesn't cross whole minimal
IOMMU pages, the bounce buffer policy is applied.
A bounce page mapped by swiotlb will be used as the DMA
target in the IOMMU page table.
* iommu_bounce_unmap(dev, addr, size, dir, attrs)
- Unmap the buffer mapped with iommu_bounce_map(). The bounce
page will be torn down after the bounced data get synced.
* iommu_bounce_sync_single(dev, addr, size, dir, target)
- Synce the bounced data in case the bounce mapped buffer is
reused.
The bounce page idea:
Based-on-idea-by: Mika Westerberg <[email protected]>
Based-on-idea-by: Ashok Raj <[email protected]>
Based-on-idea-by: Alan Cox <[email protected]>
Based-on-idea-by: Kevin Tian <[email protected]>
Based-on-idea-by: Robin Murphy <[email protected]>
The patch series has been tested by:
Tested-by: Xu Pengfei <[email protected]>
Tested-by: Mika Westerberg <[email protected]>
Reference:
[1] https://thunderclap.io/
[2] https://thunderclap.io/thunderclap-paper-ndss2019.pdf
[3] https://christian.kellner.me/2019/02/27/thunderclap-and-linux/
[4] https://lkml.org/lkml/2019/3/4/644
Best regards,
Baolu
Change log:
v8->v9:
- The previous v8 was posted here:
https://lkml.org/lkml/2019/8/30/170
- Remove the pci dependency in swiotlb by moving clearing padding
area code to the place where the bounce buffer is really used
for the untrusted devices.
- Add some extra dma map/unmap trace events.
v7->v8:
- The previous v7 was posted here:
https://lkml.org/lkml/2019/8/23/83
- Keep the swiotlb pre-allocated pages only if intel-iommu driver
needs bounce buffers, a.k.a. system has untrusted devices or
external ports.
v6->v7:
- The previous v6 was posted here:
https://lkml.org/lkml/2019/7/30/18
- Remove the unnecessary bounce page iommu APIs
v5->v6:
- The previous v5 was posted here:
https://lkml.org/lkml/2019/7/24/2134
- Move the per-device dma ops into another seperated series.
- Christoph Hellwig reviewed the patches and add his Reviewed-bys.
- Add Steven Rostedt's Review-by for the trace patch.
- Adress the review comments from Christoph Hellwig.
- This patch series is now based on v5.3-rc2.
v4->v5:
- The previous v4 was posted here:
https://lkml.org/lkml/2019/6/2/187
- Add per-device dma ops and use bounce buffer specific dma
ops for those untrusted devices.
devices with identity domains -> system default dma ops
trusted devices with dma domains -> iommu/vt-d dma ops
untrusted devices -> bounced dma ops
- Address various review comments received since v4.
- This patch series is based on v5.3-rc1.
v3->v4:
- The previous v3 was posted here:
https://lkml.org/lkml/2019/4/20/213
- Discard the optimization of only mapping head and tail
partial pages, use the standard swiotlb in order to achieve
iotlb flush efficiency.
- This patch series is based on the top of the vt-d branch of
Joerg's iommu tree.
v2->v3:
- The previous v2 was posed here:
https://lkml.org/lkml/2019/3/27/157
- Reuse the existing swiotlb APIs for bounce buffer by
extending it to support bounce page.
- Move the bouce page APIs into iommu generic layer.
- This patch series is based on 5.1-rc1.
v1->v2:
- The previous v1 was posted here:
https://lkml.org/lkml/2019/3/12/66
- Refactor the code to remove struct bounce_param;
- During the v1 review cycle, we discussed the possibility
of reusing swiotlb code to avoid code dumplication, but
we found the swiotlb implementations are not ready for the
use of bounce page pool.
https://lkml.org/lkml/2019/3/19/259
- This patch series has been rebased to v5.1-rc2.
Lu Baolu (5):
swiotlb: Split size parameter to map/unmap APIs
iommu/vt-d: Check whether device requires bounce buffer
iommu/vt-d: Don't switch off swiotlb if bounce page is used
iommu/vt-d: Add trace events for device dma map/unmap
iommu/vt-d: Use bounce buffer for untrusted devices
.../admin-guide/kernel-parameters.txt | 5 +
drivers/iommu/Kconfig | 1 +
drivers/iommu/Makefile | 1 +
drivers/iommu/intel-iommu.c | 310 +++++++++++++++++-
drivers/iommu/intel-trace.c | 14 +
drivers/xen/swiotlb-xen.c | 8 +-
include/linux/swiotlb.h | 8 +-
include/trace/events/intel_iommu.h | 106 ++++++
kernel/dma/direct.c | 2 +-
kernel/dma/swiotlb.c | 30 +-
10 files changed, 449 insertions(+), 36 deletions(-)
create mode 100644 drivers/iommu/intel-trace.c
create mode 100644 include/trace/events/intel_iommu.h
--
2.17.1
This splits the size parameter to swiotlb_tbl_map_single() and
swiotlb_tbl_unmap_single() into an alloc_size and a mapping_size
parameter, where the latter one is rounded up to the iommu page
size.
Suggested-by: Christoph Hellwig <[email protected]>
Signed-off-by: Lu Baolu <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
---
drivers/xen/swiotlb-xen.c | 8 ++++----
include/linux/swiotlb.h | 8 ++++++--
kernel/dma/direct.c | 2 +-
kernel/dma/swiotlb.c | 30 +++++++++++++++++++-----------
4 files changed, 30 insertions(+), 18 deletions(-)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index ae1df496bf38..adcabd9473eb 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -386,8 +386,8 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
*/
trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
- map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
- attrs);
+ map = swiotlb_tbl_map_single(dev, start_dma_addr, phys,
+ size, size, dir, attrs);
if (map == (phys_addr_t)DMA_MAPPING_ERROR)
return DMA_MAPPING_ERROR;
@@ -397,7 +397,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
* Ensure that the address returned is DMA'ble
*/
if (unlikely(!dma_capable(dev, dev_addr, size))) {
- swiotlb_tbl_unmap_single(dev, map, size, dir,
+ swiotlb_tbl_unmap_single(dev, map, size, size, dir,
attrs | DMA_ATTR_SKIP_CPU_SYNC);
return DMA_MAPPING_ERROR;
}
@@ -433,7 +433,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
/* NOTE: We use dev_addr here, not paddr! */
if (is_xen_swiotlb_buffer(dev_addr))
- swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
+ swiotlb_tbl_unmap_single(hwdev, paddr, size, size, dir, attrs);
}
static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 361f62bb4a8e..cde3dc18e21a 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -46,13 +46,17 @@ enum dma_sync_target {
extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
dma_addr_t tbl_dma_addr,
- phys_addr_t phys, size_t size,
+ phys_addr_t phys,
+ size_t mapping_size,
+ size_t alloc_size,
enum dma_data_direction dir,
unsigned long attrs);
extern void swiotlb_tbl_unmap_single(struct device *hwdev,
phys_addr_t tlb_addr,
- size_t size, enum dma_data_direction dir,
+ size_t mapping_size,
+ size_t alloc_size,
+ enum dma_data_direction dir,
unsigned long attrs);
extern void swiotlb_tbl_sync_single(struct device *hwdev,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 706113c6bebc..8402b29c280f 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -305,7 +305,7 @@ void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
dma_direct_sync_single_for_cpu(dev, addr, size, dir);
if (unlikely(is_swiotlb_buffer(phys)))
- swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs);
+ swiotlb_tbl_unmap_single(dev, phys, size, size, dir, attrs);
}
EXPORT_SYMBOL(dma_direct_unmap_page);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 9de232229063..89066efa3840 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -444,7 +444,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
dma_addr_t tbl_dma_addr,
- phys_addr_t orig_addr, size_t size,
+ phys_addr_t orig_addr,
+ size_t mapping_size,
+ size_t alloc_size,
enum dma_data_direction dir,
unsigned long attrs)
{
@@ -464,6 +466,9 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
pr_warn_once("%s is active and system is using DMA bounce buffers\n",
sme_active() ? "SME" : "SEV");
+ if (WARN_ON(mapping_size > alloc_size))
+ return (phys_addr_t)DMA_MAPPING_ERROR;
+
mask = dma_get_seg_boundary(hwdev);
tbl_dma_addr &= mask;
@@ -481,8 +486,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
* For mappings greater than or equal to a page, we limit the stride
* (and hence alignment) to a page size.
*/
- nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
- if (size >= PAGE_SIZE)
+ nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ if (alloc_size >= PAGE_SIZE)
stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
else
stride = 1;
@@ -547,7 +552,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
spin_unlock_irqrestore(&io_tlb_lock, flags);
if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
- size, io_tlb_nslabs, tmp_io_tlb_used);
+ alloc_size, io_tlb_nslabs, tmp_io_tlb_used);
return (phys_addr_t)DMA_MAPPING_ERROR;
found:
io_tlb_used += nslots;
@@ -562,7 +567,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
- swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
+ swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
return tlb_addr;
}
@@ -571,21 +576,24 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
* tlb_addr is the physical address of the bounce buffer to unmap.
*/
void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
- size_t size, enum dma_data_direction dir,
- unsigned long attrs)
+ size_t mapping_size, size_t alloc_size,
+ enum dma_data_direction dir, unsigned long attrs)
{
unsigned long flags;
- int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
phys_addr_t orig_addr = io_tlb_orig_addr[index];
+ if (WARN_ON(mapping_size > alloc_size))
+ return;
+
/*
* First, sync the memory before unmapping the entry
*/
if (orig_addr != INVALID_PHYS_ADDR &&
!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
- swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
+ swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_FROM_DEVICE);
/*
* Return the buffer to the free list by setting the corresponding
@@ -665,14 +673,14 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
/* Oh well, have to allocate and map a bounce buffer. */
*phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start),
- *phys, size, dir, attrs);
+ *phys, size, size, dir, attrs);
if (*phys == (phys_addr_t)DMA_MAPPING_ERROR)
return false;
/* Ensure that the address returned is DMA'ble */
*dma_addr = __phys_to_dma(dev, *phys);
if (unlikely(!dma_capable(dev, *dma_addr, size))) {
- swiotlb_tbl_unmap_single(dev, *phys, size, dir,
+ swiotlb_tbl_unmap_single(dev, *phys, size, size, dir,
attrs | DMA_ATTR_SKIP_CPU_SYNC);
return false;
}
--
2.17.1
This adds a helper to check whether a device needs to
use bounce buffer. It also provides a boot time option
to disable the bounce buffer. Users can use this to
prevent the iommu driver from using the bounce buffer
for performance gain.
Cc: Ashok Raj <[email protected]>
Cc: Jacob Pan <[email protected]>
Cc: Kevin Tian <[email protected]>
Signed-off-by: Lu Baolu <[email protected]>
Tested-by: Xu Pengfei <[email protected]>
Tested-by: Mika Westerberg <[email protected]>
---
Documentation/admin-guide/kernel-parameters.txt | 5 +++++
drivers/iommu/intel-iommu.c | 7 +++++++
2 files changed, 12 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 4c1971960afa..f441a9cea5bb 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1732,6 +1732,11 @@
Note that using this option lowers the security
provided by tboot because it makes the system
vulnerable to DMA attacks.
+ nobounce [Default off]
+ Disable bounce buffer for unstrusted devices such as
+ the Thunderbolt devices. This will treat the untrusted
+ devices as the trusted ones, hence might expose security
+ risks of DMA attacks.
intel_idle.max_cstate= [KNL,HW,ACPI,X86]
0 disables intel_idle and fall back on acpi_idle.
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index c4e0e4a9ee9e..e12aa73008df 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -362,6 +362,7 @@ static int dmar_forcedac;
static int intel_iommu_strict;
static int intel_iommu_superpage = 1;
static int iommu_identity_mapping;
+static int intel_no_bounce;
#define IDENTMAP_ALL 1
#define IDENTMAP_GFX 2
@@ -375,6 +376,9 @@ EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped);
static DEFINE_SPINLOCK(device_domain_lock);
static LIST_HEAD(device_domain_list);
+#define device_needs_bounce(d) (!intel_no_bounce && dev_is_pci(d) && \
+ to_pci_dev(d)->untrusted)
+
/*
* Iterate over elements in device_domain_list and call the specified
* callback @fn against each element.
@@ -457,6 +461,9 @@ static int __init intel_iommu_setup(char *str)
printk(KERN_INFO
"Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n");
intel_iommu_tboot_noforce = 1;
+ } else if (!strncmp(str, "nobounce", 8)) {
+ pr_info("Intel-IOMMU: No bounce buffer. This could expose security risks of DMA attacks\n");
+ intel_no_bounce = 1;
}
str += strcspn(str, ",");
--
2.17.1
The bounce page implementation depends on swiotlb. Hence, don't
switch off swiotlb if the system has untrusted devices or could
potentially be hot-added with any untrusted devices.
Cc: Ashok Raj <[email protected]>
Cc: Jacob Pan <[email protected]>
Cc: Kevin Tian <[email protected]>
Signed-off-by: Lu Baolu <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
---
drivers/iommu/Kconfig | 1 +
drivers/iommu/intel-iommu.c | 32 +++++++++++++++++---------------
2 files changed, 18 insertions(+), 15 deletions(-)
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index e15cdcd8cb3c..a4ddeade8ac4 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -182,6 +182,7 @@ config INTEL_IOMMU
select IOMMU_IOVA
select NEED_DMA_MAP_STATE
select DMAR_TABLE
+ select SWIOTLB
help
DMA remapping (DMAR) devices support enables independent address
translations for Direct Memory Access (DMA) from devices.
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index e12aa73008df..34e1265bb2ad 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4576,22 +4576,20 @@ const struct attribute_group *intel_iommu_groups[] = {
NULL,
};
-static int __init platform_optin_force_iommu(void)
+static inline bool has_untrusted_dev(void)
{
struct pci_dev *pdev = NULL;
- bool has_untrusted_dev = false;
- if (!dmar_platform_optin() || no_platform_optin)
- return 0;
+ for_each_pci_dev(pdev)
+ if (pdev->untrusted)
+ return true;
- for_each_pci_dev(pdev) {
- if (pdev->untrusted) {
- has_untrusted_dev = true;
- break;
- }
- }
+ return false;
+}
- if (!has_untrusted_dev)
+static int __init platform_optin_force_iommu(void)
+{
+ if (!dmar_platform_optin() || no_platform_optin || !has_untrusted_dev())
return 0;
if (no_iommu || dmar_disabled)
@@ -4605,9 +4603,6 @@ static int __init platform_optin_force_iommu(void)
iommu_identity_mapping |= IDENTMAP_ALL;
dmar_disabled = 0;
-#if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB)
- swiotlb = 0;
-#endif
no_iommu = 0;
return 1;
@@ -4747,7 +4742,14 @@ int __init intel_iommu_init(void)
up_write(&dmar_global_lock);
#if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB)
- swiotlb = 0;
+ /*
+ * If the system has no untrusted device or the user has decided
+ * to disable the bounce page mechanisms, we don't need swiotlb.
+ * Mark this and the pre-allocated bounce pages will be released
+ * later.
+ */
+ if (!has_untrusted_dev() || intel_no_bounce)
+ swiotlb = 0;
#endif
dma_ops = &intel_dma_ops;
--
2.17.1
This adds trace support for the Intel IOMMU driver. It
also declares some events which could be used to trace
the events when an IOVA is being mapped or unmapped in
a domain.
Cc: Ashok Raj <[email protected]>
Cc: Jacob Pan <[email protected]>
Cc: Kevin Tian <[email protected]>
Signed-off-by: Mika Westerberg <[email protected]>
Signed-off-by: Lu Baolu <[email protected]>
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
---
drivers/iommu/Makefile | 1 +
drivers/iommu/intel-iommu.c | 13 +++-
drivers/iommu/intel-trace.c | 14 ++++
include/trace/events/intel_iommu.h | 106 +++++++++++++++++++++++++++++
4 files changed, 131 insertions(+), 3 deletions(-)
create mode 100644 drivers/iommu/intel-trace.c
create mode 100644 include/trace/events/intel_iommu.h
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index f13f36ae1af6..bfe27b2755bd 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_ARM_SMMU) += arm-smmu.o
obj-$(CONFIG_ARM_SMMU_V3) += arm-smmu-v3.o
obj-$(CONFIG_DMAR_TABLE) += dmar.o
obj-$(CONFIG_INTEL_IOMMU) += intel-iommu.o intel-pasid.o
+obj-$(CONFIG_INTEL_IOMMU) += intel-trace.o
obj-$(CONFIG_INTEL_IOMMU_DEBUGFS) += intel-iommu-debugfs.o
obj-$(CONFIG_INTEL_IOMMU_SVM) += intel-svm.o
obj-$(CONFIG_IPMMU_VMSA) += ipmmu-vmsa.o
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 34e1265bb2ad..0720fd7b262b 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3541,6 +3541,9 @@ static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,
start_paddr = (phys_addr_t)iova_pfn << PAGE_SHIFT;
start_paddr += paddr & ~PAGE_MASK;
+
+ trace_map_single(dev, start_paddr, paddr, size << VTD_PAGE_SHIFT);
+
return start_paddr;
error:
@@ -3596,10 +3599,7 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
if (dev_is_pci(dev))
pdev = to_pci_dev(dev);
- dev_dbg(dev, "Device unmapping: pfn %lx-%lx\n", start_pfn, last_pfn);
-
freelist = domain_unmap(domain, start_pfn, last_pfn);
-
if (intel_iommu_strict || (pdev && pdev->untrusted) ||
!has_iova_flush_queue(&domain->iovad)) {
iommu_flush_iotlb_psi(iommu, domain, start_pfn,
@@ -3615,6 +3615,8 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
* cpu used up by the iotlb flush operation...
*/
}
+
+ trace_unmap_single(dev, dev_addr, size);
}
static void intel_unmap_page(struct device *dev, dma_addr_t dev_addr,
@@ -3705,6 +3707,8 @@ static void intel_unmap_sg(struct device *dev, struct scatterlist *sglist,
}
intel_unmap(dev, startaddr, nrpages << VTD_PAGE_SHIFT);
+
+ trace_unmap_sg(dev, startaddr, nrpages << VTD_PAGE_SHIFT);
}
static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nelems,
@@ -3761,6 +3765,9 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
return 0;
}
+ trace_map_sg(dev, iova_pfn << PAGE_SHIFT,
+ sg_phys(sglist), size << VTD_PAGE_SHIFT);
+
return nelems;
}
diff --git a/drivers/iommu/intel-trace.c b/drivers/iommu/intel-trace.c
new file mode 100644
index 000000000000..bfb6a6e37a88
--- /dev/null
+++ b/drivers/iommu/intel-trace.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel IOMMU trace support
+ *
+ * Copyright (C) 2019 Intel Corporation
+ *
+ * Author: Lu Baolu <[email protected]>
+ */
+
+#include <linux/string.h>
+#include <linux/types.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/intel_iommu.h>
diff --git a/include/trace/events/intel_iommu.h b/include/trace/events/intel_iommu.h
new file mode 100644
index 000000000000..54e61d456cdf
--- /dev/null
+++ b/include/trace/events/intel_iommu.h
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Intel IOMMU trace support
+ *
+ * Copyright (C) 2019 Intel Corporation
+ *
+ * Author: Lu Baolu <[email protected]>
+ */
+#ifdef CONFIG_INTEL_IOMMU
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM intel_iommu
+
+#if !defined(_TRACE_INTEL_IOMMU_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_INTEL_IOMMU_H
+
+#include <linux/tracepoint.h>
+#include <linux/intel-iommu.h>
+
+DECLARE_EVENT_CLASS(dma_map,
+ TP_PROTO(struct device *dev, dma_addr_t dev_addr, phys_addr_t phys_addr,
+ size_t size),
+
+ TP_ARGS(dev, dev_addr, phys_addr, size),
+
+ TP_STRUCT__entry(
+ __string(dev_name, dev_name(dev))
+ __field(dma_addr_t, dev_addr)
+ __field(phys_addr_t, phys_addr)
+ __field(size_t, size)
+ ),
+
+ TP_fast_assign(
+ __assign_str(dev_name, dev_name(dev));
+ __entry->dev_addr = dev_addr;
+ __entry->phys_addr = phys_addr;
+ __entry->size = size;
+ ),
+
+ TP_printk("dev=%s dev_addr=0x%llx phys_addr=0x%llx size=%zu",
+ __get_str(dev_name),
+ (unsigned long long)__entry->dev_addr,
+ (unsigned long long)__entry->phys_addr,
+ __entry->size)
+);
+
+DEFINE_EVENT(dma_map, map_single,
+ TP_PROTO(struct device *dev, dma_addr_t dev_addr, phys_addr_t phys_addr,
+ size_t size),
+ TP_ARGS(dev, dev_addr, phys_addr, size)
+);
+
+DEFINE_EVENT(dma_map, map_sg,
+ TP_PROTO(struct device *dev, dma_addr_t dev_addr, phys_addr_t phys_addr,
+ size_t size),
+ TP_ARGS(dev, dev_addr, phys_addr, size)
+);
+
+DEFINE_EVENT(dma_map, bounce_map_single,
+ TP_PROTO(struct device *dev, dma_addr_t dev_addr, phys_addr_t phys_addr,
+ size_t size),
+ TP_ARGS(dev, dev_addr, phys_addr, size)
+);
+
+DECLARE_EVENT_CLASS(dma_unmap,
+ TP_PROTO(struct device *dev, dma_addr_t dev_addr, size_t size),
+
+ TP_ARGS(dev, dev_addr, size),
+
+ TP_STRUCT__entry(
+ __string(dev_name, dev_name(dev))
+ __field(dma_addr_t, dev_addr)
+ __field(size_t, size)
+ ),
+
+ TP_fast_assign(
+ __assign_str(dev_name, dev_name(dev));
+ __entry->dev_addr = dev_addr;
+ __entry->size = size;
+ ),
+
+ TP_printk("dev=%s dev_addr=0x%llx size=%zu",
+ __get_str(dev_name),
+ (unsigned long long)__entry->dev_addr,
+ __entry->size)
+);
+
+DEFINE_EVENT(dma_unmap, unmap_single,
+ TP_PROTO(struct device *dev, dma_addr_t dev_addr, size_t size),
+ TP_ARGS(dev, dev_addr, size)
+);
+
+DEFINE_EVENT(dma_unmap, unmap_sg,
+ TP_PROTO(struct device *dev, dma_addr_t dev_addr, size_t size),
+ TP_ARGS(dev, dev_addr, size)
+);
+
+DEFINE_EVENT(dma_unmap, bounce_unmap_single,
+ TP_PROTO(struct device *dev, dma_addr_t dev_addr, size_t size),
+ TP_ARGS(dev, dev_addr, size)
+);
+
+#endif /* _TRACE_INTEL_IOMMU_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
+#endif /* CONFIG_INTEL_IOMMU */
--
2.17.1
The Intel VT-d hardware uses paging for DMA remapping.
The minimum mapped window is a page size. The device
drivers may map buffers not filling the whole IOMMU
window. This allows the device to access to possibly
unrelated memory and a malicious device could exploit
this to perform DMA attacks. To address this, the
Intel IOMMU driver will use bounce pages for those
buffers which don't fill whole IOMMU pages.
Cc: Ashok Raj <[email protected]>
Cc: Jacob Pan <[email protected]>
Cc: Kevin Tian <[email protected]>
Signed-off-by: Lu Baolu <[email protected]>
Tested-by: Xu Pengfei <[email protected]>
Tested-by: Mika Westerberg <[email protected]>
---
drivers/iommu/intel-iommu.c | 258 ++++++++++++++++++++++++++++++++++++
1 file changed, 258 insertions(+)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0720fd7b262b..c6935172df81 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -41,9 +41,11 @@
#include <linux/dma-direct.h>
#include <linux/crash_dump.h>
#include <linux/numa.h>
+#include <linux/swiotlb.h>
#include <asm/irq_remapping.h>
#include <asm/cacheflush.h>
#include <asm/iommu.h>
+#include <trace/events/intel_iommu.h>
#include "irq_remapping.h"
#include "intel-pasid.h"
@@ -346,6 +348,8 @@ static int domain_detach_iommu(struct dmar_domain *domain,
static bool device_is_rmrr_locked(struct device *dev);
static int intel_iommu_attach_device(struct iommu_domain *domain,
struct device *dev);
+static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
+ dma_addr_t iova);
#ifdef CONFIG_INTEL_IOMMU_DEFAULT_ON
int dmar_disabled = 0;
@@ -3783,6 +3787,252 @@ static const struct dma_map_ops intel_dma_ops = {
.dma_supported = dma_direct_supported,
};
+static void
+bounce_sync_single(struct device *dev, dma_addr_t addr, size_t size,
+ enum dma_data_direction dir, enum dma_sync_target target)
+{
+ struct dmar_domain *domain;
+ phys_addr_t tlb_addr;
+
+ domain = find_domain(dev);
+ if (WARN_ON(!domain))
+ return;
+
+ tlb_addr = intel_iommu_iova_to_phys(&domain->domain, addr);
+ if (is_swiotlb_buffer(tlb_addr))
+ swiotlb_tbl_sync_single(dev, tlb_addr, size, dir, target);
+}
+
+static dma_addr_t
+bounce_map_single(struct device *dev, phys_addr_t paddr, size_t size,
+ enum dma_data_direction dir, unsigned long attrs,
+ u64 dma_mask)
+{
+ size_t aligned_size = ALIGN(size, VTD_PAGE_SIZE);
+ struct dmar_domain *domain;
+ struct intel_iommu *iommu;
+ unsigned long iova_pfn;
+ unsigned long nrpages;
+ phys_addr_t tlb_addr;
+ int prot = 0;
+ int ret;
+
+ domain = find_domain(dev);
+ if (WARN_ON(dir == DMA_NONE || !domain))
+ return DMA_MAPPING_ERROR;
+
+ iommu = domain_get_iommu(domain);
+ if (WARN_ON(!iommu))
+ return DMA_MAPPING_ERROR;
+
+ nrpages = aligned_nrpages(0, size);
+ iova_pfn = intel_alloc_iova(dev, domain,
+ dma_to_mm_pfn(nrpages), dma_mask);
+ if (!iova_pfn)
+ return DMA_MAPPING_ERROR;
+
+ /*
+ * Check if DMAR supports zero-length reads on write only
+ * mappings..
+ */
+ if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL ||
+ !cap_zlr(iommu->cap))
+ prot |= DMA_PTE_READ;
+ if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)
+ prot |= DMA_PTE_WRITE;
+
+ /*
+ * If both the physical buffer start address and size are
+ * page aligned, we don't need to use a bounce page.
+ */
+ if (!IS_ALIGNED(paddr | size, VTD_PAGE_SIZE)) {
+ tlb_addr = swiotlb_tbl_map_single(dev,
+ __phys_to_dma(dev, io_tlb_start),
+ paddr, size, aligned_size, dir, attrs);
+ if (tlb_addr == DMA_MAPPING_ERROR) {
+ goto swiotlb_error;
+ } else {
+ /* Cleanup the padding area. */
+ void *padding_start = phys_to_virt(tlb_addr);
+ size_t padding_size = aligned_size;
+
+ if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+ (dir == DMA_TO_DEVICE ||
+ dir == DMA_BIDIRECTIONAL)) {
+ padding_start += size;
+ padding_size -= size;
+ }
+
+ memset(padding_start, 0, padding_size);
+ }
+ } else {
+ tlb_addr = paddr;
+ }
+
+ ret = domain_pfn_mapping(domain, mm_to_dma_pfn(iova_pfn),
+ tlb_addr >> VTD_PAGE_SHIFT, nrpages, prot);
+ if (ret)
+ goto mapping_error;
+
+ trace_bounce_map_single(dev, iova_pfn << PAGE_SHIFT, paddr, size);
+
+ return (phys_addr_t)iova_pfn << PAGE_SHIFT;
+
+mapping_error:
+ if (is_swiotlb_buffer(tlb_addr))
+ swiotlb_tbl_unmap_single(dev, tlb_addr, size,
+ aligned_size, dir, attrs);
+swiotlb_error:
+ free_iova_fast(&domain->iovad, iova_pfn, dma_to_mm_pfn(nrpages));
+ dev_err(dev, "Device bounce map: %zx@%llx dir %d --- failed\n",
+ size, (unsigned long long)paddr, dir);
+
+ return DMA_MAPPING_ERROR;
+}
+
+static void
+bounce_unmap_single(struct device *dev, dma_addr_t dev_addr, size_t size,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ size_t aligned_size = ALIGN(size, VTD_PAGE_SIZE);
+ struct dmar_domain *domain;
+ phys_addr_t tlb_addr;
+
+ domain = find_domain(dev);
+ if (WARN_ON(!domain))
+ return;
+
+ tlb_addr = intel_iommu_iova_to_phys(&domain->domain, dev_addr);
+ if (WARN_ON(!tlb_addr))
+ return;
+
+ intel_unmap(dev, dev_addr, size);
+ if (is_swiotlb_buffer(tlb_addr))
+ swiotlb_tbl_unmap_single(dev, tlb_addr, size,
+ aligned_size, dir, attrs);
+
+ trace_bounce_unmap_single(dev, dev_addr, size);
+}
+
+static dma_addr_t
+bounce_map_page(struct device *dev, struct page *page, unsigned long offset,
+ size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+ return bounce_map_single(dev, page_to_phys(page) + offset,
+ size, dir, attrs, *dev->dma_mask);
+}
+
+static dma_addr_t
+bounce_map_resource(struct device *dev, phys_addr_t phys_addr, size_t size,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ return bounce_map_single(dev, phys_addr, size,
+ dir, attrs, *dev->dma_mask);
+}
+
+static void
+bounce_unmap_page(struct device *dev, dma_addr_t dev_addr, size_t size,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ bounce_unmap_single(dev, dev_addr, size, dir, attrs);
+}
+
+static void
+bounce_unmap_resource(struct device *dev, dma_addr_t dev_addr, size_t size,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ bounce_unmap_single(dev, dev_addr, size, dir, attrs);
+}
+
+static void
+bounce_unmap_sg(struct device *dev, struct scatterlist *sglist, int nelems,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(sglist, sg, nelems, i)
+ bounce_unmap_page(dev, sg->dma_address,
+ sg_dma_len(sg), dir, attrs);
+}
+
+static int
+bounce_map_sg(struct device *dev, struct scatterlist *sglist, int nelems,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ int i;
+ struct scatterlist *sg;
+
+ for_each_sg(sglist, sg, nelems, i) {
+ sg->dma_address = bounce_map_page(dev, sg_page(sg),
+ sg->offset, sg->length,
+ dir, attrs);
+ if (sg->dma_address == DMA_MAPPING_ERROR)
+ goto out_unmap;
+ sg_dma_len(sg) = sg->length;
+ }
+
+ return nelems;
+
+out_unmap:
+ bounce_unmap_sg(dev, sglist, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
+ return 0;
+}
+
+static void
+bounce_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
+ size_t size, enum dma_data_direction dir)
+{
+ bounce_sync_single(dev, addr, size, dir, SYNC_FOR_CPU);
+}
+
+static void
+bounce_sync_single_for_device(struct device *dev, dma_addr_t addr,
+ size_t size, enum dma_data_direction dir)
+{
+ bounce_sync_single(dev, addr, size, dir, SYNC_FOR_DEVICE);
+}
+
+static void
+bounce_sync_sg_for_cpu(struct device *dev, struct scatterlist *sglist,
+ int nelems, enum dma_data_direction dir)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(sglist, sg, nelems, i)
+ bounce_sync_single(dev, sg_dma_address(sg),
+ sg_dma_len(sg), dir, SYNC_FOR_CPU);
+}
+
+static void
+bounce_sync_sg_for_device(struct device *dev, struct scatterlist *sglist,
+ int nelems, enum dma_data_direction dir)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(sglist, sg, nelems, i)
+ bounce_sync_single(dev, sg_dma_address(sg),
+ sg_dma_len(sg), dir, SYNC_FOR_DEVICE);
+}
+
+static const struct dma_map_ops bounce_dma_ops = {
+ .alloc = intel_alloc_coherent,
+ .free = intel_free_coherent,
+ .map_sg = bounce_map_sg,
+ .unmap_sg = bounce_unmap_sg,
+ .map_page = bounce_map_page,
+ .unmap_page = bounce_unmap_page,
+ .sync_single_for_cpu = bounce_sync_single_for_cpu,
+ .sync_single_for_device = bounce_sync_single_for_device,
+ .sync_sg_for_cpu = bounce_sync_sg_for_cpu,
+ .sync_sg_for_device = bounce_sync_sg_for_device,
+ .map_resource = bounce_map_resource,
+ .unmap_resource = bounce_unmap_resource,
+ .dma_supported = dma_direct_supported,
+};
+
static inline int iommu_domain_cache_init(void)
{
int ret = 0;
@@ -5376,6 +5626,11 @@ static int intel_iommu_add_device(struct device *dev)
}
}
+ if (device_needs_bounce(dev)) {
+ dev_info(dev, "Use Intel IOMMU bounce page dma_ops\n");
+ set_dma_ops(dev, &bounce_dma_ops);
+ }
+
return 0;
}
@@ -5393,6 +5648,9 @@ static void intel_iommu_remove_device(struct device *dev)
iommu_group_remove_device(dev);
iommu_device_unlink(&iommu->iommu, dev);
+
+ if (device_needs_bounce(dev))
+ set_dma_ops(dev, NULL);
}
static void intel_iommu_get_resv_regions(struct device *device,
--
2.17.1
On Tue, Sep 10, 2019 at 04:53:23PM +0200, Joerg Roedel wrote:
> On Fri, Sep 06, 2019 at 02:14:47PM +0800, Lu Baolu wrote:
> > Lu Baolu (5):
> > swiotlb: Split size parameter to map/unmap APIs
> > iommu/vt-d: Check whether device requires bounce buffer
> > iommu/vt-d: Don't switch off swiotlb if bounce page is used
> > iommu/vt-d: Add trace events for device dma map/unmap
> > iommu/vt-d: Use bounce buffer for untrusted devices
> >
> > .../admin-guide/kernel-parameters.txt | 5 +
> > drivers/iommu/Kconfig | 1 +
> > drivers/iommu/Makefile | 1 +
> > drivers/iommu/intel-iommu.c | 310 +++++++++++++++++-
> > drivers/iommu/intel-trace.c | 14 +
> > drivers/xen/swiotlb-xen.c | 8 +-
> > include/linux/swiotlb.h | 8 +-
> > include/trace/events/intel_iommu.h | 106 ++++++
> > kernel/dma/direct.c | 2 +-
> > kernel/dma/swiotlb.c | 30 +-
> > 10 files changed, 449 insertions(+), 36 deletions(-)
> > create mode 100644 drivers/iommu/intel-trace.c
> > create mode 100644 include/trace/events/intel_iommu.h
>
> Applied, thanks.
Please un-apply the swiotlb until the WARN_ON gets fixed. Or alternatively
squash the fix once that is done.
On Fri, Sep 06, 2019 at 02:14:47PM +0800, Lu Baolu wrote:
> Lu Baolu (5):
> swiotlb: Split size parameter to map/unmap APIs
> iommu/vt-d: Check whether device requires bounce buffer
> iommu/vt-d: Don't switch off swiotlb if bounce page is used
> iommu/vt-d: Add trace events for device dma map/unmap
> iommu/vt-d: Use bounce buffer for untrusted devices
>
> .../admin-guide/kernel-parameters.txt | 5 +
> drivers/iommu/Kconfig | 1 +
> drivers/iommu/Makefile | 1 +
> drivers/iommu/intel-iommu.c | 310 +++++++++++++++++-
> drivers/iommu/intel-trace.c | 14 +
> drivers/xen/swiotlb-xen.c | 8 +-
> include/linux/swiotlb.h | 8 +-
> include/trace/events/intel_iommu.h | 106 ++++++
> kernel/dma/direct.c | 2 +-
> kernel/dma/swiotlb.c | 30 +-
> 10 files changed, 449 insertions(+), 36 deletions(-)
> create mode 100644 drivers/iommu/intel-trace.c
> create mode 100644 include/trace/events/intel_iommu.h
Applied, thanks.
On Fri, Sep 06, 2019 at 02:14:48PM +0800, Lu Baolu wrote:
> This splits the size parameter to swiotlb_tbl_map_single() and
> swiotlb_tbl_unmap_single() into an alloc_size and a mapping_size
> parameter, where the latter one is rounded up to the iommu page
> size.
It does a bit more too. You have the WARN_ON. Can you make it be
more verbose (as in details of which device requested it) and also use printk_once or so please?
>
> Suggested-by: Christoph Hellwig <[email protected]>
> Signed-off-by: Lu Baolu <[email protected]>
> Reviewed-by: Christoph Hellwig <[email protected]>
> ---
> drivers/xen/swiotlb-xen.c | 8 ++++----
> include/linux/swiotlb.h | 8 ++++++--
> kernel/dma/direct.c | 2 +-
> kernel/dma/swiotlb.c | 30 +++++++++++++++++++-----------
> 4 files changed, 30 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index ae1df496bf38..adcabd9473eb 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -386,8 +386,8 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
> */
> trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
>
> - map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
> - attrs);
> + map = swiotlb_tbl_map_single(dev, start_dma_addr, phys,
> + size, size, dir, attrs);
> if (map == (phys_addr_t)DMA_MAPPING_ERROR)
> return DMA_MAPPING_ERROR;
>
> @@ -397,7 +397,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
> * Ensure that the address returned is DMA'ble
> */
> if (unlikely(!dma_capable(dev, dev_addr, size))) {
> - swiotlb_tbl_unmap_single(dev, map, size, dir,
> + swiotlb_tbl_unmap_single(dev, map, size, size, dir,
> attrs | DMA_ATTR_SKIP_CPU_SYNC);
> return DMA_MAPPING_ERROR;
> }
> @@ -433,7 +433,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
>
> /* NOTE: We use dev_addr here, not paddr! */
> if (is_xen_swiotlb_buffer(dev_addr))
> - swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
> + swiotlb_tbl_unmap_single(hwdev, paddr, size, size, dir, attrs);
> }
>
> static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index 361f62bb4a8e..cde3dc18e21a 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -46,13 +46,17 @@ enum dma_sync_target {
>
> extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
> dma_addr_t tbl_dma_addr,
> - phys_addr_t phys, size_t size,
> + phys_addr_t phys,
> + size_t mapping_size,
> + size_t alloc_size,
> enum dma_data_direction dir,
> unsigned long attrs);
>
> extern void swiotlb_tbl_unmap_single(struct device *hwdev,
> phys_addr_t tlb_addr,
> - size_t size, enum dma_data_direction dir,
> + size_t mapping_size,
> + size_t alloc_size,
> + enum dma_data_direction dir,
> unsigned long attrs);
>
> extern void swiotlb_tbl_sync_single(struct device *hwdev,
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 706113c6bebc..8402b29c280f 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -305,7 +305,7 @@ void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
> dma_direct_sync_single_for_cpu(dev, addr, size, dir);
>
> if (unlikely(is_swiotlb_buffer(phys)))
> - swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs);
> + swiotlb_tbl_unmap_single(dev, phys, size, size, dir, attrs);
> }
> EXPORT_SYMBOL(dma_direct_unmap_page);
>
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 9de232229063..89066efa3840 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -444,7 +444,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
>
> phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
> dma_addr_t tbl_dma_addr,
> - phys_addr_t orig_addr, size_t size,
> + phys_addr_t orig_addr,
> + size_t mapping_size,
> + size_t alloc_size,
> enum dma_data_direction dir,
> unsigned long attrs)
> {
> @@ -464,6 +466,9 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
> pr_warn_once("%s is active and system is using DMA bounce buffers\n",
> sme_active() ? "SME" : "SEV");
>
> + if (WARN_ON(mapping_size > alloc_size))
> + return (phys_addr_t)DMA_MAPPING_ERROR;
> +
> mask = dma_get_seg_boundary(hwdev);
>
> tbl_dma_addr &= mask;
> @@ -481,8 +486,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
> * For mappings greater than or equal to a page, we limit the stride
> * (and hence alignment) to a page size.
> */
> - nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
> - if (size >= PAGE_SIZE)
> + nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
> + if (alloc_size >= PAGE_SIZE)
> stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
> else
> stride = 1;
> @@ -547,7 +552,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
> spin_unlock_irqrestore(&io_tlb_lock, flags);
> if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
> dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
> - size, io_tlb_nslabs, tmp_io_tlb_used);
> + alloc_size, io_tlb_nslabs, tmp_io_tlb_used);
> return (phys_addr_t)DMA_MAPPING_ERROR;
> found:
> io_tlb_used += nslots;
> @@ -562,7 +567,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
> io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
> if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
> (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
> - swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
> + swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
>
> return tlb_addr;
> }
> @@ -571,21 +576,24 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
> * tlb_addr is the physical address of the bounce buffer to unmap.
> */
> void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
> - size_t size, enum dma_data_direction dir,
> - unsigned long attrs)
> + size_t mapping_size, size_t alloc_size,
> + enum dma_data_direction dir, unsigned long attrs)
> {
> unsigned long flags;
> - int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
> + int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
> int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
> phys_addr_t orig_addr = io_tlb_orig_addr[index];
>
> + if (WARN_ON(mapping_size > alloc_size))
> + return;
> +
> /*
> * First, sync the memory before unmapping the entry
> */
> if (orig_addr != INVALID_PHYS_ADDR &&
> !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
> ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
> - swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
> + swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_FROM_DEVICE);
>
> /*
> * Return the buffer to the free list by setting the corresponding
> @@ -665,14 +673,14 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
>
> /* Oh well, have to allocate and map a bounce buffer. */
> *phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start),
> - *phys, size, dir, attrs);
> + *phys, size, size, dir, attrs);
> if (*phys == (phys_addr_t)DMA_MAPPING_ERROR)
> return false;
>
> /* Ensure that the address returned is DMA'ble */
> *dma_addr = __phys_to_dma(dev, *phys);
> if (unlikely(!dma_capable(dev, *dma_addr, size))) {
> - swiotlb_tbl_unmap_single(dev, *phys, size, dir,
> + swiotlb_tbl_unmap_single(dev, *phys, size, size, dir,
> attrs | DMA_ATTR_SKIP_CPU_SYNC);
> return false;
> }
> --
> 2.17.1
>
Hi,
On 9/10/19 11:15 PM, Konrad Rzeszutek Wilk wrote:
> On Fri, Sep 06, 2019 at 02:14:48PM +0800, Lu Baolu wrote:
>> This splits the size parameter to swiotlb_tbl_map_single() and
>> swiotlb_tbl_unmap_single() into an alloc_size and a mapping_size
>> parameter, where the latter one is rounded up to the iommu page
>> size.
> It does a bit more too. You have the WARN_ON. Can you make it be
> more verbose (as in details of which device requested it) and also use printk_once or so please?
How about this change?
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 89066efa3840..22a7848caca3 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -466,8 +466,11 @@ phys_addr_t swiotlb_tbl_map_single(struct device
*hwdev,
pr_warn_once("%s is active and system is using DMA
bounce buffers\n",
sme_active() ? "SME" : "SEV");
- if (WARN_ON(mapping_size > alloc_size))
+ if (mapping_size > alloc_size) {
+ dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes,
alloc: %zd bytes)",
+ mapping_size, alloc_size);
return (phys_addr_t)DMA_MAPPING_ERROR;
+ }
mask = dma_get_seg_boundary(hwdev);
@@ -584,9 +587,6 @@ void swiotlb_tbl_unmap_single(struct device *hwdev,
phys_addr_t tlb_addr,
int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
phys_addr_t orig_addr = io_tlb_orig_addr[index];
- if (WARN_ON(mapping_size > alloc_size))
- return;
-
/*
* First, sync the memory before unmapping the entry
*/
Best regards,
Baolu
On Wed, Sep 11, 2019 at 02:16:07PM +0800, Lu Baolu wrote:
> How about this change?
>
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 89066efa3840..22a7848caca3 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -466,8 +466,11 @@ phys_addr_t swiotlb_tbl_map_single(struct device
> *hwdev,
> pr_warn_once("%s is active and system is using DMA bounce
> buffers\n",
> sme_active() ? "SME" : "SEV");
>
> - if (WARN_ON(mapping_size > alloc_size))
> + if (mapping_size > alloc_size) {
> + dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes,
> alloc: %zd bytes)",
> + mapping_size, alloc_size);
> return (phys_addr_t)DMA_MAPPING_ERROR;
> + }
>
> mask = dma_get_seg_boundary(hwdev);
>
> @@ -584,9 +587,6 @@ void swiotlb_tbl_unmap_single(struct device *hwdev,
> phys_addr_t tlb_addr,
> int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
> phys_addr_t orig_addr = io_tlb_orig_addr[index];
>
> - if (WARN_ON(mapping_size > alloc_size))
> - return;
> -
> /*
> * First, sync the memory before unmapping the entry
> */
Folded that into the commit, thanks Lu Baolu.