Hi all,
this patch series enables xen-swiotlb on arm and arm64.
Considering that all guests, including dom0, run on xen on arm with
second stage translation enabled, it follows that without an IOMMU no
guests could actually drive the hardware.
The solution for platforms without an IOMMU is to use swiotlb-xen,
adapted to autotranslate guests. swiotlb-xen provides a set of dma_ops
that can be used by Linux to setup a contiguous buffer in stage-2
addresses and use it for dma operations.
Basically Linux asks Xen to make a buffer contiguous and gets the
machine address for it. This buffer is going to be used by lib/swiotlb.c
to allocate bounce buffers.
The first 3 patches lay the groundwork on arm and arm64 to have
alternative dma_ops and swiotlb.
The forth patch moves Xen initialization earlier so that we already know
whether we are running on Xen at the time of initializing dma_ops on the
platform.
The following patches adapt swiotlb-xen to autotranslate guests (guest
with second stage translation in hardware) and provide an arm
implementation of xen_create_contiguous_region.
Feedback is very welcome.
Cheers,
Stefano
Changes in v2:
- fixed a couple of errors in xen_bus_to_phys, xen_phys_to_bus and
xen_swiotlb_fixup.
Stefano Stabellini (8):
arm: make SWIOTLB available
arm: introduce a global dma_ops pointer
arm64: do not initialize arm64_swiotlb if dma_ops is already set
xen/arm,arm64: move Xen initialization earlier
xen: introduce XENMEM_get_dma_buf and xen_put_dma_buf
xen: make xen_create_contiguous_region return the dma address
swiotlb-xen: support autotranslate guests
xen/arm,arm64: enable SWIOTLB_XEN
arch/arm/Kconfig | 8 ++
arch/arm/common/dmabounce.c | 10 +-
arch/arm/include/asm/dma-mapping.h | 27 ++++++-
arch/arm/include/asm/xen/hypervisor.h | 6 ++
arch/arm/include/asm/xen/page.h | 2 +
arch/arm/kernel/setup.c | 2 +
arch/arm/mm/dma-mapping.c | 3 +
arch/arm/xen/Makefile | 2 +-
arch/arm/xen/enlighten.c | 24 ++++--
arch/arm/xen/mm.c | 117 ++++++++++++++++++++++++++
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/setup.c | 2 +
arch/arm64/mm/dma-mapping.c | 2 +
arch/arm64/xen/Makefile | 2 +-
arch/x86/xen/mmu.c | 4 +-
drivers/xen/Kconfig | 1 -
drivers/xen/swiotlb-xen.c | 147 +++++++++++++++++++++++++++++----
include/xen/interface/memory.h | 62 ++++++++++++++
include/xen/xen-ops.h | 3 +-
19 files changed, 390 insertions(+), 35 deletions(-)
create mode 100644 arch/arm/xen/mm.c
git://git.kernel.org/pub/scm/linux/kernel/git/sstabellini/xen.git swiotlb-xen-2
Signed-off-by: Stefano Stabellini <[email protected]>
CC: [email protected]
CC: [email protected]
---
arch/arm/Kconfig | 7 +++++++
arch/arm/include/asm/dma-mapping.h | 24 ++++++++++++++++++++++++
2 files changed, 31 insertions(+), 0 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ba412e0..05125ab 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1832,6 +1832,13 @@ config CC_STACKPROTECTOR
neutralized via a kernel panic.
This feature requires gcc version 4.2 or above.
+config SWIOTLB
+ def_bool y
+ select NEED_SG_DMA_LENGTH
+
+config IOMMU_HELPER
+ def_bool SWIOTLB
+
config XEN_DOM0
def_bool y
depends on XEN
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 5b579b9..ad89e0f 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -86,6 +86,30 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
}
#endif
+static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
+{
+ unsigned int offset = paddr & ~PAGE_MASK;
+ return pfn_to_dma(dev, paddr >> PAGE_SHIFT) + offset;
+}
+
+static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
+{
+ unsigned int offset = dev_addr & ~PAGE_MASK;
+ return (dma_to_pfn(dev, dev_addr) << PAGE_SHIFT) + offset;
+}
+
+static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
+{
+ if (!dev->dma_mask)
+ return 0;
+
+ return addr + size - 1 <= *dev->dma_mask;
+}
+
+static inline void dma_mark_clean(void *addr, size_t size)
+{
+}
+
/*
* DMA errors are defined by all-bits-set in the DMA address.
*/
--
1.7.2.5
Signed-off-by: Stefano Stabellini <[email protected]>
---
include/xen/interface/memory.h | 62 ++++++++++++++++++++++++++++++++++++++++
1 files changed, 62 insertions(+), 0 deletions(-)
diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
index 2ecfe4f..ffd7f4e 100644
--- a/include/xen/interface/memory.h
+++ b/include/xen/interface/memory.h
@@ -263,4 +263,66 @@ struct xen_remove_from_physmap {
};
DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap);
+#define XENMEM_get_dma_buf 26
+/*
+ * This hypercall is similar to XENMEM_exchange: it exchanges the pages
+ * passed in with a new set of pages, contiguous and under 4G if so
+ * requested. The new pages are going to be "pinned": it's guaranteed
+ * that their p2m mapping won't be changed until explicitly "unpinned".
+ * If return code is zero then @out.extent_list provides the MFNs of the
+ * newly-allocated memory. Returns zero on complete success, otherwise
+ * a negative error code.
+ * On complete success then always @nr_exchanged == @in.nr_extents. On
+ * partial success @nr_exchanged indicates how much work was done.
+ */
+struct xen_get_dma_buf {
+ /*
+ * [IN] Details of memory extents to be exchanged (GMFN bases).
+ * Note that @in.address_bits is ignored and unused.
+ */
+ struct xen_memory_reservation in;
+
+ /*
+ * [IN/OUT] Details of new memory extents.
+ * We require that:
+ * 1. @in.domid == @out.domid
+ * 2. @in.nr_extents << @in.extent_order ==
+ * @out.nr_extents << @out.extent_order
+ * 3. @in.extent_start and @out.extent_start lists must not overlap
+ * 4. @out.extent_start lists GPFN bases to be populated
+ * 5. @out.extent_start is overwritten with allocated GMFN bases
+ */
+ struct xen_memory_reservation out;
+
+ /*
+ * [OUT] Number of input extents that were successfully exchanged:
+ * 1. The first @nr_exchanged input extents were successfully
+ * deallocated.
+ * 2. The corresponding first entries in the output extent list correctly
+ * indicate the GMFNs that were successfully exchanged.
+ * 3. All other input and output extents are untouched.
+ * 4. If not all input exents are exchanged then the return code of this
+ * command will be non-zero.
+ * 5. THIS FIELD MUST BE INITIALISED TO ZERO BY THE CALLER!
+ */
+ xen_ulong_t nr_exchanged;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_get_dma_buf);
+
+#define XENMEM_put_dma_buf 27
+/*
+ * XENMEM_put_dma_buf unpins a set of pages, previously pinned by
+ * XENMEM_get_dma_buf. After this call the p2m mapping of the pages can
+ * be transparently changed by the hypervisor, as usual. The pages are
+ * still accessible from the guest.
+ */
+struct xen_put_dma_buf {
+ /*
+ * [IN] Details of memory extents to be exchanged (GMFN bases).
+ * Note that @in.address_bits is ignored and unused.
+ */
+ struct xen_memory_reservation in;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_put_dma_buf);
+
#endif /* __XEN_PUBLIC_MEMORY_H__ */
--
1.7.2.5
Xen on arm and arm64 needs SWIOTLB_XEN: when running on Xen we need to
program the hardware with mfns rather than pfns for dma addresses.
Remove SWIOTLB_XEN dependency on X86 and PCI and make XEN select
SWIOTLB_XEN on arm and arm64.
Implement xen_create_contiguous_region on arm and arm64 by using
XENMEM_get_dma_buf.
Initialize the xen-swiotlb from xen_early_init (before the native
dma_ops are initialized), set dma_ops to &xen_swiotlb_dma_ops if we are
running on Xen.
Signed-off-by: Stefano Stabellini <[email protected]>
---
arch/arm/Kconfig | 1 +
arch/arm/include/asm/xen/page.h | 2 +
arch/arm/xen/Makefile | 2 +-
arch/arm/xen/enlighten.c | 3 +
arch/arm/xen/mm.c | 117 +++++++++++++++++++++++++++++++++++++++
arch/arm64/Kconfig | 1 +
arch/arm64/xen/Makefile | 2 +-
drivers/xen/Kconfig | 1 -
drivers/xen/swiotlb-xen.c | 18 ++++++
9 files changed, 144 insertions(+), 3 deletions(-)
create mode 100644 arch/arm/xen/mm.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 05125ab..72b53b9 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1849,6 +1849,7 @@ config XEN
depends on CPU_V7 && !CPU_V6
depends on !GENERIC_ATOMIC64
select ARM_PSCI
+ select SWIOTLB_XEN
help
Say Y if you want to run Linux in a Virtual Machine on Xen on ARM.
diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
index 359a7b5..b0f7150 100644
--- a/arch/arm/include/asm/xen/page.h
+++ b/arch/arm/include/asm/xen/page.h
@@ -6,12 +6,14 @@
#include <linux/pfn.h>
#include <linux/types.h>
+#include <linux/dma-mapping.h>
#include <xen/interface/grant_table.h>
#define pfn_to_mfn(pfn) (pfn)
#define phys_to_machine_mapping_valid(pfn) (1)
#define mfn_to_pfn(mfn) (mfn)
+#define mfn_to_local_pfn(m) (mfn_to_pfn(m))
#define mfn_to_virt(m) (__va(mfn_to_pfn(m) << PAGE_SHIFT))
#define pte_mfn pte_pfn
diff --git a/arch/arm/xen/Makefile b/arch/arm/xen/Makefile
index 4384103..66fc35d 100644
--- a/arch/arm/xen/Makefile
+++ b/arch/arm/xen/Makefile
@@ -1 +1 @@
-obj-y := enlighten.o hypercall.o grant-table.o
+obj-y := enlighten.o hypercall.o grant-table.o mm.o
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 14d17ab..06a6953 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -195,6 +195,7 @@ static void xen_power_off(void)
* documentation of the Xen Device Tree format.
*/
#define GRANT_TABLE_PHYSADDR 0
+extern int xen_mm_init(void);
void __init xen_early_init(void)
{
struct resource res;
@@ -230,6 +231,8 @@ void __init xen_early_init(void)
xen_start_info->flags |= SIF_INITDOMAIN|SIF_PRIVILEGED;
else
xen_start_info->flags &= ~(SIF_INITDOMAIN|SIF_PRIVILEGED);
+
+ xen_mm_init();
}
static int __init xen_guest_init(void)
diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
new file mode 100644
index 0000000..22dbf7c
--- /dev/null
+++ b/arch/arm/xen/mm.c
@@ -0,0 +1,117 @@
+#include <linux/bootmem.h>
+#include <linux/gfp.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/dma-mapping.h>
+#include <linux/vmalloc.h>
+#include <linux/swiotlb.h>
+
+#include <xen/xen.h>
+#include <xen/interface/memory.h>
+#include <xen/swiotlb-xen.h>
+
+#include <asm/cacheflush.h>
+#include <asm/xen/page.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/interface.h>
+
+static int xen_exchange_memory(xen_ulong_t extents_in,
+ unsigned int order_in,
+ xen_pfn_t *pfns_in,
+ xen_ulong_t extents_out,
+ unsigned int order_out,
+ xen_pfn_t *mfns_out,
+ unsigned int address_bits)
+{
+ long rc;
+ int success;
+
+ struct xen_memory_exchange exchange = {
+ .in = {
+ .nr_extents = extents_in,
+ .extent_order = order_in,
+ .domid = DOMID_SELF
+ },
+ .out = {
+ .nr_extents = extents_out,
+ .extent_order = order_out,
+ .address_bits = address_bits,
+ .domid = DOMID_SELF
+ }
+ };
+ set_xen_guest_handle(exchange.in.extent_start, pfns_in);
+ set_xen_guest_handle(exchange.out.extent_start, mfns_out);
+
+ BUG_ON(extents_in << order_in != extents_out << order_out);
+
+
+ rc = HYPERVISOR_memory_op(XENMEM_get_dma_buf, &exchange);
+ success = (exchange.nr_exchanged == extents_in);
+
+ BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
+ BUG_ON(success && (rc != 0));
+
+ return success;
+}
+
+int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
+ unsigned int address_bits,
+ dma_addr_t *dma_handle)
+{
+ phys_addr_t pstart = __pa(vstart);
+ xen_pfn_t in_frame, out_frame;
+ int success;
+
+ /* 2. Get a new contiguous memory extent. */
+ in_frame = out_frame = pstart >> PAGE_SHIFT;
+ success = xen_exchange_memory(1, order, &in_frame,
+ 1, order, &out_frame,
+ address_bits);
+
+ if (!success)
+ return -ENOMEM;
+
+ *dma_handle = out_frame << PAGE_SHIFT;
+
+ return success ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
+
+void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
+{
+ xen_pfn_t in_frame = __pa(vstart) >> PAGE_SHIFT;
+ struct xen_put_dma_buf buf = {
+ .in = {
+ .nr_extents = 1,
+ .extent_order = order,
+ .domid = DOMID_SELF
+ },
+ };
+ set_xen_guest_handle(buf.in.extent_start, &in_frame);
+
+ HYPERVISOR_memory_op(XENMEM_put_dma_buf, &buf);
+}
+EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
+
+static struct dma_map_ops xen_swiotlb_dma_ops = {
+ .mapping_error = xen_swiotlb_dma_mapping_error,
+ .alloc = xen_swiotlb_alloc_coherent,
+ .free = xen_swiotlb_free_coherent,
+ .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
+ .sync_single_for_device = xen_swiotlb_sync_single_for_device,
+ .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
+ .sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
+ .map_sg = xen_swiotlb_map_sg_attrs,
+ .unmap_sg = xen_swiotlb_unmap_sg_attrs,
+ .map_page = xen_swiotlb_map_page,
+ .unmap_page = xen_swiotlb_unmap_page,
+ .dma_supported = xen_swiotlb_dma_supported,
+};
+
+int __init xen_mm_init(void)
+{
+ xen_swiotlb_init(1, true);
+ dma_ops = &xen_swiotlb_dma_ops;
+ return 0;
+}
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9737e97..aa1f6fb 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -209,6 +209,7 @@ config XEN_DOM0
config XEN
bool "Xen guest support on ARM64 (EXPERIMENTAL)"
depends on ARM64 && OF
+ select SWIOTLB_XEN
help
Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
index be24040..0ef9637 100644
--- a/arch/arm64/xen/Makefile
+++ b/arch/arm64/xen/Makefile
@@ -1,2 +1,2 @@
-xen-arm-y += $(addprefix ../../arm/xen/, enlighten.o grant-table.o)
+xen-arm-y += $(addprefix ../../arm/xen/, enlighten.o grant-table.o mm.o)
obj-y := xen-arm.o hypercall.o
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 9e02d60..7e83688 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -140,7 +140,6 @@ config XEN_GRANT_DEV_ALLOC
config SWIOTLB_XEN
def_bool y
- depends on PCI && X86
select SWIOTLB
config XEN_TMEM
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 3fadb6b..d19c240 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -59,6 +59,24 @@ static unsigned long xen_io_tlb_nslabs;
* Quick lookup value of the bus address of the IOTLB.
*/
+#ifndef DMA_ERROR_CODE
+#define DMA_ERROR_CODE (~0)
+#endif
+
+#ifndef CONFIG_X86
+static unsigned long dma_alloc_coherent_mask(struct device *dev,
+ gfp_t gfp)
+{
+ unsigned long dma_mask = 0;
+
+ dma_mask = dev->coherent_dma_mask;
+ if (!dma_mask)
+ dma_mask = (gfp & GFP_DMA) ? DMA_BIT_MASK(24) : DMA_BIT_MASK(32);
+
+ return dma_mask;
+}
+#endif
+
struct xen_dma{
dma_addr_t dma_addr;
phys_addr_t phys_addr;
--
1.7.2.5
Support autotranslate guests in swiotlb-xen by keeping track of the
phys-to-bus and bus-to-phys mappings of the swiotlb buffer
(xen_io_tlb_start-xen_io_tlb_end).
Use a simple direct access on a pre-allocated array for phys-to-bus
queries. Use a red-black tree for bus-to-phys queries.
Signed-off-by: Stefano Stabellini <[email protected]>
CC: [email protected]
---
drivers/xen/swiotlb-xen.c | 127 +++++++++++++++++++++++++++++++++++++++------
1 files changed, 111 insertions(+), 16 deletions(-)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 353f013..3fadb6b 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -38,32 +38,116 @@
#include <linux/bootmem.h>
#include <linux/dma-mapping.h>
#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/spinlock_types.h>
+#include <linux/rbtree.h>
#include <xen/swiotlb-xen.h>
#include <xen/page.h>
#include <xen/xen-ops.h>
#include <xen/hvc-console.h>
+#include <xen/features.h>
/*
* Used to do a quick range check in swiotlb_tbl_unmap_single and
* swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
* API.
*/
+#define NR_DMA_SEGS ((xen_io_tlb_nslabs + IO_TLB_SEGSIZE - 1) / IO_TLB_SEGSIZE)
static char *xen_io_tlb_start, *xen_io_tlb_end;
static unsigned long xen_io_tlb_nslabs;
/*
* Quick lookup value of the bus address of the IOTLB.
*/
-static u64 start_dma_addr;
+struct xen_dma{
+ dma_addr_t dma_addr;
+ phys_addr_t phys_addr;
+ size_t size;
+ struct rb_node rbnode;
+};
+
+static struct xen_dma *xen_dma_seg;
+static struct rb_root bus_to_phys = RB_ROOT;
+static DEFINE_SPINLOCK(xen_dma_lock);
+
+static void xen_dma_insert(struct xen_dma *entry)
+{
+ struct rb_node **link = &bus_to_phys.rb_node;
+ struct rb_node *parent = NULL;
+ struct xen_dma *e;
+
+ spin_lock(&xen_dma_lock);
+
+ while (*link) {
+ parent = *link;
+ e = rb_entry(parent, struct xen_dma, rbnode);
+
+ WARN_ON(entry->dma_addr == e->dma_addr);
+
+ if (entry->dma_addr < e->dma_addr)
+ link = &(*link)->rb_left;
+ else
+ link = &(*link)->rb_right;
+ }
+ rb_link_node(&entry->rbnode, parent, link);
+ rb_insert_color(&entry->rbnode, &bus_to_phys);
+
+ spin_unlock(&xen_dma_lock);
+}
+
+static struct xen_dma *xen_dma_retrieve(dma_addr_t dma_addr)
+{
+ struct rb_node *n = bus_to_phys.rb_node;
+ struct xen_dma *e;
+
+ spin_lock(&xen_dma_lock);
+
+ while (n) {
+ e = rb_entry(n, struct xen_dma, rbnode);
+ if (e->dma_addr <= dma_addr && e->dma_addr + e->size > dma_addr) {
+ spin_unlock(&xen_dma_lock);
+ return e;
+ }
+ if (dma_addr < e->dma_addr)
+ n = n->rb_left;
+ else
+ n = n->rb_right;
+ }
+
+ spin_unlock(&xen_dma_lock);
+ return NULL;
+}
static dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
{
- return phys_to_machine(XPADDR(paddr)).maddr;
+ int nr_seg;
+ unsigned long offset;
+ char* vaddr;
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap))
+ return phys_to_machine(XPADDR(paddr)).maddr;
+
+ vaddr = (char *) phys_to_virt(paddr);
+ if (vaddr >= xen_io_tlb_end || vaddr < xen_io_tlb_start)
+ return ~0;
+
+ offset = vaddr - xen_io_tlb_start;
+ nr_seg = offset / (IO_TLB_SEGSIZE << IO_TLB_SHIFT);
+
+ return xen_dma_seg[nr_seg].dma_addr + (paddr - xen_dma_seg[nr_seg].phys_addr);
}
static phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
{
- return machine_to_phys(XMADDR(baddr)).paddr;
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ {
+ struct xen_dma *dma = xen_dma_retrieve(baddr);
+ if (dma == NULL)
+ return ~0;
+ else
+ return dma->phys_addr + (baddr - dma->dma_addr);
+ } else
+ return machine_to_phys(XMADDR(baddr)).paddr;
}
static dma_addr_t xen_virt_to_bus(void *address)
@@ -107,6 +191,9 @@ static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)
unsigned long pfn = mfn_to_local_pfn(mfn);
phys_addr_t paddr;
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return 1;
+
/* If the address is outside our domain, it CAN
* have the same virtual address as another address
* in our domain. Therefore _only_ check address within our domain.
@@ -124,13 +211,12 @@ static int max_dma_bits = 32;
static int
xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
{
- int i, rc;
+ int i, j, rc;
int dma_bits;
- dma_addr_t dma_handle;
dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
- i = 0;
+ i = j = 0;
do {
int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
@@ -138,12 +224,16 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
rc = xen_create_contiguous_region(
(unsigned long)buf + (i << IO_TLB_SHIFT),
get_order(slabs << IO_TLB_SHIFT),
- dma_bits, &dma_handle);
+ dma_bits, &xen_dma_seg[j].dma_addr);
} while (rc && dma_bits++ < max_dma_bits);
if (rc)
return rc;
+ xen_dma_seg[j].phys_addr = virt_to_phys(buf + (i << IO_TLB_SHIFT));
+ xen_dma_seg[j].size = slabs << IO_TLB_SHIFT;
+ xen_dma_insert(&xen_dma_seg[j]);
i += slabs;
+ j++;
} while (i < nslabs);
return 0;
}
@@ -193,9 +283,10 @@ retry:
/*
* Get IO TLB memory from any location.
*/
- if (early)
+ if (early) {
xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
- else {
+ xen_dma_seg = alloc_bootmem(sizeof(struct xen_dma) * NR_DMA_SEGS);
+ } else {
#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
@@ -210,6 +301,7 @@ retry:
xen_io_tlb_nslabs = SLABS_PER_PAGE << order;
bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
}
+ xen_dma_seg = kzalloc(sizeof(struct xen_dma) * NR_DMA_SEGS, GFP_KERNEL);
}
if (!xen_io_tlb_start) {
m_ret = XEN_SWIOTLB_ENOMEM;
@@ -232,7 +324,6 @@ retry:
m_ret = XEN_SWIOTLB_EFIXUP;
goto error;
}
- start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
if (early) {
if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs,
verbose))
@@ -290,7 +381,8 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
phys = virt_to_phys(ret);
dev_addr = xen_phys_to_bus(phys);
- if (((dev_addr + size - 1 <= dma_mask)) &&
+ if (!xen_feature(XENFEAT_auto_translated_physmap) &&
+ ((dev_addr + size - 1 <= dma_mask)) &&
!range_straddles_page_boundary(phys, size))
*dma_handle = dev_addr;
else {
@@ -321,8 +413,9 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
phys = virt_to_phys(vaddr);
- if (((dev_addr + size - 1 > dma_mask)) ||
- range_straddles_page_boundary(phys, size))
+ if (xen_feature(XENFEAT_auto_translated_physmap) ||
+ (((dev_addr + size - 1 > dma_mask)) ||
+ range_straddles_page_boundary(phys, size)))
xen_destroy_contiguous_region((unsigned long)vaddr, order);
free_pages((unsigned long)vaddr, order);
@@ -351,14 +444,15 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
* we can safely return the device addr and not worry about bounce
* buffering it.
*/
- if (dma_capable(dev, dev_addr, size) &&
+ if (!xen_feature(XENFEAT_auto_translated_physmap) &&
+ dma_capable(dev, dev_addr, size) &&
!range_straddles_page_boundary(phys, size) && !swiotlb_force)
return dev_addr;
/*
* Oh well, have to allocate and map a bounce buffer.
*/
- map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
+ map = swiotlb_tbl_map_single(dev, xen_dma_seg[0].dma_addr, phys, size, dir);
if (map == SWIOTLB_MAP_ERROR)
return DMA_ERROR_CODE;
@@ -494,10 +588,11 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
dma_addr_t dev_addr = xen_phys_to_bus(paddr);
if (swiotlb_force ||
+ xen_feature(XENFEAT_auto_translated_physmap) ||
!dma_capable(hwdev, dev_addr, sg->length) ||
range_straddles_page_boundary(paddr, sg->length)) {
phys_addr_t map = swiotlb_tbl_map_single(hwdev,
- start_dma_addr,
+ xen_dma_seg[0].dma_addr,
sg_phys(sg),
sg->length,
dir);
--
1.7.2.5
Modify xen_create_contiguous_region to return the dma address of the
newly contiguous buffer.
Signed-off-by: Stefano Stabellini <[email protected]>
CC: [email protected]
---
arch/x86/xen/mmu.c | 4 +++-
drivers/xen/swiotlb-xen.c | 6 +++---
include/xen/xen-ops.h | 3 ++-
3 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index fdc3ba2..df9ab44 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2329,7 +2329,8 @@ static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
}
int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
- unsigned int address_bits)
+ unsigned int address_bits,
+ dma_addr_t *dma_handle)
{
unsigned long *in_frames = discontig_frames, out_frame;
unsigned long flags;
@@ -2368,6 +2369,7 @@ int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
spin_unlock_irqrestore(&xen_reservation_lock, flags);
+ *dma_handle = xen_virt_to_bus(vstart);
return success ? 0 : -ENOMEM;
}
EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index aadffcf..353f013 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -126,6 +126,7 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
{
int i, rc;
int dma_bits;
+ dma_addr_t dma_handle;
dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
@@ -137,7 +138,7 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
rc = xen_create_contiguous_region(
(unsigned long)buf + (i << IO_TLB_SHIFT),
get_order(slabs << IO_TLB_SHIFT),
- dma_bits);
+ dma_bits, &dma_handle);
} while (rc && dma_bits++ < max_dma_bits);
if (rc)
return rc;
@@ -294,11 +295,10 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
*dma_handle = dev_addr;
else {
if (xen_create_contiguous_region(vstart, order,
- fls64(dma_mask)) != 0) {
+ fls64(dma_mask), dma_handle) != 0) {
free_pages(vstart, order);
return NULL;
}
- *dma_handle = virt_to_machine(ret).maddr;
}
memset(ret, 0, size);
return ret;
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index d6fe062..9ef704d 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -20,7 +20,8 @@ int xen_setup_shutdown_event(void);
extern unsigned long *xen_contiguous_bitmap;
int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
- unsigned int address_bits);
+ unsigned int address_bits,
+ dma_addr_t *dma_handle);
void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order);
--
1.7.2.5
Initially set dma_ops to arm_dma_ops.
Use dma_ops instead of arm_dma_ops in dmabounce.
Signed-off-by: Stefano Stabellini <[email protected]>
CC: [email protected]
CC: [email protected]
---
arch/arm/common/dmabounce.c | 10 +++++-----
arch/arm/include/asm/dma-mapping.h | 3 ++-
arch/arm/mm/dma-mapping.c | 3 +++
3 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 1143c4d..b626122 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -325,7 +325,7 @@ static dma_addr_t dmabounce_map_page(struct device *dev, struct page *page,
return DMA_ERROR_CODE;
if (ret == 0) {
- arm_dma_ops.sync_single_for_device(dev, dma_addr, size, dir);
+ dma_ops->sync_single_for_device(dev, dma_addr, size, dir);
return dma_addr;
}
@@ -353,7 +353,7 @@ static void dmabounce_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t
buf = find_safe_buffer_dev(dev, dma_addr, __func__);
if (!buf) {
- arm_dma_ops.sync_single_for_cpu(dev, dma_addr, size, dir);
+ dma_ops->sync_single_for_cpu(dev, dma_addr, size, dir);
return;
}
@@ -397,7 +397,7 @@ static void dmabounce_sync_for_cpu(struct device *dev,
if (!__dmabounce_sync_for_cpu(dev, handle, size, dir))
return;
- arm_dma_ops.sync_single_for_cpu(dev, handle, size, dir);
+ dma_ops->sync_single_for_cpu(dev, handle, size, dir);
}
static int __dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
@@ -437,7 +437,7 @@ static void dmabounce_sync_for_device(struct device *dev,
if (!__dmabounce_sync_for_device(dev, handle, size, dir))
return;
- arm_dma_ops.sync_single_for_device(dev, handle, size, dir);
+ dma_ops->sync_single_for_device(dev, handle, size, dir);
}
static int dmabounce_set_mask(struct device *dev, u64 dma_mask)
@@ -445,7 +445,7 @@ static int dmabounce_set_mask(struct device *dev, u64 dma_mask)
if (dev->archdata.dmabounce)
return 0;
- return arm_dma_ops.set_dma_mask(dev, dma_mask);
+ return dma_ops->set_dma_mask(dev, dma_mask);
}
static struct dma_map_ops dmabounce_ops = {
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index ad89e0f..f907f65 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -12,6 +12,7 @@
#include <asm/memory.h>
#define DMA_ERROR_CODE (~0)
+extern struct dma_map_ops *dma_ops;
extern struct dma_map_ops arm_dma_ops;
extern struct dma_map_ops arm_coherent_dma_ops;
@@ -19,7 +20,7 @@ static inline struct dma_map_ops *get_dma_ops(struct device *dev)
{
if (dev && dev->archdata.dma_ops)
return dev->archdata.dma_ops;
- return &arm_dma_ops;
+ return dma_ops;
}
static inline void set_dma_ops(struct device *dev, struct dma_map_ops *ops)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 7f9b179..870b12c 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -141,6 +141,9 @@ struct dma_map_ops arm_dma_ops = {
};
EXPORT_SYMBOL(arm_dma_ops);
+struct dma_map_ops *dma_ops = &arm_dma_ops;
+EXPORT_SYMBOL(dma_ops);
+
static void *arm_coherent_dma_alloc(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs);
static void arm_coherent_dma_free(struct device *dev, size_t size, void *cpu_addr,
--
1.7.2.5
Signed-off-by: Stefano Stabellini <[email protected]>
CC: [email protected]
CC: [email protected]
---
arch/arm64/mm/dma-mapping.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 4bd7579..a006e84 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -63,6 +63,8 @@ static struct dma_map_ops arm64_swiotlb_dma_ops = {
void __init arm64_swiotlb_init(void)
{
+ if (dma_ops != NULL)
+ return;
dma_ops = &arm64_swiotlb_dma_ops;
swiotlb_init(1);
}
--
1.7.2.5
Signed-off-by: Stefano Stabellini <[email protected]>
---
arch/arm/include/asm/xen/hypervisor.h | 6 ++++++
arch/arm/kernel/setup.c | 2 ++
arch/arm/xen/enlighten.c | 21 ++++++++++++++-------
arch/arm64/kernel/setup.c | 2 ++
4 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/arch/arm/include/asm/xen/hypervisor.h b/arch/arm/include/asm/xen/hypervisor.h
index d7ab99a..17b3ea2 100644
--- a/arch/arm/include/asm/xen/hypervisor.h
+++ b/arch/arm/include/asm/xen/hypervisor.h
@@ -16,4 +16,10 @@ static inline enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
return PARAVIRT_LAZY_NONE;
}
+#ifdef CONFIG_XEN
+void xen_early_init(void);
+#else
+static inline void xen_early_init(void) { return; }
+#endif
+
#endif /* _ASM_ARM_XEN_HYPERVISOR_H */
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 63af9a7..cb7b8e2 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -45,6 +45,7 @@
#include <asm/cacheflush.h>
#include <asm/cachetype.h>
#include <asm/tlbflush.h>
+#include <asm/xen/hypervisor.h>
#include <asm/prom.h>
#include <asm/mach/arch.h>
@@ -889,6 +890,7 @@ void __init setup_arch(char **cmdline_p)
arm_dt_init_cpu_maps();
psci_init();
+ xen_early_init();
#ifdef CONFIG_SMP
if (is_smp()) {
if (!mdesc->smp_init || !mdesc->smp_init()) {
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index c9770ba..14d17ab 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -195,21 +195,19 @@ static void xen_power_off(void)
* documentation of the Xen Device Tree format.
*/
#define GRANT_TABLE_PHYSADDR 0
-static int __init xen_guest_init(void)
+void __init xen_early_init(void)
{
- struct xen_add_to_physmap xatp;
- static struct shared_info *shared_info_page = 0;
+ struct resource res;
struct device_node *node;
int len;
const char *s = NULL;
const char *version = NULL;
const char *xen_prefix = "xen,xen-";
- struct resource res;
node = of_find_compatible_node(NULL, NULL, "xen,xen");
if (!node) {
pr_debug("No Xen support\n");
- return 0;
+ return;
}
s = of_get_property(node, "compatible", &len);
if (strlen(xen_prefix) + 3 < len &&
@@ -217,10 +215,10 @@ static int __init xen_guest_init(void)
version = s + strlen(xen_prefix);
if (version == NULL) {
pr_debug("Xen version not found\n");
- return 0;
+ return;
}
if (of_address_to_resource(node, GRANT_TABLE_PHYSADDR, &res))
- return 0;
+ return;
xen_hvm_resume_frames = res.start >> PAGE_SHIFT;
xen_events_irq = irq_of_parse_and_map(node, 0);
pr_info("Xen %s support found, events_irq=%d gnttab_frame_pfn=%lx\n",
@@ -232,6 +230,15 @@ static int __init xen_guest_init(void)
xen_start_info->flags |= SIF_INITDOMAIN|SIF_PRIVILEGED;
else
xen_start_info->flags &= ~(SIF_INITDOMAIN|SIF_PRIVILEGED);
+}
+
+static int __init xen_guest_init(void)
+{
+ struct xen_add_to_physmap xatp;
+ static struct shared_info *shared_info_page = 0;
+
+ if (!xen_domain())
+ return 0;
if (!shared_info_page)
shared_info_page = (struct shared_info *)
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index add6ea6..e0d438a 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -53,6 +53,7 @@
#include <asm/traps.h>
#include <asm/memblock.h>
#include <asm/psci.h>
+#include <asm/xen/hypervisor.h>
unsigned int processor_id;
EXPORT_SYMBOL(processor_id);
@@ -267,6 +268,7 @@ void __init setup_arch(char **cmdline_p)
unflatten_device_tree();
psci_init();
+ xen_early_init();
cpu_logical_map(0) = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
#ifdef CONFIG_SMP
--
1.7.2.5
On Wed, Jul 31, 2013 at 08:54:06PM +0100, Stefano Stabellini wrote:
> Initially set dma_ops to arm_dma_ops.
> Use dma_ops instead of arm_dma_ops in dmabounce.
>
> Signed-off-by: Stefano Stabellini <[email protected]>
> CC: [email protected]
> CC: [email protected]
If you're using swiotlb, there's little point in converting dmabounce
to be able to use it, because it's basically providing the same
functionality - dmabounce is there to do software buffer bouncing within
the DMA to move streaming buffers from DMA-inaccessible memory into
DMA-accessible memory.
It's original use is with older SoCs with buggy DMA (eg, those which
can only address alternate 1MB chunks of memory for example) but also
got used in situations where alternative solutions would've been better
(like using swiotlb.) I've been discouraging its use as it's suffered
from memory exhaustion problems (there's a number of threads and bug
reports which were never solved about IXP4xx(?) platforms suffering
this due to this bouncing.)
On 31/07/13 20:54, Stefano Stabellini wrote:
> Support autotranslate guests in swiotlb-xen by keeping track of the
> phys-to-bus and bus-to-phys mappings of the swiotlb buffer
> (xen_io_tlb_start-xen_io_tlb_end).
>
> Use a simple direct access on a pre-allocated array for phys-to-bus
> queries. Use a red-black tree for bus-to-phys queries.
It would be nice if the dma_map_page() etc. returned a unique handle in
addition to the dma_addr_t so the lookup on unmap could be cheaper, but
in the absence of this.
Reviewed-by: David Vrabel <[email protected]>
David
On Wed, 31 Jul 2013, Russell King - ARM Linux wrote:
> On Wed, Jul 31, 2013 at 08:54:06PM +0100, Stefano Stabellini wrote:
> > Initially set dma_ops to arm_dma_ops.
> > Use dma_ops instead of arm_dma_ops in dmabounce.
> >
> > Signed-off-by: Stefano Stabellini <[email protected]>
> > CC: [email protected]
> > CC: [email protected]
>
> If you're using swiotlb, there's little point in converting dmabounce
> to be able to use it, because it's basically providing the same
> functionality - dmabounce is there to do software buffer bouncing within
> the DMA to move streaming buffers from DMA-inaccessible memory into
> DMA-accessible memory.
>
> It's original use is with older SoCs with buggy DMA (eg, those which
> can only address alternate 1MB chunks of memory for example) but also
> got used in situations where alternative solutions would've been better
> (like using swiotlb.) I've been discouraging its use as it's suffered
> from memory exhaustion problems (there's a number of threads and bug
> reports which were never solved about IXP4xx(?) platforms suffering
> this due to this bouncing.)
OK, I'll let dmabounce keep using arm_dma_ops directly (instead of
dma_ops).
Should I add "depends on !DMABOUNCE" to the SWIOTLB Kconfig entry too?