diff --git a/arch/arm/include/asm/xen/page-coherent.h b/arch/arm/include/asm/xen/page-coherent.h
index efd5624128507fa5afd7f6ec981dc07edd2b2160..0375c8caa06194591e065f94bbb3d57a0565c847 100644
--- a/arch/arm/include/asm/xen/page-coherent.h
+++ b/arch/arm/include/asm/xen/page-coherent.h
@@ -35,11 +35,15 @@ static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
dma_addr_t dev_addr, unsigned long offset, size_t size,
enum dma_data_direction dir, struct dma_attrs *attrs)
{
- bool local = PFN_DOWN(dev_addr) == page_to_pfn(page);
- /* Dom0 is mapped 1:1, so if pfn == mfn the page is local otherwise
- * is a foreign page grant-mapped in dom0. If the page is local we
- * can safely call the native dma_ops function, otherwise we call
- * the xen specific function. */
+ bool local = XEN_PFN_DOWN(dev_addr) == page_to_xen_pfn(page);
+ /*
+ * Dom0 is mapped 1:1, while the Linux page can be spanned accross
+ * multiple Xen page, it's not possible to have a mix of local and
+ * foreign Xen page. So if the first xen_pfn == mfn the page is local
+ * otherwise it's a foreign page grant-mapped in dom0. If the page is
+ * local we can safely call the native dma_ops function, otherwise we
+ * call the xen specific function.
+ */
if (local)
__generic_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs);
else
@@ -51,10 +55,14 @@ static inline void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
struct dma_attrs *attrs)
{
unsigned long pfn = PFN_DOWN(handle);
- /* Dom0 is mapped 1:1, so calling pfn_valid on a foreign mfn will
- * always return false. If the page is local we can safely call the
- * native dma_ops function, otherwise we call the xen specific
- * function. */
+ /*
+ * Dom0 is mapped 1:1, while the Linux page can be spanned accross
+ * multiple Xen page, it's not possible to have a mix of local and
+ * foreign Xen page. Dom0 is mapped 1:1, so calling pfn_valid on a
+ * foreign mfn will always return false. If the page is local we can
+ * safely call the native dma_ops function, otherwise we call the xen
+ * specific function.
+ */
if (pfn_valid(pfn)) {
if (__generic_dma_ops(hwdev)->unmap_page)
__generic_dma_ops(hwdev)->unmap_page(hwdev, handle, size, dir, attrs);
diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 7b517e913762ceccc243dbf092c88d97ad4ddcf6..7c34f7126b046abe9d61637a1716a2ae5139bfe5 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -48,22 +48,22 @@ static void dma_cache_maint(dma_addr_t handle, unsigned long offset,
size_t size, enum dma_data_direction dir, enum dma_cache_op op)
{
struct gnttab_cache_flush cflush;
- unsigned long pfn;
+ unsigned long xen_pfn;
size_t left = size;
- pfn = (handle >> PAGE_SHIFT) + offset / PAGE_SIZE;
- offset %= PAGE_SIZE;
+ xen_pfn = (handle >> XEN_PAGE_SHIFT) + offset / XEN_PAGE_SIZE;
+ offset %= XEN_PAGE_SIZE;
do {
size_t len = left;
/* buffers in highmem or foreign pages cannot cross page
* boundaries */
- if (len + offset > PAGE_SIZE)
- len = PAGE_SIZE - offset;
+ if (len + offset > XEN_PAGE_SIZE)
+ len = XEN_PAGE_SIZE - offset;
cflush.op = 0;
- cflush.a.dev_bus_addr = pfn << PAGE_SHIFT;
+ cflush.a.dev_bus_addr = xen_pfn << XEN_PAGE_SHIFT;
cflush.offset = offset;
cflush.length = len;
@@ -79,7 +79,7 @@ static void dma_cache_maint(dma_addr_t handle, unsigned long offset,
HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1);
offset = 0;
- pfn++;
+ xen_pfn++;
left -= len;
} while (left);
}
@@ -141,10 +141,26 @@ bool xen_arch_need_swiotlb(struct device *dev,
phys_addr_t phys,
dma_addr_t dev_addr)
{
- unsigned long pfn = PFN_DOWN(phys);
- unsigned long bfn = PFN_DOWN(dev_addr);
-
- return (!hypercall_cflush && (pfn != bfn) && !is_device_dma_coherent(dev));
+ unsigned int xen_pfn = XEN_PFN_DOWN(phys);
+ unsigned int bfn = XEN_PFN_DOWN(dev_addr);
+
+ /*
+ * The swiotlb buffer should be used if
+ * - Xen doesn't have the cache flush hypercall
+ * - The Linux page refers to foreign memory
+ * - The device doesn't support coherent DMA request
+ *
+ * The Linux page may be spanned acrros multiple Xen page, although
+ * it's not possible to have a mix of local and foreign Xen page.
+ * Furthermore, range_straddles_page_boundary is already checking
+ * if buffer is physically contiguous in the host RAM.
+ *
+ * Therefore we only need to check the first Xen page to know if we
+ * require a bounce buffer because the device doesn't support coherent
+ * memory and we are not able to flush the cache.
+ */
+ return (!hypercall_cflush && (xen_pfn != bfn) &&
+ !is_device_dma_coherent(dev));
}
int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 0a5a0e949862bf469151ea4986451df9f0f8f4d7..7399782c0998eeed033afff74342a73025f831d1 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -76,27 +76,27 @@ static unsigned long xen_io_tlb_nslabs;
static u64 start_dma_addr;
/*
- * Both of these functions should avoid PFN_PHYS because phys_addr_t
+ * Both of these functions should avoid XEN_PFN_PHYS because phys_addr_t
* can be 32bit when dma_addr_t is 64bit leading to a loss in
* information if the shift is done before casting to 64bit.
*/
static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
{
- unsigned long bfn = pfn_to_bfn(PFN_DOWN(paddr));
- dma_addr_t dma = (dma_addr_t)bfn << PAGE_SHIFT;
+ unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr));
+ dma_addr_t dma = (dma_addr_t)bfn << XEN_PAGE_SHIFT;
- dma |= paddr & ~PAGE_MASK;
+ dma |= paddr & ~XEN_PAGE_MASK;
return dma;
}
static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
{
- unsigned long pfn = bfn_to_pfn(PFN_DOWN(baddr));
- dma_addr_t dma = (dma_addr_t)pfn << PAGE_SHIFT;
+ unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr));
+ dma_addr_t dma = (dma_addr_t)xen_pfn << XEN_PAGE_SHIFT;
phys_addr_t paddr = dma;
- paddr |= baddr & ~PAGE_MASK;
+ paddr |= baddr & ~XEN_PAGE_MASK;
return paddr;
}
@@ -106,7 +106,7 @@ static inline dma_addr_t xen_virt_to_bus(void *address)
return xen_phys_to_bus(virt_to_phys(address));
}
-static int check_pages_physically_contiguous(unsigned long pfn,
+static int check_pages_physically_contiguous(unsigned long xen_pfn,
unsigned int offset,
size_t length)
{
@@ -114,11 +114,11 @@ static int check_pages_physically_contiguous(unsigned long pfn,
int i;
int nr_pages;
- next_bfn = pfn_to_bfn(pfn);
- nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT;
+ next_bfn = pfn_to_bfn(xen_pfn);
+ nr_pages = (offset + length + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT;
for (i = 1; i < nr_pages; i++) {
- if (pfn_to_bfn(++pfn) != ++next_bfn)
+ if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
return 0;
}
return 1;
@@ -126,28 +126,27 @@ static int check_pages_physically_contiguous(unsigned long pfn,
static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
{
- unsigned long pfn = PFN_DOWN(p);
- unsigned int offset = p & ~PAGE_MASK;
+ unsigned long xen_pfn = XEN_PFN_DOWN(p);
+ unsigned int offset = p & ~XEN_PAGE_MASK;
- if (offset + size <= PAGE_SIZE)
+ if (offset + size <= XEN_PAGE_SIZE)
return 0;
- if (check_pages_physically_contiguous(pfn, offset, size))
+ if (check_pages_physically_contiguous(xen_pfn, offset, size))
return 0;
return 1;
}
static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)
{
- unsigned long bfn = PFN_DOWN(dma_addr);
- unsigned long pfn = bfn_to_local_pfn(bfn);
- phys_addr_t paddr;
+ unsigned long bfn = XEN_PFN_DOWN(dma_addr);
+ unsigned long xen_pfn = bfn_to_local_pfn(bfn);
+ phys_addr_t paddr = XEN_PFN_PHYS(xen_pfn);
/* 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.
*/
- if (pfn_valid(pfn)) {
- paddr = PFN_PHYS(pfn);
+ if (pfn_valid(PFN_DOWN(paddr))) {
return paddr >= virt_to_phys(xen_io_tlb_start) &&
paddr < virt_to_phys(xen_io_tlb_end);
}