[PATCH v9 11/18] swiotlb-xen: use xen_alloc/free_coherent_pages
Stefano Stabellini
stefano.stabellini at eu.citrix.com
Fri Oct 25 06:51:46 EDT 2013
Use xen_alloc_coherent_pages and xen_free_coherent_pages to allocate or
free coherent pages.
We need to be careful handling the pointer returned by
xen_alloc_coherent_pages, because on ARM the pointer is not equal to
phys_to_virt(*dma_handle). In fact virt_to_phys only works for kernel
direct mapped RAM memory.
In ARM case the pointer could be an ioremap address, therefore passing
it to virt_to_phys would give you another physical address that doesn't
correspond to it.
Make xen_create_contiguous_region take a phys_addr_t as start parameter to
avoid the virt_to_phys calls which would be incorrect.
Changes in v6:
- remove extra spaces.
Signed-off-by: Stefano Stabellini <stefano.stabellini at eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
---
arch/arm/xen/mm.c | 6 +++---
arch/x86/xen/mmu.c | 7 +++++--
drivers/xen/swiotlb-xen.c | 31 +++++++++++++++++++++----------
include/xen/xen-ops.h | 4 ++--
4 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 0d69b87..b0e77de 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -16,7 +16,7 @@
#include <asm/xen/hypercall.h>
#include <asm/xen/interface.h>
-int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
+int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
unsigned int address_bits,
dma_addr_t *dma_handle)
{
@@ -24,12 +24,12 @@ int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
return -EINVAL;
/* we assume that dom0 is mapped 1:1 for now */
- *dma_handle = virt_to_phys(pstart);
+ *dma_handle = pstart;
return 0;
}
EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
-void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
+void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
{
return;
}
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 6c34d7c..8830883 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2328,13 +2328,14 @@ static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
return success;
}
-int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
+int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
unsigned int address_bits,
dma_addr_t *dma_handle)
{
unsigned long *in_frames = discontig_frames, out_frame;
unsigned long flags;
int success;
+ unsigned long vstart = (unsigned long)phys_to_virt(pstart);
/*
* Currently an auto-translated guest will not perform I/O, nor will
@@ -2374,11 +2375,12 @@ int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
}
EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
-void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
+void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
{
unsigned long *out_frames = discontig_frames, in_frame;
unsigned long flags;
int success;
+ unsigned long vstart;
if (xen_feature(XENFEAT_auto_translated_physmap))
return;
@@ -2386,6 +2388,7 @@ void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
if (unlikely(order > MAX_CONTIG_ORDER))
return;
+ vstart = (unsigned long)phys_to_virt(pstart);
memset((void *) vstart, 0, PAGE_SIZE << order);
spin_lock_irqsave(&xen_reservation_lock, flags);
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index d8ef0bf..189b8db 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -43,6 +43,7 @@
#include <xen/xen-ops.h>
#include <xen/hvc-console.h>
#include <asm/dma-mapping.h>
+#include <asm/xen/page-coherent.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
@@ -142,6 +143,7 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
int i, rc;
int dma_bits;
dma_addr_t dma_handle;
+ phys_addr_t p = virt_to_phys(buf);
dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
@@ -151,7 +153,7 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
do {
rc = xen_create_contiguous_region(
- (unsigned long)buf + (i << IO_TLB_SHIFT),
+ p + (i << IO_TLB_SHIFT),
get_order(slabs << IO_TLB_SHIFT),
dma_bits, &dma_handle);
} while (rc && dma_bits++ < max_dma_bits);
@@ -279,7 +281,6 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
void *ret;
int order = get_order(size);
u64 dma_mask = DMA_BIT_MASK(32);
- unsigned long vstart;
phys_addr_t phys;
dma_addr_t dev_addr;
@@ -294,8 +295,12 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
if (dma_alloc_from_coherent(hwdev, size, dma_handle, &ret))
return ret;
- vstart = __get_free_pages(flags, order);
- ret = (void *)vstart;
+ /* On ARM this function returns an ioremap'ped virtual address for
+ * which virt_to_phys doesn't return the corresponding physical
+ * address. In fact on ARM virt_to_phys only works for kernel direct
+ * mapped RAM memory. Also see comment below.
+ */
+ ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
if (!ret)
return ret;
@@ -303,15 +308,19 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
if (hwdev && hwdev->coherent_dma_mask)
dma_mask = dma_alloc_coherent_mask(hwdev, flags);
- phys = virt_to_phys(ret);
+ /* At this point dma_handle is the physical address, next we are
+ * going to set it to the machine address.
+ * Do not use virt_to_phys(ret) because on ARM it doesn't correspond
+ * to *dma_handle. */
+ phys = *dma_handle;
dev_addr = xen_phys_to_bus(phys);
if (((dev_addr + size - 1 <= dma_mask)) &&
!range_straddles_page_boundary(phys, size))
*dma_handle = dev_addr;
else {
- if (xen_create_contiguous_region(vstart, order,
+ if (xen_create_contiguous_region(phys, order,
fls64(dma_mask), dma_handle) != 0) {
- free_pages(vstart, order);
+ xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);
return NULL;
}
}
@@ -334,13 +343,15 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
if (hwdev && hwdev->coherent_dma_mask)
dma_mask = hwdev->coherent_dma_mask;
- phys = virt_to_phys(vaddr);
+ /* do not use virt_to_phys because on ARM it doesn't return you the
+ * physical address */
+ phys = xen_bus_to_phys(dev_addr);
if (((dev_addr + size - 1 > dma_mask)) ||
range_straddles_page_boundary(phys, size))
- xen_destroy_contiguous_region((unsigned long)vaddr, order);
+ xen_destroy_contiguous_region(phys, order);
- free_pages((unsigned long)vaddr, order);
+ xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
}
EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent);
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index 9ef704d..fb2ea8f 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -19,11 +19,11 @@ void xen_arch_resume(void);
int xen_setup_shutdown_event(void);
extern unsigned long *xen_contiguous_bitmap;
-int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
+int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
unsigned int address_bits,
dma_addr_t *dma_handle);
-void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order);
+void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order);
struct vm_area_struct;
int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
--
1.7.2.5
More information about the linux-arm-kernel
mailing list