Make sure that xen_swiotlb_init allocates buffers that are DMA capable
when at least one memblock is available below 4G. Otherwise we assume
that all devices on the SoC can cope with >4G addresses.
No functional changes on x86.
From: Chen Baozi <[email protected]>
Signed-off-by: Chen Baozi <[email protected]>
Signed-off-by: Stefano Stabellini <[email protected]>
Tested-by: Chen Baozi <[email protected]>
diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
index 2f7e6ff..0b579b2 100644
--- a/arch/arm/include/asm/xen/page.h
+++ b/arch/arm/include/asm/xen/page.h
@@ -110,5 +110,6 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
bool xen_arch_need_swiotlb(struct device *dev,
unsigned long pfn,
unsigned long mfn);
+unsigned long xen_get_swiotlb_free_pages(unsigned int order);
#endif /* _ASM_ARM_XEN_PAGE_H */
diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 793551d..4983250 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -4,6 +4,7 @@
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/export.h>
+#include <linux/memblock.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include <linux/types.h>
@@ -21,6 +22,20 @@
#include <asm/xen/hypercall.h>
#include <asm/xen/interface.h>
+unsigned long xen_get_swiotlb_free_pages(unsigned int order)
+{
+ struct memblock_region *reg;
+ gfp_t flags = __GFP_NOWARN;
+
+ for_each_memblock(memory, reg) {
+ if (reg->base < (phys_addr_t)0xffffffff) {
+ flags |= __GFP_DMA;
+ break;
+ }
+ }
+ return __get_free_pages(flags, order);
+}
+
enum dma_cache_op {
DMA_UNMAP,
DMA_MAP,
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 358dcd3..c44a5d5 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -269,4 +269,9 @@ static inline bool xen_arch_need_swiotlb(struct device *dev,
return false;
}
+static inline unsigned long xen_get_swiotlb_free_pages(unsigned int order)
+{
+ return __get_free_pages(__GFP_NOWARN, order);
+}
+
#endif /* _ASM_X86_XEN_PAGE_H */
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 810ad41..4c54932 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -235,7 +235,7 @@ retry:
#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) {
- xen_io_tlb_start = (void *)__get_free_pages(__GFP_NOWARN, order);
+ xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order);
if (xen_io_tlb_start)
break;
order--;
On 23/04/15 10:47, Stefano Stabellini wrote:
> Make sure that xen_swiotlb_init allocates buffers that are DMA capable
> when at least one memblock is available below 4G. Otherwise we assume
> that all devices on the SoC can cope with >4G addresses.
This commit message must explain why the PFNs (IPAs) are relevant for DMA.
David
> No functional changes on x86.
>
> From: Chen Baozi <[email protected]>
>
> Signed-off-by: Chen Baozi <[email protected]>
> Signed-off-by: Stefano Stabellini <[email protected]>
> Tested-by: Chen Baozi <[email protected]>
>
> diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
> index 2f7e6ff..0b579b2 100644
> --- a/arch/arm/include/asm/xen/page.h
> +++ b/arch/arm/include/asm/xen/page.h
> @@ -110,5 +110,6 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
> bool xen_arch_need_swiotlb(struct device *dev,
> unsigned long pfn,
> unsigned long mfn);
> +unsigned long xen_get_swiotlb_free_pages(unsigned int order);
>
> #endif /* _ASM_ARM_XEN_PAGE_H */
> diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
> index 793551d..4983250 100644
> --- a/arch/arm/xen/mm.c
> +++ b/arch/arm/xen/mm.c
> @@ -4,6 +4,7 @@
> #include <linux/gfp.h>
> #include <linux/highmem.h>
> #include <linux/export.h>
> +#include <linux/memblock.h>
> #include <linux/of_address.h>
> #include <linux/slab.h>
> #include <linux/types.h>
> @@ -21,6 +22,20 @@
> #include <asm/xen/hypercall.h>
> #include <asm/xen/interface.h>
>
> +unsigned long xen_get_swiotlb_free_pages(unsigned int order)
> +{
> + struct memblock_region *reg;
> + gfp_t flags = __GFP_NOWARN;
> +
> + for_each_memblock(memory, reg) {
> + if (reg->base < (phys_addr_t)0xffffffff) {
> + flags |= __GFP_DMA;
> + break;
> + }
> + }
> + return __get_free_pages(flags, order);
> +}
> +
> enum dma_cache_op {
> DMA_UNMAP,
> DMA_MAP,
> diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
> index 358dcd3..c44a5d5 100644
> --- a/arch/x86/include/asm/xen/page.h
> +++ b/arch/x86/include/asm/xen/page.h
> @@ -269,4 +269,9 @@ static inline bool xen_arch_need_swiotlb(struct device *dev,
> return false;
> }
>
> +static inline unsigned long xen_get_swiotlb_free_pages(unsigned int order)
> +{
> + return __get_free_pages(__GFP_NOWARN, order);
> +}
> +
> #endif /* _ASM_X86_XEN_PAGE_H */
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index 810ad41..4c54932 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -235,7 +235,7 @@ retry:
> #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) {
> - xen_io_tlb_start = (void *)__get_free_pages(__GFP_NOWARN, order);
> + xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order);
> if (xen_io_tlb_start)
> break;
> order--;
>