| Message ID | 1415792454-23161-10-git-send-email-stefano.stabellini@eu.citrix.com |
|---|---|
| State | Accepted |
| Commit | a4dba130891271084344c12537731542ec77cb85 |
| Headers | show |
On Wed, 12 Nov 2014, Stefano Stabellini wrote: > Introduce an arch specific function to find out whether a particular dma > mapping operation needs to bounce on the swiotlb buffer. > > On ARM and ARM64, if the page involved is a foreign page and the device > is not coherent, we need to bounce because at unmap time we cannot > execute any required cache maintenance operations (we don't know how to > find the pfn from the mfn). > > No change of behaviour for x86. > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > Reviewed-by: David Vrabel <david.vrabel@citrix.com> > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> > Acked-by: Ian Campbell <ian.campbell@citrix.com> > Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> I am thinking of asking a backport of this patch to 3.16+ The catch is that is_device_dma_coherent is not available on older kernels, so I'll have to change the arm implementation of xen_arch_need_swiotlb to: +bool xen_arch_need_swiotlb(struct device *dev, + unsigned long pfn, + unsigned long mfn) +{ + return pfn != mfn; +} + It is going to make things slower but it is going to fix the issue with cache flushing buffers for non-coherent devices. Konrad, are you OK with that? > Changes in v6: > - fix ts. > > Changes in v5: > - fix indentation. > --- > arch/arm/include/asm/xen/page.h | 4 ++++ > arch/arm/xen/mm.c | 7 +++++++ > arch/x86/include/asm/xen/page.h | 7 +++++++ > drivers/xen/swiotlb-xen.c | 5 ++++- > 4 files changed, 22 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h > index 135c24a..68c739b 100644 > --- a/arch/arm/include/asm/xen/page.h > +++ b/arch/arm/include/asm/xen/page.h > @@ -107,4 +107,8 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) > #define xen_remap(cookie, size) ioremap_cache((cookie), (size)) > #define xen_unmap(cookie) iounmap((cookie)) > > +bool xen_arch_need_swiotlb(struct device *dev, > + unsigned long pfn, > + unsigned long mfn); > + > #endif /* _ASM_ARM_XEN_PAGE_H */ > diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c > index ab700e1..28ebf3e 100644 > --- a/arch/arm/xen/mm.c > +++ b/arch/arm/xen/mm.c > @@ -100,6 +100,13 @@ void __xen_dma_sync_single_for_device(struct device *hwdev, > __xen_dma_page_cpu_to_dev(hwdev, handle, size, dir); > } > > +bool xen_arch_need_swiotlb(struct device *dev, > + unsigned long pfn, > + unsigned long mfn) > +{ > + return ((pfn != mfn) && !is_device_dma_coherent(dev)); > +} > + > int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, > unsigned int address_bits, > dma_addr_t *dma_handle) > diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h > index c949923..f58ef6c 100644 > --- a/arch/x86/include/asm/xen/page.h > +++ b/arch/x86/include/asm/xen/page.h > @@ -236,4 +236,11 @@ void make_lowmem_page_readwrite(void *vaddr); > #define xen_remap(cookie, size) ioremap((cookie), (size)); > #define xen_unmap(cookie) iounmap((cookie)) > > +static inline bool xen_arch_need_swiotlb(struct device *dev, > + unsigned long pfn, > + unsigned long mfn) > +{ > + return false; > +} > + > #endif /* _ASM_X86_XEN_PAGE_H */ > diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c > index ad2c5eb..3725ee4 100644 > --- a/drivers/xen/swiotlb-xen.c > +++ b/drivers/xen/swiotlb-xen.c > @@ -399,7 +399,9 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, > * buffering it. > */ > if (dma_capable(dev, dev_addr, size) && > - !range_straddles_page_boundary(phys, size) && !swiotlb_force) { > + !range_straddles_page_boundary(phys, size) && > + !xen_arch_need_swiotlb(dev, PFN_DOWN(phys), PFN_DOWN(dev_addr)) && > + !swiotlb_force) { > /* we are not interested in the dma_addr returned by > * xen_dma_map_page, only in the potential cache flushes executed > * by the function. */ > @@ -557,6 +559,7 @@ 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_arch_need_swiotlb(hwdev, PFN_DOWN(paddr), PFN_DOWN(dev_addr)) || > !dma_capable(hwdev, dev_addr, sg->length) || > range_straddles_page_boundary(paddr, sg->length)) { > phys_addr_t map = swiotlb_tbl_map_single(hwdev, > -- > 1.7.10.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On Fri, Nov 21, 2014 at 04:31:31PM +0000, Stefano Stabellini wrote: > On Wed, 12 Nov 2014, Stefano Stabellini wrote: > > Introduce an arch specific function to find out whether a particular dma > > mapping operation needs to bounce on the swiotlb buffer. > > > > On ARM and ARM64, if the page involved is a foreign page and the device > > is not coherent, we need to bounce because at unmap time we cannot > > execute any required cache maintenance operations (we don't know how to > > find the pfn from the mfn). > > > > No change of behaviour for x86. > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > Reviewed-by: David Vrabel <david.vrabel@citrix.com> > > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> > > Acked-by: Ian Campbell <ian.campbell@citrix.com> > > Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > > I am thinking of asking a backport of this patch to 3.16+ > > The catch is that is_device_dma_coherent is not available on older > kernels, so I'll have to change the arm implementation of > xen_arch_need_swiotlb to: > > +bool xen_arch_need_swiotlb(struct device *dev, > + unsigned long pfn, > + unsigned long mfn) > +{ > + return pfn != mfn; > +} > + > > It is going to make things slower but it is going to fix the issue with > cache flushing buffers for non-coherent devices. > > Konrad, are you OK with that? Looks fine. > > > > Changes in v6: > > - fix ts. > > > > Changes in v5: > > - fix indentation. > > --- > > arch/arm/include/asm/xen/page.h | 4 ++++ > > arch/arm/xen/mm.c | 7 +++++++ > > arch/x86/include/asm/xen/page.h | 7 +++++++ > > drivers/xen/swiotlb-xen.c | 5 ++++- > > 4 files changed, 22 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h > > index 135c24a..68c739b 100644 > > --- a/arch/arm/include/asm/xen/page.h > > +++ b/arch/arm/include/asm/xen/page.h > > @@ -107,4 +107,8 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) > > #define xen_remap(cookie, size) ioremap_cache((cookie), (size)) > > #define xen_unmap(cookie) iounmap((cookie)) > > > > +bool xen_arch_need_swiotlb(struct device *dev, > > + unsigned long pfn, > > + unsigned long mfn); > > + > > #endif /* _ASM_ARM_XEN_PAGE_H */ > > diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c > > index ab700e1..28ebf3e 100644 > > --- a/arch/arm/xen/mm.c > > +++ b/arch/arm/xen/mm.c > > @@ -100,6 +100,13 @@ void __xen_dma_sync_single_for_device(struct device *hwdev, > > __xen_dma_page_cpu_to_dev(hwdev, handle, size, dir); > > } > > > > +bool xen_arch_need_swiotlb(struct device *dev, > > + unsigned long pfn, > > + unsigned long mfn) > > +{ > > + return ((pfn != mfn) && !is_device_dma_coherent(dev)); > > +} > > + > > int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, > > unsigned int address_bits, > > dma_addr_t *dma_handle) > > diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h > > index c949923..f58ef6c 100644 > > --- a/arch/x86/include/asm/xen/page.h > > +++ b/arch/x86/include/asm/xen/page.h > > @@ -236,4 +236,11 @@ void make_lowmem_page_readwrite(void *vaddr); > > #define xen_remap(cookie, size) ioremap((cookie), (size)); > > #define xen_unmap(cookie) iounmap((cookie)) > > > > +static inline bool xen_arch_need_swiotlb(struct device *dev, > > + unsigned long pfn, > > + unsigned long mfn) > > +{ > > + return false; > > +} > > + > > #endif /* _ASM_X86_XEN_PAGE_H */ > > diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c > > index ad2c5eb..3725ee4 100644 > > --- a/drivers/xen/swiotlb-xen.c > > +++ b/drivers/xen/swiotlb-xen.c > > @@ -399,7 +399,9 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, > > * buffering it. > > */ > > if (dma_capable(dev, dev_addr, size) && > > - !range_straddles_page_boundary(phys, size) && !swiotlb_force) { > > + !range_straddles_page_boundary(phys, size) && > > + !xen_arch_need_swiotlb(dev, PFN_DOWN(phys), PFN_DOWN(dev_addr)) && > > + !swiotlb_force) { > > /* we are not interested in the dma_addr returned by > > * xen_dma_map_page, only in the potential cache flushes executed > > * by the function. */ > > @@ -557,6 +559,7 @@ 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_arch_need_swiotlb(hwdev, PFN_DOWN(paddr), PFN_DOWN(dev_addr)) || > > !dma_capable(hwdev, dev_addr, sg->length) || > > range_straddles_page_boundary(paddr, sg->length)) { > > phys_addr_t map = swiotlb_tbl_map_single(hwdev, > > -- > > 1.7.10.4 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h index 135c24a..68c739b 100644 --- a/arch/arm/include/asm/xen/page.h +++ b/arch/arm/include/asm/xen/page.h @@ -107,4 +107,8 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) #define xen_remap(cookie, size) ioremap_cache((cookie), (size)) #define xen_unmap(cookie) iounmap((cookie)) +bool xen_arch_need_swiotlb(struct device *dev, + unsigned long pfn, + unsigned long mfn); + #endif /* _ASM_ARM_XEN_PAGE_H */ diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c index ab700e1..28ebf3e 100644 --- a/arch/arm/xen/mm.c +++ b/arch/arm/xen/mm.c @@ -100,6 +100,13 @@ void __xen_dma_sync_single_for_device(struct device *hwdev, __xen_dma_page_cpu_to_dev(hwdev, handle, size, dir); } +bool xen_arch_need_swiotlb(struct device *dev, + unsigned long pfn, + unsigned long mfn) +{ + return ((pfn != mfn) && !is_device_dma_coherent(dev)); +} + int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, unsigned int address_bits, dma_addr_t *dma_handle) diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index c949923..f58ef6c 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -236,4 +236,11 @@ void make_lowmem_page_readwrite(void *vaddr); #define xen_remap(cookie, size) ioremap((cookie), (size)); #define xen_unmap(cookie) iounmap((cookie)) +static inline bool xen_arch_need_swiotlb(struct device *dev, + unsigned long pfn, + unsigned long mfn) +{ + return false; +} + #endif /* _ASM_X86_XEN_PAGE_H */ diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index ad2c5eb..3725ee4 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -399,7 +399,9 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, * buffering it. */ if (dma_capable(dev, dev_addr, size) && - !range_straddles_page_boundary(phys, size) && !swiotlb_force) { + !range_straddles_page_boundary(phys, size) && + !xen_arch_need_swiotlb(dev, PFN_DOWN(phys), PFN_DOWN(dev_addr)) && + !swiotlb_force) { /* we are not interested in the dma_addr returned by * xen_dma_map_page, only in the potential cache flushes executed * by the function. */ @@ -557,6 +559,7 @@ 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_arch_need_swiotlb(hwdev, PFN_DOWN(paddr), PFN_DOWN(dev_addr)) || !dma_capable(hwdev, dev_addr, sg->length) || range_straddles_page_boundary(paddr, sg->length)) { phys_addr_t map = swiotlb_tbl_map_single(hwdev,