Commit a4dba130 authored by Stefano Stabellini's avatar Stefano Stabellini Committed by David Vrabel
Browse files

xen/arm/arm64: introduce xen_arch_need_swiotlb 



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: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarIan Campbell <ian.campbell@citrix.com>
Acked-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 5121872a

arch/arm/include/asm/xen/page.h

+4 −0
Original line number Diff line number Diff line
@@ -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 */

arch/arm/xen/mm.c

+7 −0
Original line number Diff line number Diff line
@@ -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)

arch/x86/include/asm/xen/page.h

+7 −0
Original line number Diff line number Diff line
@@ -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 */

drivers/xen/swiotlb-xen.c

+4 −1
Original line number Diff line number Diff line
@@ -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,

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