Commit 3567258d authored by Stefano Stabellini's avatar Stefano Stabellini Committed by David Vrabel
Browse files

xen/arm: use hypercall to flush caches in map_page 



In xen_dma_map_page, if the page is a local page, call the native
map_page dma_ops. If the page is foreign, call __xen_dma_map_page that
issues any required cache maintenane operations via hypercall.

The reason for doing this is that the native dma_ops map_page could
allocate buffers than need to be freed. If the page is foreign we don't
call the native unmap_page dma_ops function, resulting in a memory leak.

Suggested-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent a0f2dee0

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

+12 −1
Original line number Diff line number Diff line
@@ -5,6 +5,9 @@ 
#include <linux/dma-attrs.h>

#include <linux/dma-mapping.h>



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);

void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,

		size_t size, enum dma_data_direction dir,

		struct dma_attrs *attrs);
@@ -32,7 +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. */

	if (local)

		__generic_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs);

	else

		__xen_dma_map_page(hwdev, page, dev_addr, offset, size, dir, attrs);

}



static inline void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,

arch/arm/xen/mm32.c

+12 −0
Original line number Diff line number Diff line
@@ -43,6 +43,18 @@ static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle, 
	dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_MAP);

}



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)

{

	if (is_device_dma_coherent(hwdev))

		return;

	if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))

		return;



	__xen_dma_page_cpu_to_dev(hwdev, dev_addr, size, dir);

}



void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,

		size_t size, enum dma_data_direction dir,

		struct dma_attrs *attrs)

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