From 875553e317b28e66824fec73ad4459372576ec68 Mon Sep 17 00:00:00 2001 From: Oleksandr Tyshchenko Date: Sat, 8 Oct 2022 18:10:12 +0300 Subject: xen/virtio: Handle cases when page offset > PAGE_SIZE properly Passed to xen_grant_dma_map_page() offset in the page can be > PAGE_SIZE even if the guest uses the same page granularity as Xen (4KB). Before current patch, if such case happened we ended up providing grants for the whole region in xen_grant_dma_map_page() which was really unnecessary. The more, we ended up not releasing all grants which represented that region in xen_grant_dma_unmap_page(). Current patch updates the code to be able to deal with such cases. Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Stefano Stabellini Reviewed-by: Xenia Ragiadakou Link: https://lore.kernel.org/r/20221008151013.2537826-2-olekstysh@gmail.com Signed-off-by: Juergen Gross --- drivers/xen/grant-dma-ops.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index 860f37c93af4..3089940436be 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -168,7 +168,9 @@ static dma_addr_t xen_grant_dma_map_page(struct device *dev, struct page *page, unsigned long attrs) { struct xen_grant_dma_data *data; - unsigned int i, n_pages = PFN_UP(offset + size); + unsigned long dma_offset = offset_in_page(offset), + pfn_offset = PFN_DOWN(offset); + unsigned int i, n_pages = PFN_UP(dma_offset + size); grant_ref_t grant; dma_addr_t dma_handle; @@ -187,10 +189,11 @@ static dma_addr_t xen_grant_dma_map_page(struct device *dev, struct page *page, for (i = 0; i < n_pages; i++) { gnttab_grant_foreign_access_ref(grant + i, data->backend_domid, - xen_page_to_gfn(page) + i, dir == DMA_TO_DEVICE); + pfn_to_gfn(page_to_xen_pfn(page) + i + pfn_offset), + dir == DMA_TO_DEVICE); } - dma_handle = grant_to_dma(grant) + offset; + dma_handle = grant_to_dma(grant) + dma_offset; return dma_handle; } -- cgit v1.2.3 From a383dcb1cca8305497877119fba0a320f41fe853 Mon Sep 17 00:00:00 2001 From: Oleksandr Tyshchenko Date: Sat, 8 Oct 2022 18:10:13 +0300 Subject: xen/virtio: Convert PAGE_SIZE/PAGE_SHIFT/PFN_UP to Xen counterparts Currently, a grant ref is always based on the Xen page granularity (4KB), and guest commonly uses the same page granularity. But the guest may use a different page granularity (i.e 64KB). So adopt the code to be able to deal with it. Signed-off-by: Oleksandr Tyshchenko Acked-by: Stefano Stabellini Reviewed-by: Xenia Ragiadakou Link: https://lore.kernel.org/r/20221008151013.2537826-3-olekstysh@gmail.com Signed-off-by: Juergen Gross --- drivers/xen/grant-dma-ops.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index 3089940436be..daa525df7bdc 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -31,12 +31,12 @@ static DEFINE_XARRAY_FLAGS(xen_grant_dma_devices, XA_FLAGS_LOCK_IRQ); static inline dma_addr_t grant_to_dma(grant_ref_t grant) { - return XEN_GRANT_DMA_ADDR_OFF | ((dma_addr_t)grant << PAGE_SHIFT); + return XEN_GRANT_DMA_ADDR_OFF | ((dma_addr_t)grant << XEN_PAGE_SHIFT); } static inline grant_ref_t dma_to_grant(dma_addr_t dma) { - return (grant_ref_t)((dma & ~XEN_GRANT_DMA_ADDR_OFF) >> PAGE_SHIFT); + return (grant_ref_t)((dma & ~XEN_GRANT_DMA_ADDR_OFF) >> XEN_PAGE_SHIFT); } static struct xen_grant_dma_data *find_xen_grant_dma_data(struct device *dev) @@ -79,7 +79,7 @@ static void *xen_grant_dma_alloc(struct device *dev, size_t size, unsigned long attrs) { struct xen_grant_dma_data *data; - unsigned int i, n_pages = PFN_UP(size); + unsigned int i, n_pages = XEN_PFN_UP(size); unsigned long pfn; grant_ref_t grant; void *ret; @@ -91,14 +91,14 @@ static void *xen_grant_dma_alloc(struct device *dev, size_t size, if (unlikely(data->broken)) return NULL; - ret = alloc_pages_exact(n_pages * PAGE_SIZE, gfp); + ret = alloc_pages_exact(n_pages * XEN_PAGE_SIZE, gfp); if (!ret) return NULL; pfn = virt_to_pfn(ret); if (gnttab_alloc_grant_reference_seq(n_pages, &grant)) { - free_pages_exact(ret, n_pages * PAGE_SIZE); + free_pages_exact(ret, n_pages * XEN_PAGE_SIZE); return NULL; } @@ -116,7 +116,7 @@ static void xen_grant_dma_free(struct device *dev, size_t size, void *vaddr, dma_addr_t dma_handle, unsigned long attrs) { struct xen_grant_dma_data *data; - unsigned int i, n_pages = PFN_UP(size); + unsigned int i, n_pages = XEN_PFN_UP(size); grant_ref_t grant; data = find_xen_grant_dma_data(dev); @@ -138,7 +138,7 @@ static void xen_grant_dma_free(struct device *dev, size_t size, void *vaddr, gnttab_free_grant_reference_seq(grant, n_pages); - free_pages_exact(vaddr, n_pages * PAGE_SIZE); + free_pages_exact(vaddr, n_pages * XEN_PAGE_SIZE); } static struct page *xen_grant_dma_alloc_pages(struct device *dev, size_t size, @@ -168,9 +168,9 @@ static dma_addr_t xen_grant_dma_map_page(struct device *dev, struct page *page, unsigned long attrs) { struct xen_grant_dma_data *data; - unsigned long dma_offset = offset_in_page(offset), - pfn_offset = PFN_DOWN(offset); - unsigned int i, n_pages = PFN_UP(dma_offset + size); + unsigned long dma_offset = xen_offset_in_page(offset), + pfn_offset = XEN_PFN_DOWN(offset); + unsigned int i, n_pages = XEN_PFN_UP(dma_offset + size); grant_ref_t grant; dma_addr_t dma_handle; @@ -203,8 +203,8 @@ static void xen_grant_dma_unmap_page(struct device *dev, dma_addr_t dma_handle, unsigned long attrs) { struct xen_grant_dma_data *data; - unsigned long offset = dma_handle & (PAGE_SIZE - 1); - unsigned int i, n_pages = PFN_UP(offset + size); + unsigned long dma_offset = xen_offset_in_page(dma_handle); + unsigned int i, n_pages = XEN_PFN_UP(dma_offset + size); grant_ref_t grant; if (WARN_ON(dir == DMA_NONE)) -- cgit v1.2.3