This is a note to let you know that I've just added the patch titled
xen/swiotlb: add alignment check for dma buffers
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-swiotlb-add-alignment-check-for-dma-buffers.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a9b017e3be8083e8fb7ce28532223242a165f09e
Author: Juergen Gross <jgross@xxxxxxxx>
Date: Fri Sep 13 12:05:02 2024 +0200
xen/swiotlb: add alignment check for dma buffers
[ Upstream commit 9f40ec84a7976d95c34e7cc070939deb103652b0 ]
When checking a memory buffer to be consecutive in machine memory,
the alignment needs to be checked, too. Failing to do so might result
in DMA memory not being aligned according to its requested size,
leading to error messages like:
4xxx 0000:2b:00.0: enabling device (0140 -> 0142)
4xxx 0000:2b:00.0: Ring address not aligned
4xxx 0000:2b:00.0: Failed to initialise service qat_crypto
4xxx 0000:2b:00.0: Resetting device qat_dev0
4xxx: probe of 0000:2b:00.0 failed with error -14
Fixes: 9435cce87950 ("xen/swiotlb: Add support for 64KB page granularity")
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 2f4d4e36c7b36..98f82c759d1e2 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -98,9 +98,15 @@ static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
{
unsigned long next_bfn, xen_pfn = XEN_PFN_DOWN(p);
unsigned int i, nr_pages = XEN_PFN_UP(xen_offset_in_page(p) + size);
+ phys_addr_t algn = 1ULL << (get_order(size) + PAGE_SHIFT);
next_bfn = pfn_to_bfn(xen_pfn);
+ /* If buffer is physically aligned, ensure DMA alignment. */
+ if (IS_ALIGNED(p, algn) &&
+ !IS_ALIGNED((phys_addr_t)next_bfn << XEN_PAGE_SHIFT, algn))
+ return 1;
+
for (i = 1; i < nr_pages; i++)
if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
return 1;
