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Message-ID: <20240913145655.10076-1-jgross@suse.com>
Date: Fri, 13 Sep 2024 16:56:55 +0200
From: Juergen Gross <jgross@...e.com>
To: linux-kernel@...r.kernel.org,
iommu@...ts.linux.dev
Cc: Juergen Gross <jgross@...e.com>,
Stefano Stabellini <sstabellini@...nel.org>,
Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
xen-devel@...ts.xenproject.org
Subject: [PATCH] xen/swiotlb: add alignment check for dma buffers
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
Signed-off-by: Juergen Gross <jgross@...e.com>
---
drivers/xen/swiotlb-xen.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 35155258a7e2..11f4b1195324 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -78,9 +78,15 @@ 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);
+ unsigned int order = get_order(size);
next_bfn = pfn_to_bfn(xen_pfn);
+ /* If buffer is physically aligned, ensure DMA alignment. */
+ if (IS_ALIGNED(p, 1UL << (order + PAGE_SHIFT)) &&
+ !IS_ALIGNED(next_bfn, 1UL << order))
+ return 1;
+
for (i = 1; i < nr_pages; i++)
if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
return 1;
--
2.43.0
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