Commit cd9c0584 authored by John Ernberg's avatar John Ernberg Committed by Juergen Gross
Browse files

xen: swiotlb: Use swiotlb bouncing if kmalloc allocation demands it 

Xen swiotlb support was missed when the patch set starting with
4ab5f8ec ("mm/slab: decouple ARCH_KMALLOC_MINALIGN from
ARCH_DMA_MINALIGN") was merged.

When running Xen on iMX8QXP, a SoC without IOMMU, the effect was that USB
transfers ended up corrupted when there was more than one URB inflight at
the same time.

Add a call to dma_kmalloc_needs_bounce() to make sure that allocations too
small for DMA get bounced via swiotlb.

Closes: https://lore.kernel.org/linux-usb/ab2776f0-b838-4cf6-a12a-c208eb6aad59@actia.se/


Fixes: 4ab5f8ec ("mm/slab: decouple ARCH_KMALLOC_MINALIGN from ARCH_DMA_MINALIGN")
Cc: stable@kernel.org # v6.5+
Signed-off-by: default avatarJohn Ernberg <john.ernberg@actia.se>
Reviewed-by: default avatarStefano Stabellini <sstabellini@kernel.org>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Message-ID: <20250502114043.1968976-2-john.ernberg@actia.se>
parent 715ad3e0

drivers/xen/swiotlb-xen.c

+1 −0
Original line number Diff line number Diff line
@@ -217,6 +217,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, 
	 * buffering it.

	 */

	if (dma_capable(dev, dev_addr, size, true) &&

	    !dma_kmalloc_needs_bounce(dev, size, dir) &&

	    !range_straddles_page_boundary(phys, size) &&

		!xen_arch_need_swiotlb(dev, phys, dev_addr) &&

		!is_swiotlb_force_bounce(dev))