Commit 4855c92dbb7 "xen-swiotlb: fix the check condition for
xen_swiotlb_free_coherent" only fixed memory address check condition
on xen_swiotlb_free_coherent(), when memory was not physically
contiguous and tried to exchanged with Xen via
xen_destroy_contiguous_region which lead to kernel panic.
The correct check conditions to make Xen hypercall to revert the
memory back from its 32-bit pool are:
1) Above its DMA bit mask (for example 32-bit devices can only address
up to 4GB, and we may want 4GB+2K), and
2) It's physically contiguous.
Thank you Boris for pointing it out.
Fixes: 4855c92dbb7 ("xen-swiotlb: fix the check condition for
xen_swiotlb_free_coherent"
Signed-off-by: Joe Jin <[email protected]>
Reported-by: Boris Ostrovsky <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Christoph Helwig <[email protected]>
Cc: Dongli Zhang <[email protected]>
Cc: John Sobecki <[email protected]>
---
drivers/xen/swiotlb-xen.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index f5c1af4ce9ab..aed92fa019f9 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -357,8 +357,8 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
/* Convert the size to actually allocated. */
size = 1UL << (order + XEN_PAGE_SHIFT);
- if (((dev_addr + size - 1 <= dma_mask)) ||
- range_straddles_page_boundary(phys, size))
+ if ((dev_addr + size - 1 <= dma_mask) &&
+ !range_straddles_page_boundary(phys, size))
xen_destroy_contiguous_region(phys, order);
xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
--
2.17.1 (Apple Git-112)