From: Jon Pan-Doh pandoh@google.com
commit 2212fc2acf3f6ee690ea36506fb882a19d1bfcab upstream.
When running on an AMD vIOMMU, we observed multiple invalidations (of decreasing power of 2 aligned sizes) when unmapping a single page.
Domain flush takes gather bounds (end-start) as size param. However, gather->end is defined as the last inclusive address (start + size - 1). This leads to an off by 1 error.
With this patch, verified that 1 invalidation occurs when unmapping a single page.
Fixes: a270be1b3fdf ("iommu/amd: Use only natural aligned flushes in a VM") Cc: stable@vger.kernel.org # >= 5.15 Signed-off-by: Jon Pan-Doh pandoh@google.com Tested-by: Sudheer Dantuluri dantuluris@google.com Suggested-by: Gary Zibrat gzibrat@google.com Reviewed-by: Vasant Hegde vasant.hegde@amd.com Acked-by: Nadav Amit namit@vmware.com Link: https://lore.kernel.org/r/20230426203256.237116-1-pandoh@google.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/amd/iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -2396,7 +2396,7 @@ static void amd_iommu_iotlb_sync(struct unsigned long flags;
spin_lock_irqsave(&dom->lock, flags); - domain_flush_pages(dom, gather->start, gather->end - gather->start, 1); + domain_flush_pages(dom, gather->start, gather->end - gather->start + 1, 1); amd_iommu_domain_flush_complete(dom); spin_unlock_irqrestore(&dom->lock, flags); }