From d42d869b2cf45238e773e0ca193f424b77f9242f Mon Sep 17 00:00:00 2001
From: Jon Pan-Doh <pandoh@google.com>
Date: Wed, 26 Apr 2023 13:32:56 -0700
Subject: [PATCH] iommu/amd: Fix domain flush size when syncing iotlb
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(-)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index a91545b9a1cb..d9251af7f3cf 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2222,7 +2222,7 @@ static void amd_iommu_iotlb_sync(struct iommu_domain *domain,
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);
}