linux-kernel - [PATCH 3.16 080/157] iommu/amd: Set exclusion range correctly

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Message-ID: <lsq.1565469607.467361670@decadent.org.uk>
Date:   Sat, 10 Aug 2019 21:40:07 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Joerg Roedel" <jroedel@...e.de>
Subject: [PATCH 3.16 080/157] iommu/amd: Set exclusion range correctly

3.16.72-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Joerg Roedel <jroedel@...e.de>

commit 3c677d206210f53a4be972211066c0f1cd47fe12 upstream.

The exlcusion range limit register needs to contain the
base-address of the last page that is part of the range, as
bits 0-11 of this register are treated as 0xfff by the
hardware for comparisons.

So correctly set the exclusion range in the hardware to the
last page which is _in_ the range.

Fixes: b2026aa2dce44 ('x86, AMD IOMMU: add functions for programming IOMMU MMIO space')
Signed-off-by: Joerg Roedel <jroedel@...e.de>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/iommu/amd_iommu_init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -293,7 +293,7 @@ static void iommu_write_l2(struct amd_io
 static void iommu_set_exclusion_range(struct amd_iommu *iommu)
 {
 	u64 start = iommu->exclusion_start & PAGE_MASK;
-	u64 limit = (start + iommu->exclusion_length) & PAGE_MASK;
+	u64 limit = (start + iommu->exclusion_length - 1) & PAGE_MASK;
 	u64 entry;
 
 	if (!iommu->exclusion_start)