[PATCH] iommu/vt-d: Fix the size calculation of pasid table

From	Xunlei Pang <xlpang@redhat.com>
Newsgroups	linux.kernel
Subject	[PATCH] iommu/vt-d: Fix the size calculation of pasid table
Date	2016-09-12 04:50 +0200
Message-ID	<sgptM-5TD-9@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

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According to the vt-d spec, the size of pasid (state) entry is 8B
which equals 3 in power of 2, the number of pasid (state) entries
is (ecap_pss + 1) in power of 2.

Thus the right size of pasid (state) table in power of 2 should be
ecap_pss(iommu->ecap) plus "1+3=4" other than 7.

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
---
 drivers/iommu/intel-svm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 8ebb353..cfa75c2 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -39,7 +39,7 @@ int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu)
 	struct page *pages;
 	int order;
 
-	order = ecap_pss(iommu->ecap) + 7 - PAGE_SHIFT;
+	order = ecap_pss(iommu->ecap) + 4 - PAGE_SHIFT;
 	if (order < 0)
 		order = 0;
 
-- 
1.8.3.1

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[PATCH] iommu/vt-d: Fix the size calculation of pasid table Xunlei Pang <xlpang@redhat.com> - 2016-09-12 04:50 +0200
  Re: [PATCH] iommu/vt-d: Fix the size calculation of pasid table Joerg Roedel <joro@8bytes.org> - 2016-09-19 14:20 +0200

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