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| Started by | Xunlei Pang <xlpang@redhat.com> |
|---|---|
| First post | 2016-09-12 04:50 +0200 |
| Last post | 2016-09-19 14:20 +0200 |
| Articles | 2 — 2 participants |
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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
| From | Xunlei Pang <xlpang@redhat.com> |
|---|---|
| Date | 2016-09-12 04:50 +0200 |
| Subject | [PATCH] iommu/vt-d: Fix the size calculation of pasid table |
| Message-ID | <sgptM-5TD-9@gated-at.bofh.it> |
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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| From | Joerg Roedel <joro@8bytes.org> |
|---|---|
| Date | 2016-09-19 14:20 +0200 |
| Message-ID | <sj5Id-5lV-5@gated-at.bofh.it> |
| In reply to | #1480903 |
[Cc'ing David] On Mon, Sep 12, 2016 at 10:49:11AM +0800, Xunlei Pang wrote: > 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; The patch seems to be correct, but I'll let David comment on it first. Joerg
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