Messages in this thread | | | Date | Mon, 19 Sep 2016 14:18:27 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH] iommu/vt-d: Fix the size calculation of pasid table |
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[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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