From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xunlei Pang Subject: Re: [PATCH] iommu/vt-d: Fix the size calculation of pasid table Date: Mon, 10 Oct 2016 21:00:14 +0800 Message-ID: <57FB90DE.7010808@redhat.com> References: <1473648551-10025-1-git-send-email-xlpang@redhat.com> <20160919121827.GB3541@8bytes.org> Reply-To: xlpang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160919121827.GB3541-zLv9SwRftAIdnm+yROfE0A@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: David Woodhouse Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: iommu@lists.linux-foundation.org Ping David for confirmation On 2016/09/19 at 20:18, Joerg Roedel wrote: > [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 >> --- >> 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 >