Messages in this thread | | | From | Wanpeng Li <> | Date | Fri, 11 Aug 2017 14:47:40 +0800 | Subject | Re: [PATCH] KVM: MMU: Fix guest stuck during boot due to read/write emulation against GVA |
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2017-08-11 14:40 GMT+08:00 David Hildenbrand <david@redhat.com>: > On 11.08.2017 08:13, Paolo Bonzini wrote: >> On 11/08/2017 07:59, Wanpeng Li wrote: >>> From: Wanpeng Li <wanpeng.li@hotmail.com> >>> >>> Commit c016004494b0 (KVM: x86: Avoid guest page table walk when gpa_available >>> is set) avoids the page table walk when cr2 has already contained a valid GPA. >>> However, that is not the truth if ept == 0 and shadow page table is used. In >>> this scenario cr2 can just contains a valid GVA. The commit results in guest >>> stuck during boot due to read/write emulation against GVA instead of GPA of >>> the guest. >>> >>> This patch fixes it by not setting the gpa_available flag if the shadow page table >>> is used. >> >> Yup, I got these on my overnight tests too. A better fix that I was >> going to commit today is: >> >> if (vcpu->arch.mmu.direct_map) { >> vcpu->arch.gpa_available = true; >> vcpu->arch.gpa_val = fault_address; >> } >> > > Makes sense to me. Can we add a comment? > > /* with shadow page tables, cr2 could contain a GVA, not a GPA */
Yeah, thanks for the review.
Regards, Wanpeng Li
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