2017-08-11 14:40 GMT+08:00 David Hildenbrand <[email protected]>: > On 11.08.2017 08:13, Paolo Bonzini wrote: >> On 11/08/2017 07:59, Wanpeng Li wrote: >>> From: Wanpeng Li <[email protected]> >>> >>> 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
