Messages in this thread | | | Date | Wed, 14 Jul 2010 17:27:21 +0300 | From | Avi Kivity <> | Subject | Re: [PATCH 1/4] KVM: MMU: fix forgot reserved bits check in speculative path |
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On 07/14/2010 04:24 PM, Xiao Guangrong wrote: > > Avi Kivity wrote: > > >>> + >>> + if (!!is_pae(vcpu) != sp->role.cr4_pae || >>> + is_nx(vcpu) != sp->role.nxe) >>> + continue; >>> + >>> >>> >> Do we also need to check cr0.wp? I think so. >> > I think it's not too bad since we just decrease the access right, for example, > we mark the mapping readonly for cr0.wp=0's page, the later write-access will > cause #PF, and the read-access is OK. >
If current cr0.wp=0 and sp->role.cr0_wp=1, that's fine, but the other way round can relax permissions too much, marking a kernel page writeable.
-- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.
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