Re: [PATCH v2 1/3] KVM: x86: dump_vmcs should not assume GUEST_IA32_EFER is valid
From: David Edmondson
Date: Wed Feb 24 2021 - 09:42:54 EST
On Tuesday, 2021年02月23日 at 15:13:54 -08, Jim Mattson wrote:
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On Tue, Feb 23, 2021 at 2:51 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
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>
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> On Fri, Feb 19, 2021, David Edmondson wrote:
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> > If the VM entry/exit controls for loading/saving MSR_EFER are either
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> > not available (an older processor or explicitly disabled) or not
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> > used (host and guest values are the same), reading GUEST_IA32_EFER
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> > from the VMCS returns an inaccurate value.
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> >
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> > Because of this, in dump_vmcs() don't use GUEST_IA32_EFER to decide
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> > whether to print the PDPTRs - do so if the EPT is in use and CR4.PAE
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> > is set.
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> This isn't necessarily correct either. In a way, it's less correct as PDPTRs
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> are more likely to be printed when they shouldn't, assuming most guests are
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> 64-bit guests. It's annoying to calculate the effective guest EFER, but so
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> awful that it's worth risking confusion over PDTPRs.
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>
I still prefer a dump_vmcs that always dumps every VMCS field.
v3 now always shows the PDPTRs if they exist.
dme.
--
I've got a little black book with my poems in.