Re: [PATCH 00/54] KVM: x86/mmu: Bug fixes and summer cleaning

From: Paolo Bonzini
Date: Wed Jun 23 2021 - 16:30:03 EST


On 22/06/21 19:56, Sean Christopherson wrote:
Patch 01 is the only patch that is remotely 5.13 worthy, and even then
only because it's about as safe as a patch can be. Everything else is far
from urgent as these bugs have existed for quite some time.

Maybe patch 54 (not sarcastic), but I agree it's not at all necessary.

This is good stuff, I made a few comments but almost all of them (all except the last comment on patch 9, "Unconditionally zap unsync SPs") are cosmetic and I can resolve them myself.

I'd like your input on renaming is_{cr0,cr4,efer}_* to is_mmu_* (and possibly reduce the four underscores to two...).

If I get remarks by tomorrow, I'll get this into 5.14, otherwise consider everything but the first eight patches queued only for 5.15.

I labeled the "sections" of this mess in the shortlog below.

P.S. Does anyone know how PKRU interacts with NPT? I assume/hope NPT
accesses, which are always "user", ignore PKRU, but the APM doesn't
say a thing. If PKRU is ignored, KVM has some fixing to do. If PKRU
isn't ignored, AMD has some fixing to do:-)

P.S.S. This series pulled in one patch from my vCPU RESET/INIT series,
"Properly reset MMU context at vCPU RESET/INIT", as that was needed
to fix a root_level bug on VMX. My goal is to get the RESET/INIT
series refreshed later this week and thoroughly bombard everyone.

Note that it won't get into 5.14 anyway, since I plan to send my first pull request to Linus as soon as Friday.

Paolo