Re: [PATCH v4 01/12] KVM: x86/mmu: helpers to return if KVM honors guest MTRRs

From: Sean Christopherson
Date: Tue Oct 10 2023 - 20:08:18 EST


On Tue, Oct 10, 2023, Yan Zhao wrote:
> BTW, as param "kvm" is now removed from the helper, better to remove the word
> "second" in comment in patch 4, i.e.
>
> - * So, specify the second parameter as true here to indicate
> - * non-coherent DMAs are/were involved and TDP zap might be
> - * necessary.
> + * So, specify the parameter as true here to indicate non-coherent
> + * DMAs are/were involved and TDP zap might be necessary.
>
> Sorry and thanks a lot for helps on this series!

Heh, don't be sorry, it's not your fault I can't get this quite right. Fixed
up yet again, hopefully for the last time. This is what I ended up with for the
comment:

/*
* Non-coherent DMA assignment and de-assignment will affect
* whether KVM honors guest MTRRs and cause changes in memtypes
* in TDP.
* So, pass %true unconditionally to indicate non-coherent DMA was,
* or will be involved, and that zapping SPTEs might be necessary.
*/

and the hashes:

[1/5] KVM: x86/mmu: Add helpers to return if KVM honors guest MTRRs
https://github.com/kvm-x86/linux/commit/1affe455d66d
[2/5] KVM: x86/mmu: Zap SPTEs when CR0.CD is toggled iff guest MTRRs are honored
https://github.com/kvm-x86/linux/commit/7a18c7c2b69a
[3/5] KVM: x86/mmu: Zap SPTEs on MTRR update iff guest MTRRs are honored
https://github.com/kvm-x86/linux/commit/9a3768191d95
[4/5] KVM: x86/mmu: Zap KVM TDP when noncoherent DMA assignment starts/stops
https://github.com/kvm-x86/linux/commit/362ff6dca541
[5/5] KVM: VMX: drop IPAT in memtype when CD=1 for KVM_X86_QUIRK_CD_NW_CLEARED
https://github.com/kvm-x86/linux/commit/c9f65a3f2d92