linux-kernel - Re: [PATCH 0/2] KVM: SVM: Final C-bit fixes?

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Message-ID: <e406b31f-64bd-eb88-51bb-dd534719fb6e@redhat.com>
Date:   Thu, 8 Jul 2021 18:30:39 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Peter Gonda <pgonda@...gle.com>,
        Brijesh Singh <brijesh.singh@....com>,
        Tom Lendacky <thomas.lendacky@....com>
Subject: Re: [PATCH 0/2] KVM: SVM: Final C-bit fixes?

On 25/06/21 04:03, Sean Christopherson wrote:
> Patch 01 reverts the C-bit truncation patch as the reserved #PF was
> confirmed to be due to a magic HyperTransport region (how many magic
> addresses are there!?!).  Hopefully the original patch simply be dropped,
> but just in case...
> 
> Patch 02 reverts the C-bit clearing in the #NPF handler.  If that somehow
> turns out to be incorrect, i.e. there are flows where the CPU doesn't
> mask off the C-bit, then it can be conditional on a SEV guest.
> 
> I'll be offline for the next two weeks, fingers crossed I've undone all
> the damage.  :-)
> 
> Thanks!
> 
> Sean Christopherson (2):
>    Revert "KVM: x86: Truncate reported guest MAXPHYADDR to C-bit if SEV
>      is supported"
>    KVM: SVM: Revert clearing of C-bit on GPA in #NPF handler
> 
>   arch/x86/kvm/cpuid.c   | 11 -----------
>   arch/x86/kvm/svm/svm.c | 39 +++++++++------------------------------
>   arch/x86/kvm/x86.c     |  3 ---
>   arch/x86/kvm/x86.h     |  1 -
>   4 files changed, 9 insertions(+), 45 deletions(-)
> 

Queued, thanks.

Paolo