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References: <20230818233451.3615464-1-srutherford@google.com> <ZQRHIN7as8f+PFeh@gmail.com>
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From:   Steve Rutherford <srutherford@google.com>
Date:   Fri, 15 Sep 2023 11:44:16 -0700
Message-ID: <CABayD+fH+AVu1u+LAtpd4-vRO9E12tVajR9WdWMtr1x_McoO6A@mail.gmail.com>
Subject: Re: [PATCH] x86/sev: Make early_set_memory_decrypted() calls page aligned
To:     Ingo Molnar <mingo@kernel.org>
Cc:     Borislav Petkov <bp@alien8.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Ingo Molnar <mingo@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H . Peter Anvin" <hpa@zytor.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, David.Kaplan@amd.com,
        jacobhxu@google.com, patelsvishal@google.com, bhillier@google.com
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I believe V3 of this fix was already merged into both x86 and Linus'
tree (I think as ac3f9c9f1b37edaa7d1a9b908bc79d843955a1a2, "x86/sev:
Make enc_dec_hypercall() accept a size instead of npages").


On Fri, Sep 15, 2023 at 4:59=E2=80=AFAM Ingo Molnar <mingo@kernel.org> wrot=
e:
>
>
> * Steve Rutherford <srutherford@google.com> wrote:
>
> > early_set_memory_decrypted() assumes its parameters are page aligned.
> > Non-page aligned calls result in additional pages being marked as
> > decrypted via the encryption status hypercall, which results in
> > consistent corruption of pages during live migration. Live
> > migration requires accurate encryption status information to avoid
> > migrating pages from the wrong perspective.
> >
> > Fixes: 4716276184ec ("X86/KVM: Decrypt shared per-cpu variables when SE=
V is active")
> > Signed-off-by: Steve Rutherford <srutherford@google.com>
> > ---
> >  arch/x86/kernel/kvm.c | 14 +++++++++++++-
> >  1 file changed, 13 insertions(+), 1 deletion(-)
>
> I suppose this fix is going through the KVM tree, or should we pick it up
> in the x86 tree?
>
> Thanks,
>
>         Ingo