Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230504181827.130532-1-mizhang@google.com>
In-Reply-To: <20230504181827.130532-1-mizhang@google.com>
From:   Jim Mattson <jmattson@google.com>
Date:   Thu, 4 May 2023 11:26:55 -0700
Message-ID: <CALMp9eStwQAznFpNnAnNXzcj+4Gev3hP-XtAeUWqpJdtY5tShA@mail.gmail.com>
Subject: Re: [PATCH v2] KVM: VMX: add MSR_IA32_TSX_CTRL into msrs_to_save
To:     Mingwei Zhang <mizhang@google.com>
Cc:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Thu, May 4, 2023 at 11:18=E2=80=AFAM Mingwei Zhang <mizhang@google.com> =
wrote:
>
> Add MSR_IA32_TSX_CTRL into msrs_to_save[] to explicitly tell userspace to
> save/restore the register value during migration. Missing this may cause
> userspace that relies on KVM ioctl(KVM_GET_MSR_INDEX_LIST) fail to port t=
he
> value to the target VM.
>
> In addition, there is no need to add MSR_IA32_TSX_CTRL when
> ARCH_CAP_TSX_CTRL_MSR is not supported in guest. So add the checking in
> kvm_probe_msr_to_save().
>
> Fixes: b07a5c53d42a ("KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX=
 on guest that lack it")
> Reported-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Mingwei Zhang <mizhang@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>