From: Sean Christopherson <seanjc@google.com>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Joerg Roedel <joro@8bytes.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
x86@kernel.org, Brijesh Singh <brijesh.singh@amd.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Joerg Roedel <jroedel@suse.de>
Subject: Re: [PATCH v5 4/6] KVM: SVM: Add support to handle AP reset MSR protocol
Date: Wed, 20 Oct 2021 18:38:06 +0000 [thread overview]
Message-ID: <YXBiDr5mgtkgwBDR@google.com> (raw)
In-Reply-To: <95d99b9a-8600-619b-9b83-63597d937bc6@amd.com>
On Wed, Oct 20, 2021, Tom Lendacky wrote:
> On 10/20/21 12:40 PM, Sean Christopherson wrote:
> > On Wed, Oct 20, 2021, Joerg Roedel wrote:
> > This can race with the SIPI and effectively corrupt svm->vmcb->control.ghcb_gpa.
> >
> > vCPU0 vCPU1
> > #VMGEXIT(RESET_HOLD)
> > __kvm_vcpu_halt()
> > INIT
> > SIPI
> > sev_vcpu_deliver_sipi_vector()
> > ghcb_msr_ap_rst_resp(1);
>
> This isn't possible. vCPU0 doesn't set vCPU1's GHCB value. vCPU1's GHCB
> value is set when vCPU1 handles events in vcpu_enter_guest().
Argh, I was thinking of injecting regular IPIs across vCPUs. In hindsight it
makes sense that INIT and SIPI are handled on the current vCPU, stuffing all that
state from a different vCPU would be needlessly complex.
next prev parent reply other threads:[~2021-10-20 18:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 12:44 [PATCH v5 0/6] KVM: SVM: Add initial GHCB protocol version 2 support Joerg Roedel
2021-10-20 12:44 ` [PATCH v5 1/6] KVM: SVM: Get rid of set_ghcb_msr() and *ghcb_msr_bits() functions Joerg Roedel
2021-10-20 12:44 ` [PATCH v5 2/6] KVM: SVM: Add helper to generate GHCB MSR verson info, and drop macro Joerg Roedel
2021-10-20 12:44 ` [PATCH v5 3/6] KVM: SVM: Move kvm_emulate_ap_reset_hold() to AMD specific code Joerg Roedel
2021-10-20 14:29 ` Sean Christopherson
2021-10-20 12:44 ` [PATCH v5 4/6] KVM: SVM: Add support to handle AP reset MSR protocol Joerg Roedel
2021-10-20 17:40 ` Sean Christopherson
2021-10-20 18:13 ` Tom Lendacky
2021-10-20 18:38 ` Sean Christopherson [this message]
2021-10-20 18:36 ` Tom Lendacky
2021-10-20 12:44 ` [PATCH v5 5/6] KVM: SVM: Add support for Hypervisor Feature support " Joerg Roedel
2021-10-20 12:44 ` [PATCH v5 6/6] KVM: SVM: Increase supported GHCB protocol version Joerg Roedel
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