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From: Sean Christopherson <seanjc@google.com>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Brijesh Singh <brijesh.singh@amd.com>
Subject: Re: [PATCH 3/3] KVM: SVM: Sync GPRs to the GHCB only after VMGEXIT
Date: Fri, 22 Jan 2021 16:29:19 -0800	[thread overview]
Message-ID: <YAtt38s4GLG9cviK@google.com> (raw)
In-Reply-To: <0d8e9d63-1fe9-af08-dae9-edd80083e940@amd.com>

On Fri, Jan 22, 2021, Tom Lendacky wrote:
> On 1/22/21 5:50 PM, Sean Christopherson wrote:
> > Sync GPRs to the GHCB on VMRUN only if a sync is needed, i.e. if the
> > previous exit was a VMGEXIT and the guest is expecting some data back.
> > 
> 
> The start of sev_es_sync_to_ghcb() checks if the GHCB has been mapped, which
> only occurs on VMGEXIT, and exits early if not. And sev_es_sync_from_ghcb()
> is only called if the GHCB has been successfully mapped. The only thing in
> between is sev_es_validate_vmgexit(), which will terminate the VM on error.
> So I don't think this patch is needed.

Ah, nice!  Yep, this can be dropped.  Thanks!

  reply	other threads:[~2021-01-23  0:30 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-22 23:50 [PATCH 0/3] KVM: x86: Revert dirty tracking for GPRs Sean Christopherson
2021-01-22 23:50 ` [PATCH 1/3] KVM: SVM: Unconditionally sync GPRs to GHCB on VMRUN of SEV-ES guest Sean Christopherson
2021-01-25 15:05   ` Tom Lendacky
2021-01-22 23:50 ` [PATCH 2/3] KVM: x86: Revert "KVM: x86: Mark GPRs dirty when written" Sean Christopherson
2021-01-22 23:50 ` [PATCH 3/3] KVM: SVM: Sync GPRs to the GHCB only after VMGEXIT Sean Christopherson
2021-01-23  0:09   ` Tom Lendacky
2021-01-23  0:29     ` Sean Christopherson [this message]
2021-01-25 17:22 ` [PATCH 0/3] KVM: x86: Revert dirty tracking for GPRs Paolo Bonzini

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