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From: Mingwei Zhang <mizhang@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Brijesh Singh <brijesh.singh@amd.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	John Allen <john.allen@amd.com>
Cc: Sean Christopherson <seanjc@google.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-crypto@vger.kernel.org,
	linux-kernel@vger.kernel.org, Alper Gun <alpergun@google.com>,
	Borislav Petkov <bp@alien8.de>,
	David Rienjes <rientjes@google.com>,
	Marc Orr <marcorr@google.com>, Peter Gonda <pgonda@google.com>,
	Vipin Sharma <vipinsh@google.com>,
	Mingwei Zhang <mizhang@google.com>
Subject: [PATCH v2 1/4] KVM: SVM: fix missing sev_decommission in sev_receive_start
Date: Wed, 18 Aug 2021 05:39:05 +0000	[thread overview]
Message-ID: <20210818053908.1907051-2-mizhang@google.com> (raw)
In-Reply-To: <20210818053908.1907051-1-mizhang@google.com>

sev_decommission is needed in the error path of sev_bind_asid. The purpose
of this function is to clear the firmware context. Missing this step may
cause subsequent SEV launch failures.

Although missing sev_decommission issue has previously been found and was
fixed in sev_launch_start function. It is supposed to be fixed on all
scenarios where a firmware context needs to be freed. According to the AMD
SEV API v0.24 Section 1.3.3:

"The RECEIVE_START command is the only command other than the LAUNCH_START
command that generates a new guest context and guest handle."

The above indicates that RECEIVE_START command also requires calling
sev_decommission if ASID binding fails after RECEIVE_START succeeds.

So add the sev_decommission function in sev_receive_start.

Cc: Alper Gun <alpergun@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: David Rienjes <rientjes@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: John Allen <john.allen@amd.com>
Cc: Peter Gonda <pgonda@google.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vipin Sharma <vipinsh@google.com>

Fixes: af43cbbf954b ("KVM: SVM: Add support for KVM_SEV_RECEIVE_START command")
Signed-off-by: Mingwei Zhang <mizhang@google.com>
---
 arch/x86/kvm/svm/sev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 75e0b21ad07c..55d8b9c933c3 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1397,8 +1397,10 @@ static int sev_receive_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
 	/* Bind ASID to this guest */
 	ret = sev_bind_asid(kvm, start.handle, error);
-	if (ret)
+	if (ret) {
+		sev_decommission(start.handle);
 		goto e_free_session;
+	}
 
 	params.handle = start.handle;
 	if (copy_to_user((void __user *)(uintptr_t)argp->data,
-- 
2.33.0.rc1.237.g0d66db33f3-goog


  reply	other threads:[~2021-08-18  5:39 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-18  5:39 [PATCH v2 0/4] clean up interface between KVM and psp Mingwei Zhang
2021-08-18  5:39 ` Mingwei Zhang [this message]
2021-08-21  2:11   ` [PATCH v2 1/4] KVM: SVM: fix missing sev_decommission in sev_receive_start Marc Orr
2021-08-21  2:30     ` Marc Orr
2021-08-18  5:39 ` [PATCH v2 2/4] KVM: SVM: move sev_decommission to psp driver Mingwei Zhang
2021-08-18  5:39 ` [PATCH v2 3/4] KVM: SVM: move sev_bind_asid to psp Mingwei Zhang
2021-09-03 19:38   ` Sean Christopherson
2021-09-07 16:30     ` Brijesh Singh
2021-09-07 23:37       ` Sean Christopherson
2021-09-09 16:07         ` Brijesh Singh
2021-09-09 18:13           ` Sean Christopherson
2021-09-09 21:18             ` Mingwei Zhang
2021-09-09 22:25               ` Brijesh Singh
2021-09-10  1:18                 ` Mingwei Zhang
2021-09-10  1:23                   ` Marc Orr
2021-08-18  5:39 ` [PATCH v2 4/4] KVM: SVM: move sev_unbind_asid and DF_FLUSH logic into psp Mingwei Zhang

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