Messages in this thread Patch in this message | | | Date | Wed, 18 Aug 2021 05:39:05 +0000 | Subject | [PATCH v2 1/4] KVM: SVM: fix missing sev_decommission in sev_receive_start | From | Mingwei Zhang <> |
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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
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