From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.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-kernel@vger.kernel.org,
Brijesh Singh <brijesh.singh@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: [PATCH 1/3] KVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs
Date: Tue, 30 Mar 2021 20:19:34 -0700 [thread overview]
Message-ID: <20210331031936.2495277-2-seanjc@google.com> (raw)
In-Reply-To: <20210331031936.2495277-1-seanjc@google.com>
Use the kvm_for_each_vcpu() helper to iterate over vCPUs when encrypting
VMSAs for SEV, which effectively switches to use online_vcpus instead of
created_vcpus. This fixes a possible null-pointer dereference as
created_vcpus does not guarantee a vCPU exists, since it is updated at
the very beginning of KVM_CREATE_VCPU. created_vcpus exists to allow the
bulk of vCPU creation to run in parallel, while still correctly
restricting the max number of max vCPUs.
Fixes: ad73109ae7ec ("KVM: SVM: Provide support to launch and run an SEV-ES guest")
Cc: stable@vger.kernel.org
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/svm/sev.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 83e00e524513..6481d7165701 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -564,6 +564,7 @@ static int sev_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
struct sev_data_launch_update_vmsa *vmsa;
+ struct kvm_vcpu *vcpu;
int i, ret;
if (!sev_es_guest(kvm))
@@ -573,8 +574,8 @@ static int sev_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp)
if (!vmsa)
return -ENOMEM;
- for (i = 0; i < kvm->created_vcpus; i++) {
- struct vcpu_svm *svm = to_svm(kvm->vcpus[i]);
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ struct vcpu_svm *svm = to_svm(vcpu);
/* Perform some pre-encryption checks against the VMSA */
ret = sev_es_sync_vmsa(svm);
--
2.31.0.291.g576ba9dcdaf-goog
next prev parent reply other threads:[~2021-03-31 3:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 3:19 [PATCH 0/3] KVM: SVM: SEV{-ES} bug fixes Sean Christopherson
2021-03-31 3:19 ` Sean Christopherson [this message]
2021-03-31 3:19 ` [PATCH 2/3] KVM: SVM: Do not set sev->es_active until KVM_SEV_ES_INIT completes Sean Christopherson
2021-03-31 3:19 ` [PATCH 3/3] KVM: SVM: Do not allow SEV/SEV-ES initialization after vCPUs are created Sean Christopherson
2021-03-31 9:37 ` [PATCH 0/3] KVM: SVM: SEV{-ES} bug fixes Paolo Bonzini
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