| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.11 101/601] KVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs | Date | Wed, 12 May 2021 16:42:58 +0200 |
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From: Sean Christopherson <seanjc@google.com>
commit c36b16d29f3af5f32fc1b2a3401bf48f71cabee1 upstream.
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> Message-Id: <20210331031936.2495277-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/x86/kvm/svm/sev.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -563,6 +563,7 @@ static int sev_launch_update_vmsa(struct { 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)) @@ -572,8 +573,8 @@ static int sev_launch_update_vmsa(struct 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);
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