| From c36b16d29f3af5f32fc1b2a3401bf48f71cabee1 Mon Sep 17 00:00:00 2001 |
| From: Sean Christopherson <seanjc@google.com> |
| Date: Tue, 30 Mar 2021 20:19:34 -0700 |
| Subject: KVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs |
| |
| 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); |