From: Sean Christopherson Date: Wed, 31 Mar 2021 03:19:34 +0000 (-0700) Subject: KVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c36b16d29f3af5f32fc1b2a3401bf48f71cabee1;p=linux.git KVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs 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 Cc: Tom Lendacky Signed-off-by: Sean Christopherson Message-Id: <20210331031936.2495277-2-seanjc@google.com> Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 83e00e5245136..6481d71657012 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);