The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6fcee03df6a1a3101a77344be37bb85c6142d56c Mon Sep 17 00:00:00 2001 From: Maxim Levitsky mlevitsk@redhat.com Date: Tue, 22 Mar 2022 19:24:42 +0200 Subject: [PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called

This can cause various unexpected issues, since VM is partially destroyed at that point.

For example when AVIC is enabled, this causes avic_vcpu_load to access physical id page entry which is already freed by .vm_destroy.

Fixes: 8221c1370056 ("svm: Manage vcpu load/unload when enable AVIC") Cc: stable@vger.kernel.org

Signed-off-by: Maxim Levitsky mlevitsk@redhat.com Message-Id: 20220322172449.235575-2-mlevitsk@redhat.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1abce22b14d7..ba4faeb32437 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11816,20 +11816,15 @@ static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) vcpu_put(vcpu); }

-static void kvm_free_vcpus(struct kvm *kvm) +static void kvm_unload_vcpu_mmus(struct kvm *kvm) { unsigned long i; struct kvm_vcpu *vcpu;

- /* - * Unpin any mmu pages first. - */ kvm_for_each_vcpu(i, vcpu, kvm) { kvm_clear_async_pf_completion_queue(vcpu); kvm_unload_vcpu_mmu(vcpu); } - - kvm_destroy_vcpus(kvm); }

void kvm_arch_sync_events(struct kvm *kvm) @@ -11935,11 +11930,12 @@ void kvm_arch_destroy_vm(struct kvm *kvm) __x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, 0, 0); mutex_unlock(&kvm->slots_lock); } + kvm_unload_vcpu_mmus(kvm); static_call_cond(kvm_x86_vm_destroy)(kvm); kvm_free_msr_filter(srcu_dereference_check(kvm->arch.msr_filter, &kvm->srcu, 1)); kvm_pic_destroy(kvm); kvm_ioapic_destroy(kvm); - kvm_free_vcpus(kvm); + kvm_destroy_vcpus(kvm); kvfree(rcu_dereference_check(kvm->arch.apic_map, 1)); kfree(srcu_dereference_check(kvm->arch.pmu_event_filter, &kvm->srcu, 1)); kvm_mmu_uninit_vm(kvm);