From: Sean Christopherson <seanjc@google.com>
To: Maxim Levitsky <mlevitsk@redhat.com>
Cc: kvm@vger.kernel.org, Jim Mattson <jmattson@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Borislav Petkov <bp@alien8.de>, Joerg Roedel <joro@8bytes.org>,
Ingo Molnar <mingo@redhat.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
stable@vger.kernel.org
Subject: Re: [PATCH 1/8] KVM: x86: avoid loading a vCPU after .vm_destroy was called
Date: Wed, 30 Mar 2022 00:27:55 +0000 [thread overview]
Message-ID: <YkOkCwUgMD1SVfaD@google.com> (raw)
In-Reply-To: <20220322172449.235575-2-mlevitsk@redhat.com>
On Tue, Mar 22, 2022, Maxim Levitsky wrote:
> 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.
Hmm, the SEV unbinding of ASIDs should be done after MMU teardown too (which your
patch also does).
>
> Fixes: 8221c1370056 ("svm: Manage vcpu load/unload when enable AVIC")
> Cc: stable@vger.kernel.org
>
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
> arch/x86/kvm/x86.c | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index d3a9ce07a565..ba920e537ddf 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -11759,20 +11759,15 @@ 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)
> @@ -11878,11 +11873,12 @@ 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);
Rather than split kvm_free_vcpus(), can we instead move the call to svm_vm_destroy()
by adding a second hook, .vm_teardown(), which is needed for TDX? I.e. keep VMX
where it is by using vm_teardown, but effectively move SVM?
https://lore.kernel.org/all/1fa2d0db387a99352d44247728c5b8ae5f5cab4d.1637799475.git.isaku.yamahata@intel.com
> 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);
> --
> 2.26.3
>
next prev parent reply other threads:[~2022-03-30 0:28 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-22 17:24 [PATCH 0/8] SVM fixes + refactoring Maxim Levitsky
2022-03-22 17:24 ` [PATCH 1/8] KVM: x86: avoid loading a vCPU after .vm_destroy was called Maxim Levitsky
2022-03-30 0:27 ` Sean Christopherson [this message]
2022-03-30 12:07 ` Paolo Bonzini
2022-04-28 5:47 ` Maxim Levitsky
2022-03-22 17:24 ` [PATCH 2/8] KVM: x86: SVM: use vmcb01 in avic_init_vmcb and init_vmcb Maxim Levitsky
2022-03-24 18:12 ` Paolo Bonzini
2022-03-27 15:15 ` Maxim Levitsky
2022-03-22 17:24 ` [PATCH 3/8] kvm: x86: SVM: use vmcb* instead of svm->vmcb where it makes sense Maxim Levitsky
2022-03-22 17:24 ` [PATCH 4/8] KVM: x86: SVM: fix avic spec based definitions again Maxim Levitsky
2022-03-22 17:24 ` [PATCH 5/8] KVM: x86: SVM: move tsc ratio definitions to svm.h Maxim Levitsky
2022-03-22 17:24 ` [PATCH 6/8] kvm: x86: SVM: remove unused defines Maxim Levitsky
2022-03-22 17:24 ` [PATCH 7/8] KVM: x86: SVM: fix tsc scaling when the host doesn't support it Maxim Levitsky
2022-03-22 17:24 ` [PATCH 8/8] KVM: x86: SVM: remove vgif_enabled() Maxim Levitsky
2022-03-30 0:20 ` Sean Christopherson
2022-03-30 12:08 ` Paolo Bonzini
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