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KVM: SVM: Flush the "current" TLB when activating AVIC

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Flush the TLB when activating AVIC as the CPU can insert into the TLB
while AVIC is "locally" disabled.  KVM doesn't treat "APIC hardware
disabled" as VM-wide AVIC inhibition, and so when a vCPU has its APIC
hardware disabled, AVIC is not guaranteed to be inhibited.  As a result,
KVM may create a valid NPT mapping for the APIC base, which the CPU can
cache as a non-AVIC translation.

Note, Intel handles this in vmx_set_virtual_apic_mode().

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20230106011306.85230-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2023-01-06 01:12:36 +00:00 committed by Paolo Bonzini
parent 97a71c444a
commit 0ccf3e7cb9
1 changed files with 6 additions and 0 deletions
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6
arch/x86/kvm/svm/avic.c
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@ -86,6 +86,12 @@ static void avic_activate_vmcb(struct vcpu_svm *svm)
/* Disabling MSR intercept for x2APIC registers */
svm_set_x2apic_msr_interception(svm, false);
} else {
/*
* Flush the TLB, the guest may have inserted a non-APIC
* mapping into the TLB while AVIC was disabled.
*/
kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, &svm->vcpu);
/* For xAVIC and hybrid-xAVIC modes */
vmcb->control.avic_physical_id |= AVIC_MAX_PHYSICAL_ID;
/* Enabling MSR intercept for x2APIC registers */