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KVM: SVM: Always update local APIC on writes to logical dest register

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Update the vCPU's local (virtual) APIC on LDR writes even if the write
"fails".  The APIC needs to recalc the optimized logical map even if the
LDR is invalid or zero, e.g. if the guest clears its LDR, the optimized
map will be left as is and the vCPU will receive interrupts using its
old LDR.

Fixes: 18f40c53e10f ("svm: Add VMEXIT handlers for AVIC")
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-26-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2023-01-06 01:12:58 +00:00 committed by Paolo Bonzini
parent 9a364857ab
commit 1ba59a4454
1 changed files with 4 additions and 7 deletions
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11
arch/x86/kvm/svm/avic.c
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@ -573,7 +573,7 @@ static void avic_invalidate_logical_id_entry(struct kvm_vcpu *vcpu)
clear_bit(AVIC_LOGICAL_ID_ENTRY_VALID_BIT, (unsigned long *)entry);
}
static int avic_handle_ldr_update(struct kvm_vcpu *vcpu)
static void avic_handle_ldr_update(struct kvm_vcpu *vcpu)
{
int ret = 0;
struct vcpu_svm *svm = to_svm(vcpu);
@ -582,10 +582,10 @@ static int avic_handle_ldr_update(struct kvm_vcpu *vcpu)
/* AVIC does not support LDR update for x2APIC */
if (apic_x2apic_mode(vcpu->arch.apic))
return 0;
return;
if (ldr == svm->ldr_reg)
return 0;
return;
avic_invalidate_logical_id_entry(vcpu);
@ -594,8 +594,6 @@ static int avic_handle_ldr_update(struct kvm_vcpu *vcpu)
if (!ret)
svm->ldr_reg = ldr;
return ret;
}
static void avic_handle_dfr_update(struct kvm_vcpu *vcpu)
@ -617,8 +615,7 @@ static int avic_unaccel_trap_write(struct kvm_vcpu *vcpu)
switch (offset) {
case APIC_LDR:
if (avic_handle_ldr_update(vcpu))
return 0;
avic_handle_ldr_update(vcpu);
break;
case APIC_DFR:
avic_handle_dfr_update(vcpu);