From a790e338c7c4971f83e680e59a91d1b91263c8f7 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 6 Jan 2023 01:13:02 +0000 Subject: [PATCH] KVM: SVM: Ignore writes to Remote Read Data on AVIC write traps Drop writes to APIC_RRR, a.k.a. Remote Read Data Register, on AVIC unaccelerated write traps. The register is read-only and isn't emulated by KVM. Sending the register through kvm_apic_write_nodecode() will result in screaming when x2APIC is enabled due to the unexpected failure to retrieve the MSR (KVM expects that only "legal" accesses will trap). Fixes: 4d1d7942e36a ("KVM: SVM: Introduce logic to (de)activate x2AVIC mode") Signed-off-by: Sean Christopherson Reviewed-by: Maxim Levitsky Message-Id: <20230106011306.85230-30-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/avic.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 2c6737f72bd4..ff08732469cb 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -628,6 +628,9 @@ static int avic_unaccel_trap_write(struct kvm_vcpu *vcpu) case APIC_DFR: avic_handle_dfr_update(vcpu); break; + case APIC_RRR: + /* Ignore writes to Read Remote Data, it's read-only. */ + return 1; default: break; } -- 2.11.0