From ab1b1dc131cd7da4c66758e711c0f69da3633561 Mon Sep 17 00:00:00 2001 From: Suravee Suthikulpanit Date: Thu, 19 May 2022 05:26:58 -0500 Subject: [PATCH] KVM: SVM: Do not support updating APIC ID when in x2APIC mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In X2APIC mode, the Logical Destination Register is read-only, which provides a fixed mapping between the logical and physical APIC IDs. Therefore, there is no Logical APIC ID table in X2AVIC and the processor uses the X2APIC ID in the backing page to create a vCPU’s logical ID. In addition, KVM does not support updating APIC ID in x2APIC mode, which means AVIC does not need to handle this case. Therefore, check x2APIC mode when handling physical and logical APIC ID update, and when invalidating logical APIC ID table. Reviewed-by: Maxim Levitsky Suggested-by: Maxim Levitsky Signed-off-by: Suravee Suthikulpanit Message-Id: <20220519102709.24125-7-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/avic.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 8b8a221cd635..cc4da232040c 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -526,8 +526,13 @@ static void avic_invalidate_logical_id_entry(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); bool flat = svm->dfr_reg == APIC_DFR_FLAT; - u32 *entry = avic_get_logical_id_entry(vcpu, svm->ldr_reg, flat); + u32 *entry; + /* Note: x2AVIC does not use logical APIC ID table */ + if (apic_x2apic_mode(vcpu->arch.apic)) + return; + + entry = avic_get_logical_id_entry(vcpu, svm->ldr_reg, flat); if (entry) clear_bit(AVIC_LOGICAL_ID_ENTRY_VALID_BIT, (unsigned long *)entry); } @@ -539,6 +544,10 @@ static int avic_handle_ldr_update(struct kvm_vcpu *vcpu) u32 ldr = kvm_lapic_get_reg(vcpu->arch.apic, APIC_LDR); u32 id = kvm_xapic_id(vcpu->arch.apic); + /* AVIC does not support LDR update for x2APIC */ + if (apic_x2apic_mode(vcpu->arch.apic)) + return 0; + if (ldr == svm->ldr_reg) return 0;