[PATCH v6 08/17] KVM: x86: Deactivate APICv on vCPU with APIC disabled

Suravee Suthikulpanit
2022-05-19T10:28:36Z

APICv should be deactivated on vCPU that has APIC disabled.
Therefore, call kvm_vcpu_update_apicv() when changing
APIC mode, and add additional check for APIC disable mode
when determine APICV activation,

Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
arch/x86/kvm/lapic.c | 4 +++-
arch/x86/kvm/x86.c | 4 +++-
2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 8b8c4a905976..680824d7aa0d 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2346,8 +2346,10 @@ void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value)
if (((old_value ^ value) & X2APIC_ENABLE) && (value & X2APIC_ENABLE))
kvm_apic_set_x2apic_id(apic, vcpu->vcpu_id);

- if ((old_value ^ value) & (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE))
+ if ((old_value ^ value) & (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE)) {
+ kvm_vcpu_update_apicv(vcpu);
static_call_cond(kvm_x86_set_virtual_apic_mode)(vcpu);
+ }

apic->base_address = apic->vcpu->arch.apic_base &
MSR_IA32_APICBASE_BASE;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8ee8c91fa762..77e49892dea1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9836,7 +9836,9 @@ void kvm_vcpu_update_apicv(struct kvm_vcpu *vcpu)

down_read(&vcpu->kvm->arch.apicv_update_lock);

- activate = kvm_vcpu_apicv_activated(vcpu);
+ /* Do not activate APICV when APIC is disabled */
+ activate = kvm_vcpu_apicv_activated(vcpu) &&
+ (kvm_get_apic_mode(vcpu) != LAPIC_MODE_DISABLED);

if (vcpu->arch.apicv_active == activate)
goto out;
--
2.25.1