On Sat, 2022-05-07 at 21:39 -0500, Suravee Suthikulpanit wrote:
> 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@xxxxxxxxxx>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> ---
> 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);
As futher optimization, we might even get rid of .set_virtual_apic_mode
and do all of this in kvm_vcpu_update_apicv.
But no need to do this now.
> + }
>
> 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;
Looks very good!
Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Best regards,
Maxim Levitsky
