KVM: x86: latch INITs while in system management mode

Do not process INITs immediately while in system management mode, keep
it instead in apic->pending_events.  Tell userspace if an INIT is
pending when they issue GET_VCPU_EVENTS, and similarly handle the
new field in SET_VCPU_EVENTS.

Note that the same treatment should be done while in VMX non-root mode.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index b8e47e2..beeef05 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2057,8 +2057,19 @@ void kvm_apic_accept_events(struct kvm_vcpu *vcpu)
        if (!kvm_vcpu_has_lapic(vcpu) || !apic->pending_events)
                return;
 
-       pe = xchg(&apic->pending_events, 0);
+       /*
+        * INITs are latched while in SMM.  Because an SMM CPU cannot
+        * be in KVM_MP_STATE_INIT_RECEIVED state, just eat SIPIs
+        * and delay processing of INIT until the next RSM.
+        */
+       if (is_smm(vcpu)) {
+               WARN_ON_ONCE(vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED);
+               if (test_bit(KVM_APIC_SIPI, &apic->pending_events))
+                       clear_bit(KVM_APIC_SIPI, &apic->pending_events);
+               return;
+       }
 
+       pe = xchg(&apic->pending_events, 0);
        if (test_bit(KVM_APIC_INIT, &pe)) {
                kvm_lapic_reset(vcpu, true);
                kvm_vcpu_reset(vcpu, true);

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ab977e7..ab2521b 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5482,6 +5482,9 @@ static void kvm_smm_changed(struct kvm_vcpu *vcpu)
                if (unlikely(vcpu->arch.smi_pending)) {
                        kvm_make_request(KVM_REQ_SMI, vcpu);
                        vcpu->arch.smi_pending = 0;
+               } else {
+                       /* Process a latched INIT, if any.  */
+                       kvm_make_request(KVM_REQ_EVENT, vcpu);
                }
        }
 }