KVM: nVMX: Check for pending posted interrupts when looking for nested events

Check for pending (and notified!) posted interrupts when checking if L2
has a pending wake event, as fully posted/notified virtual interrupt is a
valid wake event for HLT.

Note that KVM must check vmx->nested.pi_pending to avoid prematurely
waking L2, e.g. even if KVM sees a non-zero PID.PIR and PID.0N=1, the
virtual interrupt won't actually be recognized until a notification IRQ is
received by the vCPU or the vCPU does (nested) VM-Enter.

Fixes: 26844fee6ade ("KVM: x86: never write to memory from kvm_vcpu_check_block()")
Cc: stable@vger.kernel.org
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Reported-by: Jim Mattson <jmattson@google.com>
Closes: https://lore.kernel.org/all/20231207010302.2240506-1-jmattson@google.com
Link: https://lore.kernel.org/r/20240607172609.3205077-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 411fe7aa07933369c52386e90411c557b06ef454..732340ff3300ab2140417cfc32a429e1e6f528c5 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4034,8 +4034,40 @@ static bool nested_vmx_preemption_timer_pending(struct kvm_vcpu *vcpu)
 
 static bool vmx_has_nested_events(struct kvm_vcpu *vcpu, bool for_injection)
 {
-       return nested_vmx_preemption_timer_pending(vcpu) ||
-              to_vmx(vcpu)->nested.mtf_pending;
+       struct vcpu_vmx *vmx = to_vmx(vcpu);
+       void *vapic = vmx->nested.virtual_apic_map.hva;
+       int max_irr, vppr;
+
+       if (nested_vmx_preemption_timer_pending(vcpu) ||
+           vmx->nested.mtf_pending)
+               return true;
+
+       /*
+        * Virtual Interrupt Delivery doesn't require manual injection.  Either
+        * the interrupt is already in GUEST_RVI and will be recognized by CPU
+        * at VM-Entry, or there is a KVM_REQ_EVENT pending and KVM will move
+        * the interrupt from the PIR to RVI prior to entering the guest.
+        */
+       if (for_injection)
+               return false;
+
+       if (!nested_cpu_has_vid(get_vmcs12(vcpu)) ||
+           __vmx_interrupt_blocked(vcpu))
+               return false;
+
+       if (!vapic)
+               return false;
+
+       vppr = *((u32 *)(vapic + APIC_PROCPRI));
+
+       if (vmx->nested.pi_pending && vmx->nested.pi_desc &&
+           pi_test_on(vmx->nested.pi_desc)) {
+               max_irr = pi_find_highest_vector(vmx->nested.pi_desc);
+               if (max_irr > 0 && (max_irr & 0xf0) > (vppr & 0xf0))
+                       return true;
+       }
+
+       return false;
 }
 
 /*