Commit 27c4fa42 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

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: 26844fee ("KVM: x86: never write to memory from kvm_vcpu_check_block()")
Cc: stable@vger.kernel.org
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Reported-by: default avatarJim 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: default avatarSean Christopherson <seanjc@google.com>
parent 322a569c

arch/x86/kvm/vmx/nested.c

+34 −2
Original line number Diff line number Diff line
@@ -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;

}



/*