Commit 44428e49 authored by Binbin Wu's avatar Binbin Wu Committed by Paolo Bonzini
Browse files

KVM: x86: Move pv_unhalted check out of kvm_vcpu_has_events() 



Move pv_unhalted check out of kvm_vcpu_has_events(), check pv_unhalted
explicitly when handling PV unhalt and expose kvm_vcpu_has_events().

kvm_vcpu_has_events() returns true if pv_unhalted is set, and pv_unhalted
is only cleared on transitions to KVM_MP_STATE_RUNNABLE.  If the guest
initiates a spurious wakeup, pv_unhalted could be left set in perpetuity.
Currently, this is not problematic because kvm_vcpu_has_events() is only
called when handling PV unhalt.  However, if kvm_vcpu_has_events() is used
for other purposes in the future, it could return the unexpected results.

Export kvm_vcpu_has_events() for its usage in broader contexts.

Suggested-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarBinbin Wu <binbin.wu@linux.intel.com>
Message-ID: <20250222014225.897298-3-binbin.wu@linux.intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 6162b373

arch/x86/kvm/x86.c

+5 −6
Original line number Diff line number Diff line
@@ -11143,7 +11143,7 @@ static bool kvm_vcpu_running(struct kvm_vcpu *vcpu) 
		!vcpu->arch.apf.halted);

}



static bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)

bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)

{

	if (!list_empty_careful(&vcpu->async_pf.done))

		return true;
@@ -11152,9 +11152,6 @@ static bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu) 
	    kvm_apic_init_sipi_allowed(vcpu))

		return true;



	if (vcpu->arch.pv.pv_unhalted)

		return true;



	if (kvm_is_exception_pending(vcpu))

		return true;
@@ -11192,10 +11189,12 @@ static bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu) 


	return false;

}

EXPORT_SYMBOL_GPL(kvm_vcpu_has_events);



int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)

{

	return kvm_vcpu_running(vcpu) || kvm_vcpu_has_events(vcpu);

	return kvm_vcpu_running(vcpu) || vcpu->arch.pv.pv_unhalted ||

	       kvm_vcpu_has_events(vcpu);

}



/* Called within kvm->srcu read side.  */
@@ -11331,7 +11330,7 @@ static int __kvm_emulate_halt(struct kvm_vcpu *vcpu, int state, int reason) 
	 */

	++vcpu->stat.halt_exits;

	if (lapic_in_kernel(vcpu)) {

		if (kvm_vcpu_has_events(vcpu))

		if (kvm_vcpu_has_events(vcpu) || vcpu->arch.pv.pv_unhalted)

			vcpu->arch.pv.pv_unhalted = false;

		else

			vcpu->arch.mp_state = state;

include/linux/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -1609,6 +1609,7 @@ void kvm_arch_disable_virtualization(void); 
int kvm_arch_enable_virtualization_cpu(void);

void kvm_arch_disable_virtualization_cpu(void);

#endif

bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu);

int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu);

bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu);

int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu);