KVM: PPC: Book3S HV nestedv2: Do not inject certain interrupts

There is no need to inject an external interrupt in
kvmppc_book3s_irqprio_deliver() as the test for BOOK3S_IRQPRIO_EXTERNAL
in kvmhv_run_single_vcpu() before guest entry will raise LPCR_MER if
needed. There is also no need to inject the decrementer interrupt as
this will be raised within the L2 if needed. Avoiding these injections
reduces H_GUEST_GET_STATE hcalls by the L1.

Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231201132618.555031-8-vaibhav@linux.ibm.com

Author: iamjpn

arch/powerpc/kvm/book3s.c

@@ -302,11 +302,11 @@ static int kvmppc_book3s_irqprio_deliver(struct kvm_vcpu *vcpu,
 
 	switch (priority) {
 	case BOOK3S_IRQPRIO_DECREMENTER:
-		deliver = (kvmppc_get_msr(vcpu) & MSR_EE) && !crit;
+		deliver = !kvmhv_is_nestedv2() && (kvmppc_get_msr(vcpu) & MSR_EE) && !crit;
 		vec = BOOK3S_INTERRUPT_DECREMENTER;
 		break;
 	case BOOK3S_IRQPRIO_EXTERNAL:
-		deliver = (kvmppc_get_msr(vcpu) & MSR_EE) && !crit;
+		deliver = !kvmhv_is_nestedv2() && (kvmppc_get_msr(vcpu) & MSR_EE) && !crit;
 		vec = BOOK3S_INTERRUPT_EXTERNAL;
 		break;
 	case BOOK3S_IRQPRIO_SYSTEM_RESET: