KVM: PPC: Book3S HV nestedv2: Do not check msr on hcalls

The check for a hcall coming from userspace is done for KVM-PR. This is
not supported for nestedv2 and the L0 will directly inject the necessary
exception to the L2 if userspace performs a hcall. Avoid checking the
MSR and thus avoid a H_GUEST_GET_STATE hcall in the L1.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231201132618.555031-4-vaibhav@linux.ibm.com

Author: iamjpn

arch/powerpc/kvm/book3s_hv.c

@@ -1688,7 +1688,7 @@ static int kvmppc_handle_exit_hv(struct kvm_vcpu *vcpu,
 	{
 		int i;
 
-		if (unlikely(__kvmppc_get_msr_hv(vcpu) & MSR_PR)) {
+		if (!kvmhv_is_nestedv2() && unlikely(__kvmppc_get_msr_hv(vcpu) & MSR_PR)) {
 			/*
 			 * Guest userspace executed sc 1. This can only be
 			 * reached by the P9 path because the old path
@@ -4949,7 +4949,7 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu)
 		if (run->exit_reason == KVM_EXIT_PAPR_HCALL) {
 			accumulate_time(vcpu, &vcpu->arch.hcall);
 
-			if (WARN_ON_ONCE(__kvmppc_get_msr_hv(vcpu) & MSR_PR)) {
+			if (!kvmhv_is_nestedv2() && WARN_ON_ONCE(__kvmppc_get_msr_hv(vcpu) & MSR_PR)) {
 				/*
 				 * These should have been caught reflected
 				 * into the guest by now. Final sanity check: