KVM: PPC: Book3S HV P9: Reflect userspace hcalls to hash guests to support PR KVM

The reflection of sc 1 interrupts from guest PR=1 to the guest kernel is
required to support a hash guest running PR KVM where its guest is
making hcalls with sc 1.

In preparation for hash guest support, add this hcall reflection to the
P9 path. The P7/8 path does this in its realmode hcall handler
(sc_1_fast_return).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-30-npiggin@gmail.com

arch/powerpc/kvm/book3s_hv.c

@@ -1457,13 +1457,23 @@ static int kvmppc_handle_exit_hv(struct kvm_vcpu *vcpu,
 			 * Guest userspace executed sc 1. This can only be
 			 * reached by the P9 path because the old path
 			 * handles this case in realmode hcall handlers.
-			 *
-			 * Radix guests can not run PR KVM or nested HV hash
-			 * guests which might run PR KVM, so this is always
-			 * a privilege fault. Send a program check to guest
-			 * kernel.
 			 */
-			kvmppc_core_queue_program(vcpu, SRR1_PROGPRIV);
+			if (!kvmhv_vcpu_is_radix(vcpu)) {
+				/*
+				 * A guest could be running PR KVM, so this
+				 * may be a PR KVM hcall. It must be reflected
+				 * to the guest kernel as a sc interrupt.
+				 */
+				kvmppc_core_queue_syscall(vcpu);
+			} else {
+				/*
+				 * Radix guests can not run PR KVM or nested HV
+				 * hash guests which might run PR KVM, so this
+				 * is always a privilege fault. Send a program
+				 * check to guest kernel.
+				 */
+				kvmppc_core_queue_program(vcpu, SRR1_PROGPRIV);
+			}
 			r = RESUME_GUEST;
 			break;
 		}