[PATCH 2/5] booke: exit to guest userspace for unimplemented hcalls in kvm

[Bharat Bhushan <r65777@freescale.com>]

Exit to guest user space if kvm does not implement the hcall.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
---
 arch/powerpc/kvm/booke.c   |   47 +++++++++++++++++++++++++++++++++++++------
 arch/powerpc/kvm/powerpc.c |    1 +
 include/uapi/linux/kvm.h   |    1 +
 3 files changed, 42 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 17722d8..c8b41b4 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -1005,9 +1005,25 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		break;
 
 #ifdef CONFIG_KVM_BOOKE_HV
-	case BOOKE_INTERRUPT_HV_SYSCALL:
+	case BOOKE_INTERRUPT_HV_SYSCALL: {
+		int i;
 		if (!(vcpu->arch.shared->msr & MSR_PR)) {
-			kvmppc_set_gpr(vcpu, 3, kvmppc_kvm_pv(vcpu));
+			r = kvmppc_kvm_pv(vcpu);
+			if (r != EV_UNIMPLEMENTED) {
+				/* except unimplemented return to guest */
+				kvmppc_set_gpr(vcpu, 3, r);
+				kvmppc_account_exit(vcpu, SYSCALL_EXITS);
+				r = RESUME_GUEST;
+				break;
+			}
+			/* Exit to userspace for unimplemented hcalls in kvm */
+			run->epapr_hcall.nr = kvmppc_get_gpr(vcpu, 11);
+			run->epapr_hcall.ret = 0;
+			for (i = 0; i < 8; i++)
+				run->epapr_hcall.args[i] = kvmppc_get_gpr(vcpu, 3 + i);
+			vcpu->arch.hcall_needed = 1;
+			kvmppc_account_exit(vcpu, SYSCALL_EXITS);
+			r = RESUME_HOST;
 		} else {
 			/*
 			 * hcall from guest userspace -- send privileged
@@ -1016,22 +1032,39 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 			kvmppc_core_queue_program(vcpu, ESR_PPR);
 		}
 
-		r = RESUME_GUEST;
+		run->exit_reason = KVM_EXIT_EPAPR_HCALL;
 		break;
+	}
 #else
-	case BOOKE_INTERRUPT_SYSCALL:
+	case BOOKE_INTERRUPT_SYSCALL: {
+		int i;
+		r = RESUME_GUEST;
 		if (!(vcpu->arch.shared->msr & MSR_PR) &&
 		    (((u32)kvmppc_get_gpr(vcpu, 0)) == KVM_SC_MAGIC_R0)) {
 			/* KVM PV hypercalls */
-			kvmppc_set_gpr(vcpu, 3, kvmppc_kvm_pv(vcpu));
-			r = RESUME_GUEST;
+			r = kvmppc_kvm_pv(vcpu);
+			if (r != EV_UNIMPLEMENTED) {
+				/* except unimplemented return to guest */
+				kvmppc_set_gpr(vcpu, 3, r);
+				kvmppc_account_exit(vcpu, SYSCALL_EXITS);
+				r = RESUME_GUEST;
+				break;
+			}
+			/* Exit to userspace for unimplemented hcalls in kvm */
+			run->epapr_hcall.nr = kvmppc_get_gpr(vcpu, 11);
+			run->epapr_hcall.ret = 0;
+			for (i = 0; i < 8; i++)
+				run->epapr_hcall.args[i] = kvmppc_get_gpr(vcpu, 3 + i);
+			vcpu->arch.hcall_needed = 1;
+			run->exit_reason = KVM_EXIT_EPAPR_HCALL;
+			r = RESUME_HOST;
 		} else {
 			/* Guest syscalls */
 			kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_SYSCALL);
 		}
 		kvmppc_account_exit(vcpu, SYSCALL_EXITS);
-		r = RESUME_GUEST;
 		break;
+	}
 #endif
 
 	case BOOKE_INTERRUPT_DTLB_MISS: {
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 4e05f8c..6c6199d 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -307,6 +307,7 @@ int kvm_dev_ioctl_check_extension(long ext)
 	case KVM_CAP_PPC_BOOKE_SREGS:
 	case KVM_CAP_PPC_BOOKE_WATCHDOG:
 	case KVM_CAP_PPC_EPR:
+	case KVM_CAP_EXIT_EPAPR_HCALL:
 #else
 	case KVM_CAP_PPC_SEGSTATE:
 	case KVM_CAP_PPC_HIOR:
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 01ee50e..b5266e5 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -674,6 +674,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_PPC_RTAS 91
 #define KVM_CAP_IRQ_XICS 92
 #define KVM_CAP_ARM_EL1_32BIT 93
+#define KVM_CAP_EXIT_EPAPR_HCALL 94
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
1.7.0.4