Subject: [PATCH 2/2 v5] powerpc/kvm: common sw breakpoint instr across ppc

From: Madhavan Srinivasan <[email-masked]>
Date: Sun, 7 Sep 2014 22:01:33 +0530

This patch extends the use of illegal instruction as software
breakpoint instruction across the ppc platform. Patch extends
booke program interrupt code to support software breakpoint.

Signed-off-by: Madhavan Srinivasan <[email-masked]>
---

Patch is only compile tested. Will really help if
someone can try it out and let me know comments.

 arch/powerpc/kvm/booke.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index b4c89fa..1b84853 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -870,6 +870,10 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	case BOOKE_INTERRUPT_HV_PRIV:
 		emulated = kvmppc_get_last_inst(vcpu, false, &last_inst);
 		break;
+	case BOOKE_INTERRUPT_PROGRAM:
+		/*SW breakpoints arrive as illegal instructions on HV */
+		emulated = kvmppc_get_last_inst(vcpu, false, &last_inst);
+		break;
 	default:
 		break;
 	}
@@ -947,7 +951,17 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		break;
 
 	case BOOKE_INTERRUPT_PROGRAM:
-		if (vcpu->arch.shared->msr & (MSR_PR | MSR_GS)) {
+		if ((vcpu->arch.shared->msr & (MSR_PR | MSR_GS)) &&
+			(last_inst == KVMPPC_INST_SW_BREAKPOINT)) {
+			/*
+			 * We are here because of an SW breakpoint instr,
+			 * so lets return to host to handle.
+			 */
+			r = kvmppc_handle_debug(run, vcpu);
+			run->exit_reason = KVM_EXIT_DEBUG;
+			kvmppc_account_exit(vcpu, DEBUG_EXITS);
+			break;
+		} else {	
 			/*
 			 * Program traps generated by user-level software must
 			 * be handled by the guest kernel.
@@ -1505,7 +1519,7 @@ int kvm_vcpu_ioctl_get_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 		val = get_reg_val(reg->id, vcpu->arch.tsr);
 		break;
 	case KVM_REG_PPC_DEBUG_INST:
-		val = get_reg_val(reg->id, KVMPPC_INST_EHPRIV_DEBUG);
+		val = get_reg_val(reg->id, KVMPPC_INST_SW_BREAKPOINT);
 		break;
 	case KVM_REG_PPC_VRSAVE:
 		val = get_reg_val(reg->id, vcpu->arch.vrsave);
-- 
1.7.11.4