[PATCH 2/2 v6] powerpc/kvm: common sw breakpoint instr across ppc

[Madhavan Srinivasan]

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 <maddy at linux.vnet.ibm.com>
---
Patch is only compile tested. Will really help if
someone can try it out and let me know the comments.

 arch/powerpc/include/asm/kvm_booke.h |  2 --
 arch/powerpc/kvm/booke.c             | 19 ++++++++++++++++++-
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_booke.h b/arch/powerpc/include/asm/kvm_booke.h
index f7aa5cc..ab7123a 100644
--- a/arch/powerpc/include/asm/kvm_booke.h
+++ b/arch/powerpc/include/asm/kvm_booke.h
@@ -30,8 +30,6 @@
 #define EHPRIV_OC_SHIFT			11
 /* "ehpriv 1" : ehpriv with OC = 1 is used for debug emulation */
 #define EHPRIV_OC_DEBUG			1
-#define KVMPPC_INST_EHPRIV_DEBUG	(KVMPPC_INST_EHPRIV | \
-					 (EHPRIV_OC_DEBUG << EHPRIV_OC_SHIFT))
 
 static inline void kvmppc_set_gpr(struct kvm_vcpu *vcpu, int num, ulong val)
 {
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index b4c89fa..365e85d 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -870,6 +870,11 @@ 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 */
+		if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
+			emulated = kvmppc_get_last_inst(vcpu, false, &last_inst);
+		break;
 	default:
 		break;
 	}
@@ -947,6 +952,18 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		break;
 
 	case BOOKE_INTERRUPT_PROGRAM:
+		if ((vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) &&
+			(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;
+		}
+
 		if (vcpu->arch.shared->msr & (MSR_PR | MSR_GS)) {
 			/*
 			 * Program traps generated by user-level software must
@@ -1505,7 +1522,7 @@ 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