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

Madhavan Srinivasan
2014-09-07T16:31:33Z

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@linux.vnet.ibm.com>
---

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