KVM: PPC: Book3S PR: Fix software breakpoints

QEMU's kvm_handle_debug() function identifies software breakpoints by checking
for a value of 0 in kvm_debug_exit_arch's status field. Since this field isn't
explicitly set to 0 when the software breakpoint instruction is detected, any
previous non-zero value present causes a hang in QEMU as it tries to process
the breakpoint instruction incorrectly as a hardware breakpoint.

Ensure that the kvm_debug_exit_arch status field is set to 0 when the software
breakpoint instruction is detected (similar to the existing logic in booke.c
and e500_emulate.c) to restore software breakpoint functionality under Book3S
PR.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index 9f5b8c01c4e165a969d3317be6b5c5b9ae71b2f9..e77becaad5dd263570a26088e6122c44d889c459 100644 (file)
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -282,6 +282,7 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
                 */
                if (inst == KVMPPC_INST_SW_BREAKPOINT) {
                        run->exit_reason = KVM_EXIT_DEBUG;
+                       run->debug.arch.status = 0;
                        run->debug.arch.address = kvmppc_get_pc(vcpu);
                        emulated = EMULATE_EXIT_USER;
                        advance = 0;