KVM: ppc: guest breakpoint support
Allow host userspace to program hardware debug registers to set breakpoints
inside guests.
Signed-off-by: Jerone Young <jyoung5@us.ibm.com>
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/powerpc/kvm/booke_interrupts.S b/arch/powerpc/kvm/booke_interrupts.S
index 3b653b5..8eaba26 100644
--- a/arch/powerpc/kvm/booke_interrupts.S
+++ b/arch/powerpc/kvm/booke_interrupts.S
@@ -42,7 +42,8 @@
#define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
#define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
- (1<<BOOKE_INTERRUPT_DTLB_MISS))
+ (1<<BOOKE_INTERRUPT_DTLB_MISS) | \
+ (1<<BOOKE_INTERRUPT_DEBUG))
#define NEED_DEAR_MASK ((1<<BOOKE_INTERRUPT_DATA_STORAGE) | \
(1<<BOOKE_INTERRUPT_DTLB_MISS))
@@ -431,6 +432,14 @@
oris r3, r3, KVMPPC_MSR_MASK@h
ori r3, r3, KVMPPC_MSR_MASK@l
mtsrr1 r3
+
+ /* Clear any debug events which occurred since we disabled MSR[DE].
+ * XXX This gives us a 3-instruction window in which a breakpoint
+ * intended for guest context could fire in the host instead. */
+ lis r3, 0xffff
+ ori r3, r3, 0xffff
+ mtspr SPRN_DBSR, r3
+
lwz r3, VCPU_GPR(r3)(r4)
lwz r4, VCPU_GPR(r4)(r4)
rfi