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[Qemu-ppc] [PATCH 3/4 v8] ppc: Add software breakpoint support
From: |
Bharat Bhushan |
Subject: |
[Qemu-ppc] [PATCH 3/4 v8] ppc: Add software breakpoint support |
Date: |
Mon, 14 Jul 2014 14:45:38 +0530 |
This patch allow insert/remove software breakpoint.
When QEMU is not able to handle debug exception then we inject
program exception to guest because for software breakpoint QEMU
uses a ehpriv-1 instruction;
So there cannot be any reason that we are in qemu with exit reason
KVM_EXIT_DEBUG for guest set debug exception, only possibility is
guest executed ehpriv-1 privilege instruction and that's why we are
injecting program exception.
Signed-off-by: Bharat Bhushan <address@hidden>
---
v7->v8
- Decrement nip by 4 before calling ppc_cpu_do_interrupt()
as pointed by "Madhavan Srinivasan"
- Also added missing cpu_sync()
target-ppc/kvm.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 79 insertions(+), 14 deletions(-)
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index e00a20f..0f2e8e4 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -1275,6 +1275,75 @@ static int kvmppc_handle_dcr_write(CPUPPCState *env,
uint32_t dcrn, uint32_t dat
return 0;
}
+int kvm_arch_insert_sw_breakpoint(CPUState *cs, struct kvm_sw_breakpoint *bp)
+{
+ /* Mixed endian case is not handled */
+ uint32_t sc = debug_inst_opcode;
+
+ if (cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&bp->saved_insn,
+ sizeof(sc), 0) ||
+ cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&sc, sizeof(sc), 1)) {
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+int kvm_arch_remove_sw_breakpoint(CPUState *cs, struct kvm_sw_breakpoint *bp)
+{
+ uint32_t sc;
+
+ if (cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&sc, sizeof(sc), 0) ||
+ sc != debug_inst_opcode ||
+ cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&bp->saved_insn,
+ sizeof(sc), 1)) {
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+void kvm_arch_update_guest_debug(CPUState *cs, struct kvm_guest_debug *dbg)
+{
+ /* Software Breakpoint updates */
+ if (kvm_sw_breakpoints_active(cs)) {
+ dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;
+ }
+}
+
+static int kvm_handle_debug(PowerPCCPU *cpu, struct kvm_run *run)
+{
+ CPUState *cs = CPU(cpu);
+ CPUPPCState *env = &cpu->env;
+ struct kvm_debug_exit_arch *arch_info = &run->debug.arch;
+ int handle = 0;
+
+ if (kvm_find_sw_breakpoint(cs, arch_info->address)) {
+ handle = 1;
+ } else {
+ /* QEMU is not able to handle debug exception, so inject
+ * program exception to guest;
+ * Yes program exception NOT debug exception !!
+ * For software breakpoint QEMU uses a ehpriv-1 instruction;
+ * So there cannot be any reason that we are here for guest
+ * set debug exception, only possibility is guest executed a
+ * privilege instruction and that's why we are injecting
+ * program exception.
+ */
+
+ cpu_synchronize_state(cs);
+ /* env->nip is PC, so increment this by 4 to use
+ * ppc_cpu_do_interrupt(), which set srr0 = env->nip - 4.
+ */
+ env->nip += 4;
+ cs->exception_index = POWERPC_EXCP_PROGRAM;
+ env->error_code = POWERPC_EXCP_INVAL;
+ ppc_cpu_do_interrupt(cs);
+ }
+
+ return handle;
+}
+
int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
{
PowerPCCPU *cpu = POWERPC_CPU(cs);
@@ -1315,6 +1384,16 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
*run)
ret = 0;
break;
+ case KVM_EXIT_DEBUG:
+ DPRINTF("handle debug exception\n");
+ if (kvm_handle_debug(cpu, run)) {
+ ret = EXCP_DEBUG;
+ break;
+ }
+ /* re-enter, this exception was guest-internal */
+ ret = 0;
+ break;
+
default:
fprintf(stderr, "KVM: unknown exit reason %d\n", run->exit_reason);
ret = -1;
@@ -2003,16 +2082,6 @@ void kvm_arch_init_irq_routing(KVMState *s)
{
}
-int kvm_arch_insert_sw_breakpoint(CPUState *cpu, struct kvm_sw_breakpoint *bp)
-{
- return -EINVAL;
-}
-
-int kvm_arch_remove_sw_breakpoint(CPUState *cpu, struct kvm_sw_breakpoint *bp)
-{
- return -EINVAL;
-}
-
int kvm_arch_insert_hw_breakpoint(target_ulong addr, target_ulong len, int
type)
{
return -EINVAL;
@@ -2027,10 +2096,6 @@ void kvm_arch_remove_all_hw_breakpoints(void)
{
}
-void kvm_arch_update_guest_debug(CPUState *cpu, struct kvm_guest_debug *dbg)
-{
-}
-
struct kvm_get_htab_buf {
struct kvm_get_htab_header header;
/*
--
1.9.3