[8/9] KVM: Rework of guest debug state writing

Commit Message

Jan Kiszka Feb. 19, 2010, 6:22 p.m. UTC

None

Patch

diff --git a/kvm-all.c b/kvm-all.c
index 2237239..f0c5cf6 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -994,10 +994,6 @@  static void kvm_invoke_set_guest_debug(void *data)
     struct kvm_set_guest_debug_data *dbg_data = data;
     CPUState *env = dbg_data->env;
 
-    if (env->kvm_vcpu_dirty) {
-        kvm_arch_put_registers(env);
-        env->kvm_vcpu_dirty = 0;
-    }
     dbg_data->err = kvm_vcpu_ioctl(env, KVM_SET_GUEST_DEBUG, &dbg_data->dbg);
 }
 
@@ -1005,12 +1001,12 @@  int kvm_update_guest_debug(CPUState *env, unsigned long reinject_trap)
 {
     struct kvm_set_guest_debug_data data;
 
-    data.dbg.control = 0;
-    if (env->singlestep_enabled)
-        data.dbg.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
+    data.dbg.control = reinject_trap;
 
+    if (env->singlestep_enabled) {
+        data.dbg.control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
+    }
     kvm_arch_update_guest_debug(env, &data.dbg);
-    data.dbg.control |= reinject_trap;
     data.env = env;
 
     on_vcpu(env, kvm_invoke_set_guest_debug, &data);
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 8743f32..a4130d4 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -885,6 +885,32 @@  int kvm_arch_put_registers(CPUState *env)
     if (ret < 0)
         return ret;
 
+    /*
+     * Kernels before 2.6.33 (which correlates with !kvm_has_vcpu_events())
+     * overwrote flags.TF injected via SET_GUEST_DEBUG while updating GP regs.
+     * Work around this by updating the debug state once again if
+     * single-stepping is on.
+     * Another reason to call kvm_update_guest_debug here is a pending debug
+     * trap raise by the guest. On kernels without SET_VCPU_EVENTS we have to
+     * reinject them via SET_GUEST_DEBUG.
+     */
+    if (!kvm_has_vcpu_events() &&
+        (env->exception_injected != -1 || env->singlestep_enabled)) {
+        unsigned long reinject_trap = 0;
+
+        if (env->exception_injected == 1) {
+            reinject_trap = KVM_GUESTDBG_INJECT_DB;
+        } else if (env->exception_injected == 3) {
+            reinject_trap = KVM_GUESTDBG_INJECT_BP;
+        }
+        env->exception_injected = -1;
+
+        ret = kvm_update_guest_debug(env, reinject_trap);
+        if (ret < 0) {
+            return ret;
+        }
+    }
+
     return 0;
 }
 
@@ -1130,10 +1156,13 @@  int kvm_arch_debug(struct kvm_debug_exit_arch *arch_info)
     } else if (kvm_find_sw_breakpoint(cpu_single_env, arch_info->pc))
         handle = 1;
 
-    if (!handle)
-        kvm_update_guest_debug(cpu_single_env,
-                        (arch_info->exception == 1) ?
-                        KVM_GUESTDBG_INJECT_DB : KVM_GUESTDBG_INJECT_BP);
+    if (!handle) {
+        cpu_synchronize_state(cpu_single_env);
+        assert(cpu_single_env->exception_injected == -1);
+
+        cpu_single_env->exception_injected = arch_info->exception;
+        cpu_single_env->has_error_code = 0;
+    }
 
     return handle;
 }