kvm: Separate TCG from KVM cpu execution

Mixing up TCG bits with KVM already led to problems around eflags
emulation on x86. Moreover, quite some code that TCG requires on cpu
enty/exit is useless for KVM. So dispatch between tcg_cpu_exec and
kvm_cpu_exec as early as possible.

The core logic of cpu_halted from cpu_exec is added to
kvm_arch_process_irqchip_events. Moving away from cpu_exec makes
exception_index meaningless for KVM, we can simply pass the exit reason
directly (only "EXCP_DEBUG vs. rest" is relevant).

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 9 insertions, 10 deletions

diff --git a/kvm-all.c b/kvm-all.c
index 19cf1884cf..802c6b8369 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -895,10 +895,11 @@ int kvm_cpu_exec(CPUState *env)
 
     if (kvm_arch_process_irqchip_events(env)) {
         env->exit_request = 0;
-        env->exception_index = EXCP_HLT;
-        return 0;
+        return EXCP_HLT;
     }
 
+    cpu_single_env = env;
+
     do {
         if (env->kvm_vcpu_dirty) {
             kvm_arch_put_registers(env, KVM_PUT_RUNTIME_STATE);
@@ -927,7 +928,6 @@ int kvm_cpu_exec(CPUState *env)
         kvm_flush_coalesced_mmio_buffer();
 
         if (ret == -EINTR || ret == -EAGAIN) {
-            cpu_exit(env);
             DPRINTF("io window exit\n");
             ret = 0;
             break;
@@ -978,8 +978,8 @@ int kvm_cpu_exec(CPUState *env)
             DPRINTF("kvm_exit_debug\n");
 #ifdef KVM_CAP_SET_GUEST_DEBUG
             if (kvm_arch_debug(&run->debug.arch)) {
-                env->exception_index = EXCP_DEBUG;
-                return 0;
+                ret = EXCP_DEBUG;
+                goto out;
             }
             /* re-enter, this exception was guest-internal */
             ret = 1;
@@ -995,13 +995,12 @@ int kvm_cpu_exec(CPUState *env)
     if (ret < 0) {
         cpu_dump_state(env, stderr, fprintf, CPU_DUMP_CODE);
         vm_stop(VMSTOP_PANIC);
-        env->exit_request = 1;
-    }
-    if (env->exit_request) {
-        env->exit_request = 0;
-        env->exception_index = EXCP_INTERRUPT;
     }
+    ret = EXCP_INTERRUPT;
 
+out:
+    env->exit_request = 0;
+    cpu_single_env = NULL;
     return ret;
 }