[PATCH] Do not stop VM if emulation failed in userspace.

[Gleb Natapov <gleb@redhat.com>]

Continue vcpu execution in case emulation failure happened while vcpu
was in userspace. In this case #UD will be injected into the guest
allowing guest OS to kill offending process and continue.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/kvm-all.c b/kvm-all.c
index 9ac35aa..db28d94 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -786,6 +786,8 @@ static void kvm_handle_internal_error(CPUState *env, struct kvm_run *run)
     cpu_dump_state(env, stderr, fprintf, 0);
     if (run->internal.suberror == KVM_INTERNAL_ERROR_EMULATION) {
         fprintf(stderr, "emulation failure\n");
+        if (!kvm_arch_stop_on_emulation_error(env))
+		return;
     }
     /* FIXME: Should trigger a qmp message to let management know
      * something went wrong.
diff --git a/kvm.h b/kvm.h
index 67c0392..79e59f5 100644
--- a/kvm.h
+++ b/kvm.h
@@ -187,4 +187,5 @@ int kvm_set_irqfd(int gsi, int fd, bool assigned)
 #endif
 
 int kvm_set_ioeventfd_pio_word(int fd, uint16_t adr, uint16_t val, bool assign);
+bool kvm_arch_stop_on_emulation_error(CPUState *env);
 #endif
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 76c1adb..c333f86 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -1287,4 +1287,10 @@ void kvm_arch_update_guest_debug(CPUState *env, struct kvm_guest_debug *dbg)
 }
 #endif /* KVM_CAP_SET_GUEST_DEBUG */
 
+bool kvm_arch_stop_on_emulation_error(CPUState *env)
+{
+	return !(env->cr[0] & CR0_PE_MASK) ||
+		((env->segs[R_CS].selector  & 3) != 3);
+}
+
 #include "qemu-kvm-x86.c"
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index aa3d432..7b246a1 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -321,3 +321,8 @@ uint32_t kvmppc_get_tbfreq(void)
     retval = atoi(ns);
     return retval;
 }
+
+bool kvm_arch_stop_on_emulation_error(CPUState *env)
+{
+    return true;
+}
diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 72e77b0..14f723b 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -480,3 +480,8 @@ int kvm_arch_handle_exit(CPUState *env, struct kvm_run *run)
 
     return ret;
 }
+
+bool kvm_arch_stop_on_emulation_error(CPUState *env)
+{
+    return true;
+}        
--
			Gleb.