Fix regression introduced by -machine accel=

Commit 85097db6 changed the timing when kvm_allowed is set until after
kvm is initialized.  During initialization, the ioeventfd initialization code
checks kvm_enabled() and after this change, ioeventfd is effectively disabled.

This causes a significant regression in performance.

Fix this by setting kvm_allowed before calling init.

Reported-by: Khoa Huynh <khoa@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/vl.c b/vl.c
index b362871..11f6386 100644
--- a/vl.c
+++ b/vl.c
@@ -1933,6 +1933,7 @@ static int configure_accelerator(void)
         p = get_opt_name(buf, sizeof (buf), p, ':');
         for (i = 0; i < ARRAY_SIZE(accel_list); i++) {
             if (strcmp(accel_list[i].opt_name, buf) == 0) {
+                *(accel_list[i].allowed) = 1;
                 ret = accel_list[i].init();
                 if (ret < 0) {
                     init_failed = 1;
@@ -1944,9 +1945,9 @@ static int configure_accelerator(void)
                                 accel_list[i].name,
                                 strerror(-ret));
                     }
+                    *(accel_list[i].allowed) = 0;
                 } else {
                     accel_initalised = 1;
-                    *(accel_list[i].allowed) = 1;
                 }
                 break;
             }