do not loop on an incomplete io_thread_fd read

No need to loop if less than a full buffer is read, the next
read would return EAGAIN.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

diff --git a/vl.c b/vl.c
index b87044c53c11eb6dc797ea4e87c6765f9487aa71..f98661f34e2bc8a97e7b4eddb23bd5da791fbf2c 100644 (file)
--- a/vl.c
+++ b/vl.c
@@ -3229,12 +3229,12 @@ static void qemu_event_read(void *opaque)
 {
     int fd = (unsigned long)opaque;
     ssize_t len;
+    char buffer[512];
 
     /* Drain the notify pipe */
     do {
-        char buffer[512];
         len = read(fd, buffer, sizeof(buffer));
-    } while ((len == -1 && errno == EINTR) || len > 0);
+    } while ((len == -1 && errno == EINTR) || len == sizeof(buffer));
 }
 
 static int qemu_event_init(void)