xen-platform: Replace assert() with appropriate error reporting

Commit dbb7405d8caad0814ceddd568cb49f163a847561 made it possible to
trigger an assert using "-device xen-platform". Replace it with
appropriate error reporting.

Before:

  $ qemu-system-x86_64 -device xen-platform
  qemu-system-x86_64: hw/i386/xen/xen_platform.c:391: xen_platform_initfn: Assertion `xen_enabled()' failed.
  Aborted (core dumped)
  $

After:

  $ qemu-system-x86_64 -device xen-platform
  qemu-system-x86_64: -device xen-platform: xen-platform device requires the Xen accelerator
  $

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
index 3dc68cb0fe..de83f4e3ee 100644
--- a/hw/i386/xen/xen_platform.c
+++ b/hw/i386/xen/xen_platform.c
@@ -33,6 +33,7 @@
 #include "trace.h"
 #include "exec/address-spaces.h"
 #include "sysemu/block-backend.h"
+#include "qemu/error-report.h"
 
 #include <xenguest.h>
 
@@ -388,7 +389,10 @@ static void xen_platform_realize(PCIDevice *dev, Error **errp)
     uint8_t *pci_conf;
 
     /* Device will crash on reset if xen is not initialized */
-    assert(xen_enabled());
+    if (!xen_enabled()) {
+        error_setg(errp, "xen-platform device requires the Xen accelerator");
+        return;
+    }
 
     pci_conf = dev->config;