[PATCH] hw/i386/vmmouse: Fix crash when using the vmmouse on a machine without vmport

[PATCH] hw/i386/vmmouse: Fix crash when using the vmmouse on a machine without vmport

[Thomas Huth]

QEMU currently crashes when the user tries to use the "vmmouse" on a
machine without vmport, e.g.:

 $ x86_64-softmmu/qemu-system-x86_64 -machine microvm -device vmmouse
 Segmentation fault (core dumped)

or:

 $ x86_64-softmmu/qemu-system-x86_64 -device vmmouse -M pc,vmport=off
 Segmentation fault (core dumped)

Let's avoid the crash by checking for the vmport device first.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 hw/i386/vmmouse.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/i386/vmmouse.c b/hw/i386/vmmouse.c
index 7c2a375527..e8e62bd96b 100644
--- a/hw/i386/vmmouse.c
+++ b/hw/i386/vmmouse.c
@@ -23,6 +23,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qapi/error.h"
 #include "ui/console.h"
 #include "hw/i386/pc.h"
 #include "hw/input/i8042.h"
@@ -269,6 +270,11 @@ static void vmmouse_realizefn(DeviceState *dev, Error **errp)
 
     DPRINTF("vmmouse_init\n");
 
+    if (!object_resolve_path_type("", TYPE_VMPORT, NULL)) {
+        error_setg(errp, "vmmouse needs a machine with vmport");
+        return;
+    }
+
     vmport_register(VMMOUSE_STATUS, vmmouse_ioport_read, s);
     vmport_register(VMMOUSE_COMMAND, vmmouse_ioport_read, s);
     vmport_register(VMMOUSE_DATA, vmmouse_ioport_read, s);
-- 
2.18.1

Re: [PATCH] hw/i386/vmmouse: Fix crash when using the vmmouse on a machine without vmport

[Darren Kenny]

On Wed, Jan 29, 2020 at 12:29:54PM +0100, Thomas Huth wrote:
>QEMU currently crashes when the user tries to use the "vmmouse" on a
>machine without vmport, e.g.:
>
> $ x86_64-softmmu/qemu-system-x86_64 -machine microvm -device vmmouse
> Segmentation fault (core dumped)
>
>or:
>
> $ x86_64-softmmu/qemu-system-x86_64 -device vmmouse -M pc,vmport=off
> Segmentation fault (core dumped)
>
>Let's avoid the crash by checking for the vmport device first.
>
>Signed-off-by: Thomas Huth <thuth@redhat.com>

Makes sense.

Reviewed-by: Darren Kenny <darren.kenny@oracle.com>

Thanks,

Darren

>---
> hw/i386/vmmouse.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
>diff --git a/hw/i386/vmmouse.c b/hw/i386/vmmouse.c
>index 7c2a375527..e8e62bd96b 100644
>--- a/hw/i386/vmmouse.c
>+++ b/hw/i386/vmmouse.c
>@@ -23,6 +23,7 @@
>  */
>
> #include "qemu/osdep.h"
>+#include "qapi/error.h"
> #include "ui/console.h"
> #include "hw/i386/pc.h"
> #include "hw/input/i8042.h"
>@@ -269,6 +270,11 @@ static void vmmouse_realizefn(DeviceState *dev, Error **errp)
>
>     DPRINTF("vmmouse_init\n");
>
>+    if (!object_resolve_path_type("", TYPE_VMPORT, NULL)) {
>+        error_setg(errp, "vmmouse needs a machine with vmport");
>+        return;
>+    }
>+
>     vmport_register(VMMOUSE_STATUS, vmmouse_ioport_read, s);
>     vmport_register(VMMOUSE_COMMAND, vmmouse_ioport_read, s);
>     vmport_register(VMMOUSE_DATA, vmmouse_ioport_read, s);
>-- 
>2.18.1
>
>

Re: [PATCH] hw/i386/vmmouse: Fix crash when using the vmmouse on a machine without vmport

[Laurent Vivier]

Le 29/01/2020 à 12:29, Thomas Huth a écrit :
> QEMU currently crashes when the user tries to use the "vmmouse" on a
> machine without vmport, e.g.:
> 
>  $ x86_64-softmmu/qemu-system-x86_64 -machine microvm -device vmmouse
>  Segmentation fault (core dumped)
> 
> or:
> 
>  $ x86_64-softmmu/qemu-system-x86_64 -device vmmouse -M pc,vmport=off
>  Segmentation fault (core dumped)
> 
> Let's avoid the crash by checking for the vmport device first.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  hw/i386/vmmouse.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/hw/i386/vmmouse.c b/hw/i386/vmmouse.c
> index 7c2a375527..e8e62bd96b 100644
> --- a/hw/i386/vmmouse.c
> +++ b/hw/i386/vmmouse.c
> @@ -23,6 +23,7 @@
>   */
>  
>  #include "qemu/osdep.h"
> +#include "qapi/error.h"
>  #include "ui/console.h"
>  #include "hw/i386/pc.h"
>  #include "hw/input/i8042.h"
> @@ -269,6 +270,11 @@ static void vmmouse_realizefn(DeviceState *dev, Error **errp)
>  
>      DPRINTF("vmmouse_init\n");
>  
> +    if (!object_resolve_path_type("", TYPE_VMPORT, NULL)) {
> +        error_setg(errp, "vmmouse needs a machine with vmport");
> +        return;
> +    }
> +
>      vmport_register(VMMOUSE_STATUS, vmmouse_ioport_read, s);
>      vmport_register(VMMOUSE_COMMAND, vmmouse_ioport_read, s);
>      vmport_register(VMMOUSE_DATA, vmmouse_ioport_read, s);
> 

Applied to my trivial-patches branch.

Thanks,
Laurent