[Pkg-xen-devel] [patch] Activate Qemu options

[Thomas Goirand]

On 08/30/2011 06:49 PM, Ian Campbell wrote:
> On Mon, 2011-08-29 at 17:51 +0800, Thomas Goirand wrote:
>> Hi,
>>
>> This patch makes it possible for Qemu to use the SDL library, to
>> conveniently replace VNC, which has horrible mouse support.
>>
>> It also adds a IOEMU_CONFIGURE_OPTIONS option in tools/Makefile, so that
>> later on, we can call:
>>
>> $(MAKE_CLEAN) -C $(DIR)/tools $(CONFIG)
>> IOEMU_CONFIGURE_OPTIONS="--audio-drv-list=\"pa oss alsa sdl esd\"
>> --audio-card-list=\"ac97 es1370 sb16 cs4231a adlib gus\" --enable-mixemu"
>>
>> from debian/rules.real
> 
> That's quite an extensive list of audio devices. Where did it come from?
> Do we really need to be emulating adlib and gus for example? Are people
> really virtualising OSes of that era with the expectation that audio
> will work/be useful?
> 
> The default list appears to be "ac97 es1370 sb16" which seems much more
> reasonable. Remember that each additional device-model adds to the
> security attack surface which is of particular interest for ones which
> are not commonly used by the rest of the qemu universe.
> 
> In practical terms do you activate these using the dm_extra_args stuff
> or something else?

No, you do an export of some variable so that qemu knows about what you
want. I'll disable adlib and gus if you think it's a security issue, but
I believe it's a shame to have options and not use them. It'd be quite
nice to use Xen for example, to emulate old DOS machines, play old
games, or old demos...

> --- xen-4.1.1.orig/qemu/audio/sdlaudio.c
> +++ xen-4.1.1/qemu/audio/sdlaudio.c
> 
> Is that the correct path, shouldn't this be a patch of a patch in
> debian/patches or something?
> 
> 
>> @@ -21,8 +21,8 @@
>>   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
>>   * THE SOFTWARE.
>>   */
>> -#include <SDL.h>
>> -#include <SDL_thread.h>
>> +#include <SDL/SDL.h>
>> +#include <SDL/SDL_thread.h>
>>  #include "qemu-common.h"
>> [...]
>> @@ -67,6 +67,8 @@ CFLAGS += -DCONFIG_PASSTHROUGH
>>  $(info === PCI passthrough capability has been enabled ===)
>>  endif
>>  
>> +LIBS += -lpulse -lSDL
>> +
> 
> These all seem a bit suspicious to me. Qemu's configure script contains
> runes which call sdl_config to obtain correct CFLAGS and LIBS entries
> for the library as well as code to detect a suitable version of sdl etc.
> Is --enable-sdl not sufficient?
> 
> Ian.

Unless I'm mistaking, there's no such option such as --enable-sdl.

When doing:
/usr/src/xen/new/xen-4.1.1/debian/build/build-utils_i386/tools/../qemu/xen-setup
 --audio-drv-list="pa oss alsa sdl esd" --audio-card-list="ac97 es1370
sb16" --enable-mixemu --enable-sdl

then it tells:
ERROR: unknown option --enable-sdl

Any pointer, or do you now agree with what I did?

Thomas