On Tue, Sep 22, 2009 at 11:45:02AM +0100, Daniel P. Berrange wrote:
> When using VNC for graphics + keyboard + mouse, we shouldn't
> then use the host OS for audio. Audio should go back over
> VNC.
>
> When using SDL for graphics, we should use the host OS for
> audio since that's where the display is. We need to allow
> certain QEMU env variables to be passed through to guest
> too to allow choice of QEMU audio backend.
All this makes sense !
> * qemud/libvirtd.sysconf: Mention QEMU/SDL audio env vars
> * src/qemu_conf.c: Passthrough QEMU/SDL audio env for SDL display,
> disable host audio for VNC display
> ---
> daemon/libvirtd.sysconf | 8 ++++++++
> src/qemu/qemu_conf.c | 14 ++++++++++++++
> 2 files changed, 22 insertions(+), 0 deletions(-)
>
> diff --git a/daemon/libvirtd.sysconf b/daemon/libvirtd.sysconf
> index fe4596a..28080a0 100644
> --- a/daemon/libvirtd.sysconf
> +++ b/daemon/libvirtd.sysconf
> @@ -7,3 +7,11 @@
>
> # Override Kerberos service keytab for SASL/GSSAPI
> #KRB5_KTNAME=/etc/libvirt/krb5.tab
> +
> +# Override the QEMU/SDL default audio driver probing when
> +# starting virtual machines using SDL graphics
> +#
> +# NB these have no effect for VMs using VNC
> +#QEMU_AUDIO_DRV=sdl
> +#
> +#SDL_AUDIODRIVER=pulse
> diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
> index 273aeca..74ca52b 100644
> --- a/src/qemu/qemu_conf.c
> +++ b/src/qemu/qemu_conf.c
> @@ -2109,6 +2109,13 @@ int qemudBuildCommandLine(virConnectPtr conn,
> ADD_ARG_LIT("-k");
> ADD_ARG_LIT(def->graphics[0]->data.vnc.keymap);
> }
> +
> + /* QEMU implements a VNC extension for providing audio, so we
> + * set the audio backend to none, to prevent it opening the
> + * host OS audio devices since that causes security issues
> + * and is non-sensical when using VNC.
> + */
> + ADD_ENV_LIT("QEMU_AUDIO_DRV=none");
> } else if ((def->ngraphics == 1) &&
> def->graphics[0]->type == VIR_DOMAIN_GRAPHICS_TYPE_SDL) {
> char *xauth = NULL;
> @@ -2131,6 +2138,13 @@ int qemudBuildCommandLine(virConnectPtr conn,
> ADD_ENV(display);
> if (def->graphics[0]->data.sdl.fullscreen)
> ADD_ARG_LIT("-full-screen");
> +
> + /* If using SDL for video, then we should just let it
> + * use QEMU's host audio drivers, possibly SDL too
> + * User can set these two before starting libvirtd
> + */
> + ADD_ENV_COPY("QEMU_AUDIO_DRV");
> + ADD_ENV_COPY("SDL_AUDIODRIVER");
> }
>
> if (def->nvideos) {
ACK,
I wonder if that would be sufficient to drop the
libvirt-0.6.4-svirt-sound.patch that we carry in Fedora, not sure
because we still may use the local audio in some cases. Opinion ?
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel@xxxxxxxxxxxx | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
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