[libvirt] [PATCH] qemu: Detect VGA_QXL capability correctly

[Guannan Ren]

On 01/04/2013 05:00 PM, Michal Privoznik wrote:
> Since 4c993d8a we failed to set this important capability, which
> allows starting a domain with QXL video card. We set DEVICE_QXL
> capability bit instead, which is not necessary wrong. Anyway, if
> qemu supports the new '-device qxl' it supports older '-vga qxl'
> as well. The latter is used for the primary (the first) qxl video
> card, the former for other video cards.
> ---
>
> Other approach is to set QEMU_CAPS_VGA_QXL unconditionally
> as supported by all qemu-1.2+ in qemuCapsInitQMPBasic().
> But I think this one is slightly nicer.
>
>   src/qemu/qemu_capabilities.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index f49a31c..e16bc70 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -2018,6 +2018,9 @@ qemuCapsProbeQMPObjects(qemuCapsPtr caps,
>       /* Prefer -chardev spicevmc (detected earlier) over -device spicevmc */
>       if (qemuCapsGet(caps, QEMU_CAPS_CHARDEV_SPICEVMC))
>           qemuCapsClear(caps, QEMU_CAPS_DEVICE_SPICEVMC);
> +    /* If qemu supports newer -device qxl it supports -vga qxl as well */
> +    if (qemuCapsGet(caps, QEMU_CAPS_DEVICE_QXL))
> +        qemuCapsSet(caps, QEMU_CAPS_VGA_QXL);
>   
>       return 0;
>   }

     I don't think it is necessary to add this code.
     because we have set the caps flag in qemuCapsParseHelpStr()

             if (strstr(p, "|qxl"))
             qemuCapsSet(caps, QEMU_CAPS_VGA_QXL);

     The problem here is about collecting cap flags via QMP, we need to 
set QEMU_CAPS_VGA_QXL
     unconditionally but still in discussion.

   Patch from Doug Goldstein in [libvirt] [PATCH] The -vga CLI arg 
accepts qxl in qemu 1.2+ always

The -vga command always accepts qxl in 1.2 and newer.
---
  src/qemu/qemu_capabilities.c |    1 +
  1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index f49a31c..c3ab488 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -2282,6 +2282,7 @@ qemuCapsInitQMPBasic(qemuCapsPtr caps)
      qemuCapsSet(caps, QEMU_CAPS_NO_USER_CONFIG);
      qemuCapsSet(caps, QEMU_CAPS_NETDEV_BRIDGE);
      qemuCapsSet(caps, QEMU_CAPS_SECCOMP_SANDBOX);
+    qemuCapsSet(caps, QEMU_CAPS_VGA_QXL);
  }