Re: [Qemu-devel] [v2][PATCH 2/2] libxl: introduce gfx_passthru_kind

[Ian Campbell <ian.campbell@citrix.com>]

On Fri, 2015-03-13 at 09:39 +0800, Chen, Tiejun wrote:
> > I don't think you can abort here, since a user can set
> > b_info->u.hvm.gfx_passthru_kind to default. You would need to return an
> > error.
> 
> Then, looks I should do this,
> 
>                      LOG(ERROR, "No supported IGD to passthru,"
>                          " or please force set gfx_passthru=\"igd\".\n");
>                      return NULL;

If I remember the context correctly this is in the autodetect case, so I
think shouldn't mention IGD. Something like "Unable to detect graphics
passthru kind, please set gfx_passthru_kind. See xl.cfg(5) for more
information."

> >
> >> @@ -720,6 +720,13 @@ void libxl_mac_copy(libxl_ctx *ctx, libxl_mac *dst,
> >> libxl_mac *src);
> >>    #define LIBXL_HAVE_PSR_MBM 1
> >>    #endif
> >>
> >> +/*
> >> + * LIBXL_HAVE_GFX_PASSTHRU_KIND
> >> + *
> >> + * If this is defined, the Graphic Device Passthrough Override is
> >> supported.
> >
> > Almost, please also explicitly name the type field as other similar
> > comments do for clarity.
> 
> Okay, maybe something is like this,
> 
> +/*
> + * LIBXL_HAVE_IGD_GFX_PASSTHRU
> + *
> + * If this is defined, the IGD Graphic Device Passthrough is supported.
> + *
> + * LIBXL_HAVE_IGD_GFX_PASSTHRU indicates that the
> + * libxl_device_pci field in the hvm is present in the pci_info structure
> + * fixup_ids[] which contains all supported IGD devices. So wwe use
> + * "igd-passthru=on" specify on the qemu command-line.

This:

/*
 * libxl_domain_build_info has the u.hvm.gfx_passthru_kind field and
 * the libxl_gfx_passthru_kind enumeration is defined. 
 */
#define LIBXL_HAVE_GFX_PASSTHRU_KIND

Users don't care about the internal details, just about the existence of
the support.

Ian.