libxl: introduce gfx_passthru_kind
Although we already have 'gfx_passthru' in b_info, this doesn't suffice
after we want to handle IGD specifically. Now we define a new field of
type, gfx_passthru_kind, to indicate we're trying to pass IGD. Actually
this means we can benefit this to support other specific devices just
by extending gfx_passthru_kind. And then we can cooperate with
gfx_passthru to address IGD cases as follows:
gfx_passthru = 0 => sets build_info.u.gfx_passthru to false
gfx_passthru = 1 => sets build_info.u.gfx_passthru to true and
build_info.u.gfx_passthru_kind to DEFAULT
gfx_passthru = "igd" => sets build_info.u.gfx_passthru to true
and build_info.u.gfx_passthru_kind to IGD
Here if gfx_passthru_kind = DEFAULT, we will call
libxl__is_igd_vga_passthru() to check if we're hitting that table to need
to pass that option to qemu. But if gfx_passthru_kind = "igd" we always
force to pass that.
And "-gfx_passthru" is just introduced to work for qemu-xen-traditional
so we should get this away from libxl__build_device_model_args_new() in
the case of qemu upstream.
Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>