qemu: add qemu ramfb support
Add support for qemu ramfb. This is a simple boot framebuffer device,
with normal ram being used to back the framebuffer and fw_cfg being used
to configure the device.
Use case (on x86): boot display for vgpu devices (which neither emulate
vga nor have a vgabios).
Sharing fw_cfg code with seabios turned out to be difficuilt due to
various dependencies the code has on infrastructure which only seabios
has. So include a copy of the code here, with those dependencies
removed and also stripped down because we don't need a non-dma fallback
Signed-off-by: Gerd Hoffmann <email@example.com>
(cherry picked from commit d9a8b867a3af8090290b69b8f94b24e7fba9e504)
5 files changed