QEMU implements multiple ways to expose graphics output to the virt machine, but most of them are incompatible with hardware virtualization.
The one that does work reliably is ramfb. It's a very simple mechanism in which the guest reserves a memory region for the frame buffer and then notifies the host about its location and properties. The host then just displays the contents of the frame buffer on screen.
This patch set adds support to drive the ramfb device in our QEMU arm targets. Theoretically, it should work as is with any of the other architectures as well though.
With this driver, we have a very simple, KVM compatible way to expose GOP via UEFI to payloads and thus enable development and testing of graphical OS functionality with QEMU's -M virt.
Alexander Graf (4): qfw: Add WRITE definition ramfb: Add driver for ramfb display qfw: Spawn ramfb device if its file is present qemu-arm*: Enable ramfb by default
arch/arm/Kconfig | 4 ++ board/emulation/qemu-arm/qemu-arm.c | 14 ++++ drivers/misc/qfw.c | 23 ++++++ drivers/video/Kconfig | 8 +++ drivers/video/MAINTAINERS | 4 ++ drivers/video/Makefile | 1 + drivers/video/ramfb.c | 104 ++++++++++++++++++++++++++++ include/configs/qemu-arm.h | 9 +++ include/qfw.h | 1 + 9 files changed, 168 insertions(+) create mode 100644 drivers/video/MAINTAINERS create mode 100644 drivers/video/ramfb.c