Re: [Qemu-discuss] Booting GUI ubuntu VM on Aarch64

[Alexander Spyridakis]

Hello,

On 15 February 2016 at 12:55, Yehuda Yitschak <address@hidden> wrote:

I just built qemu-2.5 so I can try the virtio-gpu-pci approach.

Btw - I found a demo from virtual open system where they show guest graphics on Exynos based Arndale board.
It doesn’t show how but maybe it gives a hint
http://www.virtualopensystems.com/en/solutions/demos/kvm-on-arndale-exynos/

Are you interested in graphics with TCG or KVM? With TCG the usual command line should work out of the box with the default bochs vga device: "-device VGA -device usb-ehci -device usb-tablet -device usb-kbd". Don't forget to enable the bochs driver in your guest kernel, and depending on your distro you might have to play around with the X configuration to get it right.

With KVM as Peter mentioned, you need some additional patches for device cache coherency. Have a look at two patches from Jeremy Fanguede: "[RFC 0/4] arm/arm64: KVM: Get around cache incoherency" and "[RFC] ARM/ARM64: KVM: Implement KVM_FLUSH_DCACHE_GPA ioctl". These patches are not meant only for the VGA, but also emulated usb devices, without them your mouse and keyboard won't work.

Additionally, with KVM you might need to brute-force the rendering of the VGA device in QEMU by removing the check on memory_region_get_dirty(). This is a very ugly hack but it should work (hw/display/vga.c in vga_draw_graphic), which is similar to this: https://github.com/virtualopensystems/qemu/commit/64dd1b3e3a2353433edb9c63d00271f515bd06fb

Regards.