Re: [PATCH v2 25/27] i386/xen: Initialize Xen backends from pc_basic_device_init() for emulation

[Paul Durrant <xadimgnik@xxxxxxxxx>]

On 07/03/2023 17:17, David Woodhouse wrote:
> From: David Woodhouse <dwmw@xxxxxxxxxxxx>
>
> Now that all the work is done to enable the PV backends to work without
> actual Xen, instantiate the bus from pc_basic_device_init() for emulated
> mode.
>
> This allows us finally to launch an emulated Xen guest with PV disk.
>
>     qemu-system-x86_64 -serial mon:stdio -M q35 -cpu host -display none \
>       -m 1G -smp 2 -accel kvm,xen-version=0x4000a,kernel-irqchip=split \
>       -kernel bzImage -append "console=ttyS0 root=/dev/xvda1" \
>       -drive file=/var/lib/libvirt/images/fedora28.qcow2,if=none,id=disk \
>       -device xen-disk,drive=disk,vdev=xvda
>
> If we use -M pc instead of q35, we can even add an IDE disk and boot a
> guest image normally through grub. But q35 gives us AHCI and that isn't
> unplugged by the Xen magic, so the guests ends up seeing "both" disks.
>
> Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
> Reviewed-by: Paul Durrant <paul@xxxxxxx>
> ---
>   hw/i386/pc.c | 7 +++++++
>   1 file changed, 7 insertions(+)
Also...

Tested-by: Paul Durrant <paul@xxxxxxx>

... on real Xen (master branch, 4.18) with a Debian guest.