Re: [PATCH v7 00/19] Add support for qemu-xen runnning in a Linux-based stubdomain

[Jason Andryuk <jandryuk@xxxxxxxxx>]

On Fri, May 22, 2020 at 5:54 AM Paul Durrant <xadimgnik@xxxxxxxxx> wrote:
>
> > -----Original Message-----
> > From: Xen-devel <xen-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of 
> > George Dunlap
> > Sent: 22 May 2020 10:11
> > To: Jason Andryuk <jandryuk@xxxxxxxxx>
> > Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>; Julien Grall 
> > <julien@xxxxxxx>; Samuel Thibault
> > <samuel.thibault@xxxxxxxxxxxx>; Wei Liu <wl@xxxxxxx>; Andrew Cooper 
> > <Andrew.Cooper3@xxxxxxxxxx>; Jan
> > Beulich <jbeulich@xxxxxxxx>; Ian Jackson <Ian.Jackson@xxxxxxxxxx>; Anthony 
> > Perard
> > <anthony.perard@xxxxxxxxxx>; xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>; 
> > Daniel De Graaf
> > <dgdegra@xxxxxxxxxxxxx>
> > Subject: Re: [PATCH v7 00/19] Add support for qemu-xen runnning in a 
> > Linux-based stubdomain
> >
> >
> > > On May 19, 2020, at 2:54 AM, Jason Andryuk <jandryuk@xxxxxxxxx> wrote:
> > >
> > > General idea is to allow freely set device_model_version and
> > > device_model_stubdomain_override and choose the right options based on 
> > > this
> > > choice.  Also, allow to specific path to stubdomain kernel/ramdisk, for 
> > > greater
> > > flexibility.
> >
> > Excited to see this patch series get in.  But I didn’t really notice any 
> > documents explaining how to
> > actually use it — is there a blog post anywhere describing how to get the 
> > kernel / initrd image and so
> > on?

Yeah, it's not really collected anywhere, but below are the quick
start instructions.

The cover letter mentioned this repo (forked from Marek's):
https://github.com/jandryuk/qubes-vmm-xen-stubdom-linux
   (branch initramfs-tools, tag for-upstream-v6)

clone it and then run:
$ make get-sources
$ make -f Makefile.stubdom

output:
kernel: build/linux/arch/x86/boot/bzImage
ramdisk: build/rootfs/stubdom-linux-rootfs

To make them available system wide, copy to
/usr/lib/xen/boot/qemu-stubdom-linux-kernel and
/usr/lib/xen/boot/qemu-stubdom-linux-rootfs respectively. Obviously
this should match your installation's "$lib/xen/boot/" location.

A second option is to set paths to those files manually in a VM's
xl.cfg with stubdomain_kernel="/path" and stubdomain_ramdisk="/path"

Update your xl configuration with:
device_model_stubdomain_override = 1
device_model_version = "qemu-xen"

Start the domain and that should be it.   Maybe additionally use
serial = "pty" to access the VM with `xl console -t serial $NAME`.

Some limitations are here:
https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=docs/misc/stubdom.txt;h=c717a95d17d2e562639a5574e89df3c4db8712fa;hb=HEAD#l124
Limitations:
 - PCI passthrough require permissive mode
 - only one nic is supported
 - at most 26 emulated disks are supported (more are still available
as PV disks)
 - graphics output (VNC/SDL/Spice) not supported

> > Also, would it be possible to add a follow-up series which modifies 
> > SUPPORT.md and CHANGELOG.md?
>
> Yes please. In future I think we should encourage the patch to CHANGELOG.md 
> to be the last patch of a series such as this.

I can do this.  What is the SUPPORT status for this?

Regards,
Jason