XEN/ARM XENFB howto

XEN/ARM XENFB howto

[Suriyan Ramasami]

Hello,
   This possibly could be a resend, as I did not see my post (that I
emailed out on Aug 17).
   I am looking for documentation on how to use XENFB on ARM. I did
see a post dated Dec 2013 from Peter
(http://lists.xen.org/archives/html/xen-users/2013-12/msg00061.html)
and discussions with Steffano and
Ian on how to achieve it. But, its not clear to me.

   I am trying to achieve this on the Odroid-XU (ARM based Exynos
5410). I am looking for the following:

1. qemu compilation upstream - I believe this has all the bits to
achieve it. Are there any special compile options. I ask this, as
qemu-system-arm seems to be spawned in dom0 with -M xenpv and I am not
able to compile this machine in qemu.
I do configure to build qemu with --enable-xen --target-list
arm-softmmu and the other options as mentioned in
http://wiki.xen.org/wiki/QEMU_Upstream#Building_your_own_qemu.

Note that I am not trying to cross compile but am compiling qemu natively.

2. What are the options in the domU2 config file to achieve this.

3. Any thing else ... Like when domU2 is created, what mice/keyboard/fb
messages to look for, or in dom0 what backend driver output to look
for. Does this need a xorg.conf file etc ...

Thanks in advance
- Suriyan

Re: XEN/ARM XENFB howto

[Stefano Stabellini]

On Mon, 18 Aug 2014, Suriyan Ramasami wrote:
> Hello,
>    This possibly could be a resend, as I did not see my post (that I
> emailed out on Aug 17).
>    I am looking for documentation on how to use XENFB on ARM. I did
> see a post dated Dec 2013 from Peter
> (http://lists.xen.org/archives/html/xen-users/2013-12/msg00061.html)
> and discussions with Steffano and
> Ian on how to achieve it. But, its not clear to me.
> 
>    I am trying to achieve this on the Odroid-XU (ARM based Exynos
> 5410). I am looking for the following:
> 
> 1. qemu compilation upstream - I believe this has all the bits to
> achieve it. Are there any special compile options. I ask this, as
> qemu-system-arm seems to be spawned in dom0 with -M xenpv and I am not
> able to compile this machine in qemu.
> I do configure to build qemu with --enable-xen --target-list
> arm-softmmu and the other options as mentioned in
> http://wiki.xen.org/wiki/QEMU_Upstream#Building_your_own_qemu.
> 
> Note that I am not trying to cross compile but am compiling qemu natively.

You just need this patch series:

http://marc.info/?l=xen-devel&m=140690717224942

then you should be able to build QEMU normally as part of the Xen build
process. The binary created is actually still called qemu-system-i386
even though we are not actually doing any x86 emulation.


> 2. What are the options in the domU2 config file to achieve this.

The option is called vfb, see man xl.cfg.


> 3. Any thing else ... Like when domU2 is created, what mice/keyboard/fb
> messages to look for, or in dom0 what backend driver output to look
> for. Does this need a xorg.conf file etc ...

You need CONFIG_XEN_FBDEV_FRONTEND in DomU and CONFIG_XEN_GNTDEV in
dom0. You can try it by simply using fbcon in the guest, see
Documentation/fb/fbcon.txt under Linux.

Re: XEN/ARM XENFB howto

[Suriyan Ramasami]

Thank you so much Stefano! It works amazingly well! I will probably
update the wiki as well.

On Thu, Aug 21, 2014 at 3:22 PM, Stefano Stabellini
<stefano.stabellini@eu.citrix.com> wrote:
> On Mon, 18 Aug 2014, Suriyan Ramasami wrote:
>> Hello,
>>    This possibly could be a resend, as I did not see my post (that I
>> emailed out on Aug 17).
>>    I am looking for documentation on how to use XENFB on ARM. I did
>> see a post dated Dec 2013 from Peter
>> (http://lists.xen.org/archives/html/xen-users/2013-12/msg00061.html)
>> and discussions with Steffano and
>> Ian on how to achieve it. But, its not clear to me.
>>
>>    I am trying to achieve this on the Odroid-XU (ARM based Exynos
>> 5410). I am looking for the following:
>>
>> 1. qemu compilation upstream - I believe this has all the bits to
>> achieve it. Are there any special compile options. I ask this, as
>> qemu-system-arm seems to be spawned in dom0 with -M xenpv and I am not
>> able to compile this machine in qemu.
>> I do configure to build qemu with --enable-xen --target-list
>> arm-softmmu and the other options as mentioned in
>> http://wiki.xen.org/wiki/QEMU_Upstream#Building_your_own_qemu.
>>
>> Note that I am not trying to cross compile but am compiling qemu natively.
>
> You just need this patch series:
>
> http://marc.info/?l=xen-devel&m=140690717224942
>
> then you should be able to build QEMU normally as part of the Xen build
> process. The binary created is actually still called qemu-system-i386
> even though we are not actually doing any x86 emulation.
>
Thanks for this. Just for the record, I used yout partch as in ->
http://www.gossamer-threads.com/lists/xen/devel/338875 and that worked
like a charm.
>
>> 2. What are the options in the domU2 config file to achieve this.
>
> The option is called vfb, see man xl.cfg.
>
Thanks the vfb option did it! Its nice to launch xl create -V <cfg
file> and see the console!

>
>> 3. Any thing else ... Like when domU2 is created, what mice/keyboard/fb
>> messages to look for, or in dom0 what backend driver output to look
>> for. Does this need a xorg.conf file etc ...
>
> You need CONFIG_XEN_FBDEV_FRONTEND in DomU and CONFIG_XEN_GNTDEV in
> dom0. You can try it by simply using fbcon in the guest, see
> Documentation/fb/fbcon.txt under Linux.
I did have the configs set approproately, and fbcon.txt was helpful too!

Thanks once again,
- Suriyan

Re: XEN/ARM XENFB howto

[Stefano Stabellini]

Great to hear!

On Fri, 22 Aug 2014, Suriyan Ramasami wrote:
> Thank you so much Stefano! It works amazingly well! I will probably
> update the wiki as well.
> 
> On Thu, Aug 21, 2014 at 3:22 PM, Stefano Stabellini
> <stefano.stabellini@eu.citrix.com> wrote:
> > On Mon, 18 Aug 2014, Suriyan Ramasami wrote:
> >> Hello,
> >>    This possibly could be a resend, as I did not see my post (that I
> >> emailed out on Aug 17).
> >>    I am looking for documentation on how to use XENFB on ARM. I did
> >> see a post dated Dec 2013 from Peter
> >> (http://lists.xen.org/archives/html/xen-users/2013-12/msg00061.html)
> >> and discussions with Steffano and
> >> Ian on how to achieve it. But, its not clear to me.
> >>
> >>    I am trying to achieve this on the Odroid-XU (ARM based Exynos
> >> 5410). I am looking for the following:
> >>
> >> 1. qemu compilation upstream - I believe this has all the bits to
> >> achieve it. Are there any special compile options. I ask this, as
> >> qemu-system-arm seems to be spawned in dom0 with -M xenpv and I am not
> >> able to compile this machine in qemu.
> >> I do configure to build qemu with --enable-xen --target-list
> >> arm-softmmu and the other options as mentioned in
> >> http://wiki.xen.org/wiki/QEMU_Upstream#Building_your_own_qemu.
> >>
> >> Note that I am not trying to cross compile but am compiling qemu natively.
> >
> > You just need this patch series:
> >
> > http://marc.info/?l=xen-devel&m=140690717224942
> >
> > then you should be able to build QEMU normally as part of the Xen build
> > process. The binary created is actually still called qemu-system-i386
> > even though we are not actually doing any x86 emulation.
> >
> Thanks for this. Just for the record, I used yout partch as in ->
> http://www.gossamer-threads.com/lists/xen/devel/338875 and that worked
> like a charm.
> >
> >> 2. What are the options in the domU2 config file to achieve this.
> >
> > The option is called vfb, see man xl.cfg.
> >
> Thanks the vfb option did it! Its nice to launch xl create -V <cfg
> file> and see the console!
> 
> >
> >> 3. Any thing else ... Like when domU2 is created, what mice/keyboard/fb
> >> messages to look for, or in dom0 what backend driver output to look
> >> for. Does this need a xorg.conf file etc ...
> >
> > You need CONFIG_XEN_FBDEV_FRONTEND in DomU and CONFIG_XEN_GNTDEV in
> > dom0. You can try it by simply using fbcon in the guest, see
> > Documentation/fb/fbcon.txt under Linux.
> I did have the configs set approproately, and fbcon.txt was helpful too!
> 
> Thanks once again,
> - Suriyan
>