progress on xen3 HVM support

Hi,
attached is a snapshot of a xentools30-vmx package, which
should install on top
of xentools30 the necessary bits for starting HVM guests.
This is based on
patches sent to me by Pierrick Brossin. It's good enough to
start a linux
bootable CD up to the X graphical installer (I didn't try to
install it yet).
It needs a very recent current kernel.

Known bugs
- as is, qemu-dm won't start. I renamed it and remplaced
with a csh script
  which does
#!/bin/csh
unlimit
setenv PTHREAD_DIAGASSERT A
/usr/pkg/libexec/qemu-dm.bin $*

  yes, it has pthread bugs :(
- the compiled hvmloader crashes early. Using the hvmloader
provided in
  xen-3.0.2-2-install-x86_32.tgz works.
- It can't boot a NetBSD CD; it crases in the boot loaded on
an unhandled
  instruction. I fear this is a limitation of Xen's 16 bit
emulation.


Now, xen-3.0.3 should be released this week; so I probably
won't do much more
work on this, and update you Xen suppport to 3.0.3 instead.
Maybe this'll
fix the issue with the NetBSD boot loader 

-- 
Manuel Bouyer <bouyerantioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la
difference
--

Hi Manuel,

On Sun, 15 Oct 2006, Manuel Bouyer wrote:
> attached is a snapshot of a xentools30-vmx package,
which should install on top
> of xentools30 the necessary bits for starting HVM
guests. This is based on
> patches sent to me by Pierrick Brossin. It's good
enough to start a linux
> bootable CD up to the X graphical installer (I didn't
try to install it yet).
> It needs a very recent current kernel.
>
> Known bugs
> - as is, qemu-dm won't start. I renamed it and
remplaced with a csh script

I'm not following Xen as close as I'd like to, and as such
your posting 
raised two questions for me that I was able to google. Maybe
you can 
confirm my understanding:

1) HVM = Hardware Virtual Machine, a Common Interface for
VT-x/VT-i and
          AMD SVM CPUs[1]

2) Qemu-dm = Qemu[2] Device Model - a modified(?) Qemu
that's used to
              emulate instruction sets for real-mode
support[3] - I guess
              to run Xen inside Xen


  - Hubert

[1] http://www.l
inuxjournal.com/article/8909
[2] http://www.qemu.org/
[3] http://www.xensource.com/files/summit_3/v2e-r
ealmode-support-v2.pdf

Hi Manuel,

On Sun, 15 Oct 2006, Manuel Bouyer wrote:
> attached is a snapshot of a xentools30-vmx package,
which should install on top
> of xentools30 the necessary bits for starting HVM
guests. This is based on
> patches sent to me by Pierrick Brossin. It's good
enough to start a linux
> bootable CD up to the X graphical installer (I didn't
try to install it yet).
> It needs a very recent current kernel.
>
> Known bugs
> - as is, qemu-dm won't start. I renamed it and
remplaced with a csh script

I'm not following Xen as close as I'd like to, and as such
your posting 
raised two questions for me that I was able to google. Maybe
you can 
confirm my understanding:

1) HVM = Hardware Virtual Machine, a Common Interface for
VT-x/VT-i and
          AMD SVM CPUs[1]

2) Qemu-dm = Qemu[2] Device Model - a modified(?) Qemu
that's used to
              emulate instruction sets for real-mode
support[3] - I guess
              to run Xen inside Xen


  - Hubert

[1] http://www.l
inuxjournal.com/article/8909
[2] http://www.qemu.org/
[3] http://www.xensource.com/files/summit_3/v2e-r
ealmode-support-v2.pdf

On Mon, Oct 16, 2006 at 03:34:09AM +0200, Hubert Feyrer
wrote:
> 
> I'm not following Xen as close as I'd like to, and as
such your posting 
> raised two questions for me that I was able to google.
Maybe you can 
> confirm my understanding:
> 
> 1) HVM = Hardware Virtual Machine, a Common Interface
for VT-x/VT-i and
>          AMD SVM CPUs[1]
> 
> 2) Qemu-dm = Qemu[2] Device Model - a modified(?) Qemu
that's used to
>              emulate instruction sets for real-mode
support[3] - I guess
>              to run Xen inside Xen

Mostly, I think, to run BIOS code for native operating
systems inside
Xen HVM domains.  And/or to provide the emulated devices
(like VGA
cards) that the BIOS and native code will poke at.

--
Dan.

On Mon, 16 Oct 2006, Daniel Carosone wrote:
>> 2) Qemu-dm = Qemu[2] Device Model - a modified(?)
Qemu that's used to
>>              emulate instruction sets for real-mode
support[3] - I guess
>>              to run Xen inside Xen
>
> Mostly, I think, to run BIOS code for native operating
systems inside
> Xen HVM domains.  And/or to provide the emulated
devices (like VGA
> cards) that the BIOS and native code will poke at.

Ah - in that context the comment from Manuel about booting a
Linux-CD 
(that was probably not prepared for Xen) makes sense.


  - Hubert

On Mon, Oct 16, 2006 at 03:34:09AM +0200, Hubert Feyrer
wrote:
> 
> I'm not following Xen as close as I'd like to, and as
such your posting 
> raised two questions for me that I was able to google.
Maybe you can 
> confirm my understanding:
> 
> 1) HVM = Hardware Virtual Machine, a Common Interface
for VT-x/VT-i and
>          AMD SVM CPUs[1]
> 
> 2) Qemu-dm = Qemu[2] Device Model - a modified(?) Qemu
that's used to
>              emulate instruction sets for real-mode
support[3] - I guess
>              to run Xen inside Xen

Mostly, I think, to run BIOS code for native operating
systems inside
Xen HVM domains.  And/or to provide the emulated devices
(like VGA
cards) that the BIOS and native code will poke at.

--
Dan.

On Mon, 16 Oct 2006, Daniel Carosone wrote:
>> 2) Qemu-dm = Qemu[2] Device Model - a modified(?)
Qemu that's used to
>>              emulate instruction sets for real-mode
support[3] - I guess
>>              to run Xen inside Xen
>
> Mostly, I think, to run BIOS code for native operating
systems inside
> Xen HVM domains.  And/or to provide the emulated
devices (like VGA
> cards) that the BIOS and native code will poke at.

Ah - in that context the comment from Manuel about booting a
Linux-CD 
(that was probably not prepared for Xen) makes sense.


  - Hubert

On Mon, Oct 16, 2006 at 03:34:09AM +0200, Hubert Feyrer
wrote:
> 
> Hi Manuel,
> 
> On Sun, 15 Oct 2006, Manuel Bouyer wrote:
> >attached is a snapshot of a xentools30-vmx package,
which should install 
> >on top
> >of xentools30 the necessary bits for starting HVM
guests. This is based on
> >patches sent to me by Pierrick Brossin. It's good
enough to start a linux
> >bootable CD up to the X graphical installer (I
didn't try to install it 
> >yet).
> >It needs a very recent current kernel.
> >
> >Known bugs
> >- as is, qemu-dm won't start. I renamed it and
remplaced with a csh script
> 
> I'm not following Xen as close as I'd like to, and as
such your posting 
> raised two questions for me that I was able to google.
Maybe you can 
> confirm my understanding:
> 
> 1) HVM = Hardware Virtual Machine, a Common Interface
for VT-x/VT-i and
>          AMD SVM CPUs[1]

Correct.

> 2) Qemu-dm = Qemu[2] Device Model - a modified(?) Qemu
that's used to
>              emulate instruction sets for real-mode
support[3] - I guess
>              to run Xen inside Xen

No.  qemu is used as the back-end for HVM domains, providing
it a
"hardware" to run on.  The part where qemu
emulates a CPU is left out,
only the hardware environment is kept.

-- 
Quentin Garnier - cubecubidou.net - cubeNetBSD.org
"You could have made it, spitting out benchmarks
Owe it to yourself not to fail"
Amplifico, Spitting Out Benchmarks, Hometakes Vol. 2, 2005.

On Mon, Oct 16, 2006 at 03:34:09AM +0200, Hubert Feyrer
wrote:
> 
> Hi Manuel,
> 
> On Sun, 15 Oct 2006, Manuel Bouyer wrote:
> >attached is a snapshot of a xentools30-vmx package,
which should install 
> >on top
> >of xentools30 the necessary bits for starting HVM
guests. This is based on
> >patches sent to me by Pierrick Brossin. It's good
enough to start a linux
> >bootable CD up to the X graphical installer (I
didn't try to install it 
> >yet).
> >It needs a very recent current kernel.
> >
> >Known bugs
> >- as is, qemu-dm won't start. I renamed it and
remplaced with a csh script
> 
> I'm not following Xen as close as I'd like to, and as
such your posting 
> raised two questions for me that I was able to google.
Maybe you can 
> confirm my understanding:
> 
> 1) HVM = Hardware Virtual Machine, a Common Interface
for VT-x/VT-i and
>          AMD SVM CPUs[1]

Correct.

> 2) Qemu-dm = Qemu[2] Device Model - a modified(?) Qemu
that's used to
>              emulate instruction sets for real-mode
support[3] - I guess
>              to run Xen inside Xen

No.  qemu is used as the back-end for HVM domains, providing
it a
"hardware" to run on.  The part where qemu
emulates a CPU is left out,
only the hardware environment is kept.

-- 
Quentin Garnier - cubecubidou.net - cubeNetBSD.org
"You could have made it, spitting out benchmarks
Owe it to yourself not to fail"
Amplifico, Spitting Out Benchmarks, Hometakes Vol. 2, 2005.

On Mon, Oct 16, 2006 at 11:41:11AM +1000, Daniel Carosone
wrote:
> On Mon, Oct 16, 2006 at 03:34:09AM +0200, Hubert Feyrer
wrote:
> > 
> > I'm not following Xen as close as I'd like to, and
as such your posting 
> > raised two questions for me that I was able to
google. Maybe you can 
> > confirm my understanding:
> > 
> > 1) HVM = Hardware Virtual Machine, a Common
Interface for VT-x/VT-i and
> >          AMD SVM CPUs[1]
> > 
> > 2) Qemu-dm = Qemu[2] Device Model - a modified(?)
Qemu that's used to
> >              emulate instruction sets for
real-mode support[3] - I guess
> >              to run Xen inside Xen
> 
> Mostly, I think, to run BIOS code for native operating
systems inside
> Xen HVM domains.  And/or to provide the emulated
devices (like VGA
> cards) that the BIOS and native code will poke at.

It's only used to emulate devices (disks, network, audio,
usb, ...)
The 32/64bit code can run native on the CPU (this is the
point of the
Virtual Machine extentions). AMD SVM can also run 16 bit
code but
for Intel VT this has to be emuled and this is done by the
hypervisor.
This is probably why I couldn't boot native NetBSD: some
16bit instructions
we use are not emuled by the hypervisor.

-- 
Manuel Bouyer, LIP6, Universite Paris VI.          
Manuel.Bouyerlip6.fr
     NetBSD: 26 ans d'experience feront toujours la
difference
--