Xen device model support in QEMU

Xen device model support in QEMU

[Kamala Narasimhan]

I got the latest qemu repo with xen device model support from -

git://xenbits.xen.org/people/sstabellini/qemu-dm.git

Here are some of the issues I encounter/questions I have -

1) Passing --enable-xen while running ./configure results in

ERROR
ERROR: User requested feature xen
ERROR: configure was not able to find it
ERROR

Turned out there are some interface version compatibilities between
qemu from the above repo and everything else from
staging/xen-unstable.  Tweaking xc_interface_open parameter under "xen
probe" in the configure file got past this problem.

2) Passing --target-list=xen-dm-softmmu to configure resulted in
"ERROR: Target 'xen-dm-softmmu' not recognised" error as target_arch2
is xen and not xen-dm.  Switching to
--target-list=xen-softmmu got me going.  Perhaps this should be fixed
in the configure file if the expectation is to pass xen-dm-softmmu.

3) When I attempt to build after this point I get all kinds of errors
due to interface compatibility mentioned in #1 above.  Is there a
specific version of libxc/libxenstore/libxenctrl etc. and relevant
headers I should be using with this qemu?  If so, that would be good
to know as I would rather switch to a compatible interface than go
about fixing all the resulting build errors.

Kamala

Re: Xen device model support in QEMU

[Stefano Stabellini]

On Mon, 23 Aug 2010, Kamala Narasimhan wrote:
> I got the latest qemu repo with xen device model support from -
> 
> git://xenbits.xen.org/people/sstabellini/qemu-dm.git
> 
> Here are some of the issues I encounter/questions I have -
> 
> 1) Passing --enable-xen while running ./configure results in
> 
> ERROR
> ERROR: User requested feature xen
> ERROR: configure was not able to find it
> ERROR
> 
> Turned out there are some interface version compatibilities between
> qemu from the above repo and everything else from
> staging/xen-unstable.  Tweaking xc_interface_open parameter under "xen
> probe" in the configure file got past this problem.

I have seen this problem too, another thing to be fixed.


> 
> 2) Passing --target-list=xen-dm-softmmu to configure resulted in
> "ERROR: Target 'xen-dm-softmmu' not recognised" error as target_arch2
> is xen and not xen-dm.  Switching to
> --target-list=xen-softmmu got me going.  Perhaps this should be fixed
> in the configure file if the expectation is to pass xen-dm-softmmu.
> 

you are right about this, in any case the target will be dropped
completely next time we send an update of this series.


> 3) When I attempt to build after this point I get all kinds of errors
> due to interface compatibility mentioned in #1 above.  Is there a
> specific version of libxc/libxenstore/libxenctrl etc. and relevant
> headers I should be using with this qemu?  If so, that would be good
> to know as I would rather switch to a compatible interface than go
> about fixing all the resulting build errors.
> 

Anthony is mainly working with xen-unstable so I expect that building
the new qemu against xen-unstable headers and libraries is the safest
option.
If you are having build issues please let us know (keep in mind that
Anthony is on vacation this week so it might take some times to get
all the answers you need).

Re: Xen device model support in QEMU

[Kamala Narasimhan]

On Mon, Aug 23, 2010 at 11:17 AM, Stefano Stabellini
<stefano.stabellini@eu.citrix.com> wrote:
> On Mon, 23 Aug 2010, Kamala Narasimhan wrote:
>> 3) When I attempt to build after this point I get all kinds of errors
>> due to interface compatibility mentioned in #1 above.  Is there a
>> specific version of libxc/libxenstore/libxenctrl etc. and relevant
>> headers I should be using with this qemu?  If so, that would be good
>> to know as I would rather switch to a compatible interface than go
>> about fixing all the resulting build errors.
>>
>
> Anthony is mainly working with xen-unstable so I expect that building
> the new qemu against xen-unstable headers and libraries is the safest
> option.
> If you are having build issues please let us know (keep in mind that
> Anthony is on vacation this week so it might take some times to get
> all the answers you need).
>

Yes, I do encounter build issues while using headers from
staging/xen-unstable.  Most of them are in xen_disk.c, xen_backend.c
while calling methods like xc_interface_* or xc_gnttab_* etc.  They
are all trivial to fix locally though there are more than a few places
to fix.  I will make local changes to keep going and Anthony can
confirm and fix the issues when he is back.  I am not attaching the
build errors here as they are readily reproducible when using
staging/xen-unstable headers.

Kamala

>

Re: Xen device model support in QEMU

[Kamala Narasimhan]

On Mon, Aug 23, 2010 at 11:02 AM, Kamala Narasimhan
<kamala.narasimhan@gmail.com> wrote:
> I got the latest qemu repo with xen device model support from -
>
> git://xenbits.xen.org/people/sstabellini/qemu-dm.git
>

Looks like the above tree is not up-to-date with all the Xen device
model patches that were submitted.  It would help if this could be
verified.

When it felt like I was rewriting some of the patches in the process
of fixing the issues I mentioned earlier, I checked and manually
merged all the patches Stefano submitted and in the process found the
submitted patches weren't merged in the above tree I cloned from.
After the merge I did not encounter any of the issues I mentioned
earlier.

Kamala

Re: Re: Xen device model support in QEMU

[Stefano Stabellini]

On Wed, 25 Aug 2010, Kamala Narasimhan wrote:
> On Mon, Aug 23, 2010 at 11:02 AM, Kamala Narasimhan
> <kamala.narasimhan@gmail.com> wrote:
> > I got the latest qemu repo with xen device model support from -
> >
> > git://xenbits.xen.org/people/sstabellini/qemu-dm.git
> >
> 
> Looks like the above tree is not up-to-date with all the Xen device
> model patches that were submitted.  It would help if this could be
> verified.
> 
> When it felt like I was rewriting some of the patches in the process
> of fixing the issues I mentioned earlier, I checked and manually
> merged all the patches Stefano submitted and in the process found the
> submitted patches weren't merged in the above tree I cloned from.
> After the merge I did not encounter any of the issues I mentioned
> earlier.
> 

did you checkout out the branch qemu-dm-v2?

Re: Re: Xen device model support in QEMU

[Kamala Narasimhan]

On Wed, Aug 25, 2010 at 3:43 PM, Stefano Stabellini
<stefano.stabellini@eu.citrix.com> wrote:
> On Wed, 25 Aug 2010, Kamala Narasimhan wrote:
>> On Mon, Aug 23, 2010 at 11:02 AM, Kamala Narasimhan
>> <kamala.narasimhan@gmail.com> wrote:
>> > I got the latest qemu repo with xen device model support from -
>> >
>> > git://xenbits.xen.org/people/sstabellini/qemu-dm.git
>> >
>>
>> Looks like the above tree is not up-to-date with all the Xen device
>> model patches that were submitted.  It would help if this could be
>> verified.
>>
>> When it felt like I was rewriting some of the patches in the process
>> of fixing the issues I mentioned earlier, I checked and manually
>> merged all the patches Stefano submitted and in the process found the
>> submitted patches weren't merged in the above tree I cloned from.
>> After the merge I did not encounter any of the issues I mentioned
>> earlier.
>>
>
> did you checkout out the branch qemu-dm-v2?
>
>

git branch doesn't list that branch and I am not able to checkout that
branch.  Am I missing something obvious?

Kamala

Re: Re: Xen device model support in QEMU

[Vincent Hanquez]

On 25/08/10 21:52, Kamala Narasimhan wrote:
> git branch doesn't list that branch and I am not able to checkout that
> branch.  Am I missing something obvious?

Hi Kamala,

git branch will list only local branch, unless you're using -a.
to create a local branch tracking the remote branch 'qemu-dm-v2' on the 
remote 'origin' do:

git checkout --track origin/qemu-dm-v2

-- 
Vincent

Re: Re: Xen device model support in QEMU

[Kamala Narasimhan]

Hi Vincent,

Thanks for the info.

Kamala

On Thu, Aug 26, 2010 at 6:57 AM, Vincent Hanquez
<vincent.hanquez@eu.citrix.com> wrote:
> On 25/08/10 21:52, Kamala Narasimhan wrote:
>>
>> git branch doesn't list that branch and I am not able to checkout that
>> branch.  Am I missing something obvious?
>
> Hi Kamala,
>
> git branch will list only local branch, unless you're using -a.
> to create a local branch tracking the remote branch 'qemu-dm-v2' on the
> remote 'origin' do:
>
> git checkout --track origin/qemu-dm-v2
>
> --
> Vincent
>

RE: Xen device model support in QEMU

[Ross Philipson]

Yeah, she is going to move to the UK and work in your office is what I heard :)

-----Original Message-----
From: xen-devel-bounces@lists.xensource.com [mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of Kamala Narasimhan
Sent: Monday, August 23, 2010 11:02 AM
To: xen-devel@lists.xensource.com
Subject: [Xen-devel] Xen device model support in QEMU

I got the latest qemu repo with xen device model support from -

git://xenbits.xen.org/people/sstabellini/qemu-dm.git

Here are some of the issues I encounter/questions I have -

1) Passing --enable-xen while running ./configure results in

ERROR
ERROR: User requested feature xen
ERROR: configure was not able to find it
ERROR

Turned out there are some interface version compatibilities between
qemu from the above repo and everything else from
staging/xen-unstable.  Tweaking xc_interface_open parameter under "xen
probe" in the configure file got past this problem.

2) Passing --target-list=xen-dm-softmmu to configure resulted in
"ERROR: Target 'xen-dm-softmmu' not recognised" error as target_arch2
is xen and not xen-dm.  Switching to
--target-list=xen-softmmu got me going.  Perhaps this should be fixed
in the configure file if the expectation is to pass xen-dm-softmmu.

3) When I attempt to build after this point I get all kinds of errors
due to interface compatibility mentioned in #1 above.  Is there a
specific version of libxc/libxenstore/libxenctrl etc. and relevant
headers I should be using with this qemu?  If so, that would be good
to know as I would rather switch to a compatible interface than go
about fixing all the resulting build errors.

Kamala

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

Re: Xen device model support in QEMU

[Kamala Narasimhan]

On Wed, Aug 25, 2010 at 3:50 PM, Ross Philipson
<Ross.Philipson@citrix.com> wrote:
> Yeah, she is going to move to the UK and work in your office is what I heard :)
>

Well, I don't have the smarts to build a career out of broken RMRR
regions.  We have already established that.  So, I might as well have
to :-)

I have more of these goodies and all the time in the world; so if you
want to play it out in the public domain, I am game :-)

And to those willing to judge with little or no background - NOTHING
comes unprovoked; including this.

Kamala

> -----Original Message-----
> From: xen-devel-bounces@lists.xensource.com [mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of Kamala Narasimhan
> Sent: Monday, August 23, 2010 11:02 AM
> To: xen-devel@lists.xensource.com
> Subject: [Xen-devel] Xen device model support in QEMU
>
> I got the latest qemu repo with xen device model support from -
>
> git://xenbits.xen.org/people/sstabellini/qemu-dm.git
>
> Here are some of the issues I encounter/questions I have -
>
> 1) Passing --enable-xen while running ./configure results in
>
> ERROR
> ERROR: User requested feature xen
> ERROR: configure was not able to find it
> ERROR
>
> Turned out there are some interface version compatibilities between
> qemu from the above repo and everything else from
> staging/xen-unstable.  Tweaking xc_interface_open parameter under "xen
> probe" in the configure file got past this problem.
>
> 2) Passing --target-list=xen-dm-softmmu to configure resulted in
> "ERROR: Target 'xen-dm-softmmu' not recognised" error as target_arch2
> is xen and not xen-dm.  Switching to
> --target-list=xen-softmmu got me going.  Perhaps this should be fixed
> in the configure file if the expectation is to pass xen-dm-softmmu.
>
> 3) When I attempt to build after this point I get all kinds of errors
> due to interface compatibility mentioned in #1 above.  Is there a
> specific version of libxc/libxenstore/libxenctrl etc. and relevant
> headers I should be using with this qemu?  If so, that would be good
> to know as I would rather switch to a compatible interface than go
> about fixing all the resulting build errors.
>
> Kamala
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>

L1 entry error

[Ruslan Nikolaev]

Hi

I've just tried to configure & install latest xen 4.0.1 from repository and linux 2.6.32.18 (from pvops repository). When I launch 'xm create -c /etc/xen/xen.cfg', I get Error: (22, Invalid argument'). This problem did not appear with previous version (around month ago). Dom0, however, boots without any problem.

XEN issues the following messages when error occurs:
(XEN) mm.c:860:d0 Error getting mfn a7a4b (pfn a7820) from L1 entry 80000000a7a1
(XEN) mm.c:860:d0 Error getting mfn a7a4c (pfn a781f) from L1 entry 80000000a7a1
(XEN) mm.c:860:d0 Error getting mfn a7a4d (pfn a781e) from L1 entry 80000000a7a1
(XEN) mm.c:860:d0 Error getting mfn a7a4e (pfn a781d) from L1 entry 80000000a7a1
(XEN) mm.c:860:d0 Error getting mfn a7a4f (pfn a781c) from L1 entry 80000000a7a1
(XEN) mm.c:860:d0 Error getting mfn a7a50 (pfn a781b) from L1 entry 80000000a7a1
(XEN) mm.c:860:d0 Error getting mfn a7a51 (pfn a781a) from L1 entry 80000000a7a1

CPU is multicore Xeon 5600 (Nehalem arhitecture).

Thanks,
Ruslan

Re: L1 entry error

[Pasi Kärkkäinen]

On Wed, Aug 25, 2010 at 02:18:22PM -0700, Ruslan Nikolaev wrote:
> Hi
> 

Hello,

Please don't reply to existing mails (hijacking the thread),
but start a new thread for new topics..

> I've just tried to configure & install latest xen 4.0.1 from repository and linux 2.6.32.18 (from pvops repository). When I launch 'xm create -c /etc/xen/xen.cfg', I get Error: (22, Invalid argument'). This problem did not appear with previous version (around month ago). Dom0, however, boots without any problem.
> 

Please paste the xen.cfg.

-- Pasi

> XEN issues the following messages when error occurs:
> (XEN) mm.c:860:d0 Error getting mfn a7a4b (pfn a7820) from L1 entry 80000000a7a1
> (XEN) mm.c:860:d0 Error getting mfn a7a4c (pfn a781f) from L1 entry 80000000a7a1
> (XEN) mm.c:860:d0 Error getting mfn a7a4d (pfn a781e) from L1 entry 80000000a7a1
> (XEN) mm.c:860:d0 Error getting mfn a7a4e (pfn a781d) from L1 entry 80000000a7a1
> (XEN) mm.c:860:d0 Error getting mfn a7a4f (pfn a781c) from L1 entry 80000000a7a1
> (XEN) mm.c:860:d0 Error getting mfn a7a50 (pfn a781b) from L1 entry 80000000a7a1
> (XEN) mm.c:860:d0 Error getting mfn a7a51 (pfn a781a) from L1 entry 80000000a7a1
> 
> CPU is multicore Xeon 5600 (Nehalem arhitecture).
> 

Re: L1 entry error

[Ruslan Nikolaev]

Sorry for the delay. Here is my config file. Computer has 12Gb of RAM, and I am using 64-bit version:

#  -*- mode: python; -*-
#============================================================================
# Python configuration setup for 'xm create'.
# This script sets the parameters used when a domain is created using 'xm create'.
# You use a separate script for each domain you want to create, or 
# you can set the parameters for the domain on the xm command line.
#============================================================================

#----------------------------------------------------------------------------
# Kernel image file.
kernel = "/boot/vmlinuz-2.6.32.18"

# Optional ramdisk.
ramdisk = "/boot/initrd-2.6.32.18.img"

# The domain build function. Default is 'linux'.
#builder='linux'

# Initial memory allocation (in megabytes) for the new domain.
#
# WARNING: Creating a domain with insufficient memory may cause out of
#          memory errors. The domain needs enough memory to boot kernel
#          and modules. Allocating less than 32MBs is not recommended.
memory = 4096

# A name for your domain. All domains must have different names.
name = "XenDomainU"

# 128-bit UUID for the domain.  The default behavior is to generate a new UUID
# on each call to 'xm create'.
#uuid = "06ed00fe-1162-4fc4-b5d8-11993ee4a8b9"

# List of which CPUS this domain is allowed to use, default Xen picks
#cpus = ""         # leave to Xen to pick
#cpus = "0"        # all vcpus run on CPU0
#cpus = "0-3,5,^1" # all vcpus run on cpus 0,2,3,5
#cpus = ["2", "3"] # VCPU0 runs on CPU2, VCPU1 runs on CPU3

# Number of Virtual CPUS to use, default is 1
vcpus = 1

#----------------------------------------------------------------------------
# Define network interfaces.

# By default, no network interfaces are configured.  You may have one created
# with sensible defaults using an empty vif clause:
#
# vif = [ '' ]
#
# or optionally override backend, bridge, ip, mac, script, type, or vifname:
#
# vif = [ 'mac=00:16:3e:00:00:11, bridge=xenbr0' ]
#
# or more than one interface may be configured:
#
# vif = [ '', 'bridge=xenbr1' ]

vif = [ 'ip=192.168.0.1' ]

#----------------------------------------------------------------------------
# Define the disk devices you want the domain to have access to, and
# what you want them accessible as.
# Each disk entry is of the form phy:UNAME,DEV,MODE
# where UNAME is the device, DEV is the device name the domain will see,
# and MODE is r for read-only, w for read-write.

disk = [ 'phy:sda8,xvda8,w' ]

#----------------------------------------------------------------------------
# Define frame buffer device.
#
# By default, no frame buffer device is configured.
#
# To create one using the SDL backend and sensible defaults:
#
# vfb = [ 'sdl=1' ]
#
# This uses environment variables XAUTHORITY and DISPLAY.  You
# can override that:
#
# vfb = [ 'sdl=1,xauthority=/home/bozo/.Xauthority,display=:1' ]
#
# To create one using the VNC backend and sensible defaults:
#
# vfb = [ 'vnc=1' ]
#
# The backend listens on 127.0.0.1 port 5900+N by default, where N is
# the domain ID.  You can override both address and N:
#
# vfb = [ 'vnc=1,vnclisten=127.0.0.1,vncdisplay=1' ]
#
# Or you can bind the first unused port above 5900:
#
# vfb = [ 'vnc=1,vnclisten=0.0.0.0,vncunused=1' ]
#
# You can override the password:
#
# vfb = [ 'vnc=1,vncpasswd=MYPASSWD' ]
#
# Empty password disables authentication.  Defaults to the vncpasswd
# configured in xend-config.sxp.

#----------------------------------------------------------------------------
# Define to which TPM instance the user domain should communicate.
# The vtpm entry is of the form 'instance=INSTANCE,backend=DOM'
# where INSTANCE indicates the instance number of the TPM the VM
# should be talking to and DOM provides the domain where the backend
# is located.
# Note that no two virtual machines should try to connect to the same
# TPM instance. The handling of all TPM instances does require
# some management effort in so far that VM configration files (and thus
# a VM) should be associated with a TPM instance throughout the lifetime
# of the VM / VM configuration file. The instance number must be
# greater or equal to 1.
#vtpm = [ 'instance=1,backend=0' ]

#----------------------------------------------------------------------------
# Set the kernel command line for the new domain.
# You only need to define the IP parameters and hostname if the domain's
# IP config doesn't, e.g. in ifcfg-eth0 or via DHCP.
# You can use 'extra' to set the runlevel and custom environment
# variables used by custom rc scripts (e.g. VMID=, usr= ).

# Set if you want dhcp to allocate the IP address.
#dhcp="dhcp"
# Set netmask.
#netmask=
# Set default gateway.
gateway="192.168.0.128"
# Set the hostname.
#hostname= "vm%d" % vmid

# Set root device.
root = "/dev/xvda8 ro"

# Root device for nfs.
#root = "/dev/nfs"
# The nfs server.
#nfs_server = '192.0.2.1'  
# Root directory on the nfs server.
#nfs_root   = '/full/path/to/root/directory'

# Sets runlevel 4.
#extra = "xencons=tty"
extra = 'console=hvc0 xencons=tty'

#----------------------------------------------------------------------------
# Configure the behaviour when a domain exits.  There are three 'reasons'
# for a domain to stop: poweroff, reboot, and crash.  For each of these you
# may specify:
#
#   "destroy",        meaning that the domain is cleaned up as normal;
#   "restart",        meaning that a new domain is started in place of the old
#                     one;
#   "preserve",       meaning that no clean-up is done until the domain is
#                     manually destroyed (using xm destroy, for example); or
#   "rename-restart", meaning that the old domain is not cleaned up, but is
#                     renamed and a new domain started in its place.
#
# In the event a domain stops due to a crash, you have the additional options:
#
#   "coredump-destroy", meaning dump the crashed domain's core and then destroy;
#   "coredump-restart', meaning dump the crashed domain's core and the restart.
#
# The default is
#
#   on_poweroff = 'destroy'
#   on_reboot   = 'restart'
#   on_crash    = 'restart'
#
# For backwards compatibility we also support the deprecated option restart
#
# restart = 'onreboot' means on_poweroff = 'destroy'
#                            on_reboot   = 'restart'
#                            on_crash    = 'destroy'
#
# restart = 'always'   means on_poweroff = 'restart'
#                            on_reboot   = 'restart'
#                            on_crash    = 'restart'
#
# restart = 'never'    means on_poweroff = 'destroy'
#                            on_reboot   = 'destroy'
#                            on_crash    = 'destroy'

#on_poweroff = 'destroy'
#on_reboot   = 'restart'
#on_crash    = 'restart'

#-----------------------------------------------------------------------------
#   Configure PVSCSI devices:
#
#vscsi=[ 'PDEV, VDEV' ]
#
#   PDEV   gives physical SCSI device to be attached to specified guest
#          domain by one of the following identifier format.
#          - XX:XX:XX:XX (4-tuples with decimal notation which shows
#                          "host:channel:target:lun")
#          - /dev/sdxx or sdx
#          - /dev/stxx or stx
#          - /dev/sgxx or sgx
#          - result of 'scsi_id -gu -s'.
#            ex. # scsi_id -gu -s /block/sdb
#                  36000b5d0006a0000006a0257004c0000
#
#   VDEV   gives virtual SCSI device by 4-tuples (XX:XX:XX:XX) as 
#          which the specified guest domain recognize.
#

#vscsi = [ '/dev/sdx, 0:0:0:0' ]

#============================================================================


--- On Thu, 8/26/10, Pasi Kärkkäinen <pasik@iki.fi> wrote:

> From: Pasi Kärkkäinen <pasik@iki.fi>
> Subject: Re: [Xen-devel] L1 entry error
> To: "Ruslan Nikolaev" <nruslan_devel@yahoo.com>
> Cc: xen-devel@lists.xensource.com
> Date: Thursday, August 26, 2010, 10:24 AM
> On Wed, Aug 25, 2010 at 02:18:22PM
> -0700, Ruslan Nikolaev wrote:
> > Hi
> > 
> 
> Hello,
> 
> Please don't reply to existing mails (hijacking the
> thread),
> but start a new thread for new topics..
> 
> > I've just tried to configure & install latest xen
> 4.0.1 from repository and linux 2.6.32.18 (from pvops
> repository). When I launch 'xm create -c /etc/xen/xen.cfg',
> I get Error: (22, Invalid argument'). This problem did not
> appear with previous version (around month ago). Dom0,
> however, boots without any problem.
> > 
> 
> Please paste the xen.cfg.
> 
> -- Pasi
> 
> > XEN issues the following messages when error occurs:
> > (XEN) mm.c:860:d0 Error getting mfn a7a4b (pfn a7820)
> from L1 entry 80000000a7a1
> > (XEN) mm.c:860:d0 Error getting mfn a7a4c (pfn a781f)
> from L1 entry 80000000a7a1
> > (XEN) mm.c:860:d0 Error getting mfn a7a4d (pfn a781e)
> from L1 entry 80000000a7a1
> > (XEN) mm.c:860:d0 Error getting mfn a7a4e (pfn a781d)
> from L1 entry 80000000a7a1
> > (XEN) mm.c:860:d0 Error getting mfn a7a4f (pfn a781c)
> from L1 entry 80000000a7a1
> > (XEN) mm.c:860:d0 Error getting mfn a7a50 (pfn a781b)
> from L1 entry 80000000a7a1
> > (XEN) mm.c:860:d0 Error getting mfn a7a51 (pfn a781a)
> from L1 entry 80000000a7a1
> > 
> > CPU is multicore Xeon 5600 (Nehalem arhitecture).
> > 
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>