Xen devel - Feb 2013 - [PATCH 0/8] kexec: extended kexec hypercall for use with pv-ops kernels

The series improves the kexec hypercall by making Xen responsible for
loading and relocating the image.  This allows kexec to be usable by
pv-ops kernels and should allow kexec to be usable from a HVM or PVH
privileged domain.

The first patch is a simple clean-up.

The second patch allows hypercall structures to be ABI compatible
between 32- and 64-bit guests (by reusing stuff present for domctls
and sysctls).  This seems better than having to keep adding compat
handling for new hypercalls etc.

Patch 3 introduces the new ABI.

Patch 4 and 5 nearly completely reimplement the kexec load, unload and
exec sub-ops.  The old load_v1 sub-op is then implemented on top of
the new code.

Patch 6 calls the kexec image when dom0 crashes.  This avoids having
to alter dom0 kernels to do a exec sub-op call on crash -- an existing
SHUTDOWN_crash.

Patches 7 and 8 add the libxc API for the kexec calls.

The required patch series for kexec-tools will be posted shortly.

David

On Thu, Feb 21, 2013 at 05:48:06PM +0000, David Vrabel
wrote:
> The series improves the kexec hypercall by making Xen responsible for
> loading and relocating the image.  This allows kexec to be usable by
> pv-ops kernels and should allow kexec to be usable from a HVM or PVH
> privileged domain.
>
> The first patch is a simple clean-up.
>
> The second patch allows hypercall structures to be ABI compatible
> between 32- and 64-bit guests (by reusing stuff present for domctls
> and sysctls).  This seems better than having to keep adding compat
> handling for new hypercalls etc.
>
> Patch 3 introduces the new ABI.
>
> Patch 4 and 5 nearly completely reimplement the kexec load, unload and
> exec sub-ops.  The old load_v1 sub-op is then implemented on top of
> the new code.
>
> Patch 6 calls the kexec image when dom0 crashes.  This avoids having
> to alter dom0 kernels to do a exec sub-op call on crash -- an existing
> SHUTDOWN_crash.
>
> Patches 7 and 8 add the libxc API for the kexec calls.
>
> The required patch series for kexec-tools will be posted shortly.
On first sight both patch series looks quite good for me.
Give me a week or two to do some tests.

Daniel

>>> On 21.02.13 at 18:48, David Vrabel <david.vrabel@citrix.com>
wrote:
> The series improves the kexec hypercall by making Xen responsible for
> loading and relocating the image.  This allows kexec to be usable by
> pv-ops kernels and should allow kexec to be usable from a HVM or PVH
> privileged domain.
> 
> The first patch is a simple clean-up.
> 
> The second patch allows hypercall structures to be ABI compatible
> between 32- and 64-bit guests (by reusing stuff present for domctls
> and sysctls).  This seems better than having to keep adding compat
> handling for new hypercalls etc.
> 
> Patch 3 introduces the new ABI.
> 
> Patch 4 and 5 nearly completely reimplement the kexec load, unload and
> exec sub-ops.  The old load_v1 sub-op is then implemented on top of
> the new code.
> 
> Patch 6 calls the kexec image when dom0 crashes.  This avoids having
> to alter dom0 kernels to do a exec sub-op call on crash -- an existing
> SHUTDOWN_crash.
Am I right in understanding that at this point no kexec support is
necessary in the Dom0 kernel at all anymore? If so, that''s a very
nice move - thanks for doing that!

Jan

On 22/02/13 08:17, Jan Beulich wrote:
>>>> On 21.02.13 at 18:48, David Vrabel
<david.vrabel@citrix.com> wrote:
>> The series improves the kexec hypercall by making Xen responsible for
>> loading and relocating the image.  This allows kexec to be usable by
>> pv-ops kernels and should allow kexec to be usable from a HVM or PVH
>> privileged domain.
>>
>> The first patch is a simple clean-up.
>>
>> The second patch allows hypercall structures to be ABI compatible
>> between 32- and 64-bit guests (by reusing stuff present for domctls
>> and sysctls).  This seems better than having to keep adding compat
>> handling for new hypercalls etc.
>>
>> Patch 3 introduces the new ABI.
>>
>> Patch 4 and 5 nearly completely reimplement the kexec load, unload and
>> exec sub-ops.  The old load_v1 sub-op is then implemented on top of
>> the new code.
>>
>> Patch 6 calls the kexec image when dom0 crashes.  This avoids having
>> to alter dom0 kernels to do a exec sub-op call on crash -- an existing
>> SHUTDOWN_crash.
> 
> Am I right in understanding that at this point no kexec support is
> necessary in the Dom0 kernel at all anymore? If so, that''s a very
> nice move - thanks for doing that!
Yes.  It will kexec slightly later than it would on native (or classic)
but I don''t think this will be a problem in practice.

David

On 02/21/13 12:48, David Vrabel wrote:
> The series improves the kexec hypercall by making Xen responsible for
> loading and relocating the image.  This allows kexec to be usable by
> pv-ops kernels and should allow kexec to be usable from a HVM or PVH
> privileged domain.
>
> The first patch is a simple clean-up.
>
> The second patch allows hypercall structures to be ABI compatible
> between 32- and 64-bit guests (by reusing stuff present for domctls
> and sysctls).  This seems better than having to keep adding compat
> handling for new hypercalls etc.
>
> Patch 3 introduces the new ABI.
>
> Patch 4 and 5 nearly completely reimplement the kexec load, unload and
> exec sub-ops.  The old load_v1 sub-op is then implemented on top of
> the new code.
>
> Patch 6 calls the kexec image when dom0 crashes.  This avoids having
> to alter dom0 kernels to do a exec sub-op call on crash -- an existing
> SHUTDOWN_crash.
>
> Patches 7 and 8 add the libxc API for the kexec calls.
>
> The required patch series for kexec-tools will be posted shortly.
>
> David
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
I have tested this patch set on a Fedora 17 dom0 with kernels:

3.7.3-101.fc17.x86_64
3.6.5-1.fc17.x86_64

So:

Tested-by: Don Slutz <Don@CloudSwitch.com>

    -Don Slutz

On 21/02/13 17:48, David Vrabel wrote:
> The series improves the kexec hypercall by making Xen responsible for
> loading and relocating the image.  This allows kexec to be usable by
> pv-ops kernels and should allow kexec to be usable from a HVM or PVH
> privileged domain.
Any further comments/acks for any of these patches? Specifically patch 2
and the toolstack patches (7 and 8).

Thanks.
> The first patch is a simple clean-up.
> 
> The second patch allows hypercall structures to be ABI compatible
> between 32- and 64-bit guests (by reusing stuff present for domctls
> and sysctls).  This seems better than having to keep adding compat
> handling for new hypercalls etc.
> 
> Patch 3 introduces the new ABI.
> 
> Patch 4 and 5 nearly completely reimplement the kexec load, unload and
> exec sub-ops.  The old load_v1 sub-op is then implemented on top of
> the new code.
> 
> Patch 6 calls the kexec image when dom0 crashes.  This avoids having
> to alter dom0 kernels to do a exec sub-op call on crash -- an existing
> SHUTDOWN_crash.
> 
> Patches 7 and 8 add the libxc API for the kexec calls.
> 
> The required patch series for kexec-tools will be posted shortly.
David

> On 21/02/13 17:48, David Vrabel wrote:
> > The series improves the kexec hypercall by making Xen responsible for
> > loading and relocating the image.  This allows kexec to be usable by
> > pv-ops kernels and should allow kexec to be usable from a HVM or PVH
> > privileged domain.
>
> Any further comments/acks for any of these patches? Specifically patch 2
> and the toolstack patches (7 and 8).
I am reviewing patches more deeply right now.
I will send you my comments by the end
of this week (as I promised earlier).

Daniel