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Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on secondary vCPUs

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  Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on  secondary vCPUs David Vrabel <david.vrabel@citrix.com> - 2016-07-25 14:40 +0200
    Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on  secondary vCPUs Julien Grall <julien.grall@arm.com> - 2016-07-25 15:20 +0200
      Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on secondary vCPUs Vitaly Kuznetsov <vkuznets@redhat.com> - 2016-07-25 15:40 +0200
        Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on  secondary vCPUs Julien Grall <julien.grall@arm.com> - 2016-07-25 16:10 +0200
          Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on  secondary vCPUs David Vrabel <david.vrabel@citrix.com> - 2016-07-25 16:10 +0200
          Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on secondary vCPUs Vitaly Kuznetsov <vkuznets@redhat.com> - 2016-07-25 16:30 +0200
            Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on  secondary vCPUs Stefano Stabellini <sstabellini@kernel.org> - 2016-07-25 21:20 +0200
          Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on  secondary vCPUs Stefano Stabellini <sstabellini@kernel.org> - 2016-07-25 23:40 +0200
      Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on  secondary vCPUs David Vrabel <david.vrabel@citrix.com> - 2016-07-25 15:50 +0200
        Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on  secondary vCPUs Stefano Stabellini <sstabellini@kernel.org> - 2016-07-25 23:20 +0200

#1449446 — Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on secondary vCPUs

On 30/06/16 16:56, Vitaly Kuznetsov wrote:
> It may happen that Xen's and Linux's ideas of vCPU id diverge. In
> particular, when we crash on a secondary vCPU we may want to do kdump
> and unlike plain kexec where we do migrate_to_reboot_cpu() we try booting
> on the vCPU which crashed. This doesn't work very well for PVHVM guests as
> we have a number of hypercalls where we pass vCPU id as a parameter. These
> hypercalls either fail or do something unexpected. To solve the issue we
> need to have a mapping between Linux's and Xen's vCPU ids.
> 
> This series solves the issue for x86 PVHVM guests. PV guests don't (and
> probably won't) support kdump so I always assume Xen's vCPU id == Linux's
> vCPU id. ARM guests will probably need to get proper mapping once we start
> supporting kexec/kdump there.

Applied to for-linus-4.8, thanks.

David

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#1449469

Hi David,

On 25/07/16 13:38, David Vrabel wrote:
> On 30/06/16 16:56, Vitaly Kuznetsov wrote:
>> It may happen that Xen's and Linux's ideas of vCPU id diverge. In
>> particular, when we crash on a secondary vCPU we may want to do kdump
>> and unlike plain kexec where we do migrate_to_reboot_cpu() we try booting
>> on the vCPU which crashed. This doesn't work very well for PVHVM guests as
>> we have a number of hypercalls where we pass vCPU id as a parameter. These
>> hypercalls either fail or do something unexpected. To solve the issue we
>> need to have a mapping between Linux's and Xen's vCPU ids.
>>
>> This series solves the issue for x86 PVHVM guests. PV guests don't (and
>> probably won't) support kdump so I always assume Xen's vCPU id == Linux's
>> vCPU id. ARM guests will probably need to get proper mapping once we start
>> supporting kexec/kdump there.
>
> Applied to for-linus-4.8, thanks.

It would have been nice to send a ping before applying. This patch 
series is containing Xen ARM code which has not been acked by Stefano, 
nor had feedback from ARM side.

For instance given that all the hypercalls are representing a "vcpu id" 
using "uint32_t" it is a bit weird to use "int" to define xen_vcpu_id 
(see patch #3).

Regards,

-- 
Julien Grall

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#1449493 — Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on secondary vCPUs

Julien Grall <julien.grall@arm.com> writes:

> Hi David,
>
> On 25/07/16 13:38, David Vrabel wrote:
>> On 30/06/16 16:56, Vitaly Kuznetsov wrote:
>>> It may happen that Xen's and Linux's ideas of vCPU id diverge. In
>>> particular, when we crash on a secondary vCPU we may want to do kdump
>>> and unlike plain kexec where we do migrate_to_reboot_cpu() we try booting
>>> on the vCPU which crashed. This doesn't work very well for PVHVM guests as
>>> we have a number of hypercalls where we pass vCPU id as a parameter. These
>>> hypercalls either fail or do something unexpected. To solve the issue we
>>> need to have a mapping between Linux's and Xen's vCPU ids.
>>>
>>> This series solves the issue for x86 PVHVM guests. PV guests don't (and
>>> probably won't) support kdump so I always assume Xen's vCPU id == Linux's
>>> vCPU id. ARM guests will probably need to get proper mapping once we start
>>> supporting kexec/kdump there.
>>
>> Applied to for-linus-4.8, thanks.
>
> It would have been nice to send a ping before applying. This patch
> series is containing Xen ARM code which has not been acked by Stefano,
> nor had feedback from ARM side.
>
> For instance given that all the hypercalls are representing a "vcpu
> id" using "uint32_t" it is a bit weird to use "int" to define
> xen_vcpu_id (see patch #3).

CPU id is usually 'int' in linux and now we pass it to all
hypercalls as it is. It is a bit more convenient in the mapping I
introduce as we can set it to a negative value to indicate there is no
mapping available. I can definitely change that and use something like
U32_MAX-1 to instead but I'm not sure it is worth it...

-- 
  Vitaly

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#1449505

Hello,

On 25/07/16 14:39, Vitaly Kuznetsov wrote:
> Julien Grall <julien.grall@arm.com> writes:
>
>> Hi David,
>>
>> On 25/07/16 13:38, David Vrabel wrote:
>>> On 30/06/16 16:56, Vitaly Kuznetsov wrote:
>>>> It may happen that Xen's and Linux's ideas of vCPU id diverge. In
>>>> particular, when we crash on a secondary vCPU we may want to do kdump
>>>> and unlike plain kexec where we do migrate_to_reboot_cpu() we try booting
>>>> on the vCPU which crashed. This doesn't work very well for PVHVM guests as
>>>> we have a number of hypercalls where we pass vCPU id as a parameter. These
>>>> hypercalls either fail or do something unexpected. To solve the issue we
>>>> need to have a mapping between Linux's and Xen's vCPU ids.
>>>>
>>>> This series solves the issue for x86 PVHVM guests. PV guests don't (and
>>>> probably won't) support kdump so I always assume Xen's vCPU id == Linux's
>>>> vCPU id. ARM guests will probably need to get proper mapping once we start
>>>> supporting kexec/kdump there.
>>>
>>> Applied to for-linus-4.8, thanks.
>>
>> It would have been nice to send a ping before applying. This patch
>> series is containing Xen ARM code which has not been acked by Stefano,
>> nor had feedback from ARM side.
>>
>> For instance given that all the hypercalls are representing a "vcpu
>> id" using "uint32_t" it is a bit weird to use "int" to define
>> xen_vcpu_id (see patch #3).
>
> CPU id is usually 'int' in linux and now we pass it to all
> hypercalls as it is.

Well, we need to differentiate between the internal representation of 
the CPU which is based on the boot order and the logical CPU ID. For 
instance on ARM, the logical CPU ID may not be contiguous nor 0 for the 
first CPU.

 From my understanding, the macros in patch #3 will be used at the last 
minute when prepare the hypercall data. IHMO this is very similar to a 
logical ID and defined as uint32_t by the hypercall ABI.

Although, I agree that currently we use the internal CPU id on ARM which 
is very unfortunate because this value is based on the order of the 
nodes in the device tree.

One way to abolish it on ARM would be to use the MPIDR (or at least a 
part) for the VCPU ID.

> It is a bit more convenient in the mapping I
> introduce as we can set it to a negative value to indicate there is no
> mapping available. I can definitely change that and use something like
> U32_MAX-1 to instead but I'm not sure it is worth it...

I looked at the definition of cpu_acpi_id on x86 which return 
x86_cpu_to_acpiid that has been defined to an uint32_t.

So you are assuming that it will never be possible to have an ID > 
0x80000000.

Also, this may not be true on ARM depending how we define the VCPU 
mapping. We could decide to use the MPIDR which is in this case may be 
considered as "negative".

Regards,

-- 
Julien Grall

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#1449506

On 25/07/16 15:01, Julien Grall wrote:
> Hello,
> 
> On 25/07/16 14:39, Vitaly Kuznetsov wrote:
>> Julien Grall <julien.grall@arm.com> writes:
>>
>>> Hi David,
>>>
>>> On 25/07/16 13:38, David Vrabel wrote:
>>>> On 30/06/16 16:56, Vitaly Kuznetsov wrote:
>>>>> It may happen that Xen's and Linux's ideas of vCPU id diverge. In
>>>>> particular, when we crash on a secondary vCPU we may want to do kdump
>>>>> and unlike plain kexec where we do migrate_to_reboot_cpu() we try
>>>>> booting
>>>>> on the vCPU which crashed. This doesn't work very well for PVHVM
>>>>> guests as
>>>>> we have a number of hypercalls where we pass vCPU id as a
>>>>> parameter. These
>>>>> hypercalls either fail or do something unexpected. To solve the
>>>>> issue we
>>>>> need to have a mapping between Linux's and Xen's vCPU ids.
>>>>>
>>>>> This series solves the issue for x86 PVHVM guests. PV guests don't
>>>>> (and
>>>>> probably won't) support kdump so I always assume Xen's vCPU id ==
>>>>> Linux's
>>>>> vCPU id. ARM guests will probably need to get proper mapping once
>>>>> we start
>>>>> supporting kexec/kdump there.
>>>>
>>>> Applied to for-linus-4.8, thanks.
>>>
>>> It would have been nice to send a ping before applying. This patch
>>> series is containing Xen ARM code which has not been acked by Stefano,
>>> nor had feedback from ARM side.
>>>
>>> For instance given that all the hypercalls are representing a "vcpu
>>> id" using "uint32_t" it is a bit weird to use "int" to define
>>> xen_vcpu_id (see patch #3).
>>
>> CPU id is usually 'int' in linux and now we pass it to all
>> hypercalls as it is.
> 
> Well, we need to differentiate between the internal representation of
> the CPU which is based on the boot order and the logical CPU ID. For
> instance on ARM, the logical CPU ID may not be contiguous nor 0 for the
> first CPU.
> 
> From my understanding, the macros in patch #3 will be used at the last
> minute when prepare the hypercall data. IHMO this is very similar to a
> logical ID and defined as uint32_t by the hypercall ABI.
> 
> Although, I agree that currently we use the internal CPU id on ARM which
> is very unfortunate because this value is based on the order of the
> nodes in the device tree.
> 
> One way to abolish it on ARM would be to use the MPIDR (or at least a
> part) for the VCPU ID.
> 
>> It is a bit more convenient in the mapping I
>> introduce as we can set it to a negative value to indicate there is no
>> mapping available. I can definitely change that and use something like
>> U32_MAX-1 to instead but I'm not sure it is worth it...
> 
> I looked at the definition of cpu_acpi_id on x86 which return
> x86_cpu_to_acpiid that has been defined to an uint32_t.
> 
> So you are assuming that it will never be possible to have an ID >
> 0x80000000.
> 
> Also, this may not be true on ARM depending how we define the VCPU
> mapping. We could decide to use the MPIDR which is in this case may be
> considered as "negative".

If you want to change how you number vCPUs on ARM in the future, you can
(if necessary) change the type of this per-cpu variable as well.

David

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#1449539 — Re: [Xen-devel] [PATCH linux v2 0/9] xen: pvhvm: support bootup on secondary vCPUs

Julien Grall <julien.grall@arm.com> writes:

> Hello,
>
> On 25/07/16 14:39, Vitaly Kuznetsov wrote:
>> Julien Grall <julien.grall@arm.com> writes:
>>
>>> Hi David,
>>>
>>> On 25/07/16 13:38, David Vrabel wrote:
>>>> On 30/06/16 16:56, Vitaly Kuznetsov wrote:
>>>>> It may happen that Xen's and Linux's ideas of vCPU id diverge. In
>>>>> particular, when we crash on a secondary vCPU we may want to do kdump
>>>>> and unlike plain kexec where we do migrate_to_reboot_cpu() we try booting
>>>>> on the vCPU which crashed. This doesn't work very well for PVHVM guests as
>>>>> we have a number of hypercalls where we pass vCPU id as a parameter. These
>>>>> hypercalls either fail or do something unexpected. To solve the issue we
>>>>> need to have a mapping between Linux's and Xen's vCPU ids.
>>>>>
>>>>> This series solves the issue for x86 PVHVM guests. PV guests don't (and
>>>>> probably won't) support kdump so I always assume Xen's vCPU id == Linux's
>>>>> vCPU id. ARM guests will probably need to get proper mapping once we start
>>>>> supporting kexec/kdump there.
>>>>
>>>> Applied to for-linus-4.8, thanks.
>>>
>>> It would have been nice to send a ping before applying. This patch
>>> series is containing Xen ARM code which has not been acked by Stefano,
>>> nor had feedback from ARM side.
>>>
>>> For instance given that all the hypercalls are representing a "vcpu
>>> id" using "uint32_t" it is a bit weird to use "int" to define
>>> xen_vcpu_id (see patch #3).
>>
>> CPU id is usually 'int' in linux and now we pass it to all
>> hypercalls as it is.
>
> Well, we need to differentiate between the internal representation of
> the CPU which is based on the boot order and the logical CPU ID. For
> instance on ARM, the logical CPU ID may not be contiguous nor 0 for
> the first CPU.
>
> From my understanding, the macros in patch #3 will be used at the last
> minute when prepare the hypercall data. IHMO this is very similar to a
> logical ID and defined as uint32_t by the hypercall ABI.
>
> Although, I agree that currently we use the internal CPU id on ARM
> which is very unfortunate because this value is based on the order of
> the nodes in the device tree.
>
> One way to abolish it on ARM would be to use the MPIDR (or at least a
> part) for the VCPU ID.
>

I probably know too little about ARM but it seems that unlike x86 we
don't need the knowledge of _other_ vCPU ids before we start them so
MPIDR looks very suitable.

>> It is a bit more convenient in the mapping I
>> introduce as we can set it to a negative value to indicate there is no
>> mapping available. I can definitely change that and use something like
>> U32_MAX-1 to instead but I'm not sure it is worth it...
>
> I looked at the definition of cpu_acpi_id on x86 which return
> x86_cpu_to_acpiid that has been defined to an uint32_t.
>
> So you are assuming that it will never be possible to have an ID >
> 0x80000000.
>
> Also, this may not be true on ARM depending how we define the VCPU
> mapping. We could decide to use the MPIDR which is in this case may be
> considered as "negative".

While we're not obliged to have the same type for xen_vcpu_id on all
arches I see no point in diverging without a reason. I can do v3 making
the mapping uint32 and indicating the missing value as U32_MAX-1 if
nobody is against the idea.

-- 
  Vitaly

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#1449765

On Mon, 25 Jul 2016, Vitaly Kuznetsov wrote:
> Julien Grall <julien.grall@arm.com> writes:
> 
> > Hello,
> >
> > On 25/07/16 14:39, Vitaly Kuznetsov wrote:
> >> Julien Grall <julien.grall@arm.com> writes:
> >>
> >>> Hi David,
> >>>
> >>> On 25/07/16 13:38, David Vrabel wrote:
> >>>> On 30/06/16 16:56, Vitaly Kuznetsov wrote:
> >>>>> It may happen that Xen's and Linux's ideas of vCPU id diverge. In
> >>>>> particular, when we crash on a secondary vCPU we may want to do kdump
> >>>>> and unlike plain kexec where we do migrate_to_reboot_cpu() we try booting
> >>>>> on the vCPU which crashed. This doesn't work very well for PVHVM guests as
> >>>>> we have a number of hypercalls where we pass vCPU id as a parameter. These
> >>>>> hypercalls either fail or do something unexpected. To solve the issue we
> >>>>> need to have a mapping between Linux's and Xen's vCPU ids.
> >>>>>
> >>>>> This series solves the issue for x86 PVHVM guests. PV guests don't (and
> >>>>> probably won't) support kdump so I always assume Xen's vCPU id == Linux's
> >>>>> vCPU id. ARM guests will probably need to get proper mapping once we start
> >>>>> supporting kexec/kdump there.
> >>>>
> >>>> Applied to for-linus-4.8, thanks.
> >>>
> >>> It would have been nice to send a ping before applying. This patch
> >>> series is containing Xen ARM code which has not been acked by Stefano,
> >>> nor had feedback from ARM side.
> >>>
> >>> For instance given that all the hypercalls are representing a "vcpu
> >>> id" using "uint32_t" it is a bit weird to use "int" to define
> >>> xen_vcpu_id (see patch #3).
> >>
> >> CPU id is usually 'int' in linux and now we pass it to all
> >> hypercalls as it is.
> >
> > Well, we need to differentiate between the internal representation of
> > the CPU which is based on the boot order and the logical CPU ID. For
> > instance on ARM, the logical CPU ID may not be contiguous nor 0 for
> > the first CPU.
> >
> > From my understanding, the macros in patch #3 will be used at the last
> > minute when prepare the hypercall data. IHMO this is very similar to a
> > logical ID and defined as uint32_t by the hypercall ABI.
> >
> > Although, I agree that currently we use the internal CPU id on ARM
> > which is very unfortunate because this value is based on the order of
> > the nodes in the device tree.
> >
> > One way to abolish it on ARM would be to use the MPIDR (or at least a
> > part) for the VCPU ID.
> >
> 
> I probably know too little about ARM but it seems that unlike x86 we
> don't need the knowledge of _other_ vCPU ids before we start them so
> MPIDR looks very suitable.
> 
> >> It is a bit more convenient in the mapping I
> >> introduce as we can set it to a negative value to indicate there is no
> >> mapping available. I can definitely change that and use something like
> >> U32_MAX-1 to instead but I'm not sure it is worth it...
> >
> > I looked at the definition of cpu_acpi_id on x86 which return
> > x86_cpu_to_acpiid that has been defined to an uint32_t.
> >
> > So you are assuming that it will never be possible to have an ID >
> > 0x80000000.
> >
> > Also, this may not be true on ARM depending how we define the VCPU
> > mapping. We could decide to use the MPIDR which is in this case may be
> > considered as "negative".
> 
> While we're not obliged to have the same type for xen_vcpu_id on all
> arches I see no point in diverging without a reason. I can do v3 making
> the mapping uint32 

I agree that making the mapping uint32_t would be desirable. It would
even make sense from the int types point of view in Linux.


>and indicating the missing value as U32_MAX-1 if nobody is against the
>idea.

Why U32_MAX-1? (int)-1 is (unsigned)U32_MAX. Even
XEN_INVALID_MAX_VCPU_ID is defined as (~0U).

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#1449947

On Mon, 25 Jul 2016, Julien Grall wrote:
> On 25/07/16 14:39, Vitaly Kuznetsov wrote:
> > Julien Grall <julien.grall@arm.com> writes:
> > 
> > > Hi David,
> > > 
> > > On 25/07/16 13:38, David Vrabel wrote:
> > > > On 30/06/16 16:56, Vitaly Kuznetsov wrote:
> > > > > It may happen that Xen's and Linux's ideas of vCPU id diverge. In
> > > > > particular, when we crash on a secondary vCPU we may want to do kdump
> > > > > and unlike plain kexec where we do migrate_to_reboot_cpu() we try
> > > > > booting
> > > > > on the vCPU which crashed. This doesn't work very well for PVHVM
> > > > > guests as
> > > > > we have a number of hypercalls where we pass vCPU id as a parameter.
> > > > > These
> > > > > hypercalls either fail or do something unexpected. To solve the issue
> > > > > we
> > > > > need to have a mapping between Linux's and Xen's vCPU ids.
> > > > > 
> > > > > This series solves the issue for x86 PVHVM guests. PV guests don't
> > > > > (and
> > > > > probably won't) support kdump so I always assume Xen's vCPU id ==
> > > > > Linux's
> > > > > vCPU id. ARM guests will probably need to get proper mapping once we
> > > > > start
> > > > > supporting kexec/kdump there.
> > > > 
> > > > Applied to for-linus-4.8, thanks.
> > > 
> > > It would have been nice to send a ping before applying. This patch
> > > series is containing Xen ARM code which has not been acked by Stefano,
> > > nor had feedback from ARM side.
> > > 
> > > For instance given that all the hypercalls are representing a "vcpu
> > > id" using "uint32_t" it is a bit weird to use "int" to define
> > > xen_vcpu_id (see patch #3).
> > 
> > CPU id is usually 'int' in linux and now we pass it to all
> > hypercalls as it is.
> 
> Well, we need to differentiate between the internal representation of the CPU
> which is based on the boot order and the logical CPU ID. For instance on ARM,
> the logical CPU ID may not be contiguous nor 0 for the first CPU.
> 
> From my understanding, the macros in patch #3 will be used at the last minute
> when prepare the hypercall data. IHMO this is very similar to a logical ID and
> defined as uint32_t by the hypercall ABI.
> 
> Although, I agree that currently we use the internal CPU id on ARM which is
> very unfortunate because this value is based on the order of the nodes in the
> device tree.
> 
> One way to abolish it on ARM would be to use the MPIDR (or at least a part)
> for the VCPU ID.

That's a good idea -- much more reliable than the device tree cpu order.

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#1449498

On 25/07/16 14:17, Julien Grall wrote:
> Hi David,
> 
> On 25/07/16 13:38, David Vrabel wrote:
>> On 30/06/16 16:56, Vitaly Kuznetsov wrote:
>>> It may happen that Xen's and Linux's ideas of vCPU id diverge. In
>>> particular, when we crash on a secondary vCPU we may want to do kdump
>>> and unlike plain kexec where we do migrate_to_reboot_cpu() we try
>>> booting
>>> on the vCPU which crashed. This doesn't work very well for PVHVM
>>> guests as
>>> we have a number of hypercalls where we pass vCPU id as a parameter.
>>> These
>>> hypercalls either fail or do something unexpected. To solve the issue we
>>> need to have a mapping between Linux's and Xen's vCPU ids.
>>>
>>> This series solves the issue for x86 PVHVM guests. PV guests don't (and
>>> probably won't) support kdump so I always assume Xen's vCPU id ==
>>> Linux's
>>> vCPU id. ARM guests will probably need to get proper mapping once we
>>> start
>>> supporting kexec/kdump there.
>>
>> Applied to for-linus-4.8, thanks.
> 
> It would have been nice to send a ping before applying. This patch
> series is containing Xen ARM code which has not been acked by Stefano,
> nor had feedback from ARM side.

The ARM parts are trivial and such a small part of this series, I saw no
need to wait.

David

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#1449879

On Mon, 25 Jul 2016, David Vrabel wrote:
> On 25/07/16 14:17, Julien Grall wrote:
> > Hi David,
> > 
> > On 25/07/16 13:38, David Vrabel wrote:
> >> On 30/06/16 16:56, Vitaly Kuznetsov wrote:
> >>> It may happen that Xen's and Linux's ideas of vCPU id diverge. In
> >>> particular, when we crash on a secondary vCPU we may want to do kdump
> >>> and unlike plain kexec where we do migrate_to_reboot_cpu() we try
> >>> booting
> >>> on the vCPU which crashed. This doesn't work very well for PVHVM
> >>> guests as
> >>> we have a number of hypercalls where we pass vCPU id as a parameter.
> >>> These
> >>> hypercalls either fail or do something unexpected. To solve the issue we
> >>> need to have a mapping between Linux's and Xen's vCPU ids.
> >>>
> >>> This series solves the issue for x86 PVHVM guests. PV guests don't (and
> >>> probably won't) support kdump so I always assume Xen's vCPU id ==
> >>> Linux's
> >>> vCPU id. ARM guests will probably need to get proper mapping once we
> >>> start
> >>> supporting kexec/kdump there.
> >>
> >> Applied to for-linus-4.8, thanks.
> > 
> > It would have been nice to send a ping before applying. This patch
> > series is containing Xen ARM code which has not been acked by Stefano,
> > nor had feedback from ARM side.
> 
> The ARM parts are trivial and such a small part of this series, I saw no
> need to wait.

That's OK, no worries. In the future it would be nice to wait a few more
hours, until morning PST.

Cheers,

Stefano

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