[PATCH 0 of 5] PV on HVM Xen

[PATCH 0 of 5] PV on HVM Xen

[Stefano Stabellini]

Hi all,
this is a reduced and rebased version of the patch series I sent
yesterday "enhanced PV on HVM": this series is based on Linux 2.5.32 and
can be applied now, it includes everything but the pirq remapping
related functions that are not ready to be upstreamed at the moment.

Therefore it just achieves the goal of enabling PV devices in Linux
running in a Xen HVM domain, it doesn't allow event channels delivery in
place of interrupts.

The patch series consists of 5 patches, each patch comes with a detailed
description.
In order for this to work we also need a patch for Xen, that is being
worked on as we speak.

Any comment, critic or suggestion is very welcome.

Cheers,

Stefano

Re: [Xen-devel] [PATCH 0 of 5] PV on HVM Xen

[Pasi Kärkkäinen]

On Wed, Mar 10, 2010 at 03:46:54PM +0000, Stefano Stabellini wrote:
> Hi all,
> this is a reduced and rebased version of the patch series I sent
> yesterday "enhanced PV on HVM": this series is based on Linux 2.5.32 and
> can be applied now, it includes everything but the pirq remapping
> related functions that are not ready to be upstreamed at the moment.
> 
> Therefore it just achieves the goal of enabling PV devices in Linux
> running in a Xen HVM domain, it doesn't allow event channels delivery in
> place of interrupts.
> 
> The patch series consists of 5 patches, each patch comes with a detailed
> description.
> In order for this to work we also need a patch for Xen, that is being
> worked on as we speak.
>

Hmm.. is it possible to get PV-on-HVM drivers working on older Xen versions,
that don't have additional patches? 

Just like the unmodified_drivers works for 2.6.18 and 2.6.27.

-- Pasi

Re: [Xen-devel] [PATCH 0 of 5] PV on HVM Xen

[Stefano Stabellini]

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On Wed, 10 Mar 2010, Pasi Kärkkäinen wrote:
> On Wed, Mar 10, 2010 at 03:46:54PM +0000, Stefano Stabellini wrote:
> > Hi all,
> > this is a reduced and rebased version of the patch series I sent
> > yesterday "enhanced PV on HVM": this series is based on Linux 2.5.32 and
> > can be applied now, it includes everything but the pirq remapping
> > related functions that are not ready to be upstreamed at the moment.
> > 
> > Therefore it just achieves the goal of enabling PV devices in Linux
> > running in a Xen HVM domain, it doesn't allow event channels delivery in
> > place of interrupts.
> > 
> > The patch series consists of 5 patches, each patch comes with a detailed
> > description.
> > In order for this to work we also need a patch for Xen, that is being
> > worked on as we speak.
> >
> 
> Hmm.. is it possible to get PV-on-HVM drivers working on older Xen versions,
> that don't have additional patches? 
> 
> Just like the unmodified_drivers works for 2.6.18 and 2.6.27.
> 

The problem is that the old unmodified_drivers use a normal interrupt
from the xen pci platform device to receive event channels, and this
doesn't play well with the idea of remapping all the interrupts with
event channels, that is one if the main goals of the previous "enhanced"
patch series.
For this reason the new PV on HVM patch series sets up a new vector
based callback mechanism.

However it might be still possible to provide an additional, backward
compatible, delivery mechanism in case the new one fails.
I'll try to explore this option.

Re: [Xen-devel] [PATCH 0 of 5] PV on HVM Xen

[Jeremy Fitzhardinge]

On 03/10/2010 09:55 AM, Stefano Stabellini wrote:
> However it might be still possible to provide an additional, backward
> compatible, delivery mechanism in case the new one fails.
> I'll try to explore this option.
>    

Yes, please.  A lot of the interest in pv drivers for hvm comes from 
people running long-deployed Xen systems based on RHEL, etc.

     J

Re: [Xen-devel] [PATCH 0 of 5] PV on HVM Xen

[Sheng Yang]

On Wednesday 10 March 2010 23:46:54 Stefano Stabellini wrote:
> Hi all,

Stefano,

And next time when you send out the patch, please be more respect to my work.

You dropped all the original author(me) of patchset, and only add a sign-off 
for me. If you don't aware the difference, here is a snippet of 
linux/Documentation/SummittingPatches

532 The "from" line must be the very first line in the message body,
533 and has the form:
534
535         From: Original Author <author@example.com>
536
537 The "from" line specifies who will be credited as the author of the
538 patch in the permanent changelog.  If the "from" line is missing,
539 then the "From:" line from the email header will be used to determine
540 the patch author in the changelog.

As you see, the first two kernel patches of mine contained file from Jeremy 
and Keir, and I add the "From" for them properly to respect their works.

Another thing is, you were keeping using my old patches as your base, while I 
was working with the reviewers to update the patch quickly. I don't think 
that's a kind of respect to both reviewers' and my work. You would duplicate 
reviewer's effect, especially you always repost the whole patch(and drop my 
authorship) rather than the different part. I've split patches in order to 
provide a code base for further development, but you complete ignored them and 
keeping post the whole patchset based on my old patches.

Please be more professional. Thanks.

-- 
regards
Yang, Sheng

> this is a reduced and rebased version of the patch series I sent
> yesterday "enhanced PV on HVM": this series is based on Linux 2.5.32 and
> can be applied now, it includes everything but the pirq remapping
> related functions that are not ready to be upstreamed at the moment.
> 
> Therefore it just achieves the goal of enabling PV devices in Linux
> running in a Xen HVM domain, it doesn't allow event channels delivery in
> place of interrupts.
> 
> The patch series consists of 5 patches, each patch comes with a detailed
> description.
> In order for this to work we also need a patch for Xen, that is being
> worked on as we speak.
> 
> Any comment, critic or suggestion is very welcome.
> 
> Cheers,
> 
> Stefano
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
> 

Re: [Xen-devel] [PATCH 0 of 5] PV on HVM Xen

[Stefano Stabellini]

On Fri, 12 Mar 2010, Sheng Yang wrote:
> On Wednesday 10 March 2010 23:46:54 Stefano Stabellini wrote:
> > Hi all,
> 
> Stefano,
> 
> And next time when you send out the patch, please be more respect to my work.
> 
> You dropped all the original author(me) of patchset, and only add a sign-off 
> for me. If you don't aware the difference, here is a snippet of 
> linux/Documentation/SummittingPatches
> 

I am truly sorry and apologise for it, I would never want to give you
the impression of being disrespectful of you and your work.
If you pay attention I manually wrote in the comments of all the past
versions of the patches that you were the original author, this time I
just forgot.
I guess it is really the time I start using git-send-email :)

Your work has been really important for my series and you deserve the
credit for it independently from which patch series gets applied.


> Another thing is, you were keeping using my old patches as your base, while I 
> was working with the reviewers to update the patch quickly. I don't think 
> that's a kind of respect to both reviewers' and my work. You would duplicate 
> reviewer's effect, especially you always repost the whole patch(and drop my 
> authorship) rather than the different part. I've split patches in order to 
> provide a code base for further development, but you complete ignored them and 
> keeping post the whole patchset based on my old patches.
> 

I don't keep using your old patches as a base but I manually rebase over
the most recent patch series you sent every time.
Obviously it is not a perfect system and sometimes I can miss something,
this is why at the beginning I asked you to work together on the same
tree: I wanted to avoid exactly this sort of issues.

My intentions are true so my proposal of working on a common tree is
still valid, just let me know when you are interested.

Re: [Xen-devel] [PATCH 0 of 5] PV on HVM Xen

[Jeremy Fitzhardinge]

On 03/12/2010 02:42 AM, Stefano Stabellini wrote:
> On Fri, 12 Mar 2010, Sheng Yang wrote:
>    
>> On Wednesday 10 March 2010 23:46:54 Stefano Stabellini wrote:
>>      
>>> Hi all,
>>>        
>> Stefano,
>>
>> And next time when you send out the patch, please be more respect to my work.
>>
>> You dropped all the original author(me) of patchset, and only add a sign-off
>> for me. If you don't aware the difference, here is a snippet of
>> linux/Documentation/SummittingPatches
>>
>>      
> I am truly sorry and apologise for it, I would never want to give you
> the impression of being disrespectful of you and your work.
> If you pay attention I manually wrote in the comments of all the past
> versions of the patches that you were the original author, this time I
> just forgot.
> I guess it is really the time I start using git-send-email :)
>
> Your work has been really important for my series and you deserve the
> credit for it independently from which patch series gets applied.
>    

Best practise for this kind of thing is to use Sheng's patch verbatim, 
then apply a separate delta on top to make the changes you want.  That way:

    * credit can be property attributed
    * it helps with maintaining two parallel-but-converging git
      branches, because all the common stuff is genuinely common, and
      the variations can work from there, and
    * if Sheng updates his patches (review, bugfix, etc), then we can
      easily see how those changes affect your changes.

For example, I just rebased your previous patch posting so that it is 
rooted on Sheng's two base patches, as they're completely common.

The latest of both patches is in xen/pvhvm-sheng and -stefano.

     J