From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dagaen Golomb Subject: Re: Problem Reading from XenStore in DomU Date: Mon, 16 May 2016 09:16:45 -0400 Message-ID: References:

<242b1768-e958-0752-a6c2-8ac1a68468aa@cardoe.com>

Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1405931741446443391==" Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" To: Jonathan Creekmore Cc: Meng Xu , Doug Goldstein , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org --===============1405931741446443391== Content-Type: multipart/alternative; boundary=001a11c04e20b3beed0532f56ff1 --001a11c04e20b3beed0532f56ff1 Content-Type: text/plain; charset=UTF-8 Regards, Dagaen Golomb On May 16, 2016 09:13, "Jonathan Creekmore" wrote: > > > Dagaen Golomb writes: > > > It does, being the custom kernel on version 4.1.0. But Dom0 uses this same > > exact kernel and reads/writes just fine! The only solution if this is > > indeed the problem appears to be changing the kernel source we build on or > > some hacky method such as symlinking /proc/.. to /dev/.., there has to be > > an elegant real solution to this... > > When I was chasing down a similar problem back in August, I discovered > that Dom0 accesses XenStore through a unix domain socket and not through > the kernel interface, so hitting it through xenstore-ls always seemed to > work. That is why Dom0 reads/writes to XenStore ok with the same kernel > that fails for your DomU. When I moved XenStore to a stubdomain, I /did/ > see the problem in Dom0 with new enough kernels, which is why the > XenStore access library was changed to prefer the dev device instead of > the proc file. Great, I'll try out the XENSTORED_PATH variable when I get the chance and see if it resolves the issue. Regards, Dagaen Golomb Regards, Dagaen Golomb --001a11c04e20b3beed0532f56ff1 Content-Type: text/html; charset=UTF-8

Regards,
Dagaen Golomb
On May 16, 2016 09:13, "Jonathan Creekmore" <jonathan.creekmore@gmail.com> wrote:
>
>
> Dagaen Golomb writes:
>
> > It does, being the custom kernel on version 4.1.0. But Dom0 uses this same
> > exact kernel and reads/writes just fine! The only solution if this is
> > indeed the problem appears to be changing the kernel source we build on or
> > some hacky method such as symlinking /proc/.. to /dev/.., there has to be
> > an elegant real solution to this...
>
> When I was chasing down a similar problem back in August, I discovered
> that Dom0 accesses XenStore through a unix domain socket and not through
> the kernel interface, so hitting it through xenstore-ls always seemed to
> work. That is why Dom0 reads/writes to XenStore ok with the same kernel
> that fails for your DomU. When I moved XenStore to a stubdomain, I /did/
> see the problem in Dom0 with new enough kernels, which is why the
> XenStore access library was changed to prefer the dev device instead of
> the proc file.

Great, I'll try out the XENSTORED_PATH variable when I get the chance and see if it resolves the issue.

Regards,
Dagaen Golomb

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