Re: [Xen-devel] [PATCH 08/18] PVH xen: tools changes to create PVH domain

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2013-08-29 at 17:45 -0700, Mukesh Rathor wrote:
> On Thu, 29 Aug 2013 10:01:25 +0100
> Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> 
> > On Wed, 2013-08-28 at 18:51 -0700, Mukesh Rathor wrote:
> > > On Thu, 1 Aug 2013 09:01:31 +0100
> > > Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> > > 
> > > > On Wed, 2013-07-31 at 19:02 -0700, Mukesh Rathor wrote:
> > > > > On Wed, 31 Jul 2013 13:00:57 +0100
> > > > > Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> ...
> > > Hmm.. the problem I am running here now is setting of PVH flag in 
> > > xch->flags from libxl? struct xch seems to be private to libxc.
> > 
> > xch is the libxc handle used by all the api calls, so it can't be
> > private to libxc. There is an xch inside the libxl ctx, use either
> > ctx->xch or CTX->xch depending on whether you have a ctx or a gc in
> > the function in question.
> > 
> > Actually, xch->flags & PVH is not the right place. xch is a handle
> > onto an open libxc instance, it is not per-domain, so adding PVH to
> > xch->flags is wrong. Not sure how I missed that initially.
> > 
> > I think you need to add the flag to the dom->flags in
> > libxl__build_pv. I don't think anything before the existing setting
> > of that field needs to know if the guest is PVH or not. The calls
> > between xc_dom_allocate and there are
> > xc_dom_(kernel|ramdisk)_(file|mem) which are just setting up internal
> > state and not touching the guest yet. If I'm wrong about that then I
> > think the block setting all of those dom->fields can be moved up.
> 
> The problem is I need to tell xc_dom_allocate() it's a PVH guest somehow 
> so it can call elf_xen_parse_features for PVH also.

I think you can do the PVH version of this call later, at whichever
point consuming dom->flags&PVH makes sense.

>  Since,
> thats not feasible, I can set the pvh flag in libxl__build_pv, and 
> xc_dom_parse_image() can then parse PVH features by calling
> elf_xen_parse_features(). LMK if thats not OK.

I can see how that would make sense, yes.

Ian.


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