[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH RFC 04/12] libxl: create a local xenstore libxl and device-model dir for guests
On Thu, 2013-09-26 at 12:20 +0200, Roger Pau Monnà wrote: > On 26/09/13 12:15, Ian Campbell wrote: > > On Thu, 2013-09-26 at 11:57 +0200, Roger Pau Monnà wrote: > >> On 26/09/13 11:39, Ian Campbell wrote: > >>> On Thu, 2013-09-26 at 11:27 +0200, Roger Pau Monnà wrote: > >>>> On 25/09/13 15:48, Ian Campbell wrote: > >>>>> On Mon, 2013-09-23 at 12:30 +0200, Roger Pau Monne wrote: > >>>>>> If libxl is executed inside a guest domain it needs write access to > >>>>>> the local libxl xenstore dir (/local/<domid>/libxl) to store internal > >>>>>> data. > >>>>> > >>>>> These sorts of changes need a patch against docs/misc/xenstore-paths.txt > >>>>> too. > >>>> > >>>> Ack. > >>>> > >>>>> > >>>>>> This also applies to Qemu which needs a > >>>>>> /local/<domid>/device-model xenstore directory. > >>>>> > >>>>> Is this a new requirement or a separate preexisting issue? How have we > >>>>> lived without it? > >>>> > >>>> This entry is so far only created on Dom0 (because it's the only domain > >>>> that launches Qemu, and is created by Qemu if needed), but when running > >>>> on a guest, the guest doesn't have permissions to write on > >>>> /local/<domid>/, so we have to create the directory in the toolstack > >>>> domain and assign write permissions for the guest. > >>>> > >>>> This path is hardcoded in Qemu, so it's quite difficult to change it, > >>>> that's why I've opted for creating it on domain creation. > >>> > >>> OK :-/ > >>> > >>>>>> This patch creates the mentioned directories for each guest launched > >>>>>> from libxl. > >>>>> > >>>>> I don't really like leaking toolstack "internals" into the normal guest > >>>>> namespace. Can we add an option to specify "this is a toolstack domain" > >>>>> and key off that? > >>>> > >>>> OK, something like driver_domain=1|0 > >>> > >>> Something like that, yes. > >>> > >>>>> I also wonder if this shouldn't be /libxl/<domid> at the top level. > >>>> > >>>> I don't have a strong opinion on this, but I generally prefer to keep > >>>> all the xenstore related keys for a domain inside /libxl/<domid>. > >>> > >>> Are you agreeing with me or did you mean /local/(domain/)<domid> ? > >> > >> I would prefer to place it in /local/domain/<domid>/libxl/ because I get > >> the feeling it's more contained, but frankly I don't have a strong > >> opinion on this, if you prefer to use /libxl/<domid> I can go for it. > >> > >> However keep in mind that we will have to create the > >> /local/domain/<domid>/libxl dir anyway, because we have to write the > >> hotplug disable key there (/local/domain/<domid>/libxl/disable_udev). > > > > That's a toolstack "internal" key isn't it, which we can move? Or is it? > > Yes, we can move it with some modifications to the hotplug scripts, but > we will still need to create a directory like /libxl/<domid>/, or > something similar where the guest has write permissions, but I don't see > how this is any better than /local/domain/<domid>/libxl/. I suppose as long as the path is clearly documented as for being for code implementing dissagregated toolstack functionality (driver domains) only then there's not much distinction. I thought the /libxl path was a bit more "self enforcing/documenting" is all by being outside the regular path. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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