[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] xenstore -- read UUID
Hi everyone, Sorry for the late joining to this thread. If you really want to gather a domain's uuid from within the hypervisor, it's actually possible to do without xenstore. A domain's uuid gets stored as a xen_domain_handle_t in the domain handle field (see xen/include/xen/sched.h and xen/commom/domctl.c). The uuid of a domain gets passed to xen on domain creation. The uuid can also be read from a privileged domain by issuing the XEN_DOMCTL_getdomaininfo hypercall. But as Derek mentioned earlier, you can read the domain uuid from a guest via xenstore which is probably a better idea. cheers, geoffrey On Wed, Sep 10, 2008 at 4:49 AM, Derek Murray <Derek.Murray@xxxxxxxxxxxx> wrote: > Hi Dinesh, > > On Wed, Sep 10, 2008 at 1:24 AM, dinesh chandrasekaran > <dinesh_chan8@xxxxxxxxxxx> wrote: >> they were 2 seperate questions... sorry for the typos... >> How to access xenstore from Dom-0? -- which you said 'YES'... > > Yes, this is certainly possible: your code should work (I haven't > tested it) in Dom0 user-space. For another example, see > tools/xenstore/xsls.c, which implements ls functionality for xenstore > using the same interface. > >> And How to access xenstore from hypervosor? > > There is no code to do this in Xen at the moment. > >> If the hypervisor has no knowledge about XenStore, Dom-0 must have the full >> control over the xenstore. > > Correct. XenStore is simply implemented as a user-space daemon > (xenstored), running as root in Dom0. > >> I need to build a table with some fields one of which should never change >> during a VMs lifetime. >> For example, if I chose the domain_id whose value is transient, If the VM >> reboots, its domain_id changes. >> That is the reason why I opted for the UUID of a domain that persists over >> time even after migration to another machine. >> The only way I could get a domain's UUID is through the xenstore and want to >> take away domain-0 from the picture, which >> according to you is almost impossible. > > Instead of Dom0, you could possibly do this in a stubdomain. It is > possible to access XenStore from a MiniOS-based domain. > > Regards, > > Derek Murray. > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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