[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] questions regarding interdomain communication and xen-guest communication
On 24 October 2013 09:09, Jan Beulich <jbeulich@xxxxxxxx> wrote: >>>> Aastha Mehta <aasthakm@xxxxxxxxx> 10/23/13 7:44 PM >>> >>If there is an interdomain event channel set up between two guests, do >>they communicate directly with each other, bypassing the hypervisor >>completely? > > No, event channel delivery works via the hypervisor. > >> In case of an asynchronous I/O does one guest have to >>register its callbacks with the other guest directly? >>Or does one guest hypercall into xen, which then upcalls into the >>other guest and then transfer reply in the reverse using another pair >>of hypercall and upcall? > > Again, the latter. So when one guest (G1) shares pages with second (G2), for example for block I/O, G1 will inform second via xen about a shared page. G1 will also register a callback with Xen. When Xen upcalls into G2 to forward G1's request, does it block on G2's reponse? How does G2 send back the result of I/O to G1? > >> Can event channels be set up ad hoc between >>two, for example, dom0 and a guest domain? Or can they only be used by >>drivers, e.g. between network frontend and backend drivers? > > The former. > >>Regarding xen -- domain communication: how can xen send some request >>to dom0 for some operation that needs to be performed in the dom0 and >>get back results from the dom0? > > Look at the MCE polling Dom0 performs for example, or the memory pressure > threshold handling: One model would be for Dom0 to set up a (dedicated) > vIRQ for that purpose, and Xen trigger that vIRQ when it needs Dom0's help. > Just to clarify, will guest return the result of the operation using a hypercall? >> Does such a communication have to be synchronous? > > I would say no, unless your use case has such a requirement. > > Jan > Thanks for the response. -- Aastha Mehta MPI-SWS, Germany E-mail: aasthakm@xxxxxxxxxxx _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |