Re: [RFC PATCH 06/16] x86/xen: add shared_info support to xenhost_t

[Ankur Arora]

On 2019-06-07 8:08 a.m., Juergen Gross wrote:
> On 09.05.19 19:25, Ankur Arora wrote:
> > HYPERVISOR_shared_info is used for irq/evtchn communication between the
> > guest and the host. Abstract out the setup/reset in xenhost_t such that
> > nested configurations can use both xenhosts simultaneously.
>
> I have mixed feelings about this patch. Most of the shared_info stuff we
> don't need for the nested case. In the end only the event channels might
> be interesting, but we obviously want them not for all vcpus of the L1
> hypervisor, but for those of the current guest.
Agreed about the mixed feelings part. shared_info does feel far too
heavy to drag along just for the event-channel state.
Infact, on thinking a bit more, a better abstraction for nested
event-channels would have been as an extension to the primary
xenhost's event-channel bits.
(The nested upcalls also go via the primary xenhost in patch-8.)

Ankur

> So I think just drop that patch for now. We can dig it out later in case > nesting wants it again.
>
>
> Juergen