Re: [Xen-devel] Xen/arm: Virtual ITS command queue handling

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Tue, 2015-05-19 at 17:40 +0530, Vijay Kilari wrote:
> > If a guest issues (for example) a MOVI which is not followed by an
> > INV/INVALL on native then what would trigger the LPI configuration to be
> > applied by the h/w?
> >
> > If a guest is required to send an INV/INVALL in order for some change to
> > take affect and it does not do so then it is buggy, isn't it?
> 
> agreed.
> 
> >
> > IOW all Xen needs to do is to propagate any guest initiated INV/INVALL
> > as/when it occurs in the command queue. I don't think we need to
> > fabricate an additional INV/INVALL while emulating a MOVI.
> >
> > What am I missing?
> 
> back to point:
> 
> INV has device id so not an issue.
> INVALL does not have device id to know pITS to send.
> For that reason Xen is expected to insert INVALL at proper
> places similar to SYNC and ignore INV/INVALL of guest.

Why wouldn't Xen just insert an INVALL in to all relevant pITS in
response to an INVALL from the guest?

If you are proposing something different then please be explicit by what
you mean by "proper places similar to SYNC". Ideally by proposing some
new text which I can use in the document.

Ian.


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