Re: [Xen-devel] [PATCH 3/4] xen/arm: introduce XENMEM_cache_flush

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 02.10.14 at 13:41, <stefano.stabellini@xxxxxxxxxxxxx> wrote:
> On Thu, 2 Oct 2014, Jan Beulich wrote:
>> With that, wouldn't the whole operation be a better fit with
>> the other MMUEXT_* ones instead of being XENMEM_*?
> 
> Or maybe a GNTTABOP_?
> After all we are only interested in flushing foreign pages with the
> hypercall. It would still need to take an mfn (or better a dev_bus_addr)
> because dom0 doesn't know the grant_ref either.

If the op is really meant to only be used on grants, then yes,
XENMEM_ as well as MMUEXT_ would seem the wrong ones (but
then you also incorrectly implemented it, as right now it permits
flushes on non-foreign pages).

But again I don't see why Dom0 can't track state for the mappings
it establishes - after all, a grant-ref would be the most natural
thing to pass in here.

Jan


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