Re: [Xen-devel] [PATCH v2] xen: arm: clarify cacheability requirements of hypercall arguments.

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2013-12-18 at 11:59 +0000, Stefano Stabellini wrote:
> On Wed, 18 Dec 2013, Ian Campbell wrote:
> > Accepting hypercall arguments which are either consistently in cached or
> > uncached is tricky and/or potentially slow, requiring a guest mapping lookup
> > to determine whether/when to do a cache clean or invalidate.
> > 
> > There are very few reasons, and no current use cases in practice, for a 
> > guest
> > to use uncached memory for their hypercall arguments. Therefore mandate that
> > all hypercall arguments must be mapped inner-cacheable.
> > 
> > Do not place any restriction on the outer-cacheability or on the cache
> > fill/flush strategy used.
> > 
> > If use cases arise then we can consider specific exemptions to this rule.
> > 
> > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> 
> Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

I don't think this needs a freeze exception. applied, thanks.



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