Re: [Xen-devel] [PATCH 07/11] x86/altp2m: introduce p2m_ram_rw_ve type.

[Tim Deegan <tim@xxxxxxx>]

At 12:38 -0800 on 15 Jan (1421321902), Ed White wrote:
> On 01/15/2015 09:03 AM, Tim Deegan wrote:
> > At 13:26 -0800 on 09 Jan (1420806397), Ed White wrote:
> >> This is treated exactly like p2m_ram_rw, except that suppress_ve is not
> >> set in the EPTE.
> > 
> > I don't think this is going to work -- you probably want to support
> > p2m_ram_ro at least, and maybe other types, but duplicating each of
> > them as a 'type foo with #VE' doesn't seem right.
> > 
> > Since the default is to set the ignore-#ve flag everywhere, how about
> > having an operation to enable #ve for a frame that just clears that
> > bit, and then having all other updates to altp2m entries preserve it?
> 
> I hear you, but #VE is only even relevant for the in-domain agent
> model, and as the only current user of that model we not only don't
> want #VE to work on other page types, we specifically want it to be
> prohibited.

I see.  I think it would be very useful if you could add some
documentation of the new feature, covering this sort of thing, as well
as the exact semantics of the hypercalls.

> Can we do it this way, and then change it later if required?

No thank you.  It shouldn't be hard to do it the clean way from the
start.

Cheers,

Tim.

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