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

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



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