Re: [Xen-devel] [PATCH 00/11] Alternate p2m: support multiple copies of host p2m

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 10.01.15 at 00:04, <edmund.h.white@xxxxxxxxx> wrote:
> On 01/09/2015 02:41 PM, Andrew Cooper wrote:
>> Having some non-OS part of the guest swap the EPT tables and
>> accidentally turn a DMA buffer read-only is not going to end well.
>> 
> 
> The agent can certainly do bad things, and at some level you have to assume it
> is sensible enough not to. However, I'm not sure this is fundamentally more
> dangerous than what a privileged domain can do today using the MEMOP...
> operations, and people are already using those for very similar purposes.

I don't follow - how is what privileged domain can do related to the
proposed changes here (which are - via VMFUNC - at least partially
guest controllable, and that's also the case Andrew mentioned in his
reply)? I'm having a hard time understanding how a P2M stripped of
anything that's not plain RAM can be very useful to a guest. IOW
without such fundamental aspects clarified I don't see a point in
looking at the individual patches (which btw, according to your
wording elsewhere, should have been marked RFC).

Jan


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