Re: [Xen-devel] [v3][PATCH 1/1] xen:vtd: missing RMRR mapping while share EPT

[Tim Deegan <tim@xxxxxxx>]

At 09:02 +0100 on 25 Jul (1406275321), Jan Beulich wrote:
> >>> On 25.07.14 at 09:53, <tiejun.chen@xxxxxxxxx> wrote:
> > Such this kind of problem just happens in shared EPT case, right? In 
> > non-shared EPT case, we don't create these EPT tables to override other 
> > EPTs, so its okay?
> 
> At least I think/hope it is okay in the non-shared case - there's still
> the problem of the two translation tables not being consistent with
> one another, but I can't currently see problems arising from that.

It's _not_ OK in the non-shared case: if a guest has RAM at that
address and uses a passed-through device to DMA to it, the DMA will
end up in the RMRR area.  Add we know that this guest has at least one
passed-through device. :P

Tim.

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