Re: Using EPT to map guest MMIO to host MMIO

Cyclonus J
2011-08-05T08:46:44Z

On Fri, Aug 5, 2011 at 12:41 AM, Jan Kiszka <jan.kiszka@siemens.com> wrote:
> On 2011-08-05 09:20, Cyclonus J wrote:
>> hi,
>>
>> I am wondering if it is possible to map guest MMIO to host MMIO, the
>> purpose is to reduce VM_EXIT as the page tables will be setup before
>> MMIO accessing from guest. Here is what I have in mind:
>
> This is already the case if you pass through devices AND aligment&size
> of the MMIO resource allows this.

I assume here pass through means using VT-d? Unfortunately, I can't
use it for my case and I need to para-virtualize guest OS as well.

Thanks,
CJ

>
> What MMIOs do you see that are not mapped 1:1? For what kind of devices?
>
> Jan
>
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