Re: RFC: virtio-hostmem (+ Continuation of discussion from [virtio-dev] Memory sharing device)

From
Roman Kiryanov <>
Date
2019-02-25T23:08:32+00:00
ID
CAOGAQer=
Thread
Re: RFC: virtio-hostmem (+ Continuation of discussion from [virtio-dev] Memory sharing device)
Michael, thank you for your comments.

> I'm not sure how does above answer the comment.

Sorry for leaving this unclear, our guest driver tells the
device guest's page size and then we do aligning-unaligning.

> To try and put things in your terms, if you try to map a range of memory
> you get access to a page that can be bigger than the range you asked
> for.

This is correct.

>  It can cause two ranges to violate a security boundary, cause
> information leaks, etc.

Could you please correct me if I am wrong. If I ask glMapBufferRange
(without hosts and guests) for a 1K buffer with 4K pages, I will have
access to other 3K. If a driver decides to put sensitive bits there -
will this be the same situation?

We assume pages are not shared between processes.
If this assumption does not work then it is hard to share arbitrary pointers.

Regards,
Roman.