Re: [kvm-devel] [PATCH][RFC] pte notifiers -- support for external page tables

Rusty Russell
2007-09-05T19:56:23Z

On Wed, 2007-09-05 at 22:32 +0300, Avi Kivity wrote:
> [resend due to bad alias expansion resulting in some recipients
> being bogus]
>
> Some hardware and software systems maintain page tables outside the normal
> Linux page tables, which reference userspace memory. This includes
> Infiniband, other RDMA-capable devices, and kvm (with a pending patch).

And lguest. I can't tell until I've actually implemented it, but I
think it will seriously reduce the need for page pinning which is why
only root can currently launch guests.

My concern is locking: this is called with the page lock held, and I
guess we have to bump the guest out if it's currently running.

(Oh, and this means lguest needs to do a reverse mapping somehow, but
I'll come up with something).

Cheers,
Rusty.