Re: KVM: MMU: nuke shadowed pgtable pages and pte's on memslot destruction

Hollis Blanchard
2008-07-21T22:22:29Z

On Monday 21 July 2008 16:34:40 Marcelo Tosatti wrote:
> On Mon, Jul 21, 2008 at 04:03:27PM -0500, Hollis Blanchard wrote:
> >
> > By the way, what is the testcase for this, i.e. how do I remove a
> > memslot?
>
> The testcase I used was RH6.2 graphical install, which changes the
> cirrus mode from linear frame buffer to the standard one, thus
> destroying the vram memory slot (should be able to do that with the
> framebuffer driver).

Hmm, we're not using any graphics adapters with PowerPC right now.

I've skimmed through cirrus_vga.c but I don't see any obvious "mode change"
routine; what is the function that triggers this behavior? Some "(un)register
physical memory" call?

> All you need on this callback is destroy all shadow mappings, to avoid
> the MMU code from referencing a memslot that is no longer existant.

In addition to that, I also need a testcase to actually exercise the
code... :)

--
Hollis Blanchard
IBM Linux Technology Center