Re: [patch] paravirt: VDSO page is essential

Rusty Russell
2007-03-05T13:33:15Z

On Mon, 2007-03-05 at 15:00 +0200, Avi Kivity wrote:
> Ingo Molnar wrote:
> > * Avi Kivity <avi@qumranet.com> wrote:
> > but yes, i agree that the hypervisor should have the ability to patch
> > the syscall instruction of both the hypervisor interface and of the VDSO
> > interface. But this wasnt implemented like that, and the #ifdef quirk
> > just /prevents/ a sane solution like that from ever getting done the
> > right way.
> >
>
> Rusty, shouldn't this be a one-liner? No need to involve the hypervisor
> here; the guest can s/syscall/int 80/ on its vdso page like it patches
> cli and its ilk.

Probably, but this is a red herring: see previous reply. Andi was a
little overzealous w/ CONFIG_PARAVIRT & COMPAT_VDSO, that's all.

I've never thought of replacing the syscall insn. I'll see if I can
come up with a good reason to want to 8)

Rusty.