Re: [Xen-ia64-devel] [PATCH][RFC][TAKE4] the P2M/VP patches

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Mercredi 12 Avril 2006 10:09, Tian, Kevin a écrit :
> From: Tristan Gingold [mailto:Tristan.Gingold@xxxxxxxx]
>
> >Sent: 2006年4月12日 16:02
> >
> >> First, current code is taking mfn 0 as the result when mapping is not
> >> found which is more problematic like write access as you mentioned
> >>
> >> Second, mapping to a dummy page has similar effect, but no harm
> >> for write
> >
> >Writing page 0 is harmless!
>
> It's harmless because it's trimmed down by efi memmap walker,
> which means it's free and no one use it. So, it's same concept to
> dummy page here.
Yes, except we save one page :-)

> >> Last, the only way to prevent such io access is from guest itself,
> >> meant not compiling native drivers in. Or else there's no way for
> >> xen to handle it correctly.
> >
> >User should disable drivers in domU.  Everybody agree with that!
>
> Yes, except driver domain.
Ok.

> >You can also use command line options to do that.
>
> Can cmdline disable all the native drivers, like keyboard? Previous
> we have different config file for xen0 and xenU, and thus unwanted
> drivers are removed from config file. But now xen0 and xenU share
> same config file, how x86 solves this issue?
I don't know.  I have *always* used vmlinux-xen0 for dom0 *and* domU.
keyboard is on USB.

> >But without warnings, you don't know there are drivers enabled.
>
> Agree to keep warning there, but stack dump may be enabled
> conditionally which scares people to think something corrupted.
Ok.

Tristan.


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