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

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Jeudi 13 Avril 2006 03:06, Tian, Kevin a écrit :
> From: Alex Williamson [mailto:alex.williamson@xxxxxx]
>
> >Sent: 2006年4月12日 23:29
> >
> >On Wed, 2006-04-12 at 09:01 +0100, Tristan Gingold wrote:
> >> > 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!
> >
> >   I don't.  Xen needs to handle this better.  domU I/O port space
> >should be mapped to fault on access.  Writes should be dropped and
> >reads
> >return -1.  This is how a legacy system would behave.  We don't really
> >care about performance here, I/O port space is already slow, and this is
> >really only meant to handle startup time probing.  IMHO, it's
> >unreasonable to ask users to disable all drivers or even try to tell
> >them what that means.  The Linux/ia64 kernel currently does a pretty
> >good job of not blindly probing address spaces looking for hardware.  I
> >think as long as we handle I/O port space reasonably, we'll make the
> >driver situation in domU more flexible.  Thanks,
> >
> >     Alex
>
> Yes, it's better to emulate hardware behavior.
I also agree.

Tristan.



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