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

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

>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. 


Thanks,
Kevin

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