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

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

>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.

>
>> 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.

>
>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?

>
>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.

Thanks,
Kevin

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