Re: pv_ops & gntdev?

[Jeremy Fitzhardinge <jeremy@goop.org>]

Gerd Hoffmann wrote:
>> Yes, my plan is:
>>
>>   1. when installing a grant in a pte page, allocate a shadow page and
>>      hang it off page->private; also set a page flag on the pgd page
>>      flags (steal something spare)
>>     
>
> pgd or pte page flags?  or both?
>   

Just pgd, so that the unpinner can see it needs to make a second pass.  
At the pte level, looking for a non-NULL page->private should be enough.

>>   3. when clearing the pte, check to see if there's a grant handle and
>>      zap it
>>     
>
> That needs a new paravirt hook I think ...
>   

Hm, I hope not.  Doesn't it always end up using set_pte*?

>>   4. when unpinning the pagetable, check to see if there's the "grant
>>      mapping" flag in the pgd, and do a grant-zap pass before unpinning
>>     
>
> ok.
>
> Prelimary patches by chance?
>   

No, I haven't got around to implementing this at all.

Thanks,
    J