Re: [PATCH 2/2] drm/ttm: Fix vm page protection handling

[Thomas HellstrÃm (VMware)]

On 12/3/19 10:58 AM, Christian KÃnig wrote:
> Am 03.12.19 um 10:55 schrieb Kirill A. Shutemov:
> > On Tue, Dec 03, 2019 at 08:54:46AM +0100, Thomas HellstrÃm (VMware) 
> > wrote:
> > > From: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
> > >
> > > We were using an ugly hack to set the page protection correctly.
> > > Fix that and instead use vmf_insert_mixed_prot() and / or
> > > vmf_insert_pfn_prot().
> > > Also get the default page protection from
> > > struct vm_area_struct::vm_page_prot rather than using 
> > > vm_get_page_prot().
> > > This way we catch modifications done by the vm system for drivers that
> > > want write-notification.
> > Hm. Why doesn't your VMA have the right prot flags in the first 
> > place? Why
> > do you need to override them? More context, please.
>
> TTM allows for graphics buffer to move between system and IO memory. 
> So the prot flags can change on the fly for a VMA.
I'll add that and some additional info to the commit message. And fix 
that CC'd dri-devel address.

Thanks,
Thomas





> Regards,
> Christian.