Re: [PATCH v6 3/3] drm/doc/rfc: VM_BIND uapi definition

[Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>]

On 30/06/2022 20:12, Zanoni, Paulo R wrote:

> > > > Can you please explain what happens when we try to write to a range
> > > > that's bound as read-only?
> > > >
> > > >           
> > > It will be mapped as read-only in device page table. Hence any
> > > write access will fail. I would expect a CAT error reported.
> > >         
> > What's a CAT error? Does this lead to machine freeze or a GPU hang?
> > Let's make sure we document this.
> >
> >       
> Catastrophic error.
>
>

Reading the documentation, it seems the behavior depends on the context type.

With the Legacy 64bit context type, writes are ignored (BSpec 531) :

    - "For legacy context, the access rights are not applicable and should not be considered during page walk."

For Advanced 64bit context type, I think the HW will generate a pagefault.

-Lionel