[Intel-gfx] [PATCH v6 3/3] drm/doc/rfc: VM_BIND uapi definition

[Lionel Landwerlin]

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
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