Re: [RFC PATCH 8/8] kvm: gmem: Allow restricted userspace mappings

[David Hildenbrand]

On 09.07.24 16:48, Fuad Tabba wrote:
> Hi Patrick,
>
> On Tue, Jul 9, 2024 at 2:21 PM Patrick Roy <roypat@xxxxxxxxxxxx> wrote:
> > Allow mapping guest_memfd into userspace. Since AS_INACCESSIBLE is set
> > on the underlying address_space struct, no GUP of guest_memfd will be
> > possible.
>
> This patch allows mapping guest_memfd() unconditionally. Even if it's
> not guppable, there are other reasons why you wouldn't want to allow
> this. Maybe a config flag to gate it? e.g.,


As discussed with Jason, maybe not the direction we want to take with 
guest_memfd.
If it's private memory, it shall not be mapped. Also not via magic 
config options.

We'll likely discuss some of that in the meeting MM tomorrow I guess 
(having both shared and private memory in guest_memfd).

Note that just from staring at this commit, I don't understand the 
motivation *why* we would want to do that.

--
Cheers,

David / dhildenb