Re: [PATCH RFC 05/15] vhost-user: add memory_isolation to VhostUserState

On Fri, Jul 24, 2026 at 4:09=E2=80=AFAM Akihiko Odaki
<[email protected]> wrote:
>
> The signature of the stub for !defined(CONFIG_VHOST_USER) is not
> updated, breaking builds.
>
> Regards,
> Akihiko Odaki

Good catch!  I have fixed this in passt.c, which I believe is the only
location affected.

On Mon, Jul 27, 2026 at 12:06=E2=80=AFPM Stefan Hajnoczi <[email protected]=
om> wrote:
>
> On Thu, Jul 23, 2026 at 03:30:04PM -0700, Connor Kite wrote:
> > @@ -73,12 +74,14 @@ typedef struct VhostUserState {
> >      int memory_slots;
> >      bool supports_config;
> >      bool supports_inflight_migration;
> > +    bool memory_isolation;
> >  } VhostUserState;
> >
> >  /**
> >   * vhost_user_init() - initialise shared vhost_user state
> >   * @user: allocated area for storing shared state
> >   * @chr: the chardev for the vhost socket
> > + * @memory_isolation: disables device access to guest memory
>
> "Device" is confusing because it has several meanings. "vhost-user
> back-end" would be clearer.
>
> "Disables" is also a little confusing because the vhost-user back-end
> still needs to access guest memory somehow. Memory access cannot be
> completely disabled. Something like "restricts vhost-user back-end
> access to guest memory via bounce buffers" could be clearer, but it's up
> to you. We probably don't want to repeat the full explanation in every
> comment about memory isolation, so it's fine to omit the details as long
> as there is user-facing documentation somewhere that explains what the
> feature does.

Perhaps for brevity it might make sense to say "@memory_isolation: restrict
direct access to guest memory from back-end".