Re: [PATCH vhost v4 02/15] vdpa: Add VHOST_BACKEND_F_CHANGEABLE_VQ_ADDR_IN_SUSPEND flag

[Dragos Tatulea <dtatulea@nvidia.com>]

On Fri, 2023-12-22 at 11:51 +0100, Dragos Tatulea wrote:
> On Fri, 2023-12-22 at 03:29 -0500, Michael S. Tsirkin wrote:
> > On Thu, Dec 21, 2023 at 03:07:22PM +0000, Dragos Tatulea wrote:
> > > > > > In that case you're right, we don't need feature flags. But I think it
> > > > > > would be great to also move the error return in case userspace tries
> > > > > > to modify vq parameters out of suspend state.
> > > > > > 
> > > > > On the driver side or on the core side?
> > > > > 
> > > > 
> > > > Core side.
> > > > 
> > > Checking my understanding: instead of the feature flags there would be a check
> > > (for .set_vq_addr and .set_vq_state) to return an error if they are called under
> > > DRIVER_OK and not suspended state?
> > 
> > Yea this looks much saner, if we start adding feature flags for
> > each OPERATION_X_LEGAL_IN_STATE_Y then we will end up with N^2
> > feature bits which is not reasonable.
> > 
> Ack. Is the v2 enough or should I respin a v5 with the updated Acked-by tags?
> 
> I will prepare the core part as a different series without the flags.
> 
Core part sent:
https://lore.kernel.org/virtualization/20231225134210.151540-1-dtatulea@nvidia.com/T/#t

I also have a v2 respin with extra Acked-by tags if necessary as a v5. Just let
me know if it is needed.

Thanks,
Dragos