On Tue, Sep 06, 2022 at 04:41:54PM -0600, Alex Williamson wrote:
> On Mon, 5 Sep 2022 13:58:47 +0300
> Yishai Hadas <yishaih@xxxxxxxxxx> wrote:
> > diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> > index e05ddc6fe6a5..b17f2f454389 100644
> > --- a/include/linux/vfio.h
> > +++ b/include/linux/vfio.h
> > @@ -108,6 +110,21 @@ struct vfio_migration_ops {
> > enum vfio_device_mig_state *curr_state);
> > };
> >
> > +/**
> > + * @log_start: Optional callback to ask the device start DMA logging.
> > + * @log_stop: Optional callback to ask the device stop DMA logging.
> > + * @log_read_and_clear: Optional callback to ask the device read
> > + * and clear the dirty DMAs in some given range.
>
> I don't see anywhere in the core that we track the device state
> relative to the DEVICE_FEATURE_DMA_LOGGING features, nor do we
> explicitly put the responsibility on the driver implementation to
> handle invalid user requests. The mlx5 driver implementation appears
> to do this, but maybe we should at least include a requirement here, ex.
>
> The vfio core implementation of the DEVICE_FEATURE_DMA_LOGGING_ set
> of features does not track logging state relative to the device,
> therefore the device implementation of vfio_log_ops must handle
> arbitrary user requests. This includes rejecting subsequent calls
> to log_start without an intervening log_stop, as well as graceful
> handling of log_stop and log_read_and_clear from invalid states.
>
> With something like that.
>
> Acked-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
>
> You can also add my Ack on 3, 4, and (fwiw) 6-10 as I assume this would
> be a PR from Leon. Thanks,
Yes, it is.
I sent PR based on clean 6.0-rc4.
Thanks
>
> Alex
>
> > + */
> > +struct vfio_log_ops {
> > + int (*log_start)(struct vfio_device *device,
> > + struct rb_root_cached *ranges, u32 nnodes, u64 *page_size);
> > + int (*log_stop)(struct vfio_device *device);
> > + int (*log_read_and_clear)(struct vfio_device *device,
> > + unsigned long iova, unsigned long length,
> > + struct iova_bitmap *dirty);
> > +};
> > +
> > /**
> > * vfio_check_feature - Validate user input for the VFIO_DEVICE_FEATURE ioctl
> > * @flags: Arg from the device_feature op
>
