On Tue, 7 Apr 2015 17:01:31 +0200 Cornelia Huck <[email protected]> wrote:
> On Tue, 07 Apr 2015 14:19:31 +0200 > Greg Kurz <[email protected]> wrote: > > > This patch brings cross-endian support to vhost when used to implement > > legacy virtio devices. Since it is a relatively rare situation, the > > feature availability is controlled by a kernel config option (not set > > by default). > > > > The ioctls introduced by this patch are for legacy only: virtio 1.0 > > devices are returned EPERM. > > > > Signed-off-by: Greg Kurz <[email protected]> > > --- > > drivers/vhost/Kconfig | 10 ++++++++ > > drivers/vhost/vhost.c | 55 > > ++++++++++++++++++++++++++++++++++++++++++++ > > drivers/vhost/vhost.h | 17 +++++++++++++- > > include/uapi/linux/vhost.h | 5 ++++ > > 4 files changed, 86 insertions(+), 1 deletion(-) > > > +#ifdef CONFIG_VHOST_SET_ENDIAN_LEGACY > > +static long vhost_set_vring_endian_legacy(struct vhost_virtqueue *vq, > > + void __user *argp) > > +{ > > + struct vhost_vring_state s; > > + > > + if (vhost_has_feature(vq, VIRTIO_F_VERSION_1)) > > + return -EPERM; > > + > > + if (copy_from_user(&s, argp, sizeof(s))) > > + return -EFAULT; > > + > > + vq->legacy_is_little_endian = !!s.num; > > + return 0; > > +} > > + > > +static long vhost_get_vring_endian_legacy(struct vhost_virtqueue *vq, > > + u32 idx, > > + void __user *argp) > > +{ > > + struct vhost_vring_state s = { > > + .index = idx, > > + .num = vq->legacy_is_little_endian > > + }; > > + > > + if (vhost_has_feature(vq, VIRTIO_F_VERSION_1)) > > + return -EPERM; > > + > > + if (copy_to_user(argp, &s, sizeof(s))) > > + return -EFAULT; > > + > > + return 0; > > +} > > +#else > > +static long vhost_set_vring_endian_legacy(struct vhost_virtqueue *vq, > > + void __user *argp) > > +{ > > + return 0; > > I'm wondering whether this handler should return an error if the > feature is not configured for the kernel? How can the userspace caller > find out whether it has successfully prompted the kernel to handle the > endianness correctly? > Yes you're right. I think -ENOIOCTLCMD as suggested by Michael is a good candidate. Thanks. > > +} > > + > > +static long vhost_get_vring_endian_legacy(struct vhost_virtqueue *vq, > > + u32 idx, > > + void __user *argp) > > +{ > > + return 0; > > +} > > +#endif /* CONFIG_VHOST_SET_ENDIAN_LEGACY */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
