From: Greg Kurz <gkurz@linux.vnet.ibm.com> To: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au>, "Michael S. Tsirkin" <mst@redhat.com>, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v3 7/7] vhost: feature to set the vring endianness Date: Wed, 8 Apr 2015 09:36:38 +0200 [thread overview] Message-ID: <20150408093638.7a233137@bahia.local> (raw) In-Reply-To: <20150407170131.3899d62c.cornelia.huck@de.ibm.com> On Tue, 7 Apr 2015 17:01:31 +0200 Cornelia Huck <cornelia.huck@de.ibm.com> wrote: > On Tue, 07 Apr 2015 14:19:31 +0200 > Greg Kurz <gkurz@linux.vnet.ibm.com> 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 <gkurz@linux.vnet.ibm.com> > > --- > > 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 */
WARNING: multiple messages have this Message-ID (diff)
From: Greg Kurz <gkurz@linux.vnet.ibm.com> To: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v3 7/7] vhost: feature to set the vring endianness Date: Wed, 8 Apr 2015 09:36:38 +0200 [thread overview] Message-ID: <20150408093638.7a233137@bahia.local> (raw) In-Reply-To: <20150407170131.3899d62c.cornelia.huck@de.ibm.com> On Tue, 7 Apr 2015 17:01:31 +0200 Cornelia Huck <cornelia.huck@de.ibm.com> wrote: > On Tue, 07 Apr 2015 14:19:31 +0200 > Greg Kurz <gkurz@linux.vnet.ibm.com> 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 <gkurz@linux.vnet.ibm.com> > > --- > > 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 */
next prev parent reply other threads:[~2015-04-08 7:36 UTC|newest] Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-04-07 12:09 [PATCH v3 0/7] vhost: support for cross endian guests Greg Kurz 2015-04-07 12:09 ` Greg Kurz 2015-04-07 12:09 ` [PATCH v3 1/7] virtio: introduce virtio_is_little_endian() helper Greg Kurz 2015-04-07 12:09 ` [PATCH v3 2/7] tun: add tun_is_little_endian() helper Greg Kurz 2015-04-07 12:09 ` [PATCH v3 3/7] macvtap: introduce macvtap_is_little_endian() helper Greg Kurz 2015-04-07 12:15 ` [PATCH v3 4/7] vringh: introduce vringh_is_little_endian() helper Greg Kurz 2015-04-07 12:15 ` Greg Kurz 2015-04-07 12:15 ` [PATCH v3 5/7] vhost: introduce vhost_is_little_endian() helper Greg Kurz 2015-04-07 12:15 ` [PATCH v3 6/7] virtio: add explicit big-endian support to memory accessors Greg Kurz 2015-04-07 12:15 ` Greg Kurz 2015-04-07 15:56 ` Michael S. Tsirkin 2015-04-07 15:56 ` Michael S. Tsirkin 2015-04-21 7:47 ` Greg Kurz 2015-04-21 7:47 ` Greg Kurz 2015-04-21 7:47 ` Greg Kurz 2015-04-07 12:15 ` Greg Kurz 2015-04-07 12:19 ` [PATCH v3 7/7] vhost: feature to set the vring endianness Greg Kurz 2015-04-07 15:01 ` Cornelia Huck 2015-04-07 15:01 ` Cornelia Huck 2015-04-08 7:36 ` Greg Kurz [this message] 2015-04-08 7:36 ` Greg Kurz 2015-04-07 15:01 ` Cornelia Huck 2015-04-07 15:52 ` Michael S. Tsirkin 2015-04-07 15:52 ` Michael S. Tsirkin 2015-04-07 15:52 ` Michael S. Tsirkin 2015-04-08 8:23 ` Greg Kurz 2015-04-08 8:23 ` Greg Kurz 2015-04-07 16:11 ` Michael S. Tsirkin 2015-04-07 16:11 ` Michael S. Tsirkin 2015-04-08 8:25 ` Greg Kurz 2015-04-08 8:25 ` Greg Kurz 2015-04-07 15:55 ` [PATCH v3 0/7] vhost: support for cross endian guests Michael S. Tsirkin 2015-04-07 15:55 ` Michael S. Tsirkin 2015-04-07 16:08 ` Greg Kurz 2015-04-07 16:08 ` Greg Kurz 2015-04-07 16:08 ` Greg Kurz 2015-04-07 15:55 ` Michael S. Tsirkin
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