From: Alex Williamson <alex.williamson@redhat.com>
To: Cornelia Huck <cohuck@redhat.com>
Cc: kvm@vger.kernel.org, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org, dev@dpdk.org, mtosatti@redhat.com,
thomas@monjalon.net, bluca@debian.org, jerinjacobk@gmail.com,
bruce.richardson@intel.com
Subject: Re: [dpdk-dev] [PATCH v2 4/7] vfio: Introduce VFIO_DEVICE_FEATURE ioctl and first user
Date: Thu, 5 Mar 2020 13:51:08 -0700 [thread overview]
Message-ID: <20200305135108.7b4b8a7f@w520.home> (raw)
In-Reply-To: <20200227183407.74a5c5b4.cohuck@redhat.com>
On Thu, 27 Feb 2020 18:34:07 +0100
Cornelia Huck <cohuck@redhat.com> wrote:
> On Wed, 19 Feb 2020 11:54:18 -0700
> Alex Williamson <alex.williamson@redhat.com> wrote:
>
> > The VFIO_DEVICE_FEATURE ioctl is meant to be a general purpose, device
> > agnostic ioctl for setting, retrieving, and probing device features.
> > This implementation provides a 16-bit field for specifying a feature
> > index, where the data porition of the ioctl is determined by the
> > semantics for the given feature. Additional flag bits indicate the
> > direction and nature of the operation; SET indicates user data is
> > provided into the device feature, GET indicates the device feature is
> > written out into user data. The PROBE flag augments determining
> > whether the given feature is supported, and if provided, whether the
> > given operation on the feature is supported.
> >
> > The first user of this ioctl is for setting the vfio-pci VF token,
> > where the user provides a shared secret key (UUID) on a SR-IOV PF
> > device, which users must provide when opening associated VF devices.
> >
> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> > ---
> > drivers/vfio/pci/vfio_pci.c | 52 +++++++++++++++++++++++++++++++++++++++++++
> > include/uapi/linux/vfio.h | 37 +++++++++++++++++++++++++++++++
> > 2 files changed, 89 insertions(+)
> >
> > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> > index 8dd6ef9543ca..e4d5d26e5e71 100644
> > --- a/drivers/vfio/pci/vfio_pci.c
> > +++ b/drivers/vfio/pci/vfio_pci.c
> > @@ -1180,6 +1180,58 @@ static long vfio_pci_ioctl(void *device_data,
> >
> > return vfio_pci_ioeventfd(vdev, ioeventfd.offset,
> > ioeventfd.data, count, ioeventfd.fd);
> > + } else if (cmd == VFIO_DEVICE_FEATURE) {
> > + struct vfio_device_feature feature;
> > + uuid_t uuid;
> > +
> > + minsz = offsetofend(struct vfio_device_feature, flags);
> > +
> > + if (copy_from_user(&feature, (void __user *)arg, minsz))
> > + return -EFAULT;
> > +
> > + if (feature.argsz < minsz)
> > + return -EINVAL;
> > +
> > + if (feature.flags & ~(VFIO_DEVICE_FEATURE_MASK |
> > + VFIO_DEVICE_FEATURE_SET |
> > + VFIO_DEVICE_FEATURE_GET |
> > + VFIO_DEVICE_FEATURE_PROBE))
> > + return -EINVAL;
>
> GET|SET|PROBE is well-defined, but what about GET|SET without PROBE? Do
> we want to fence this in the generic ioctl handler part? Or is there
> any sane way to implement that (read and then write back something?)
I'd be ok with discouraging combinations of GET|SET|!PROBE generically.
I don't think there's an intuitive answer to whether it should be
applied as GET|SET or SET|GET. If some future feature wanted an atomic
op we could add something like a test-and-set. Thanks,
Alex
> > +
> > + switch (feature.flags & VFIO_DEVICE_FEATURE_MASK) {
> > + case VFIO_DEVICE_FEATURE_PCI_VF_TOKEN:
> > + if (!vdev->vf_token)
> > + return -ENOTTY;
> > +
> > + /*
> > + * We do not support GET of the VF Token UUID as this
> > + * could expose the token of the previous device user.
> > + */
> > + if (feature.flags & VFIO_DEVICE_FEATURE_GET)
> > + return -EINVAL;
> > +
> > + if (feature.flags & VFIO_DEVICE_FEATURE_PROBE)
> > + return 0;
> > +
> > + /* Don't SET unless told to do so */
> > + if (!(feature.flags & VFIO_DEVICE_FEATURE_SET))
> > + return -EINVAL;
> > +
> > + if (feature.argsz < minsz + sizeof(uuid))
> > + return -EINVAL;
> > +
> > + if (copy_from_user(&uuid, (void __user *)(arg + minsz),
> > + sizeof(uuid)))
> > + return -EFAULT;
> > +
> > + mutex_lock(&vdev->vf_token->lock);
> > + uuid_copy(&vdev->vf_token->uuid, &uuid);
> > + mutex_unlock(&vdev->vf_token->lock);
> > +
> > + return 0;
> > + default:
> > + return -ENOTTY;
> > + }
> > }
> >
> > return -ENOTTY;
> (...)
next prev parent reply other threads:[~2020-03-05 20:51 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-19 18:53 [dpdk-dev] [PATCH v2 0/7] vfio/pci: SR-IOV support Alex Williamson
2020-02-19 18:53 ` [dpdk-dev] [PATCH v2 1/7] vfio: Include optional device match in vfio_device_ops callbacks Alex Williamson
2020-02-19 18:54 ` [dpdk-dev] [PATCH v2 2/7] vfio/pci: Implement match ops Alex Williamson
2020-02-19 18:54 ` [dpdk-dev] [PATCH v2 3/7] vfio/pci: Introduce VF token Alex Williamson
2020-02-25 2:59 ` Tian, Kevin
2020-03-05 18:17 ` Alex Williamson
2020-03-06 8:32 ` Tian, Kevin
2020-03-06 15:39 ` Alex Williamson
2020-03-07 1:04 ` Tian, Kevin
2020-03-09 0:46 ` Alex Williamson
2020-03-09 1:22 ` Tian, Kevin
2020-03-09 1:33 ` Tian, Kevin
2020-03-09 15:35 ` Alex Williamson
2020-02-19 18:54 ` [dpdk-dev] [PATCH v2 4/7] vfio: Introduce VFIO_DEVICE_FEATURE ioctl and first user Alex Williamson
2020-02-27 17:34 ` Cornelia Huck
2020-03-05 20:51 ` Alex Williamson [this message]
2020-02-19 18:54 ` [dpdk-dev] [PATCH v2 5/7] vfio/pci: Add sriov_configure support Alex Williamson
2020-02-25 3:08 ` Tian, Kevin
2020-03-05 18:22 ` Alex Williamson
2020-03-05 20:08 ` Ajit Khaparde
2020-03-06 7:57 ` Tian, Kevin
2020-03-06 22:17 ` Alex Williamson
2020-03-07 1:35 ` Tian, Kevin
2020-03-09 0:46 ` Alex Williamson
2020-03-09 1:48 ` Tian, Kevin
2020-03-09 14:56 ` Alex Williamson
2020-03-06 9:45 ` Tian, Kevin
2020-03-06 15:50 ` Alex Williamson
2020-02-19 18:54 ` [dpdk-dev] [PATCH v2 6/7] vfio/pci: Remove dev_fmt definition Alex Williamson
2020-02-19 18:54 ` [dpdk-dev] [PATCH v2 7/7] vfio/pci: Cleanup .probe() exit paths Alex Williamson
2020-02-25 2:33 ` [dpdk-dev] [PATCH v2 0/7] vfio/pci: SR-IOV support Tian, Kevin
2020-02-25 6:09 ` Jason Wang
2020-03-05 17:14 ` Alex Williamson
2020-03-06 3:35 ` Jason Wang
2020-03-06 16:24 ` Alex Williamson
2020-03-09 3:36 ` Jason Wang
2020-03-09 14:45 ` Alex Williamson
2020-03-05 17:33 ` Alex Williamson
2020-03-06 9:21 ` Tian, Kevin
2020-03-05 6:38 ` Vamsi Krishna Attunuru
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