| Message ID | 158213845865.17090.13613582696110253458.stgit@gimli.home |
|---|---|
| State | New |
| Headers | show |
| Series | vfio/pci: SR-IOV support | expand |
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?) > + > + 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; (...)
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; > (...)
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; + + 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; diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 9e843a147ead..aa37f90a2180 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -707,6 +707,43 @@ struct vfio_device_ioeventfd { #define VFIO_DEVICE_IOEVENTFD _IO(VFIO_TYPE, VFIO_BASE + 16) +/** + * VFIO_DEVICE_FEATURE - _IORW(VFIO_TYPE, VFIO_BASE + 17, + * struct vfio_device_feature) + * + * Get, set, or probe feature data of the device. The feature is selected + * using the FEATURE_MASK portion of the flags field. Support for a feature + * can be probed by setting both the FEATURE_MASK and PROBE bits. A probe + * may optionally include the GET and/or SET bits to determine read vs write + * access of the feature respectively. Probing a feature will return success + * if the feature is supported and all of the optionally indicated GET/SET + * methods are supported. The format of the data portion of the structure is + * specific to the given feature. The data portion is not required for + * probing. + * + * Return 0 on success, -errno on failure. + */ +struct vfio_device_feature { + __u32 argsz; + __u32 flags; +#define VFIO_DEVICE_FEATURE_MASK (0xffff) /* 16-bit feature index */ +#define VFIO_DEVICE_FEATURE_GET (1 << 16) /* Get feature into data[] */ +#define VFIO_DEVICE_FEATURE_SET (1 << 17) /* Set feature from data[] */ +#define VFIO_DEVICE_FEATURE_PROBE (1 << 18) /* Probe feature support */ + __u8 data[]; +}; + +#define VFIO_DEVICE_FEATURE _IO(VFIO_TYPE, VFIO_BASE + 17) + +/* + * Provide support for setting a PCI VF Token, which is used as a shared + * secret between PF and VF drivers. This feature may only be set on a + * PCI SR-IOV PF when SR-IOV is enabled on the PF and there are no existing + * open VFs. Data provided when setting this feature is a 16-byte array + * (__u8 b[16]), representing a UUID. + */ +#define VFIO_DEVICE_FEATURE_PCI_VF_TOKEN (0) + /* -------- API for Type1 VFIO IOMMU -------- */ /**
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(+)