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.
Unified · Split
| @@ -1180,6 +1180,65 @@ hot_reset_release: · 1179 unmodified lines | |||
| 1180 | 1180 | ||
| 1181 | return vfio_pci_ioeventfd(vdev, ioeventfd.offset, | 1181 | return vfio_pci_ioeventfd(vdev, ioeventfd.offset, |
| 1182 | ioeventfd.data, count, ioeventfd.fd); | 1182 | ioeventfd.data, count, ioeventfd.fd); |
| 1183 | } else if (cmd == VFIO_DEVICE_FEATURE) { | ||
| 1184 | struct vfio_device_feature feature; | ||
| 1185 | uuid_t uuid; | ||
| 1186 | |||
| 1187 | minsz = offsetofend(struct vfio_device_feature, flags); | ||
| 1188 | |||
| 1189 | if (copy_from_user(&feature, (void __user *)arg, minsz)) | ||
| 1190 | return -EFAULT; | ||
| 1191 | |||
| 1192 | if (feature.argsz < minsz) | ||
| 1193 | return -EINVAL; | ||
| 1194 | |||
| 1195 | /* Check unknown flags */ | ||
| 1196 | if (feature.flags & ~(VFIO_DEVICE_FEATURE_MASK | | ||
| 1197 | VFIO_DEVICE_FEATURE_SET | | ||
| 1198 | VFIO_DEVICE_FEATURE_GET | | ||
| 1199 | VFIO_DEVICE_FEATURE_PROBE)) | ||
| 1200 | return -EINVAL; | ||
| 1201 | |||
| 1202 | /* GET & SET are mutually exclusive except with PROBE */ | ||
| 1203 | if (!(feature.flags & VFIO_DEVICE_FEATURE_PROBE) && | ||
| 1204 | (feature.flags & VFIO_DEVICE_FEATURE_SET) && | ||
| 1205 | (feature.flags & VFIO_DEVICE_FEATURE_GET)) | ||
| 1206 | return -EINVAL; | ||
| 1207 | |||
| 1208 | switch (feature.flags & VFIO_DEVICE_FEATURE_MASK) { | ||
| 1209 | case VFIO_DEVICE_FEATURE_PCI_VF_TOKEN: | ||
| 1210 | if (!vdev->vf_token) | ||
| 1211 | return -ENOTTY; | ||
| 1212 | |||
| 1213 | /* | ||
| 1214 | * We do not support GET of the VF Token UUID as this | ||
| 1215 | * could expose the token of the previous device user. | ||
| 1216 | */ | ||
| 1217 | if (feature.flags & VFIO_DEVICE_FEATURE_GET) | ||
| 1218 | return -EINVAL; | ||
| 1219 | |||
| 1220 | if (feature.flags & VFIO_DEVICE_FEATURE_PROBE) | ||
| 1221 | return 0; | ||
| 1222 | |||
| 1223 | /* Don't SET unless told to do so */ | ||
| 1224 | if (!(feature.flags & VFIO_DEVICE_FEATURE_SET)) | ||
| 1225 | return -EINVAL; | ||
| 1226 | |||
| 1227 | if (feature.argsz < minsz + sizeof(uuid)) | ||
| 1228 | return -EINVAL; | ||
| 1229 | |||
| 1230 | if (copy_from_user(&uuid, (void __user *)(arg + minsz), | ||
| 1231 | sizeof(uuid))) | ||
| 1232 | return -EFAULT; | ||
| 1233 | |||
| 1234 | mutex_lock(&vdev->vf_token->lock); | ||
| 1235 | uuid_copy(&vdev->vf_token->uuid, &uuid); | ||
| 1236 | mutex_unlock(&vdev->vf_token->lock); | ||
| 1237 | |||
| 1238 | return 0; | ||
| 1239 | default: | ||
| 1240 | return -ENOTTY; | ||
| 1241 | } | ||
| 1183 | } | 1242 | } |
| 1184 | 1243 | ||
| 1185 | return -ENOTTY; | 1244 | return -ENOTTY; |
| @@ -707,6 +707,43 @@ struct vfio_device_ioeventfd { · 706 unmodified lines | |||
| 707 | 707 | ||
| 708 | #define VFIO_DEVICE_IOEVENTFD _IO(VFIO_TYPE, VFIO_BASE + 16) | 708 | #define VFIO_DEVICE_IOEVENTFD _IO(VFIO_TYPE, VFIO_BASE + 16) |
| 709 | 709 | ||
| 710 | /** | ||
| 711 | * VFIO_DEVICE_FEATURE - _IORW(VFIO_TYPE, VFIO_BASE + 17, | ||
| 712 | * struct vfio_device_feature) | ||
| 713 | * | ||
| 714 | * Get, set, or probe feature data of the device. The feature is selected | ||
| 715 | * using the FEATURE_MASK portion of the flags field. Support for a feature | ||
| 716 | * can be probed by setting both the FEATURE_MASK and PROBE bits. A probe | ||
| 717 | * may optionally include the GET and/or SET bits to determine read vs write | ||
| 718 | * access of the feature respectively. Probing a feature will return success | ||
| 719 | * if the feature is supported and all of the optionally indicated GET/SET | ||
| 720 | * methods are supported. The format of the data portion of the structure is | ||
| 721 | * specific to the given feature. The data portion is not required for | ||
| 722 | * probing. GET and SET are mutually exclusive, except for use with PROBE. | ||
| 723 | * | ||
| 724 | * Return 0 on success, -errno on failure. | ||
| 725 | */ | ||
| 726 | struct vfio_device_feature { | ||
| 727 | __u32 argsz; | ||
| 728 | __u32 flags; | ||
| 729 | #define VFIO_DEVICE_FEATURE_MASK (0xffff) /* 16-bit feature index */ | ||
| 730 | #define VFIO_DEVICE_FEATURE_GET (1 << 16) /* Get feature into data[] */ | ||
| 731 | #define VFIO_DEVICE_FEATURE_SET (1 << 17) /* Set feature from data[] */ | ||
| 732 | #define VFIO_DEVICE_FEATURE_PROBE (1 << 18) /* Probe feature support */ | ||
| 733 | __u8 data[]; | ||
| 734 | }; | ||
| 735 | |||
| 736 | #define VFIO_DEVICE_FEATURE _IO(VFIO_TYPE, VFIO_BASE + 17) | ||
| 737 | |||
| 738 | /* | ||
| 739 | * Provide support for setting a PCI VF Token, which is used as a shared | ||
| 740 | * secret between PF and VF drivers. This feature may only be set on a | ||
| 741 | * PCI SR-IOV PF when SR-IOV is enabled on the PF and there are no existing | ||
| 742 | * open VFs. Data provided when setting this feature is a 16-byte array | ||
| 743 | * (__u8 b[16]), representing a UUID. | ||
| 744 | */ | ||
| 745 | #define VFIO_DEVICE_FEATURE_PCI_VF_TOKEN (0) | ||
| 746 | |||
| 710 | /* -------- API for Type1 VFIO IOMMU -------- */ | 747 | /* -------- API for Type1 VFIO IOMMU -------- */ |
| 711 | 748 | ||
| 712 | /** | 749 | /** |