1 /* 2 * Virtio driver bits 3 * 4 * Copyright (c) 2013 Alexander Graf <agraf@suse.de> 5 * 6 * This work is licensed under the terms of the GNU GPL, version 2 or (at 7 * your option) any later version. See the COPYING file in the top-level 8 * directory. 9 */ 10 11 #ifndef VIRTIO_H 12 #define VIRTIO_H 13 14 #include "s390-ccw.h" 15 16 /* Status byte for guest to report progress, and synchronize features. */ 17 /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */ 18 #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1 19 /* We have found a driver for the device. */ 20 #define VIRTIO_CONFIG_S_DRIVER 2 21 /* Driver has used its parts of the config, and is happy */ 22 #define VIRTIO_CONFIG_S_DRIVER_OK 4 23 /* We've given up on this device. */ 24 #define VIRTIO_CONFIG_S_FAILED 0x80 25 26 enum virtio_dev_type { 27 VIRTIO_ID_NET = 1, 28 VIRTIO_ID_BLOCK = 2, 29 VIRTIO_ID_CONSOLE = 3, 30 VIRTIO_ID_BALLOON = 5, 31 }; 32 33 struct virtio_dev_header { 34 enum virtio_dev_type type : 8; 35 u8 num_vq; 36 u8 feature_len; 37 u8 config_len; 38 u8 status; 39 u8 vqconfig[]; 40 } __attribute__((packed)); 41 42 struct virtio_vqconfig { 43 u64 token; 44 u64 address; 45 u16 num; 46 u8 pad[6]; 47 } __attribute__((packed)); 48 49 struct vq_info_block { 50 u64 queue; 51 u32 align; 52 u16 index; 53 u16 num; 54 } __attribute__((packed)); 55 56 struct vq_config_block { 57 u16 index; 58 u16 num; 59 } __attribute__((packed)); 60 61 struct virtio_dev { 62 struct virtio_dev_header *header; 63 struct virtio_vqconfig *vqconfig; 64 char *host_features; 65 char *guest_features; 66 char *config; 67 }; 68 69 #define KVM_S390_VIRTIO_RING_ALIGN 4096 70 71 #define VRING_USED_F_NO_NOTIFY 1 72 73 /* This marks a buffer as continuing via the next field. */ 74 #define VRING_DESC_F_NEXT 1 75 /* This marks a buffer as write-only (otherwise read-only). */ 76 #define VRING_DESC_F_WRITE 2 77 /* This means the buffer contains a list of buffer descriptors. */ 78 #define VRING_DESC_F_INDIRECT 4 79 80 /* Internal flag to mark follow-up segments as such */ 81 #define VRING_HIDDEN_IS_CHAIN 256 82 83 /* Virtio ring descriptors: 16 bytes. These can chain together via "next". */ 84 struct vring_desc { 85 /* Address (guest-physical). */ 86 u64 addr; 87 /* Length. */ 88 u32 len; 89 /* The flags as indicated above. */ 90 u16 flags; 91 /* We chain unused descriptors via this, too */ 92 u16 next; 93 } __attribute__((packed)); 94 95 struct vring_avail { 96 u16 flags; 97 u16 idx; 98 u16 ring[]; 99 } __attribute__((packed)); 100 101 /* u32 is used here for ids for padding reasons. */ 102 struct vring_used_elem { 103 /* Index of start of used descriptor chain. */ 104 u32 id; 105 /* Total length of the descriptor chain which was used (written to) */ 106 u32 len; 107 } __attribute__((packed)); 108 109 struct vring_used { 110 u16 flags; 111 u16 idx; 112 struct vring_used_elem ring[]; 113 } __attribute__((packed)); 114 115 struct vring { 116 unsigned int num; 117 int next_idx; 118 int used_idx; 119 struct vring_desc *desc; 120 struct vring_avail *avail; 121 struct vring_used *used; 122 struct subchannel_id schid; 123 }; 124 125 126 /*********************************************** 127 * Virtio block * 128 ***********************************************/ 129 130 /* 131 * Command types 132 * 133 * Usage is a bit tricky as some bits are used as flags and some are not. 134 * 135 * Rules: 136 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or 137 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own 138 * and may not be combined with any of the other flags. 139 */ 140 141 /* These two define direction. */ 142 #define VIRTIO_BLK_T_IN 0 143 #define VIRTIO_BLK_T_OUT 1 144 145 /* This bit says it's a scsi command, not an actual read or write. */ 146 #define VIRTIO_BLK_T_SCSI_CMD 2 147 148 /* Cache flush command */ 149 #define VIRTIO_BLK_T_FLUSH 4 150 151 /* Barrier before this op. */ 152 #define VIRTIO_BLK_T_BARRIER 0x80000000 153 154 /* This is the first element of the read scatter-gather list. */ 155 struct virtio_blk_outhdr { 156 /* VIRTIO_BLK_T* */ 157 u32 type; 158 /* io priority. */ 159 u32 ioprio; 160 /* Sector (ie. 512 byte offset) */ 161 u64 sector; 162 }; 163 164 #endif /* VIRTIO_H */ 165