pc-bios/s390-ccw/virtio.h

   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 VirtioDevType {
  27     VIRTIO_ID_NET = 1,
  28     VIRTIO_ID_BLOCK = 2,
  29     VIRTIO_ID_CONSOLE = 3,
  30     VIRTIO_ID_BALLOON = 5,
  31 };
  32 typedef enum VirtioDevType VirtioDevType;
  33
  34 struct VirtioDevHeader {
  35     VirtioDevType type:8;
  36     uint8_t num_vq;
  37     uint8_t feature_len;
  38     uint8_t config_len;
  39     uint8_t status;
  40     uint8_t vqconfig[];
  41 } __attribute__((packed));
  42 typedef struct VirtioDevHeader VirtioDevHeader;
  43
  44 struct VirtioVqConfig {
  45     uint64_t token;
  46     uint64_t address;
  47     uint16_t num;
  48     uint8_t pad[6];
  49 } __attribute__((packed));
  50 typedef struct VirtioVqConfig VirtioVqConfig;
  51
  52 struct VqInfo {
  53     uint64_t queue;
  54     uint32_t align;
  55     uint16_t index;
  56     uint16_t num;
  57 } __attribute__((packed));
  58 typedef struct VqInfo VqInfo;
  59
  60 struct VqConfig {
  61     uint16_t index;
  62     uint16_t num;
  63 } __attribute__((packed));
  64 typedef struct VqConfig VqConfig;
  65
  66 struct VirtioDev {
  67     VirtioDevHeader *header;
  68     VirtioVqConfig *vqconfig;
  69     char *host_features;
  70     char *guest_features;
  71     char *config;
  72 };
  73 typedef struct VirtioDev VirtioDev;
  74
  75 #define VIRTIO_RING_SIZE            (PAGE_SIZE * 8)
  76 #define VIRTIO_MAX_VQS              3
  77 #define KVM_S390_VIRTIO_RING_ALIGN  4096
  78
  79 #define VRING_USED_F_NO_NOTIFY  1
  80
  81 /* This marks a buffer as continuing via the next field. */
  82 #define VRING_DESC_F_NEXT       1
  83 /* This marks a buffer as write-only (otherwise read-only). */
  84 #define VRING_DESC_F_WRITE      2
  85 /* This means the buffer contains a list of buffer descriptors. */
  86 #define VRING_DESC_F_INDIRECT   4
  87
  88 /* Internal flag to mark follow-up segments as such */
  89 #define VRING_HIDDEN_IS_CHAIN   256
  90
  91 /* Virtio ring descriptors: 16 bytes.  These can chain together via "next". */
  92 struct VRingDesc {
  93     /* Address (guest-physical). */
  94     uint64_t addr;
  95     /* Length. */
  96     uint32_t len;
  97     /* The flags as indicated above. */
  98     uint16_t flags;
  99     /* We chain unused descriptors via this, too */
 100     uint16_t next;
 101 } __attribute__((packed));
 102 typedef struct VRingDesc VRingDesc;
 103
 104 struct VRingAvail {
 105     uint16_t flags;
 106     uint16_t idx;
 107     uint16_t ring[];
 108 } __attribute__((packed));
 109 typedef struct VRingAvail VRingAvail;
 110
 111 /* uint32_t is used here for ids for padding reasons. */
 112 struct VRingUsedElem {
 113     /* Index of start of used descriptor chain. */
 114     uint32_t id;
 115     /* Total length of the descriptor chain which was used (written to) */
 116     uint32_t len;
 117 } __attribute__((packed));
 118 typedef struct VRingUsedElem VRingUsedElem;
 119
 120 struct VRingUsed {
 121     uint16_t flags;
 122     uint16_t idx;
 123     VRingUsedElem ring[];
 124 } __attribute__((packed));
 125 typedef struct VRingUsed VRingUsed;
 126
 127 struct VRing {
 128     unsigned int num;
 129     int next_idx;
 130     int used_idx;
 131     VRingDesc *desc;
 132     VRingAvail *avail;
 133     VRingUsed *used;
 134     SubChannelId schid;
 135     long cookie;
 136     int id;
 137 };
 138 typedef struct VRing VRing;
 139
 140
 141 /***********************************************
 142  *               Virtio block                  *
 143  ***********************************************/
 144
 145 /*
 146  * Command types
 147  *
 148  * Usage is a bit tricky as some bits are used as flags and some are not.
 149  *
 150  * Rules:
 151  *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
 152  *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
 153  *   and may not be combined with any of the other flags.
 154  */
 155
 156 /* These two define direction. */
 157 #define VIRTIO_BLK_T_IN         0
 158 #define VIRTIO_BLK_T_OUT        1
 159
 160 /* This bit says it's a scsi command, not an actual read or write. */
 161 #define VIRTIO_BLK_T_SCSI_CMD   2
 162
 163 /* Cache flush command */
 164 #define VIRTIO_BLK_T_FLUSH      4
 165
 166 /* Barrier before this op. */
 167 #define VIRTIO_BLK_T_BARRIER    0x80000000
 168
 169 /* This is the first element of the read scatter-gather list. */
 170 struct VirtioBlkOuthdr {
 171         /* VIRTIO_BLK_T* */
 172         uint32_t type;
 173         /* io priority. */
 174         uint32_t ioprio;
 175         /* Sector (ie. 512 byte offset) */
 176         uint64_t sector;
 177 };
 178 typedef struct VirtioBlkOuthdr VirtioBlkOuthdr;
 179
 180 struct VirtioBlkConfig {
 181     uint64_t capacity; /* in 512-byte sectors */
 182     uint32_t size_max; /* max segment size (if VIRTIO_BLK_F_SIZE_MAX) */
 183     uint32_t seg_max;  /* max number of segments (if VIRTIO_BLK_F_SEG_MAX) */
 184
 185     struct VirtioBlkGeometry {
 186         uint16_t cylinders;
 187         uint8_t heads;
 188         uint8_t sectors;
 189     } geometry; /* (if VIRTIO_BLK_F_GEOMETRY) */
 190
 191     uint32_t blk_size; /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
 192
 193     /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY  */
 194     uint8_t physical_block_exp; /* exponent for physical blk per logical blk */
 195     uint8_t alignment_offset;   /* alignment offset in logical blocks */
 196     uint16_t min_io_size;       /* min I/O size without performance penalty
 197                               in logical blocks */
 198     uint32_t opt_io_size;       /* optimal sustained I/O size in logical blks */
 199
 200     uint8_t wce; /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
 201 } __attribute__((packed));
 202 typedef struct VirtioBlkConfig VirtioBlkConfig;
 203
 204 enum guessed_disk_nature_type {
 205     VIRTIO_GDN_NONE     = 0,
 206     VIRTIO_GDN_DASD     = 1,
 207     VIRTIO_GDN_CDROM    = 2,
 208     VIRTIO_GDN_SCSI     = 3,
 209 };
 210 typedef enum guessed_disk_nature_type VirtioGDN;
 211
 212 VirtioGDN virtio_guessed_disk_nature(void);
 213 void virtio_assume_scsi(void);
 214 void virtio_assume_eckd(void);
 215 void virtio_assume_iso9660(void);
 216
 217 extern bool virtio_disk_is_scsi(void);
 218 extern bool virtio_disk_is_eckd(void);
 219 extern bool virtio_ipl_disk_is_valid(void);
 220 extern int virtio_get_block_size(void);
 221 extern uint8_t virtio_get_heads(void);
 222 extern uint8_t virtio_get_sectors(void);
 223 extern uint64_t virtio_get_blocks(void);
 224 extern int virtio_read_many(ulong sector, void *load_addr, int sec_num);
 225
 226 #define VIRTIO_SECTOR_SIZE 512
 227
 228 static inline ulong virtio_sector_adjust(ulong sector)
 229 {
 230     return sector * (virtio_get_block_size() / VIRTIO_SECTOR_SIZE);
 231 }
 232
 233 struct VDev {
 234     int nr_vqs;
 235     VRing *vrings;
 236     int cmd_vr_idx;
 237     void *ring_area;
 238     long wait_reply_timeout;
 239     VirtioGDN guessed_disk_nature;
 240     SubChannelId schid;
 241     SenseId senseid;
 242     union {
 243         VirtioBlkConfig blk;
 244     } config;
 245 };
 246 typedef struct VDev VDev;
 247
 248 VDev *virtio_get_device(void);
 249 VirtioDevType virtio_get_device_type(void);
 250
 251 #endif /* VIRTIO_H */