648 lines
21 KiB
C
648 lines
21 KiB
C
/* virtio_blk.c — UTSM virtio-blk 设备模拟后端。
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*
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* 为 Linux guest 提供 virtio-blk 块设备。guest 的块读写请求经
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* virtqueue 传入，本后端桥接到 UTSM 真实块设备（block API，AHCI/SATA）。
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*
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* Virtio Spec 1.1 §5.2 (Block Device)。
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* 请求描述符链： [header(16B, R)] [data(N*512B, R/W)] [status(1B, W)]
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* 支持的操作：VIRTIO_BLK_T_IN(读)、VIRTIO_BLK_T_OUT(写)、VIRTIO_BLK_T_GET_ID。
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*
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* 设计说明：
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* - 桥接到 UTSM block API 的第 0 个设备（ahci0 SATA 盘）。
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* - guest 把 Arch rootfs 镜像当作 /dev/vda 挂载；镜像需预先写入 SATA 盘
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* 的某个分区/LBA 区间（由 mkfat32/build 流程或独立 raw 区提供）。
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* - 当前为最小可用：扇区 512B，单队列，无 flush/discard。
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*/
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#include <utsm/virtio_mmio.h>
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#include <utsm/linux_loader.h>
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#include <utsm/block.h>
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#include <utsm/log.h>
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#include <utsm/types.h>
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/* virtio-blk 请求头（Virtio Spec 1.1 §5.2.6.2） */
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struct virtio_blk_outhdr {
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u32 type; /* VIRTIO_BLK_T_* */
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u32 reserved; /* (ioprio) */
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u64 sector; /* 起始扇区（512B 单位） */
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} __attribute__((packed));
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#define VIRTIO_BLK_T_IN 0 /* 读 */
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#define VIRTIO_BLK_T_OUT 1 /* 写 */
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#define VIRTIO_BLK_T_FLUSH 4
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#define VIRTIO_BLK_T_GET_ID 8
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#define VIRTIO_BLK_S_OK 0
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#define VIRTIO_BLK_S_IOERR 1
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#define VIRTIO_BLK_S_UNSUPP 2
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/* feature bits */
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#define VIRTIO_BLK_F_SIZE_MAX 1
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#define VIRTIO_BLK_F_SEG_MAX 2
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#define VIRTIO_BLK_F_BLK_SIZE 6
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#define VIRTIO_BLK_F_FLUSH 9
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/* device config 空间（VIRTIO_MMIO_CONFIG 起） */
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struct virtio_blk_config {
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u64 capacity; /* 总扇区数（512B） */
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u32 size_max;
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u32 seg_max;
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u16 geometry[4];
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u32 blk_size;
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/* ... 其余字段省略 */
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} __attribute__((packed));
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/* 后端状态 */
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static u64 g_blk_capacity; /* 扇区数 */
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static u32 g_blk_sector_size = 512;
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static int g_blk_bound = -1; /* 绑定的 UTSM block 设备索引 */
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/* 读取 device config 空间 */
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static u32 blk_read_config(u32 offset, int width) {
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(void)width;
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struct virtio_blk_config cfg;
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/* 填零后逐字段读取 */
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u8 *c = (u8 *)&cfg;
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for (u32 i = 0; i < sizeof(cfg); i++) c[i] = 0;
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cfg.capacity = g_blk_capacity;
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cfg.size_max = 128; /* 单请求最大 128 扇区 */
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cfg.seg_max = 32;
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cfg.blk_size = g_blk_sector_size;
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/* 按 offset 返回 32 位窗口 */
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if (offset + 4 <= sizeof(cfg)) {
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u32 v;
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u8 *src = (u8 *)&cfg + offset;
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v = (u32)src[0] | ((u32)src[1] << 8) | ((u32)src[2] << 16) | ((u32)src[3] << 24);
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return v;
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}
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return 0;
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}
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/* 处理一个块请求描述符链。返回写入 guest 的字节数（用于 used.len）。 */
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static u32 blk_handle_chain(struct virtq_desc *desc, u16 head, u32 qnum) {
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(void)qnum;
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if (!desc) return 0;
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/* 第一个描述符：请求头（driver→device，16 字节） */
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struct virtio_blk_outhdr *hdr =
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(struct virtio_blk_outhdr *)virtio_gpa_to_host(desc[head].addr);
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if (!hdr) return 0;
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u32 type = hdr->type;
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u64 sector = hdr->sector;
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/* 沿描述符链找到 data 与 status 描述符 */
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u16 cur = head;
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u16 data_idx = 0xFFFF, status_idx = 0xFFFF;
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int hops = 0;
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if (desc[cur].flags & VIRTQ_DESC_F_NEXT) {
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data_idx = desc[cur].next;
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cur = data_idx;
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/* data 之后可能还有 status */
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while ((desc[cur].flags & VIRTQ_DESC_F_NEXT) && hops < 16) {
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cur = desc[cur].next;
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hops++;
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}
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/* 最后一个是 status（device write，1 字节） */
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status_idx = cur;
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}
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u8 *status = (u8 *)0;
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if (status_idx != 0xFFFF && (desc[status_idx].flags & VIRTQ_DESC_F_WRITE)) {
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status = (u8 *)virtio_gpa_to_host(desc[status_idx].addr);
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}
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u32 bytes_done = 0;
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u8 result = VIRTIO_BLK_S_OK;
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const dkm_block_api *blk = block_get_api();
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switch (type) {
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case VIRTIO_BLK_T_IN: { /* 读：块设备 → guest data buffer */
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if (data_idx == 0xFFFF || g_blk_bound < 0 || !blk) {
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result = VIRTIO_BLK_S_IOERR;
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break;
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}
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u8 *dbuf = (u8 *)virtio_gpa_to_host(desc[data_idx].addr);
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u32 dlen = desc[data_idx].len;
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if (!dbuf) { result = VIRTIO_BLK_S_IOERR; break; }
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u32 nsec = dlen / 512;
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if (nsec == 0) nsec = 1;
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if (blk->read((u32)g_blk_bound, sector, nsec, dbuf) != 0) {
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result = VIRTIO_BLK_S_IOERR;
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} else {
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bytes_done = dlen;
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}
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break;
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}
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case VIRTIO_BLK_T_OUT: { /* 写：guest data buffer → 块设备 */
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if (data_idx == 0xFFFF || g_blk_bound < 0 || !blk) {
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result = VIRTIO_BLK_S_IOERR;
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break;
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}
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const u8 *dbuf = (const u8 *)virtio_gpa_to_host(desc[data_idx].addr);
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u32 dlen = desc[data_idx].len;
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if (!dbuf) { result = VIRTIO_BLK_S_IOERR; break; }
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u32 nsec = dlen / 512;
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if (nsec == 0) nsec = 1;
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if (blk->write((u32)g_blk_bound, sector, nsec, dbuf) != 0) {
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result = VIRTIO_BLK_S_IOERR;
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} else {
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bytes_done = 0; /* 写操作 used.len=0 */
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}
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break;
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}
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case VIRTIO_BLK_T_GET_ID: {
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if (data_idx != 0xFFFF) {
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char *idbuf = (char *)virtio_gpa_to_host(desc[data_idx].addr);
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if (idbuf) {
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const char *id = "DESHAB-VIRTIO-BLK";
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u32 i = 0;
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for (; id[i] && i < desc[data_idx].len - 1; i++) idbuf[i] = id[i];
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idbuf[i] = 0;
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bytes_done = i + 1;
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}
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}
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break;
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}
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case VIRTIO_BLK_T_FLUSH:
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result = VIRTIO_BLK_S_OK; /* 无写缓存，直接成功 */
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break;
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default:
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result = VIRTIO_BLK_S_UNSUPP;
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break;
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}
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/* 写状态字节 */
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if (status) *status = result;
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return bytes_done;
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}
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/* queue_notify：guest 提交了块请求，处理队列。 */
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static u16 g_blk_last_avail;
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static void blk_queue_notify(u32 queue_idx) {
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struct virtq_desc *desc;
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struct virtq_avail *avail;
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struct virtq_used *used;
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u32 qnum;
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if (virtio_queue_get_ptrs(VIRTIO_ID_BLOCK, queue_idx,
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&desc, &avail, &used, &qnum) != 0) {
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return;
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}
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/* 处理自上次以来的所有新 avail 请求 */
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u16 cur = g_blk_last_avail;
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u16 used_idx = used->idx;
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while (cur != avail->idx) {
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u16 head = avail->ring[cur % qnum];
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u32 len = blk_handle_chain(desc, head, qnum);
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/* 写 used 回执 */
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used->ring[used_idx % qnum].id = head;
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used->ring[used_idx % qnum].len = len;
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used_idx++;
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cur++;
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}
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virtio_queue_bump_used(used, used_idx);
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g_blk_last_avail = cur;
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}
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static void blk_reset(void) {
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g_blk_last_avail = 0;
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}
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/* 后端结构体 */
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static struct virtio_backend g_blk_backend = {
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.device_id = VIRTIO_ID_BLOCK,
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.gpa_base = VIRTIO_MMIO_BLK_GPA,
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.irq = 5, /* guest ISA IRQ5（cmdline :5，vector 0x35） */
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.num_queues = 1,
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.queue_size = 128,
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.device_features = (1ULL << VIRTIO_F_VERSION_1) |
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(1ULL << VIRTIO_BLK_F_SIZE_MAX) |
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(1ULL << VIRTIO_BLK_F_SEG_MAX) |
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(1ULL << VIRTIO_BLK_F_BLK_SIZE) |
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(1ULL << VIRTIO_BLK_F_FLUSH),
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.config_len = sizeof(struct virtio_blk_config),
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.read_config = blk_read_config,
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.queue_notify = blk_queue_notify,
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.reset = blk_reset,
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};
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void virtio_blk_backend_init(void) {
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/* 绑定 UTSM 第 0 个块设备（ahci0 SATA 盘）作为后端存储 */
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const dkm_block_api *blk = block_get_api();
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if (blk && blk->device_count() > 0) {
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g_blk_bound = 0;
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u64 ssize = blk->sector_size(0);
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if (ssize > 0) g_blk_sector_size = (u32)ssize;
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/* 从设备名推算容量不可得，用默认值（guest 端可再探测）。
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* 实际 capacity 需读 ATA IDENTIFY；这里给 4GB 占位，
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* guest mkfs/mount 会按此上限工作。 */
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g_blk_capacity = 8ULL * 1024 * 1024 * 1024 / 512; /* 8GB in sectors */
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log_info("[VBLK] bound to UTSM block device 0");
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log_hex64("[VBLK] capacity(sectors)=", g_blk_capacity);
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} else {
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g_blk_bound = -1;
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g_blk_capacity = 0;
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log_warn("[VBLK] no UTSM block device, blk backend degraded");
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}
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virtio_mmio_register(&g_blk_backend);
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}
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/* ===== Memory-backed rootfs virtio-blk 后端 =====
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*
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* 第二个 virtio-blk 设备，后端为内存中的 Arch rootfs 镜像（Limine boot module）。
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* guest 看到 /dev/vdb，挂载为真实根文件系统（ext4），switch_root 进入 Arch。
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*
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* 读写直接操作内存（memcpy），无需块设备 API。 */
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/* byte-wise memcpy helper (freestanding, no libc) */
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static void rf_memcpy(void *dst, const void *src, u64 n) {
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u8 *d = (u8 *)dst;
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const u8 *s = (const u8 *)src;
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while (n--) *d++ = *s++;
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}
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static const u8 *g_rootfs_data; /* rootfs 镜像内存指针（HHDM 虚拟地址） */
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static u64 g_rootfs_size; /* rootfs 镜像大小（字节） */
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static u64 g_rootfs_capacity; /* rootfs 容量（扇区数，512B 单位） */
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static u32 rootfs_blk_read_config(u32 offset, int width) {
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(void)width;
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struct virtio_blk_config cfg;
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u8 *c = (u8 *)&cfg;
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for (u32 i = 0; i < sizeof(cfg); i++) c[i] = 0;
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cfg.capacity = g_rootfs_capacity;
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cfg.size_max = 128;
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cfg.seg_max = 32;
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cfg.blk_size = 512;
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if (offset + 4 <= sizeof(cfg)) {
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u32 val = 0;
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rf_memcpy(&val, c + offset, 4);
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return val;
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}
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if (offset < sizeof(cfg)) {
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u32 val = 0;
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rf_memcpy(&val, c + offset, 4);
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return val;
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}
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return 0;
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}
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/* rootfs 请求处理：直接内存拷贝 */
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static u32 rootfs_blk_handle_chain(struct virtq_desc *desc, u16 head, u32 qnum) {
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(void)qnum;
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struct virtio_blk_outhdr hdr;
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u8 *hptr = (u8 *)virtio_gpa_to_host(desc[head].addr);
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if (!hptr) return 0;
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rf_memcpy(&hdr, hptr, sizeof(hdr));
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u32 type = hdr.type;
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u64 sector = hdr.sector;
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u16 data_idx = 0xFFFF;
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u16 status_idx = 0xFFFF;
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if (desc[head].flags & VIRTQ_DESC_F_NEXT) {
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data_idx = desc[head].next;
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u16 cur = data_idx;
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int hops = 0;
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while ((desc[cur].flags & VIRTQ_DESC_F_NEXT) && hops < 16) {
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cur = desc[cur].next;
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hops++;
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}
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status_idx = cur;
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}
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u8 *status = (u8 *)0;
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if (status_idx != 0xFFFF && (desc[status_idx].flags & VIRTQ_DESC_F_WRITE)) {
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status = (u8 *)virtio_gpa_to_host(desc[status_idx].addr);
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}
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u32 bytes_done = 0;
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u8 result = VIRTIO_BLK_S_OK;
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switch (type) {
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case VIRTIO_BLK_T_IN: { /* 读：rootfs 内存 → guest */
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if (data_idx == 0xFFFF || !g_rootfs_data) {
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result = VIRTIO_BLK_S_IOERR;
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break;
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}
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u8 *dbuf = (u8 *)virtio_gpa_to_host(desc[data_idx].addr);
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u32 dlen = desc[data_idx].len;
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if (!dbuf) { result = VIRTIO_BLK_S_IOERR; break; }
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u64 offset = sector * 512ULL;
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if (offset + dlen > g_rootfs_size) {
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/* 超出范围：截断或填零 */
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u64 avail = (offset < g_rootfs_size) ? (g_rootfs_size - offset) : 0;
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if (avail > 0) {
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rf_memcpy(dbuf, g_rootfs_data + offset, avail);
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}
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/* 剩余部分填零 */
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if (dlen > avail) {
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u8 *p = dbuf + avail;
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u32 rem = dlen - (u32)avail;
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while (rem--) *p++ = 0;
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}
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bytes_done = dlen;
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} else {
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rf_memcpy(dbuf, g_rootfs_data + offset, dlen);
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bytes_done = dlen;
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}
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break;
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}
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case VIRTIO_BLK_T_OUT: /* 写：暂不支持（rootfs 只读） */
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result = VIRTIO_BLK_S_IOERR;
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break;
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case VIRTIO_BLK_T_GET_ID:
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if (data_idx != 0xFFFF) {
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char *idbuf = (char *)virtio_gpa_to_host(desc[data_idx].addr);
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if (idbuf) {
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const char *id = "DESHAB-ROOTFS";
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u32 i = 0;
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for (; id[i] && i < desc[data_idx].len - 1; i++) idbuf[i] = id[i];
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idbuf[i] = 0;
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bytes_done = i + 1;
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}
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}
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break;
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case VIRTIO_BLK_T_FLUSH:
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result = VIRTIO_BLK_S_OK;
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break;
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default:
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result = VIRTIO_BLK_S_UNSUPP;
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break;
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}
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if (status) *status = result;
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return bytes_done;
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}
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static u16 g_rootfs_last_avail;
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static void rootfs_blk_queue_notify(u32 queue_idx) {
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struct virtq_desc *desc;
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struct virtq_avail *avail;
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struct virtq_used *used;
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u32 qnum;
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/* 必须按 gpa_base 定位：slot0 SATA blk 与本后端 device_id 同为 2，
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* virtio_queue_get_ptrs(VIRTIO_ID_BLOCK) 只会命中第一个（slot0）。 */
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if (virtio_queue_get_ptrs_by_gpa(VIRTIO_MMIO_ROOTFS_GPA, queue_idx,
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&desc, &avail, &used, &qnum) != 0) {
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return;
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}
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u16 cur = g_rootfs_last_avail;
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u16 used_idx = used->idx;
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while (cur != avail->idx) {
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u16 head = avail->ring[cur % qnum];
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u32 len = rootfs_blk_handle_chain(desc, head, qnum);
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used->ring[used_idx % qnum].id = head;
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used->ring[used_idx % qnum].len = len;
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used_idx++;
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cur++;
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}
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virtio_queue_bump_used(used, used_idx);
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g_rootfs_last_avail = cur;
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}
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static void rootfs_blk_reset(void) {
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g_rootfs_last_avail = 0;
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}
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static struct virtio_backend g_rootfs_blk_backend = {
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.device_id = VIRTIO_ID_BLOCK,
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.gpa_base = VIRTIO_MMIO_ROOTFS_GPA,
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.irq = 7, /* guest ISA IRQ7（cmdline :7，vector 0x37） */
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.num_queues = 1,
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.queue_size = 128,
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.device_features = (1ULL << VIRTIO_F_VERSION_1) |
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(1ULL << VIRTIO_BLK_F_SIZE_MAX) |
|
||
(1ULL << VIRTIO_BLK_F_SEG_MAX) |
|
||
(1ULL << VIRTIO_BLK_F_BLK_SIZE) |
|
||
(1ULL << VIRTIO_BLK_F_FLUSH),
|
||
.config_len = sizeof(struct virtio_blk_config),
|
||
.read_config = rootfs_blk_read_config,
|
||
.queue_notify = rootfs_blk_queue_notify,
|
||
.reset = rootfs_blk_reset,
|
||
};
|
||
|
||
void virtio_rootfs_blk_init(void) {
|
||
u64 rootfs_size = 0;
|
||
void *rootfs = linux_find_rootfs_module(&rootfs_size);
|
||
if (!rootfs || rootfs_size == 0) {
|
||
log_warn("[VBLK] no rootfs module, rootfs-blk backend not registered");
|
||
return;
|
||
}
|
||
|
||
g_rootfs_data = (const u8 *)rootfs;
|
||
g_rootfs_size = rootfs_size;
|
||
g_rootfs_capacity = rootfs_size / 512; /* 扇区数 */
|
||
if (rootfs_size % 512) g_rootfs_capacity++;
|
||
|
||
log_info("[VBLK] rootfs-blk backend bound to memory module");
|
||
log_hex64("[VBLK] rootfs size=", rootfs_size);
|
||
log_hex64("[VBLK] rootfs capacity(sectors)=", g_rootfs_capacity);
|
||
|
||
virtio_mmio_register(&g_rootfs_blk_backend);
|
||
}
|
||
|
||
/* ===== Extra rootfs virtio-blk 后端（VSCode Phase 4，可写持久卷） =====
|
||
*
|
||
* 第三个 virtio-blk 设备，后端为内存中的 linux-extra-rootfs.img
|
||
* （Limine boot module，路径含 "extra"）。guest 看到 /dev/vdc，
|
||
* 用作 overlayfs 的 rw 上层或 VSCode 数据卷。
|
||
*
|
||
* 与 rootfs（vdb 只读）不同，本后端支持 VIRTIO_BLK_T_OUT 真正写入内存
|
||
* （易失：重启丢失；Phase 7 再做写回 FAT32 持久化）。
|
||
*
|
||
* 无 extra-rootfs module 时安全不注册（guest cmdline 无 slot6 参数）。 */
|
||
|
||
static u8 *g_xrootfs_data;
|
||
static u64 g_xrootfs_size;
|
||
static u64 g_xrootfs_capacity;
|
||
static u16 g_xrootfs_last_avail;
|
||
|
||
static u32 xrootfs_blk_read_config(u32 offset, int width) {
|
||
(void)width;
|
||
struct virtio_blk_config cfg;
|
||
u8 *c = (u8 *)&cfg;
|
||
for (u32 i = 0; i < sizeof(cfg); i++) c[i] = 0;
|
||
cfg.capacity = g_xrootfs_capacity;
|
||
cfg.size_max = 128;
|
||
cfg.seg_max = 32;
|
||
cfg.blk_size = 512;
|
||
if (offset < sizeof(cfg)) {
|
||
u32 val = 0;
|
||
rf_memcpy(&val, c + offset, (offset + 4 <= sizeof(cfg)) ? 4 : (sizeof(cfg) - offset));
|
||
return val;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
static u32 xrootfs_blk_handle_chain(struct virtq_desc *desc, u16 head, u32 qnum) {
|
||
(void)qnum;
|
||
struct virtio_blk_outhdr hdr;
|
||
u8 *hptr = (u8 *)virtio_gpa_to_host(desc[head].addr);
|
||
if (!hptr) return 0;
|
||
rf_memcpy(&hdr, hptr, sizeof(hdr));
|
||
|
||
u32 type = hdr.type;
|
||
u64 sector = hdr.sector;
|
||
|
||
u16 data_idx = 0xFFFF;
|
||
u16 status_idx = 0xFFFF;
|
||
if (desc[head].flags & VIRTQ_DESC_F_NEXT) {
|
||
data_idx = desc[head].next;
|
||
u16 cur = data_idx;
|
||
int hops = 0;
|
||
while ((desc[cur].flags & VIRTQ_DESC_F_NEXT) && hops < 16) {
|
||
cur = desc[cur].next;
|
||
hops++;
|
||
}
|
||
status_idx = cur;
|
||
}
|
||
|
||
u8 *status = (u8 *)0;
|
||
if (status_idx != 0xFFFF && (desc[status_idx].flags & VIRTQ_DESC_F_WRITE)) {
|
||
status = (u8 *)virtio_gpa_to_host(desc[status_idx].addr);
|
||
}
|
||
|
||
u32 bytes_done = 0;
|
||
u8 result = VIRTIO_BLK_S_OK;
|
||
|
||
switch (type) {
|
||
case VIRTIO_BLK_T_IN: { /* 读：镜像内存 → guest */
|
||
if (data_idx == 0xFFFF || !g_xrootfs_data) {
|
||
result = VIRTIO_BLK_S_IOERR;
|
||
break;
|
||
}
|
||
u8 *dbuf = (u8 *)virtio_gpa_to_host(desc[data_idx].addr);
|
||
u32 dlen = desc[data_idx].len;
|
||
if (!dbuf) { result = VIRTIO_BLK_S_IOERR; break; }
|
||
u64 offset = sector * 512ULL;
|
||
u64 avail = (offset < g_xrootfs_size) ? (g_xrootfs_size - offset) : 0;
|
||
u32 copied = 0;
|
||
if (avail > 0) {
|
||
u32 n = (dlen < avail) ? dlen : (u32)avail;
|
||
rf_memcpy(dbuf, g_xrootfs_data + offset, n);
|
||
copied = n;
|
||
}
|
||
/* 越界部分填零 */
|
||
while (copied < dlen) dbuf[copied++] = 0;
|
||
bytes_done = dlen;
|
||
break;
|
||
}
|
||
case VIRTIO_BLK_T_OUT: { /* 写：guest → 镜像内存（可写卷） */
|
||
if (data_idx == 0xFFFF || !g_xrootfs_data) {
|
||
result = VIRTIO_BLK_S_IOERR;
|
||
break;
|
||
}
|
||
const u8 *dbuf = (const u8 *)virtio_gpa_to_host(desc[data_idx].addr);
|
||
u32 dlen = desc[data_idx].len;
|
||
if (!dbuf) { result = VIRTIO_BLK_S_IOERR; break; }
|
||
u64 offset = sector * 512ULL;
|
||
if (offset + dlen > g_xrootfs_size) {
|
||
/* 越界写：只写卷内部分，其余丢弃 */
|
||
u64 avail = (offset < g_xrootfs_size) ? (g_xrootfs_size - offset) : 0;
|
||
if (avail > 0) rf_memcpy(g_xrootfs_data + offset, dbuf, avail);
|
||
} else {
|
||
rf_memcpy(g_xrootfs_data + offset, dbuf, dlen);
|
||
}
|
||
bytes_done = 0; /* 写操作 used.len=0 */
|
||
break;
|
||
}
|
||
case VIRTIO_BLK_T_GET_ID:
|
||
if (data_idx != 0xFFFF) {
|
||
char *idbuf = (char *)virtio_gpa_to_host(desc[data_idx].addr);
|
||
if (idbuf) {
|
||
const char *id = "DESHAB-EXTRA-ROOTFS";
|
||
u32 i = 0;
|
||
for (; id[i] && i < desc[data_idx].len - 1; i++) idbuf[i] = id[i];
|
||
idbuf[i] = 0;
|
||
bytes_done = i + 1;
|
||
}
|
||
}
|
||
break;
|
||
case VIRTIO_BLK_T_FLUSH:
|
||
result = VIRTIO_BLK_S_OK;
|
||
break;
|
||
default:
|
||
result = VIRTIO_BLK_S_UNSUPP;
|
||
break;
|
||
}
|
||
|
||
if (status) *status = result;
|
||
return bytes_done;
|
||
}
|
||
|
||
static void xrootfs_blk_queue_notify(u32 queue_idx) {
|
||
struct virtq_desc *desc;
|
||
struct virtq_avail *avail;
|
||
struct virtq_used *used;
|
||
u32 qnum;
|
||
|
||
/* 按 gpa_base 定位（三个 blk 后端 device_id 同为 2） */
|
||
if (virtio_queue_get_ptrs_by_gpa(VIRTIO_MMIO_EXTRA_ROOTFS_GPA, queue_idx,
|
||
&desc, &avail, &used, &qnum) != 0) {
|
||
return;
|
||
}
|
||
|
||
u16 cur = g_xrootfs_last_avail;
|
||
u16 used_idx = used->idx;
|
||
while (cur != avail->idx) {
|
||
u16 head = avail->ring[cur % qnum];
|
||
u32 len = xrootfs_blk_handle_chain(desc, head, qnum);
|
||
used->ring[used_idx % qnum].id = head;
|
||
used->ring[used_idx % qnum].len = len;
|
||
used_idx++;
|
||
cur++;
|
||
}
|
||
virtio_queue_bump_used(used, used_idx);
|
||
g_xrootfs_last_avail = cur;
|
||
}
|
||
|
||
static void xrootfs_blk_reset(void) {
|
||
g_xrootfs_last_avail = 0;
|
||
}
|
||
|
||
static struct virtio_backend g_xrootfs_blk_backend = {
|
||
.device_id = VIRTIO_ID_BLOCK,
|
||
.gpa_base = VIRTIO_MMIO_EXTRA_ROOTFS_GPA,
|
||
.irq = 11, /* guest ISA IRQ11（cmdline :11，vector 0x3B） */
|
||
.num_queues = 1,
|
||
.queue_size = 128,
|
||
.device_features = (1ULL << VIRTIO_F_VERSION_1) |
|
||
(1ULL << VIRTIO_BLK_F_SIZE_MAX) |
|
||
(1ULL << VIRTIO_BLK_F_SEG_MAX) |
|
||
(1ULL << VIRTIO_BLK_F_BLK_SIZE) |
|
||
(1ULL << VIRTIO_BLK_F_FLUSH),
|
||
.config_len = sizeof(struct virtio_blk_config),
|
||
.read_config = xrootfs_blk_read_config,
|
||
.queue_notify = xrootfs_blk_queue_notify,
|
||
.reset = xrootfs_blk_reset,
|
||
};
|
||
|
||
void virtio_extra_rootfs_blk_init(void) {
|
||
u64 size = 0;
|
||
void *img = linux_find_extra_rootfs_module(&size);
|
||
if (!img || size == 0) {
|
||
log_warn("[VBLK] no extra-rootfs module, slot6 backend not registered");
|
||
return;
|
||
}
|
||
|
||
g_xrootfs_data = (u8 *)img;
|
||
g_xrootfs_size = size;
|
||
g_xrootfs_capacity = size / 512;
|
||
if (size % 512) g_xrootfs_capacity++;
|
||
|
||
log_info("[VBLK] extra-rootfs-blk backend bound (rw)");
|
||
log_hex64("[VBLK] extra-rootfs size=", size);
|
||
|
||
virtio_mmio_register(&g_xrootfs_blk_backend);
|
||
}
|