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Deshab-OS/CODE/UTSM/vmm/virtio_blk.c
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2026-07-28 21:11:10 +08:00
/* virtio_blk.c — UTSM virtio-blk 设备模拟后端。
*
* 为 Linux guest 提供 virtio-blk 块设备。guest 的块读写请求经
* virtqueue 传入,本后端桥接到 UTSM 真实块设备(block API,AHCI/SATA)。
*
* Virtio Spec 1.1 §5.2 (Block Device)。
* 请求描述符链: [header(16B, R)] [data(N*512B, R/W)] [status(1B, W)]
* 支持的操作:VIRTIO_BLK_T_IN(读)、VIRTIO_BLK_T_OUT(写)、VIRTIO_BLK_T_GET_ID。
*
* 设计说明:
* - 桥接到 UTSM block API 的第 0 个设备(ahci0 SATA 盘)。
* - guest 把 Arch rootfs 镜像当作 /dev/vda 挂载;镜像需预先写入 SATA 盘
* 的某个分区/LBA 区间(由 mkfat32/build 流程或独立 raw 区提供)。
* - 当前为最小可用:扇区 512B,单队列,无 flush/discard。
*/
#include <utsm/virtio_mmio.h>
#include <utsm/linux_loader.h>
#include <utsm/block.h>
#include <utsm/log.h>
#include <utsm/types.h>
/* virtio-blk 请求头(Virtio Spec 1.1 §5.2.6.2) */
struct virtio_blk_outhdr {
u32 type; /* VIRTIO_BLK_T_* */
u32 reserved; /* (ioprio) */
u64 sector; /* 起始扇区(512B 单位) */
} __attribute__((packed));
#define VIRTIO_BLK_T_IN 0 /* 读 */
#define VIRTIO_BLK_T_OUT 1 /* 写 */
#define VIRTIO_BLK_T_FLUSH 4
#define VIRTIO_BLK_T_GET_ID 8
#define VIRTIO_BLK_S_OK 0
#define VIRTIO_BLK_S_IOERR 1
#define VIRTIO_BLK_S_UNSUPP 2
/* feature bits */
#define VIRTIO_BLK_F_SIZE_MAX 1
#define VIRTIO_BLK_F_SEG_MAX 2
#define VIRTIO_BLK_F_BLK_SIZE 6
#define VIRTIO_BLK_F_FLUSH 9
/* device config 空间(VIRTIO_MMIO_CONFIG 起) */
struct virtio_blk_config {
u64 capacity; /* 总扇区数(512B) */
u32 size_max;
u32 seg_max;
u16 geometry[4];
u32 blk_size;
/* ... 其余字段省略 */
} __attribute__((packed));
/* 后端状态 */
static u64 g_blk_capacity; /* 扇区数 */
static u32 g_blk_sector_size = 512;
static int g_blk_bound = -1; /* 绑定的 UTSM block 设备索引 */
/* 读取 device config 空间 */
static u32 blk_read_config(u32 offset, int width) {
(void)width;
struct virtio_blk_config cfg;
/* 填零后逐字段读取 */
u8 *c = (u8 *)&cfg;
for (u32 i = 0; i < sizeof(cfg); i++) c[i] = 0;
cfg.capacity = g_blk_capacity;
cfg.size_max = 128; /* 单请求最大 128 扇区 */
cfg.seg_max = 32;
cfg.blk_size = g_blk_sector_size;
/* 按 offset 返回 32 位窗口 */
if (offset + 4 <= sizeof(cfg)) {
u32 v;
u8 *src = (u8 *)&cfg + offset;
v = (u32)src[0] | ((u32)src[1] << 8) | ((u32)src[2] << 16) | ((u32)src[3] << 24);
return v;
}
return 0;
}
/* 处理一个块请求描述符链。返回写入 guest 的字节数(用于 used.len)。 */
static u32 blk_handle_chain(struct virtq_desc *desc, u16 head, u32 qnum) {
(void)qnum;
if (!desc) return 0;
/* 第一个描述符:请求头(driver→device,16 字节) */
struct virtio_blk_outhdr *hdr =
(struct virtio_blk_outhdr *)virtio_gpa_to_host(desc[head].addr);
if (!hdr) return 0;
u32 type = hdr->type;
u64 sector = hdr->sector;
/* 沿描述符链找到 data 与 status 描述符 */
u16 cur = head;
u16 data_idx = 0xFFFF, status_idx = 0xFFFF;
int hops = 0;
if (desc[cur].flags & VIRTQ_DESC_F_NEXT) {
data_idx = desc[cur].next;
cur = data_idx;
/* data 之后可能还有 status */
while ((desc[cur].flags & VIRTQ_DESC_F_NEXT) && hops < 16) {
cur = desc[cur].next;
hops++;
}
/* 最后一个是 status(device write,1 字节) */
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;
const dkm_block_api *blk = block_get_api();
switch (type) {
case VIRTIO_BLK_T_IN: { /* 读:块设备 → guest data buffer */
if (data_idx == 0xFFFF || g_blk_bound < 0 || !blk) {
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; }
u32 nsec = dlen / 512;
if (nsec == 0) nsec = 1;
if (blk->read((u32)g_blk_bound, sector, nsec, dbuf) != 0) {
result = VIRTIO_BLK_S_IOERR;
} else {
bytes_done = dlen;
}
break;
}
case VIRTIO_BLK_T_OUT: { /* 写:guest data buffer → 块设备 */
if (data_idx == 0xFFFF || g_blk_bound < 0 || !blk) {
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; }
u32 nsec = dlen / 512;
if (nsec == 0) nsec = 1;
if (blk->write((u32)g_blk_bound, sector, nsec, dbuf) != 0) {
result = VIRTIO_BLK_S_IOERR;
} else {
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-VIRTIO-BLK";
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; /* 无写缓存,直接成功 */
break;
default:
result = VIRTIO_BLK_S_UNSUPP;
break;
}
/* 写状态字节 */
if (status) *status = result;
return bytes_done;
}
/* queue_notify:guest 提交了块请求,处理队列。 */
static u16 g_blk_last_avail;
static void blk_queue_notify(u32 queue_idx) {
struct virtq_desc *desc;
struct virtq_avail *avail;
struct virtq_used *used;
u32 qnum;
if (virtio_queue_get_ptrs(VIRTIO_ID_BLOCK, queue_idx,
&desc, &avail, &used, &qnum) != 0) {
return;
}
/* 处理自上次以来的所有新 avail 请求 */
u16 cur = g_blk_last_avail;
u16 used_idx = used->idx;
while (cur != avail->idx) {
u16 head = avail->ring[cur % qnum];
u32 len = blk_handle_chain(desc, head, qnum);
/* 写 used 回执 */
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_blk_last_avail = cur;
}
static void blk_reset(void) {
g_blk_last_avail = 0;
}
/* 后端结构体 */
static struct virtio_backend g_blk_backend = {
.device_id = VIRTIO_ID_BLOCK,
.gpa_base = VIRTIO_MMIO_BLK_GPA,
.irq = 5, /* guest ISA IRQ5(cmdline :5,vector 0x35) */
.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 = blk_read_config,
.queue_notify = blk_queue_notify,
.reset = blk_reset,
};
void virtio_blk_backend_init(void) {
/* 绑定 UTSM 第 0 个块设备(ahci0 SATA 盘)作为后端存储 */
const dkm_block_api *blk = block_get_api();
if (blk && blk->device_count() > 0) {
g_blk_bound = 0;
u64 ssize = blk->sector_size(0);
if (ssize > 0) g_blk_sector_size = (u32)ssize;
/* 从设备名推算容量不可得,用默认值(guest 端可再探测)。
* 实际 capacity 需读 ATA IDENTIFY;这里给 4GB 占位,
* guest mkfs/mount 会按此上限工作。 */
g_blk_capacity = 8ULL * 1024 * 1024 * 1024 / 512; /* 8GB in sectors */
log_info("[VBLK] bound to UTSM block device 0");
log_hex64("[VBLK] capacity(sectors)=", g_blk_capacity);
} else {
g_blk_bound = -1;
g_blk_capacity = 0;
log_warn("[VBLK] no UTSM block device, blk backend degraded");
}
virtio_mmio_register(&g_blk_backend);
}
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/* ===== Memory-backed rootfs virtio-blk 后端 =====
*
* 第二个 virtio-blk 设备,后端为内存中的 Arch rootfs 镜像(Limine boot module)。
* guest 看到 /dev/vdb,挂载为真实根文件系统(ext4),switch_root 进入 Arch。
*
* 读写直接操作内存(memcpy),无需块设备 API。 */
/* byte-wise memcpy helper (freestanding, no libc) */
static void rf_memcpy(void *dst, const void *src, u64 n) {
u8 *d = (u8 *)dst;
const u8 *s = (const u8 *)src;
while (n--) *d++ = *s++;
}
static const u8 *g_rootfs_data; /* rootfs 镜像内存指针(HHDM 虚拟地址) */
static u64 g_rootfs_size; /* rootfs 镜像大小(字节) */
static u64 g_rootfs_capacity; /* rootfs 容量(扇区数,512B 单位) */
static u32 rootfs_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_rootfs_capacity;
cfg.size_max = 128;
cfg.seg_max = 32;
cfg.blk_size = 512;
if (offset + 4 <= sizeof(cfg)) {
u32 val = 0;
rf_memcpy(&val, c + offset, 4);
return val;
}
if (offset < sizeof(cfg)) {
u32 val = 0;
rf_memcpy(&val, c + offset, 4);
return val;
}
return 0;
}
/* rootfs 请求处理:直接内存拷贝 */
static u32 rootfs_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:rootfs 内存 → guest */
if (data_idx == 0xFFFF || !g_rootfs_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;
if (offset + dlen > g_rootfs_size) {
/* 超出范围:截断或填零 */
u64 avail = (offset < g_rootfs_size) ? (g_rootfs_size - offset) : 0;
if (avail > 0) {
rf_memcpy(dbuf, g_rootfs_data + offset, avail);
}
/* 剩余部分填零 */
if (dlen > avail) {
u8 *p = dbuf + avail;
u32 rem = dlen - (u32)avail;
while (rem--) *p++ = 0;
}
bytes_done = dlen;
} else {
rf_memcpy(dbuf, g_rootfs_data + offset, dlen);
bytes_done = dlen;
}
break;
}
case VIRTIO_BLK_T_OUT: /* 写:暂不支持(rootfs 只读) */
result = VIRTIO_BLK_S_IOERR;
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-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 u16 g_rootfs_last_avail;
static void rootfs_blk_queue_notify(u32 queue_idx) {
struct virtq_desc *desc;
struct virtq_avail *avail;
struct virtq_used *used;
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,
* virtio_queue_get_ptrs(VIRTIO_ID_BLOCK) 只会命中第一个(slot0)。 */
if (virtio_queue_get_ptrs_by_gpa(VIRTIO_MMIO_ROOTFS_GPA, queue_idx,
&desc, &avail, &used, &qnum) != 0) {
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return;
}
u16 cur = g_rootfs_last_avail;
u16 used_idx = used->idx;
while (cur != avail->idx) {
u16 head = avail->ring[cur % qnum];
u32 len = rootfs_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_rootfs_last_avail = cur;
}
static void rootfs_blk_reset(void) {
g_rootfs_last_avail = 0;
}
static struct virtio_backend g_rootfs_blk_backend = {
.device_id = VIRTIO_ID_BLOCK,
.gpa_base = VIRTIO_MMIO_ROOTFS_GPA,
.irq = 7, /* guest ISA IRQ7(cmdline :7,vector 0x37) */
.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 = 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);
}
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/* ===== 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);
}