Host independent implementation for virtio block devices. The host
dependent part of the host library must provide an implementation for
lkl_dev_block_ops.
Disks can be added to the LKL configuration via lkl_disk_add(), a new
LKL application API.
Signed-off-by: Octavian Purdila <octavian.purdila@xxxxxxxxx>
---
tools/lkl/include/lkl.h | 20 ++++++++
tools/lkl/include/lkl_host.h | 21 ++++++++
tools/lkl/lib/virtio_blk.c | 116 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 157 insertions(+)
create mode 100644 tools/lkl/lib/virtio_blk.c
diff --git a/tools/lkl/include/lkl.h b/tools/lkl/include/lkl.h
index 958614d..0c30b23 100644
--- a/tools/lkl/include/lkl.h
+++ b/tools/lkl/include/lkl.h
@@ -20,4 +20,24 @@ static inline long lkl_sys_lseek(unsigned int fd, __lkl__kernel_loff_t off,
*/
const char *lkl_strerror(int err);
+/**
+ * lkl_disk_backstore - host dependend disk backstore
+ *
+ * @fd - an open file descriptor that can be used by preadv/pwritev; used by
+ * POSIX hosts
+ */
+union lkl_disk_backstore {
+ int fd;
+};
+
+/**
+ * lkl_disk_add - add a new disk
+ *
+ * Must be called before calling lkl_start_kernel.
+ *
+ * @backstore - the disk backstore
+ * @returns a disk id (0 is valid) or a strictly negative value in case of error
+ */
+int lkl_disk_add(union lkl_disk_backstore backstore);
+
#endif
diff --git a/tools/lkl/include/lkl_host.h b/tools/lkl/include/lkl_host.h
index 26d3e43..2dafaa8 100644
--- a/tools/lkl/include/lkl_host.h
+++ b/tools/lkl/include/lkl_host.h
@@ -20,4 +20,25 @@ struct lkl_dev_buf {
unsigned int len;
};
+extern struct lkl_dev_blk_ops lkl_dev_blk_ops;
+
+#define LKL_DEV_BLK_TYPE_READ 0
+#define LKL_DEV_BLK_TYPE_WRITE 1
+#define LKL_DEV_BLK_TYPE_FLUSH 4
+#define LKL_DEV_BLK_TYPE_FLUSH_OUT 5
+
+struct lkl_dev_blk_ops {
+ int (*get_capacity)(union lkl_disk_backstore bs,
+ unsigned long long *res);
+ void (*request)(union lkl_disk_backstore bs, unsigned int type,
+ unsigned int prio, unsigned long long sector,
+ struct lkl_dev_buf *bufs, int count);
+};
+
+#define LKL_DEV_BLK_STATUS_OK 0
+#define LKL_DEV_BLK_STATUS_IOERR 1
+#define LKL_DEV_BLK_STATUS_UNSUP 2
+
+void lkl_dev_blk_complete(struct lkl_dev_buf *bufs, unsigned char status,
+ int len);
#endif
diff --git a/tools/lkl/lib/virtio_blk.c b/tools/lkl/lib/virtio_blk.c
new file mode 100644
index 0000000..3262f42
--- /dev/null
+++ b/tools/lkl/lib/virtio_blk.c
@@ -0,0 +1,116 @@
+#include <lkl_host.h>
+#include "virtio.h"
+
+struct virtio_blk_dev {
+ struct virtio_dev dev;
+ struct {
+ uint64_t capacity;
+ } config;
+ struct lkl_dev_blk_ops *ops;
+ union lkl_disk_backstore backstore;
+};
+
+struct virtio_blk_req_header {
+ uint32_t type;
+ uint32_t prio;
+ uint64_t sector;
+};
+
+struct virtio_blk_req_trailer {
+ uint8_t status;
+};
+
+static int blk_check_features(uint32_t features)
+{
+ if (!features)
+ return 0;
+
+ return -LKL_EINVAL;
+}
+
+void lkl_dev_blk_complete(struct lkl_dev_buf *bufs, unsigned char status,
+ int len)
+{
+ struct virtio_dev_req *req;
+ struct virtio_blk_req_trailer *f;
+
+ req = container_of(bufs - 1, struct virtio_dev_req, buf);
+
+ if (req->buf_count < 2) {
+ lkl_printf("virtio_blk: no status buf\n");
+ return;
+ }
+
+ if (req->buf[req->buf_count - 1].len != sizeof(*f)) {
+ lkl_printf("virtio_blk: bad status buf\n");
+ } else {
+ f = req->buf[req->buf_count - 1].addr;
+ f->status = status;
+ }
+
+ virtio_dev_complete(req, len);
+}
+
+static void blk_queue(struct virtio_dev *dev, struct virtio_dev_req *req)
+{
+ struct virtio_blk_req_header *h;
+ struct virtio_blk_dev *blk_dev;
+
+ if (req->buf[0].len != sizeof(struct virtio_blk_req_header)) {
+ lkl_printf("virtio_blk: bad header buf\n");
+ lkl_dev_blk_complete(&req->buf[1], LKL_DEV_BLK_STATUS_UNSUP, 0);
+ return;
+ }
+
+ h = req->buf[0].addr;
+ blk_dev = container_of(dev, struct virtio_blk_dev, dev);
+
+ blk_dev->ops->request(blk_dev->backstore, le32toh(h->type),
+ le32toh(h->prio), le32toh(h->sector),
+ &req->buf[1], req->buf_count - 2);
+}
+
+static struct virtio_dev_ops blk_ops = {
+ .check_features = blk_check_features,
+ .queue = blk_queue,
+};
+
+int lkl_disk_add(union lkl_disk_backstore backstore)
+{
+ struct virtio_blk_dev *dev;
+ unsigned long long capacity;
+ int ret;
+ static int count;
+
+ dev = lkl_host_ops.mem_alloc(sizeof(*dev));
+ if (!dev)
+ return -LKL_ENOMEM;
+
+ dev->dev.device_id = 2;
+ dev->dev.vendor_id = 0;
+ dev->dev.device_features = 0;
+ dev->dev.config_gen = 0;
+ dev->dev.config_data = &dev->config;
+ dev->dev.config_len = sizeof(dev->config);
+ dev->dev.ops = &blk_ops;
+ dev->ops = &lkl_dev_blk_ops;
+ dev->backstore = backstore;
+
+ ret = dev->ops->get_capacity(backstore, &capacity);
+ if (ret) {
+ ret = -LKL_ENOMEM;
+ goto out_free;
+ }
+ dev->config.capacity = capacity;
+
+ ret = virtio_dev_setup(&dev->dev, 1, 65536);
+ if (ret)
+ goto out_free;
+
+ return count++;
+
+out_free:
+ lkl_host_ops.mem_free(dev);
+
+ return ret;
+}
--
2.1.0
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