[Minios-devel] [UNIKRAFT PATCH v3 05/14] plat/drivers: Init virtio block device

[Roxana Nicolescu <nicolescu.roxana1996@xxxxxxxxx>]

This patch introduces the initialization of virtio block device.
First, the driver sets what features supports, and then the driver
negotiates with the device for the common features.

Signed-off-by: Roxana Nicolescu <nicolescu.roxana1996@xxxxxxxxx>
---
 plat/drivers/include/virtio/virtio_blk.h | 52 ++++++++++++++
 plat/drivers/virtio/virtio_blk.c         | 87 ++++++++++++++++++++++++
 2 files changed, 139 insertions(+)
 create mode 100644 plat/drivers/include/virtio/virtio_blk.h

diff --git a/plat/drivers/include/virtio/virtio_blk.h 
b/plat/drivers/include/virtio/virtio_blk.h
new file mode 100644
index 00000000..48625258
--- /dev/null
+++ b/plat/drivers/include/virtio/virtio_blk.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/* This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ **/
+/**
+ * Taken and modified from Linux kernel
+ * include/uapi/linux/virtio_blk.h
+ *
+ * commit-id: 8005803a2
+ */
+#ifndef __PLAT_DRV_VIRTIO_BLK_H
+#define __PLAT_DRV_VIRTIO_BLK_H
+#include <virtio/virtio_ids.h>
+#include <virtio/virtio_config.h>
+#include <virtio/virtio_types.h>
+
+/* Feature bits */
+#define VIRTIO_BLK_F_RO                5       /* Disk is read-only */
+#define VIRTIO_BLK_F_BLK_SIZE  6       /* Block size of disk is available*/
+
+struct virtio_blk_config {
+       /* The capacity (in 512-byte sectors). */
+       __u64 capacity;
+       /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
+       __u32 blk_size;
+} __packed;
+
+#endif /* __PLAT_DRV_VIRTIO_BLK_H */
diff --git a/plat/drivers/virtio/virtio_blk.c b/plat/drivers/virtio/virtio_blk.c
index 884f86d9..2dfe8f27 100644
--- a/plat/drivers/virtio/virtio_blk.c
+++ b/plat/drivers/virtio/virtio_blk.c
@@ -28,13 +28,22 @@
 #include <virtio/virtio_bus.h>
 #include <virtio/virtio_ids.h>
 #include <uk/blkdev.h>
+#include <virtio/virtio_blk.h>
 #include <uk/blkdev_driver.h>
 
 #define DRIVER_NAME            "virtio-blk"
+#define DEFAULT_SECTOR_SIZE    512
 
 #define to_virtioblkdev(bdev) \
        __containerof(bdev, struct virtio_blk_device, blkdev)
 
+/* Features are:
+ *     Access Mode
+ *     Sector_size;
+ **/
+#define VIRTIO_BLK_DRV_FEATURES(features) \
+       (VIRTIO_FEATURES_UPDATE(features, VIRTIO_BLK_F_RO | \
+       VIRTIO_BLK_F_BLK_SIZE))
 
 static struct uk_alloc *a;
 static const char *drv_name = DRIVER_NAME;
@@ -44,8 +53,75 @@ struct virtio_blk_device {
        struct uk_blkdev blkdev;
        /* The blkdevice identifier */
        __u16 uid;
+       /* Virtio Device */
+       struct virtio_dev *vdev;
 };
 
+static int virtio_blkdev_feature_negotiate(struct virtio_blk_device *vbdev)
+{
+       struct uk_blkdev_cap *cap;
+       __u64 host_features = 0;
+       int bytes_to_read;
+       __sector sectors;
+       __sector ssize;
+       int rc = 0;
+
+       UK_ASSERT(vbdev);
+       cap = &vbdev->blkdev.capabilities;
+       host_features = virtio_feature_get(vbdev->vdev);
+
+       /* Get size of device */
+       bytes_to_read = virtio_config_get(vbdev->vdev,
+                       __offsetof(struct virtio_blk_config, capacity),
+                       &sectors,
+                       sizeof(sectors),
+                       1);
+       if (bytes_to_read != sizeof(sectors))  {
+               uk_pr_err("Failed to get nb of sectors from device %d\n", rc);
+               rc = -EAGAIN;
+               goto exit;
+       }
+
+       if (!virtio_has_features(host_features, VIRTIO_BLK_F_BLK_SIZE)) {
+               ssize = DEFAULT_SECTOR_SIZE;
+       } else {
+               bytes_to_read = virtio_config_get(vbdev->vdev,
+                               __offsetof(struct virtio_blk_config, blk_size),
+                               &ssize,
+                               sizeof(ssize),
+                               1);
+               if (bytes_to_read != sizeof(ssize))  {
+                       uk_pr_err("Failed to get ssize from the device %d\n",
+                                       rc);
+                       rc = -EAGAIN;
+                       goto exit;
+               }
+       }
+
+       cap->ssize = ssize;
+       cap->sectors = sectors;
+       cap->ioalign = sizeof(void *);
+       cap->mode = (virtio_has_features(
+                       host_features, VIRTIO_BLK_F_RO)) ? O_RDONLY : O_RDWR;
+
+       /**
+        * Mask out features supported by both driver and device.
+        */
+       vbdev->vdev->features &= host_features;
+       virtio_feature_set(vbdev->vdev, vbdev->vdev->features);
+
+exit:
+       return rc;
+}
+
+static inline void virtio_blkdev_feature_set(struct virtio_blk_device *vbdev)
+{
+       vbdev->vdev->features = 0;
+
+       /* Setting the feature the driver support */
+       VIRTIO_BLK_DRV_FEATURES(vbdev->vdev->features);
+}
+
 static int virtio_blk_add_dev(struct virtio_dev *vdev)
 {
        struct virtio_blk_device *vbdev;
@@ -57,6 +133,8 @@ static int virtio_blk_add_dev(struct virtio_dev *vdev)
        if (!vbdev)
                return -ENOMEM;
 
+       vbdev->vdev = vdev;
+
        rc = uk_blkdev_drv_register(&vbdev->blkdev, a, drv_name);
        if (rc < 0) {
                uk_pr_err("Failed to register virtio_blk device: %d\n", rc);
@@ -64,10 +142,19 @@ static int virtio_blk_add_dev(struct virtio_dev *vdev)
        }
 
        vbdev->uid = rc;
+       virtio_blkdev_feature_set(vbdev);
+       rc = virtio_blkdev_feature_negotiate(vbdev);
+       if (rc) {
+               uk_pr_err("Failed to negotiate the device feature %d\n", rc);
+               goto err_negotiate_feature;
+       }
+
        uk_pr_info("Virtio-blk device registered with libukblkdev\n");
 
 out:
        return rc;
+err_negotiate_feature:
+       virtio_dev_status_update(vbdev->vdev, VIRTIO_CONFIG_STATUS_FAIL);
 err_out:
        uk_free(a, vbdev);
        goto out;
-- 
2.17.1


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