[Minios-devel] [UNIKRAFT PATCH v3 06/17] plat/xen/drivers/blk: Configure block device

[Roxana Nicolescu <nicolescu.roxana1996@xxxxxxxxx>]

This patch introduces the configuration of block device consisting of:
        - finding multi-queue-max-queue number provided by Backend;
        - setting the number of queues to be used (between 1 and max).

Signed-off-by: Roxana Nicolescu <nicolescu.roxana1996@xxxxxxxxx>
---
 plat/xen/drivers/blk/blkfront.c    | 51 ++++++++++++++++++++++++++++++
 plat/xen/drivers/blk/blkfront.h    |  2 ++
 plat/xen/drivers/blk/blkfront_xb.h |  7 +++-
 plat/xen/drivers/blk/blkfront_xs.c | 47 +++++++++++++++++++++++++++
 4 files changed, 106 insertions(+), 1 deletion(-)

diff --git a/plat/xen/drivers/blk/blkfront.c b/plat/xen/drivers/blk/blkfront.c
index 09302f45..ae98a79c 100644
--- a/plat/xen/drivers/blk/blkfront.c
+++ b/plat/xen/drivers/blk/blkfront.c
@@ -55,6 +55,56 @@
 static struct uk_alloc *drv_allocator;
 
 
+static int blkfront_configure(struct uk_blkdev *blkdev,
+               const struct uk_blkdev_conf *conf)
+{
+       struct blkfront_dev *dev;
+       int err = 0;
+
+       UK_ASSERT(blkdev != NULL);
+       UK_ASSERT(conf != NULL);
+
+       dev = to_blkfront(blkdev);
+       dev->nb_queues = conf->nb_queues;
+       err = blkfront_xb_write_nb_queues(dev);
+       if (err) {
+               uk_pr_err("Failed to write nb of queues: %d.\n", err);
+               goto out;
+       }
+
+       uk_pr_info(DRIVER_NAME": %"PRIu16" configured\n", dev->uid);
+out:
+       return err;
+}
+
+static int blkfront_unconfigure(struct uk_blkdev *blkdev)
+{
+       struct blkfront_dev *dev;
+
+       UK_ASSERT(blkdev != NULL);
+       dev = to_blkfront(blkdev);
+
+       return 0;
+}
+
+static void blkfront_get_info(struct uk_blkdev *blkdev,
+               struct uk_blkdev_info *dev_info)
+{
+       struct blkfront_dev *dev = NULL;
+
+       UK_ASSERT(blkdev);
+       UK_ASSERT(dev_info);
+
+       dev = to_blkfront(blkdev);
+       dev_info->max_queues = dev->nb_queues;
+}
+
+static const struct uk_blkdev_ops blkfront_ops = {
+       .get_info = blkfront_get_info,
+       .dev_configure = blkfront_configure,
+       .dev_unconfigure = blkfront_unconfigure,
+};
+
 /**
  * Assign callbacks to uk_blkdev
  */
@@ -70,6 +120,7 @@ static int blkfront_add_dev(struct xenbus_device *dev)
                return -ENOMEM;
 
        d->xendev = dev;
+       d->blkdev.dev_ops = &blkfront_ops;
 
        /* Xenbus initialization */
        rc = blkfront_xb_init(d);
diff --git a/plat/xen/drivers/blk/blkfront.h b/plat/xen/drivers/blk/blkfront.h
index f00ed41b..5833f826 100644
--- a/plat/xen/drivers/blk/blkfront.h
+++ b/plat/xen/drivers/blk/blkfront.h
@@ -53,6 +53,8 @@ struct blkfront_dev {
        struct uk_blkdev blkdev;
        /* Blkfront device number from Xenstore path. */
        blkif_vdev_t    handle;
+       /* Number of configured queues used for requests */
+       uint16_t nb_queues;
        /* The blkdev identifier */
        __u16 uid;
 };
diff --git a/plat/xen/drivers/blk/blkfront_xb.h 
b/plat/xen/drivers/blk/blkfront_xb.h
index 7b62dbeb..668206a0 100644
--- a/plat/xen/drivers/blk/blkfront_xb.h
+++ b/plat/xen/drivers/blk/blkfront_xb.h
@@ -46,7 +46,7 @@
 
 /*
  * Get initial info from the xenstore.
- * Ex: backend path, handle.
+ * Ex: backend path, handle, max-queues.
  *
  * Return 0 on success, a negative errno value on error.
  */
@@ -57,4 +57,9 @@ int blkfront_xb_init(struct blkfront_dev *dev);
  */
 void blkfront_xb_fini(struct blkfront_dev *dev);
 
+/**
+ * Write nb of queues for further use to Xenstore.
+ * Return 0 on success, a negative errno value on error.
+ */
+int blkfront_xb_write_nb_queues(struct blkfront_dev *dev);
 #endif /* __BLKFRONT_XB_H__ */
diff --git a/plat/xen/drivers/blk/blkfront_xs.c 
b/plat/xen/drivers/blk/blkfront_xs.c
index 366c069b..9f44246e 100644
--- a/plat/xen/drivers/blk/blkfront_xs.c
+++ b/plat/xen/drivers/blk/blkfront_xs.c
@@ -66,6 +66,25 @@ out:
        return err;
 }
 
+static int blkfront_xb_get_nb_max_queues(struct blkfront_dev *dev)
+{
+       int err = 0;
+       struct xenbus_device *xendev;
+
+       UK_ASSERT(dev != NULL);
+       xendev = dev->xendev;
+
+       err = xs_scanf(XBT_NIL, xendev->otherend, "multi-queue-max-queues",
+                               "%"PRIu16,
+                               &dev->nb_queues);
+       if (err < 0) {
+               uk_pr_err("Failed to read multi-queue-max-queues: %d\n", err);
+               return err;
+       }
+
+       return 0;
+}
+
 int blkfront_xb_init(struct blkfront_dev *dev)
 {
        struct xenbus_device *xendev;
@@ -101,6 +120,11 @@ int blkfront_xb_init(struct blkfront_dev *dev)
                goto out;
        }
 
+       err = blkfront_xb_get_nb_max_queues(dev);
+       if (err) {
+               uk_pr_err("Failed to read multi-queue-max-queues: %d\n", err);
+               goto out;
+       }
 out:
        return err;
 }
@@ -117,3 +141,26 @@ void blkfront_xb_fini(struct blkfront_dev *dev)
                xendev->otherend = NULL;
        }
 }
+
+int blkfront_xb_write_nb_queues(struct blkfront_dev *dev)
+{
+       int err;
+       struct xenbus_device *xendev;
+
+       UK_ASSERT(dev);
+
+       xendev = dev->xendev;
+       err = xs_printf(XBT_NIL, xendev->nodename,
+                       "multi-queue-num-queues",
+                       "%u",
+                       dev->nb_queues);
+       if (err < 0) {
+               uk_pr_err("Failed to write multi-queue-num-queue: %d\n", err);
+               goto out;
+       }
+
+       err = 0;
+
+out:
+       return err;
+}
-- 
2.17.1


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