[PATCH v4 15/17] dmaengine: idxd: add dedicated wq mdev type

Dave Jiang
2020-10-30T18:54:01Z

Add the support code for "1dwq" mdev type. This mdev type follows the
standard VFIO mdev flow. The "1dwq" type will export a single dedicated wq
to the mdev. The dwq will have read-only configuration that is configured
by the host. The mdev type does not support PASID and SVA and will match
the stage 1 driver in functional support. For backward compatibility, the
mdev will maintain the DSA spec definition of this mdev type once the
commit goes upstream.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
drivers/dma/idxd/mdev.c | 141 ++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 133 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/idxd/mdev.c b/drivers/dma/idxd/mdev.c
index ed79c85e692e..16b56f8f7fc1 100644
--- a/drivers/dma/idxd/mdev.c
+++ b/drivers/dma/idxd/mdev.c
@@ -111,20 +111,58 @@ static void idxd_vdcm_release(struct mdev_device *mdev)
mutex_unlock(&vidxd->dev_lock);
}

+static struct idxd_wq *find_any_dwq(struct idxd_device *idxd)
+{
+ int i;
+ struct idxd_wq *wq;
+ unsigned long flags;
+
+ spin_lock_irqsave(&idxd->dev_lock, flags);
+ for (i = 0; i < idxd->max_wqs; i++) {
+ wq = &idxd->wqs[i];
+
+ if (wq->state != IDXD_WQ_ENABLED)
+ continue;
+
+ if (!wq_dedicated(wq))
+ continue;
+
+ if (idxd_wq_refcount(wq) != 0)
+ continue;
+
+ spin_unlock_irqrestore(&idxd->dev_lock, flags);
+ mutex_lock(&wq->wq_lock);
+ if (idxd_wq_refcount(wq)) {
+ spin_lock_irqsave(&idxd->dev_lock, flags);
+ continue;
+ }
+
+ idxd_wq_get(wq);
+ mutex_unlock(&wq->wq_lock);
+ return wq;
+ }
+
+ spin_unlock_irqrestore(&idxd->dev_lock, flags);
+ return NULL;
+}
+
static struct vdcm_idxd *vdcm_vidxd_create(struct idxd_device *idxd, struct mdev_device *mdev,
struct vdcm_idxd_type *type)
{
struct vdcm_idxd *vidxd;
struct idxd_wq *wq = NULL;
+ int rc;

- /* PLACEHOLDER, wq matching comes later */
-
+ if (type->type == IDXD_MDEV_TYPE_1_DWQ)
+ wq = find_any_dwq(idxd);
if (!wq)
return ERR_PTR(-ENODEV);

vidxd = kzalloc(sizeof(*vidxd), GFP_KERNEL);
- if (!vidxd)
- return ERR_PTR(-ENOMEM);
+ if (!vidxd) {
+ rc = -ENOMEM;
+ goto err;
+ }

mutex_init(&vidxd->dev_lock);
vidxd->idxd = idxd;
@@ -135,14 +173,23 @@ static struct vdcm_idxd *vdcm_vidxd_create(struct idxd_device *idxd, struct mdev
vidxd->num_wqs = VIDXD_MAX_WQS;

idxd_vdcm_init(vidxd);
- mutex_lock(&wq->wq_lock);
- idxd_wq_get(wq);
- mutex_unlock(&wq->wq_lock);

return vidxd;
+
+ err:
+ mutex_lock(&wq->wq_lock);
+ idxd_wq_put(wq);
+ mutex_unlock(&wq->wq_lock);
+ return ERR_PTR(rc);
}

-static struct vdcm_idxd_type idxd_mdev_types[IDXD_MDEV_TYPES];
+static struct vdcm_idxd_type idxd_mdev_types[IDXD_MDEV_TYPES] = {
+ {
+ .name = "1dwq-v1",
+ .description = "IDXD MDEV with 1 dedicated workqueue",
+ .type = IDXD_MDEV_TYPE_1_DWQ,
+ },
+};

static struct vdcm_idxd_type *idxd_vdcm_find_vidxd_type(struct device *dev,
const char *name)
@@ -934,7 +981,85 @@ static long idxd_vdcm_ioctl(struct mdev_device *mdev, unsigned int cmd,
return rc;
}

+static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
+{
+ struct vdcm_idxd_type *type;
+
+ type = idxd_vdcm_find_vidxd_type(dev, kobject_name(kobj));
+
+ if (type)
+ return sprintf(buf, "%s\n", type->description);
+
+ return -EINVAL;
+}
+static MDEV_TYPE_ATTR_RO(name);
+
+static int find_available_mdev_instances(struct idxd_device *idxd, struct vdcm_idxd_type *type)
+{
+ int count = 0, i;
+ unsigned long flags;
+
+ if (type->type != IDXD_MDEV_TYPE_1_DWQ)
+ return 0;
+
+ spin_lock_irqsave(&idxd->dev_lock, flags);
+ for (i = 0; i < idxd->max_wqs; i++) {
+ struct idxd_wq *wq;
+
+ wq = &idxd->wqs[i];
+ if (!is_idxd_wq_mdev(wq) || !wq_dedicated(wq) || idxd_wq_refcount(wq))
+ continue;
+
+ count++;
+ }
+ spin_unlock_irqrestore(&idxd->dev_lock, flags);
+
+ return count;
+}
+
+static ssize_t available_instances_show(struct kobject *kobj,
+ struct device *dev, char *buf)
+{
+ int count;
+ struct idxd_device *idxd = dev_get_drvdata(dev);
+ struct vdcm_idxd_type *type;
+
+ type = idxd_vdcm_find_vidxd_type(dev, kobject_name(kobj));
+ if (!type)
+ return -EINVAL;
+
+ count = find_available_mdev_instances(idxd, type);
+
+ return sprintf(buf, "%d\n", count);
+}
+static MDEV_TYPE_ATTR_RO(available_instances);
+
+static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
+ char *buf)
+{
+ return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
+}
+static MDEV_TYPE_ATTR_RO(device_api);
+
+static struct attribute *idxd_mdev_types_attrs[] = {
+ &mdev_type_attr_name.attr,
+ &mdev_type_attr_device_api.attr,
+ &mdev_type_attr_available_instances.attr,
+ NULL,
+};
+
+static struct attribute_group idxd_mdev_type_group0 = {
+ .name = "1dwq-v1",
+ .attrs = idxd_mdev_types_attrs,
+};
+
+static struct attribute_group *idxd_mdev_type_groups[] = {
+ &idxd_mdev_type_group0,
+ NULL,
+};
+
static const struct mdev_parent_ops idxd_vdcm_ops = {
+ .supported_type_groups = idxd_mdev_type_groups,
.create = idxd_vdcm_create,
.remove = idxd_vdcm_remove,
.open = idxd_vdcm_open,