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Jason Wang

2021-Jun-01 08:44 UTC

[PATCH 0/4] Packed virtqueue state support for vDPA

Hi:

This series implements the packed virtqueue state support for
vDPA. This is done via extending the vdpa_vq_state to support packed
virtqueue.

For virtio-vDPA, an initial state required by the virtio spec is set.

For vhost-vDPA, the packed virtqueue support still needs to be done at
both vhost core and vhost-vDPA in the future.

Please review.

Eli Cohen (1):
  virtio/vdpa: clear the virtqueue state during probe

Jason Wang (3):
  vdpa: support packed virtqueue for set/get_vq_state()
  virtio-pci library: introduce vp_modern_get_driver_features()
  vp_vdpa: allow set vq state to initial state after reset

 drivers/vdpa/ifcvf/ifcvf_main.c        |  4 +--
 drivers/vdpa/vdpa_sim/vdpa_sim.c       |  4 +--
 drivers/vdpa/virtio_pci/vp_vdpa.c      | 42 ++++++++++++++++++++++++--
 drivers/vhost/vdpa.c                   |  4 +--
 drivers/virtio/virtio_pci_modern_dev.c | 21 +++++++++++++
 drivers/virtio/virtio_vdpa.c           | 15 +++++++++
 include/linux/vdpa.h                   | 25 +++++++++++++--
 include/linux/virtio_pci_modern.h      |  1 +
 8 files changed, 105 insertions(+), 11 deletions(-)

-- 
2.25.1

Jason Wang

2021-Jun-01 08:45 UTC

head link

[PATCH 1/4] vdpa: support packed virtqueue for set/get_vq_state()

This patch extends the vdpa_vq_state to support packed virtqueue
state which is basically the device/driver ring wrap counters and the
avail and used index. This will be used for the virito-vdpa support
for the packed virtqueue and the future vhost/vhost-vdpa support for
the packed virtqueue.

Signed-off-by: Jason Wang <jasowang at redhat.com>
---
 drivers/vdpa/ifcvf/ifcvf_main.c  |  4 ++--
 drivers/vdpa/vdpa_sim/vdpa_sim.c |  4 ++--
 drivers/vhost/vdpa.c             |  4 ++--
 include/linux/vdpa.h             | 25 +++++++++++++++++++++++--
 4 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index ab0ab5cf0f6e..5d3891b1ca28 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -264,7 +264,7 @@ static int ifcvf_vdpa_get_vq_state(struct vdpa_device
*vdpa_dev, u16 qid,
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	state->avail_index = ifcvf_get_vq_state(vf, qid);
+	state->split.avail_index = ifcvf_get_vq_state(vf, qid);
 	return 0;
 }
 
@@ -273,7 +273,7 @@ static int ifcvf_vdpa_set_vq_state(struct vdpa_device
*vdpa_dev, u16 qid,
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	return ifcvf_set_vq_state(vf, qid, state->avail_index);
+	return ifcvf_set_vq_state(vf, qid, state->split.avail_index);
 }
 
 static void ifcvf_vdpa_set_vq_cb(struct vdpa_device *vdpa_dev, u16 qid,
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 98f793bc9376..14e024de5cbf 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -374,7 +374,7 @@ static int vdpasim_set_vq_state(struct vdpa_device *vdpa,
u16 idx,
 	struct vringh *vrh = &vq->vring;
 
 	spin_lock(&vdpasim->lock);
-	vrh->last_avail_idx = state->avail_index;
+	vrh->last_avail_idx = state->split.avail_index;
 	spin_unlock(&vdpasim->lock);
 
 	return 0;
@@ -387,7 +387,7 @@ static int vdpasim_get_vq_state(struct vdpa_device *vdpa,
u16 idx,
 	struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 	struct vringh *vrh = &vq->vring;
 
-	state->avail_index = vrh->last_avail_idx;
+	state->split.avail_index = vrh->last_avail_idx;
 	return 0;
 }
 
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index fb41db3da611..210ab35a7ebf 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -383,7 +383,7 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v,
unsigned int cmd,
 		if (r)
 			return r;
 
-		vq->last_avail_idx = vq_state.avail_index;
+		vq->last_avail_idx = vq_state.split.avail_index;
 		break;
 	}
 
@@ -401,7 +401,7 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v,
unsigned int cmd,
 		break;
 
 	case VHOST_SET_VRING_BASE:
-		vq_state.avail_index = vq->last_avail_idx;
+		vq_state.split.avail_index = vq->last_avail_idx;
 		if (ops->set_vq_state(vdpa, idx, &vq_state))
 			r = -EINVAL;
 		break;
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index f311d227aa1b..3357ac98878d 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -28,13 +28,34 @@ struct vdpa_notification_area {
 };
 
 /**
- * struct vdpa_vq_state - vDPA vq_state definition
+ * struct vdpa_vq_state_split - vDPA split virtqueue state
  * @avail_index: available index
  */
-struct vdpa_vq_state {
+struct vdpa_vq_state_split {
 	u16	avail_index;
 };
 
+/**
+ * struct vdpa_vq_state_packed - vDPA packed virtqueue state
+ * @last_avail_counter: last driver ring wrap counter observed by device
+ * @last_avail_idx: device available index
+ * @last_used_counter: device ring wrap counter
+ * @last_used_idx: used index
+ */
+struct vdpa_vq_state_packed {
+        u16	last_avail_counter:1;
+        u16	last_avail_idx:15;
+        u16	last_used_counter:1;
+        u16	last_used_idx:15;
+};
+
+struct vdpa_vq_state {
+     union {
+          struct vdpa_vq_state_split split;
+          struct vdpa_vq_state_packed packed;
+     };
+};
+
 struct vdpa_mgmt_dev;
 
 /**
-- 
2.25.1

Jason Wang

2021-Jun-01 08:45 UTC

head link

[PATCH 2/4] virtio-pci library: introduce vp_modern_get_driver_features()

This patch introduce a helper to get driver/guest features from the
device.

Signed-off-by: Jason Wang <jasowang at redhat.com>
---
 drivers/virtio/virtio_pci_modern_dev.c | 21 +++++++++++++++++++++
 include/linux/virtio_pci_modern.h      |  1 +
 2 files changed, 22 insertions(+)

diff --git a/drivers/virtio/virtio_pci_modern_dev.c
b/drivers/virtio/virtio_pci_modern_dev.c
index 54f297028586..e11ed748e661 100644
--- a/drivers/virtio/virtio_pci_modern_dev.c
+++ b/drivers/virtio/virtio_pci_modern_dev.c
@@ -383,6 +383,27 @@ u64 vp_modern_get_features(struct virtio_pci_modern_device
*mdev)
 }
 EXPORT_SYMBOL_GPL(vp_modern_get_features);
 
+/*
+ * vp_modern_get_driver_features - get driver features from device
+ * @mdev: the modern virtio-pci device
+ *
+ * Returns the driver features read from the device
+ */
+u64 vp_modern_get_driver_features(struct virtio_pci_modern_device *mdev)
+{
+	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
+
+	u64 features;
+
+	vp_iowrite32(0, &cfg->guest_feature_select);
+	features = vp_ioread32(&cfg->guest_feature);
+	vp_iowrite32(1, &cfg->guest_feature_select);
+	features |= ((u64)vp_ioread32(&cfg->guest_feature) << 32);
+
+	return features;
+}
+EXPORT_SYMBOL_GPL(vp_modern_get_driver_features);
+
 /*
  * vp_modern_set_features - set features to device
  * @mdev: the modern virtio-pci device
diff --git a/include/linux/virtio_pci_modern.h
b/include/linux/virtio_pci_modern.h
index 6a95b58fd0f4..eb2bd9b4077d 100644
--- a/include/linux/virtio_pci_modern.h
+++ b/include/linux/virtio_pci_modern.h
@@ -79,6 +79,7 @@ static inline void vp_iowrite64_twopart(u64 val,
 }
 
 u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev);
+u64 vp_modern_get_driver_features(struct virtio_pci_modern_device *mdev);
 void vp_modern_set_features(struct virtio_pci_modern_device *mdev,
 		     u64 features);
 u32 vp_modern_generation(struct virtio_pci_modern_device *mdev);
-- 
2.25.1

Jason Wang

2021-Jun-01 08:45 UTC

head link

[PATCH 3/4] vp_vdpa: allow set vq state to initial state after reset

We used to fail the set_vq_state() since it was not supported yet by
the virtio spec. But if the bus tries to set the state which is equal
to the device initial state after reset, we can let it go.

This is a must for virtio_vdpa() to set vq state during probe which is
required for some vDPA parents.

Signed-off-by: Jason Wang <jasowang at redhat.com>
---
 drivers/vdpa/virtio_pci/vp_vdpa.c | 42 ++++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 3 deletions(-)

diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c
b/drivers/vdpa/virtio_pci/vp_vdpa.c
index c76ebb531212..18bf4a422772 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -210,13 +210,49 @@ static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa,
u16 qid,
 	return -EOPNOTSUPP;
 }
 
+static int vp_vdpa_set_vq_state_split(struct vdpa_device *vdpa,
+				      const struct vdpa_vq_state *state)
+{
+	const struct vdpa_vq_state_split *split = &state->split;
+
+	if (split->avail_index == 0)
+		return 0;
+
+	return -EOPNOTSUPP;
+}
+
+static int vp_vdpa_set_vq_state_packed(struct vdpa_device *vdpa,
+				       const struct vdpa_vq_state *state)
+{
+	const struct vdpa_vq_state_packed *packed = &state->packed;
+
+	if (packed->last_avail_counter == 1 &&
+	    packed->last_avail_idx == 0 &&
+	    packed->last_used_counter == 1 &&
+	    packed->last_used_idx == 0)
+		return 0;
+
+	return -EOPNOTSUPP;
+}
+
 static int vp_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 qid,
 				const struct vdpa_vq_state *state)
 {
-	/* Note that this is not supported by virtio specification, so
-	 * we return -ENOPOTSUPP here. This means we can't support live
-	 * migration, vhost device start/stop.
+	struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
+
+	/* Note that this is not supported by virtio specification.
+	 * But if the state is by chance equal to the device initial
+	 * state, we can let it go.
 	 */
+	if ((vp_modern_get_status(mdev) & VIRTIO_CONFIG_S_FEATURES_OK) &&
+	    !vp_modern_get_queue_enable(mdev, qid)) {
+		if (vp_modern_get_driver_features(mdev) &
+		    BIT_ULL(VIRTIO_F_RING_PACKED))
+			return vp_vdpa_set_vq_state_packed(vdpa, state);
+		else
+			return vp_vdpa_set_vq_state_split(vdpa,	state);
+	}
+
 	return -EOPNOTSUPP;
 }
 
-- 
2.25.1

Jason Wang

2021-Jun-01 08:45 UTC

head link

[PATCH 4/4] virtio/vdpa: clear the virtqueue state during probe

From: Eli Cohen <elic at nvidia.com>

Clear the available index as part of the initialization process to
clear and values that might be left from previous usage of the device.
For example, if the device was previously used by vhost_vdpa and now
probed by vhost_vdpa, you want to start with indices.

Fixes: c043b4a8cf3b ("virtio: introduce a vDPA based transport")
Signed-off-by: Eli Cohen <elic at nvidia.com>
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
 drivers/virtio/virtio_vdpa.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
index e28acf482e0c..e1a141135992 100644
--- a/drivers/virtio/virtio_vdpa.c
+++ b/drivers/virtio/virtio_vdpa.c
@@ -142,6 +142,8 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned
int index,
 	struct vdpa_callback cb;
 	struct virtqueue *vq;
 	u64 desc_addr, driver_addr, device_addr;
+	/* Assume split virtqueue, switch to packed if necessary */
+	struct vdpa_vq_state state = {0};
 	unsigned long flags;
 	u32 align, num;
 	int err;
@@ -191,6 +193,19 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned
int index,
 		goto err_vq;
 	}
 
+	/* reset virtqueue state index */
+	if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
+		struct vdpa_vq_state_packed *s = &state.packed;
+
+		s->last_avail_counter = 1;
+		s->last_avail_idx = 0;
+		s->last_used_counter = 1;
+		s->last_used_idx = 0;
+	}
+	err = ops->set_vq_state(vdpa, index, &state);
+	if (err)
+		goto err_vq;
+
 	ops->set_vq_ready(vdpa, index, 1);
 
 	vq->priv = info;
-- 
2.25.1

Virtualization - Jun 2021 - [PATCH 1/4] vdpa: support packed virtqueue for set/get_vq_state()

[PATCH 0/4] Packed virtqueue state support for vDPA

[PATCH 1/4] vdpa: support packed virtqueue for set/get_vq_state()

[PATCH 2/4] virtio-pci library: introduce vp_modern_get_driver_features()

[PATCH 3/4] vp_vdpa: allow set vq state to initial state after reset

[PATCH 4/4] virtio/vdpa: clear the virtqueue state during probe