Virtualization - Feb 2023 - [PATCH v3 0/6] features provisioning fixes and mlx5_vdpa support

This patchset is pre-requisite to export and provision device
config attributes and features for vdpa live migration, in a way
backward and forward compatibility can be retained. The follow up
work [1] will need to be built around the new feature provisioning
uAPI, with which it's easier to formalize migration compatibility
support at the driver level.

Thanks,
-Siwei

[1] [PATCH v3 0/4] vDPA: initial config export via "vdpa dev show"
https://lore.kernel.org/virtualization/1666392237-4042-1-git-send-email-si-wei.liu
at oracle.com/

---
v2 -> v3:
  - fix incorrect reference of local variable in future patch
  - prohibit per-device bitmask macro from exposure in uapi header
  - add fixes tag
v1 -> v2:
  - include specific attribute info to error message 
  - move conditional feature presence in mlx5_vdpa config space
    to a separate patch
  - remove redundant check
---

Si-Wei Liu (6):
  vdpa: fix improper error message when adding vdpa dev
  vdpa: conditionally read STATUS in config space
  vdpa: validate provisioned device features against specified attribute
  vdpa: validate device feature provisioning against supported class
  vdpa/mlx5: conditionally show MTU and STATUS in config space
  vdpa/mlx5: support device features provisioning

 drivers/vdpa/mlx5/net/mlx5_vnet.c |  71 +++++++++++++++++++++-----
 drivers/vdpa/vdpa.c               | 105 ++++++++++++++++++++++++++++++++------
 2 files changed, 146 insertions(+), 30 deletions(-)

-- 
1.8.3.1

In below example, before the fix, mtu attribute is supported
by the parent mgmtdev, but the error message showing "All
provided are not supported" is just misleading.

$ vdpa mgmtdev show
vdpasim_net:
  supported_classes net
  max_supported_vqs 3
  dev_features MTU MAC CTRL_VQ CTRL_MAC_ADDR ANY_LAYOUT VERSION_1
ACCESS_PLATFORM

$ vdpa dev add mgmtdev vdpasim_net name vdpasim0 mtu 5000 max_vqp 2
Error: vdpa: All provided attributes are not supported.
kernel answers: Operation not supported

After fix, the relevant error message will be like:

$ vdpa dev add mgmtdev vdpasim_net name vdpasim0 mtu 5000 max_vqp 2
Error: vdpa: Some provided attributes are not supported: 0x1000.
kernel answers: Operation not supported

Fixes: d8ca2fa5be1b ("vdpa: Enable user to set mac and mtu of vdpa
device")
Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
Reviewed-by: Parav Pandit <parav at nvidia.com>
Reviewed-by: Eli Cohen <elic at nvidia.com>
---
 drivers/vdpa/vdpa.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 8ef7aa1..3a82ca78 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -622,9 +622,11 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff
*skb, struct genl_info *i
 		err = PTR_ERR(mdev);
 		goto err;
 	}
+
 	if ((config.mask & mdev->config_attr_mask) != config.mask) {
-		NL_SET_ERR_MSG_MOD(info->extack,
-				   "All provided attributes are not supported");
+		NL_SET_ERR_MSG_FMT_MOD(info->extack,
+				       "Some provided attributes are not supported: 0x%llx",
+				       config.mask & ~mdev->config_attr_mask);
 		err = -EOPNOTSUPP;
 		goto err;
 	}
-- 
1.8.3.1

The spec says:
    status only exists if VIRTIO_NET_F_STATUS is set

Similar to MAC and MTU, vdpa_dev_net_config_fill() should read
STATUS conditionally depending on the feature bits.

Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
Reviewed-by: Parav Pandit <parav at nvidia.com>
---
 drivers/vdpa/vdpa.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 3a82ca78..21c8aa3 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -843,18 +843,25 @@ static int vdpa_dev_net_mac_config_fill(struct sk_buff
*msg, u64 features,
 			sizeof(config->mac), config->mac);
 }
 
+static int vdpa_dev_net_status_config_fill(struct sk_buff *msg, u64 features,
+					   const struct virtio_net_config *config)
+{
+	u16 val_u16;
+
+	if ((features & BIT_ULL(VIRTIO_NET_F_STATUS)) == 0)
+		return 0;
+
+	val_u16 = __virtio16_to_cpu(true, config->status);
+	return nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, val_u16);
+}
+
 static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff
*msg)
 {
 	struct virtio_net_config config = {};
 	u64 features_device;
-	u16 val_u16;
 
 	vdev->config->get_config(vdev, 0, &config, sizeof(config));
 
-	val_u16 = __virtio16_to_cpu(true, config.status);
-	if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, val_u16))
-		return -EMSGSIZE;
-
 	features_device = vdev->config->get_device_features(vdev);
 
 	if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_FEATURES, features_device,
@@ -867,6 +874,9 @@ static int vdpa_dev_net_config_fill(struct vdpa_device
*vdev, struct sk_buff *ms
 	if (vdpa_dev_net_mac_config_fill(msg, features_device, &config))
 		return -EMSGSIZE;
 
+	if (vdpa_dev_net_status_config_fill(msg, features_device, &config))
+		return -EMSGSIZE;
+
 	return vdpa_dev_net_mq_config_fill(msg, features_device, &config);
 }
 
-- 
1.8.3.1

With device feature provisioning, there's a chance for misconfiguration
that the vdpa feature attribute supplied in 'vdpa dev add' command
doesn't
get selected on the device_features to be provisioned. For instance, when
a @mac attribute is specified, the corresponding feature bit _F_MAC in
device_features should be set for consistency. If there's conflict on
provisioned features against the attribute, it should be treated as an
error to fail the ambiguous command. Noted the opposite is not
necessarily true, for e.g. it's okay to have _F_MAC set in device_features
without providing a corresponding @mac attribute, in which case the vdpa
vendor driver could load certain default value for attribute that is not
explicitly specified.

Generalize this check in vdpa core so that there's no duplicate code in
each vendor driver.

Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
---
 drivers/vdpa/vdpa.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 21c8aa3..1eba978 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -601,8 +601,26 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff
*skb, struct genl_info *i
 		config.mask |= BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP);
 	}
 	if (nl_attrs[VDPA_ATTR_DEV_FEATURES]) {
+		u64 missing = 0x0ULL;
+
 		config.device_features  			nla_get_u64(nl_attrs[VDPA_ATTR_DEV_FEATURES]);
+		if (nl_attrs[VDPA_ATTR_DEV_NET_CFG_MACADDR] &&
+		    !(config.device_features & BIT_ULL(VIRTIO_NET_F_MAC)))
+			missing |= BIT_ULL(VIRTIO_NET_F_MAC);
+		if (nl_attrs[VDPA_ATTR_DEV_NET_CFG_MTU] &&
+		    !(config.device_features & BIT_ULL(VIRTIO_NET_F_MTU)))
+			missing |= BIT_ULL(VIRTIO_NET_F_MTU);
+		if (nl_attrs[VDPA_ATTR_DEV_NET_CFG_MAX_VQP] &&
+		    config.net.max_vq_pairs > 1 &&
+		    !(config.device_features & BIT_ULL(VIRTIO_NET_F_MQ)))
+			missing |= BIT_ULL(VIRTIO_NET_F_MQ);
+		if (missing) {
+			NL_SET_ERR_MSG_FMT_MOD(info->extack,
+					       "Missing features 0x%llx for provided attributes",
+					       missing);
+			return -EINVAL;
+		}
 		config.mask |= BIT_ULL(VDPA_ATTR_DEV_FEATURES);
 	}
 
-- 
1.8.3.1

Today when device features are explicitly provisioned, the features
user supplied may contain device class specific features that are
not supported by the parent managment device. On the other hand,
when parent managment device supports more than one class, the
device features to provision may be ambiguous if none of the class
specific attributes is provided at the same time. Validate these
cases and prompt appropriate user errors accordingly.

Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
---
 drivers/vdpa/vdpa.c | 61 +++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 52 insertions(+), 9 deletions(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 1eba978..4aa2160 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -460,12 +460,30 @@ static int vdpa_nl_mgmtdev_handle_fill(struct sk_buff
*msg, const struct vdpa_mg
 	return 0;
 }
 
+static u64 vdpa_mgmtdev_get_classes(const struct vdpa_mgmt_dev *mdev,
+				    unsigned int *nclasses)
+{
+	u64 supported_classes = 0;
+	unsigned int n = 0;
+	int i = 0;
+
+	while (mdev->id_table[i].device) {
+		if (mdev->id_table[i].device <= 63) {
+			supported_classes |= BIT_ULL(mdev->id_table[i].device);
+			n++;
+		}
+		i++;
+	}
+	if (nclasses)
+		*nclasses = n;
+
+	return supported_classes;
+}
+
 static int vdpa_mgmtdev_fill(const struct vdpa_mgmt_dev *mdev, struct sk_buff
*msg,
 			     u32 portid, u32 seq, int flags)
 {
-	u64 supported_classes = 0;
 	void *hdr;
-	int i = 0;
 	int err;
 
 	hdr = genlmsg_put(msg, portid, seq, &vdpa_nl_family, flags,
VDPA_CMD_MGMTDEV_NEW);
@@ -475,14 +493,9 @@ static int vdpa_mgmtdev_fill(const struct vdpa_mgmt_dev
*mdev, struct sk_buff *m
 	if (err)
 		goto msg_err;
 
-	while (mdev->id_table[i].device) {
-		if (mdev->id_table[i].device <= 63)
-			supported_classes |= BIT_ULL(mdev->id_table[i].device);
-		i++;
-	}
-
 	if (nla_put_u64_64bit(msg, VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES,
-			      supported_classes, VDPA_ATTR_UNSPEC)) {
+			      vdpa_mgmtdev_get_classes(mdev, NULL),
+			      VDPA_ATTR_UNSPEC)) {
 		err = -EMSGSIZE;
 		goto msg_err;
 	}
@@ -566,13 +579,25 @@ static int vdpa_nl_cmd_mgmtdev_get_doit(struct sk_buff
*skb, struct genl_info *i
 				 BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU)     | \
 				 BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP))
 
+/*
+ * Bitmask for all per-device features: feature bits VIRTIO_TRANSPORT_F_START
+ * through VIRTIO_TRANSPORT_F_END are unset, i.e. 0xfffffc000fffffff for
+ * all 64bit features. If the features are extended beyond 64 bits, or new
+ * "holes" are reserved for other type of features than per-device,
this
+ * macro would have to be updated.
+ */
+#define VIRTIO_DEVICE_F_MASK (~0ULL << (VIRTIO_TRANSPORT_F_END + 1) | \
+			      ((1ULL << VIRTIO_TRANSPORT_F_START) - 1))
+
 static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info
*info)
 {
 	struct vdpa_dev_set_config config = {};
 	struct nlattr **nl_attrs = info->attrs;
 	struct vdpa_mgmt_dev *mdev;
+	unsigned int ncls = 0;
 	const u8 *macaddr;
 	const char *name;
+	u64 classes;
 	int err = 0;
 
 	if (!info->attrs[VDPA_ATTR_DEV_NAME])
@@ -649,6 +674,24 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff
*skb, struct genl_info *i
 		goto err;
 	}
 
+	classes = vdpa_mgmtdev_get_classes(mdev, &ncls);
+	if (config.mask & VDPA_DEV_NET_ATTRS_MASK &&
+	    !(classes & BIT_ULL(VIRTIO_ID_NET))) {
+		NL_SET_ERR_MSG_MOD(info->extack,
+				   "Network class attributes provided on unsupported management
device");
+		err = -EINVAL;
+		goto err;
+	}
+	if (!(config.mask & VDPA_DEV_NET_ATTRS_MASK) &&
+	    config.mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES) &&
+	    classes & BIT_ULL(VIRTIO_ID_NET) && ncls > 1 &&
+	    config.device_features & VIRTIO_DEVICE_F_MASK) {
+		NL_SET_ERR_MSG_MOD(info->extack,
+				   "Management device supports multi-class while device features
specified are ambiguous");
+		err = -EINVAL;
+		goto err;
+	}
+
 	err = mdev->ops->dev_add(mdev, name, &config);
 err:
 	up_write(&vdpa_dev_lock);
-- 
1.8.3.1

The spec says:
    mtu only exists if VIRTIO_NET_F_MTU is set
    status only exists if VIRTIO_NET_F_STATUS is set

We should only show MTU and STATUS conditionally depending on
the feature bits.

Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
---
 drivers/vdpa/mlx5/net/mlx5_vnet.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 3a6dbbc6..867ac18 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -3009,6 +3009,8 @@ static int event_handler(struct notifier_block *nb,
unsigned long event, void *p
 	struct mlx5_vdpa_wq_ent *wqent;
 
 	if (event == MLX5_EVENT_TYPE_PORT_CHANGE) {
+		if (!(ndev->mvdev.actual_features & BIT_ULL(VIRTIO_NET_F_STATUS)))
+			return NOTIFY_DONE;
 		switch (eqe->sub_type) {
 		case MLX5_PORT_CHANGE_SUBTYPE_DOWN:
 		case MLX5_PORT_CHANGE_SUBTYPE_ACTIVE:
@@ -3118,16 +3120,20 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev
*v_mdev, const char *name,
 			goto err_alloc;
 	}
 
-	err = query_mtu(mdev, &mtu);
-	if (err)
-		goto err_alloc;
+	if (ndev->mvdev.mlx_features & BIT_ULL(VIRTIO_NET_F_MTU)) {
+		err = query_mtu(mdev, &mtu);
+		if (err)
+			goto err_alloc;
 
-	ndev->config.mtu = cpu_to_mlx5vdpa16(mvdev, mtu);
+		ndev->config.mtu = cpu_to_mlx5vdpa16(mvdev, mtu);
+	}
 
-	if (get_link_state(mvdev))
-		ndev->config.status |= cpu_to_mlx5vdpa16(mvdev, VIRTIO_NET_S_LINK_UP);
-	else
-		ndev->config.status &= cpu_to_mlx5vdpa16(mvdev,
~VIRTIO_NET_S_LINK_UP);
+	if (ndev->mvdev.mlx_features & BIT_ULL(VIRTIO_NET_F_STATUS)) {
+		if (get_link_state(mvdev))
+			ndev->config.status |= cpu_to_mlx5vdpa16(mvdev, VIRTIO_NET_S_LINK_UP);
+		else
+			ndev->config.status &= cpu_to_mlx5vdpa16(mvdev,
~VIRTIO_NET_S_LINK_UP);
+	}
 
 	if (add_config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR)) {
 		memcpy(ndev->config.mac, add_config->net.mac, ETH_ALEN);
-- 
1.8.3.1

This patch implements features provisioning for mlx5_vdpa.

1) Validate the provisioned features are a subset of the parent
    features.
2) Clearing features that are not wanted by userspace.

For example:

    # vdpa mgmtdev show
    pci/0000:41:04.2:
      supported_classes net
      max_supported_vqs 65
      dev_features CSUM GUEST_CSUM MTU MAC HOST_TSO4 HOST_TSO6 STATUS CTRL_VQ
CTRL_VLAN MQ CTRL_MAC_ADDR VERSION_1 ACCESS_PLATFORM

1) Provision vDPA device with all features derived from the parent

    # vdpa dev add name vdpa1 mgmtdev pci/0000:41:04.2
    # vdpa dev config show
    vdpa1: mac e4:11:c6:d3:45:f0 link up link_announce false max_vq_pairs 1 mtu
1500
      negotiated_features CSUM GUEST_CSUM MTU HOST_TSO4 HOST_TSO6 STATUS CTRL_VQ
CTRL_VLAN MQ CTRL_MAC_ADDR VERSION_1 ACCESS_PLATFORM

2) Provision vDPA device with a subset of parent features

    # vdpa dev add name vdpa1 mgmtdev pci/0000:41:04.2 device_features
0x300020000
    # vdpa dev config show
    vdpa1:
      negotiated_features CTRL_VQ VERSION_1 ACCESS_PLATFORM

Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
---
 drivers/vdpa/mlx5/net/mlx5_vnet.c | 53 +++++++++++++++++++++++++++++++++------
 1 file changed, 45 insertions(+), 8 deletions(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 867ac18..b40dd1a 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2183,6 +2183,7 @@ static u64 get_supported_features(struct mlx5_core_dev
*mdev)
 	mlx_vdpa_features |= BIT_ULL(VIRTIO_NET_F_STATUS);
 	mlx_vdpa_features |= BIT_ULL(VIRTIO_NET_F_MTU);
 	mlx_vdpa_features |= BIT_ULL(VIRTIO_NET_F_CTRL_VLAN);
+	mlx_vdpa_features |= BIT_ULL(VIRTIO_NET_F_MAC);
 
 	return mlx_vdpa_features;
 }
@@ -3062,6 +3063,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev,
const char *name,
 	struct mlx5_vdpa_dev *mvdev;
 	struct mlx5_vdpa_net *ndev;
 	struct mlx5_core_dev *mdev;
+	u64 device_features;
 	u32 max_vqs;
 	u16 mtu;
 	int err;
@@ -3070,6 +3072,24 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev
*v_mdev, const char *name,
 		return -ENOSPC;
 
 	mdev = mgtdev->madev->mdev;
+	device_features = mgtdev->mgtdev.supported_features;
+	if (add_config->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) {
+		if (add_config->device_features & ~device_features) {
+			dev_warn(mdev->device,
+				 "The provisioned features 0x%llx are not supported by this device
with features 0x%llx\n",
+				 add_config->device_features, device_features);
+			return -EINVAL;
+		}
+		device_features &= add_config->device_features;
+	}
+	if (!(device_features & BIT_ULL(VIRTIO_F_VERSION_1) &&
+	      device_features & BIT_ULL(VIRTIO_F_ACCESS_PLATFORM))) {
+		dev_warn(mdev->device,
+			 "Must provision minimum features 0x%llx for this device",
+			 BIT_ULL(VIRTIO_F_VERSION_1) | BIT_ULL(VIRTIO_F_ACCESS_PLATFORM));
+		return -EOPNOTSUPP;
+	}
+
 	if (!(MLX5_CAP_DEV_VDPA_EMULATION(mdev, virtio_queue_type) &
 	    MLX5_VIRTIO_EMULATION_CAP_VIRTIO_QUEUE_TYPE_SPLIT)) {
 		dev_warn(mdev->device, "missing support for split
virtqueues\n");
@@ -3098,7 +3118,6 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev,
const char *name,
 	if (IS_ERR(ndev))
 		return PTR_ERR(ndev);
 
-	ndev->mvdev.mlx_features = mgtdev->mgtdev.supported_features;
 	ndev->mvdev.max_vqs = max_vqs;
 	mvdev = &ndev->mvdev;
 	mvdev->mdev = mdev;
@@ -3120,7 +3139,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev,
const char *name,
 			goto err_alloc;
 	}
 
-	if (ndev->mvdev.mlx_features & BIT_ULL(VIRTIO_NET_F_MTU)) {
+	if (device_features & BIT_ULL(VIRTIO_NET_F_MTU)) {
 		err = query_mtu(mdev, &mtu);
 		if (err)
 			goto err_alloc;
@@ -3128,7 +3147,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev,
const char *name,
 		ndev->config.mtu = cpu_to_mlx5vdpa16(mvdev, mtu);
 	}
 
-	if (ndev->mvdev.mlx_features & BIT_ULL(VIRTIO_NET_F_STATUS)) {
+	if (device_features & BIT_ULL(VIRTIO_NET_F_STATUS)) {
 		if (get_link_state(mvdev))
 			ndev->config.status |= cpu_to_mlx5vdpa16(mvdev, VIRTIO_NET_S_LINK_UP);
 		else
@@ -3137,7 +3156,9 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev,
const char *name,
 
 	if (add_config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR)) {
 		memcpy(ndev->config.mac, add_config->net.mac, ETH_ALEN);
-	} else {
+	/* No bother setting mac address in config if not going to provision _F_MAC */
+	} else if ((add_config->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) == 0 ||
+		   device_features & BIT_ULL(VIRTIO_NET_F_MAC)) {
 		err = mlx5_query_nic_vport_mac_address(mdev, 0, 0, config->mac);
 		if (err)
 			goto err_alloc;
@@ -3148,11 +3169,26 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev
*v_mdev, const char *name,
 		err = mlx5_mpfs_add_mac(pfmdev, config->mac);
 		if (err)
 			goto err_alloc;
-
-		ndev->mvdev.mlx_features |= BIT_ULL(VIRTIO_NET_F_MAC);
+	} else if ((add_config->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) == 0) {
+		/*
+		 * We used to clear _F_MAC feature bit if seeing
+		 * zero mac address when device features are not
+		 * specifically provisioned. Keep the behaviour
+		 * so old scripts do not break.
+		 */
+		device_features &= ~BIT_ULL(VIRTIO_NET_F_MAC);
+	} else if (device_features & BIT_ULL(VIRTIO_NET_F_MAC)) {
+		/* Don't provision zero mac address for _F_MAC */
+		mlx5_vdpa_warn(&ndev->mvdev,
+			       "No mac address provisioned?\n");
+		err = -EINVAL;
+		goto err_alloc;
 	}
 
-	config->max_virtqueue_pairs = cpu_to_mlx5vdpa16(mvdev, max_vqs / 2);
+	if (device_features & BIT_ULL(VIRTIO_NET_F_MQ))
+		config->max_virtqueue_pairs = cpu_to_mlx5vdpa16(mvdev, max_vqs / 2);
+
+	ndev->mvdev.mlx_features = device_features;
 	mvdev->vdev.dma_dev = &mdev->pdev->dev;
 	err = mlx5_vdpa_alloc_resources(&ndev->mvdev);
 	if (err)
@@ -3249,7 +3285,8 @@ static int mlx5v_probe(struct auxiliary_device *adev,
 	mgtdev->mgtdev.id_table = id_table;
 	mgtdev->mgtdev.config_attr_mask = BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MACADDR) |
 					  BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP) |
-					  BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU);
+					  BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) |
+					  BIT_ULL(VDPA_ATTR_DEV_FEATURES);
 	mgtdev->mgtdev.max_supported_vqs  		MLX5_CAP_DEV_VDPA_EMULATION(mdev,
max_num_virtio_queues) + 1;
 	mgtdev->mgtdev.supported_features = get_supported_features(mdev);
-- 
1.8.3.1