Thread (14 messages) 14 messages, 2 authors, 2022-09-27

Re: [PATCH V2 RESEND 1/6] vDPA: allow userspace to query features of a vDPA device

From: Jason Wang <jasowang@redhat.com>
Date: 2022-09-27 04:36:28
Also in: kvm, virtualization

On Tue, Sep 27, 2022 at 11:09 AM Zhu Lingshan [off-list ref] wrote:
quoted hunk ↗ jump to hunk
This commit adds a new vDPA netlink attribution
VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES. Userspace can query
features of vDPA devices through this new attr.

This commit invokes vdpa_config_ops.get_config()
rather than vdpa_get_config_unlocked() to read
the device config spcae, so no races in
vdpa_set_features_unlocked()

Userspace tool iproute2 example:
$ vdpa dev config show vdpa0
vdpa0: mac 00:e8:ca:11:be:05 link up link_announce false max_vq_pairs 4 mtu 1500
  negotiated_features MRG_RXBUF CTRL_VQ MQ VERSION_1 ACCESS_PLATFORM
  dev_features MTU MAC MRG_RXBUF CTRL_VQ MQ ANY_LAYOUT VERSION_1 ACCESS_PLATFORM

Signed-off-by: Zhu Lingshan <redacted>
---
 drivers/vdpa/vdpa.c       | 17 ++++++++++++-----
 include/uapi/linux/vdpa.h |  4 ++++
 2 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index c06c02704461..2035700d6fc8 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -491,6 +491,7 @@ static int vdpa_mgmtdev_fill(const struct vdpa_mgmt_dev *mdev, struct sk_buff *m
                err = -EMSGSIZE;
                goto msg_err;
        }
+
Nit: Unnecessary changes.
quoted hunk ↗ jump to hunk
        if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_SUPPORTED_FEATURES,
                              mdev->supported_features, VDPA_ATTR_PAD)) {
                err = -EMSGSIZE;
@@ -815,10 +816,10 @@ static int vdpa_dev_net_mq_config_fill(struct vdpa_device *vdev,
 static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg)
 {
        struct virtio_net_config config = {};
-       u64 features;
+       u64 features_device, features_driver;
        u16 val_u16;

-       vdpa_get_config_unlocked(vdev, 0, &config, sizeof(config));
+       vdev->config->get_config(vdev, 0, &config, sizeof(config));

        if (nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR, sizeof(config.mac),
                    config.mac))
@@ -832,12 +833,18 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
        if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16))
                return -EMSGSIZE;

-       features = vdev->config->get_driver_features(vdev);
-       if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES, features,
+       features_driver = vdev->config->get_driver_features(vdev);
+       if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES, features_driver,
+                             VDPA_ATTR_PAD))
+               return -EMSGSIZE;
It looks to me that those parts were removed in patch 2. I wonder if
it's better to reorder the patch to let patch 2 come first?

Thanks
quoted hunk ↗ jump to hunk
+
+       features_device = vdev->config->get_device_features(vdev);
+
+       if (nla_put_u64_64bit(msg, VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES, features_device,
                              VDPA_ATTR_PAD))
                return -EMSGSIZE;

-       return vdpa_dev_net_mq_config_fill(vdev, msg, features, &config);
+       return vdpa_dev_net_mq_config_fill(vdev, msg, features_driver, &config);
 }

 static int
diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
index 25c55cab3d7c..07474183fdb3 100644
--- a/include/uapi/linux/vdpa.h
+++ b/include/uapi/linux/vdpa.h
@@ -46,12 +46,16 @@ enum vdpa_attr {

        VDPA_ATTR_DEV_NEGOTIATED_FEATURES,      /* u64 */
        VDPA_ATTR_DEV_MGMTDEV_MAX_VQS,          /* u32 */
+       /* virtio features that are supported by the vDPA management device */
        VDPA_ATTR_DEV_SUPPORTED_FEATURES,       /* u64 */

        VDPA_ATTR_DEV_QUEUE_INDEX,              /* u32 */
        VDPA_ATTR_DEV_VENDOR_ATTR_NAME,         /* string */
        VDPA_ATTR_DEV_VENDOR_ATTR_VALUE,        /* u64 */

+       /* virtio features that are supported by the vDPA device */
+       VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES,  /* u64 */
+
        /* new attributes must be added above here */
        VDPA_ATTR_MAX,
 };
--
2.31.1
  
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