Re: [PATCH V2 3/3] vp_vdpa: support feature provisioning

[Jason Wang <jasowang@redhat.com>]

On Sat, Sep 24, 2022 at 4:11 AM Si-Wei Liu <si-wei.liu@oracle.com> wrote:
>
>
>
> On 9/21/2022 7:43 PM, Jason Wang wrote:
> > This patch allows the device features to be provisioned via
> > netlink. This is done by:
> >
> > 1) validating the provisioned features to be a subset of the parent
> >     features.
> > 2) clearing the features that is not wanted by the userspace
> >
> > For example:
> >
> > # vdpa mgmtdev show
> > pci/0000:02:00.0:
> >    supported_classes net
> >    max_supported_vqs 3
> >    dev_features CSUM GUEST_CSUM CTRL_GUEST_OFFLOADS MAC GUEST_TSO4
> >    GUEST_TSO6 GUEST_ECN GUEST_UFO HOST_TSO4 HOST_TSO6 HOST_ECN HOST_UFO
> >    MRG_RXBUF STATUS CTRL_VQ CTRL_RX CTRL_VLAN CTRL_RX_EXTRA
> >    GUEST_ANNOUNCE CTRL_MAC_ADDR RING_INDIRECT_DESC RING_EVENT_IDX
> >    VERSION_1 ACCESS_PLATFORM
> >
> > 1) provision vDPA device with all features that are supported by the virtio-pci
> >
> > # vdpa dev add name dev1 mgmtdev pci/0000:02:00.0
> > # vdpa dev config show
> > dev1: mac 52:54:00:12:34:56 link up link_announce false mtu 65535
> >    negotiated_features CSUM GUEST_CSUM CTRL_GUEST_OFFLOADS MAC
> >    GUEST_TSO4 GUEST_TSO6 GUEST_ECN GUEST_UFO HOST_TSO4 HOST_TSO6
> >    HOST_ECN HOST_UFO MRG_RXBUF STATUS CTRL_VQ CTRL_RX CTRL_VLAN
> >    GUEST_ANNOUNCE CTRL_MAC_ADDR RING_INDIRECT_DESC RING_EVENT_IDX
> >    VERSION_1 ACCESS_PLATFORM
> >
> > 2) provision vDPA device with a subset of the features
> >
> > # vdpa dev add name dev1 mgmtdev pci/0000:02:00.0 device_features 0x300020000
> > # dev1: mac 52:54:00:12:34:56 link up link_announce false mtu 65535
> >    negotiated_features CTRL_VQ VERSION_1 ACCESS_PLATFORM
> >
> > Reviewed-by: Eli Cohen <elic@nvidia.com>
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> >   drivers/vdpa/virtio_pci/vp_vdpa.c | 16 ++++++++++++++--
> >   1 file changed, 14 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> > index 04522077735b..4b28e0c95ba2 100644
> > --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> > +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> > @@ -17,6 +17,7 @@
> >   #include <linux/virtio_ring.h>
> >   #include <linux/virtio_pci.h>
> >   #include <linux/virtio_pci_modern.h>
> > +#include <uapi/linux/vdpa.h>
> >
> >   #define VP_VDPA_QUEUE_MAX 256
> >   #define VP_VDPA_DRIVER_NAME "vp_vdpa"
> > @@ -35,6 +36,7 @@ struct vp_vdpa {
> >       struct virtio_pci_modern_device *mdev;
> >       struct vp_vring *vring;
> >       struct vdpa_callback config_cb;
> > +     u64 device_features;
> >       char msix_name[VP_VDPA_NAME_SIZE];
> >       int config_irq;
> >       int queues;
> > @@ -66,9 +68,9 @@ static struct virtio_pci_modern_device *vp_vdpa_to_mdev(struct vp_vdpa *vp_vdpa)
> >
> >   static u64 vp_vdpa_get_device_features(struct vdpa_device *vdpa)
> >   {
> > -     struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
> > +     struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
> >
> > -     return vp_modern_get_features(mdev);
> > +     return vp_vdpa->device_features;
> >   }
> >
> >   static int vp_vdpa_set_driver_features(struct vdpa_device *vdpa, u64 features)
> > @@ -475,6 +477,7 @@ static int vp_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
> >       struct pci_dev *pdev = mdev->pci_dev;
> >       struct device *dev = &pdev->dev;
> >       struct vp_vdpa *vp_vdpa = NULL;
> > +     u64 device_features;
> >       int ret, i;
> >
> >       vp_vdpa = vdpa_alloc_device(struct vp_vdpa, vdpa,
> > @@ -491,6 +494,14 @@ static int vp_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
> >       vp_vdpa->queues = vp_modern_get_num_queues(mdev);
> >       vp_vdpa->mdev = mdev;
> >
> > +     device_features = vp_modern_get_features(mdev);
> > +     if (add_config->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) {
> > +             if (add_config->device_features & ~device_features)
> > +                     return -EINVAL;
> Should use "goto err" rather than direct return. Also, would be the best
> to tell user the reason why device creation is failing. In the other
> places of the same function, dev_err() or dev_warn() is used.

Right, let me fix this.

Thanks

>
> -Siwei
>
> > +             device_features &= add_config->device_features;
> > +     }
> > +     vp_vdpa->device_features = device_features;
> > +
> >       ret = devm_add_action_or_reset(dev, vp_vdpa_free_irq_vectors, pdev);
> >       if (ret) {
> >               dev_err(&pdev->dev,
> > @@ -599,6 +610,7 @@ static int vp_vdpa_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> >       mgtdev->id_table = mdev_id;
> >       mgtdev->max_supported_vqs = vp_modern_get_num_queues(mdev);
> >       mgtdev->supported_features = vp_modern_get_features(mdev);
> > +     mgtdev->config_attr_mask = (1 << VDPA_ATTR_DEV_FEATURES);
> >       pci_set_master(pdev);
> >       pci_set_drvdata(pdev, vp_vdpa_mgtdev);
> >
>