vDPA/ifcvf: implement doorbell mapping for ifcvf

This commit implements doorbell mapping feature for ifcvf.
This feature maps the notify page to userspace, to eliminate
vmexit when kick a vq.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Link: https://lore.kernel.org/r/20210602084550.289599-3-lingshan.zhu@intel.com
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index ab0ab5c..46a992e 100644 (file)
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -413,6 +413,21 @@ static int ifcvf_vdpa_get_vq_irq(struct vdpa_device *vdpa_dev,
        return vf->vring[qid].irq;
 }
 
+static struct vdpa_notification_area ifcvf_get_vq_notification(struct vdpa_device *vdpa_dev,
+                                                              u16 idx)
+{
+       struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
+       struct vdpa_notification_area area;
+
+       area.addr = vf->vring[idx].notify_pa;
+       if (!vf->notify_off_multiplier)
+               area.size = PAGE_SIZE;
+       else
+               area.size = vf->notify_off_multiplier;
+
+       return area;
+}
+
 /*
  * IFCVF currently does't have on-chip IOMMU, so not
  * implemented set_map()/dma_map()/dma_unmap()
@@ -440,6 +455,7 @@ static const struct vdpa_config_ops ifc_vdpa_ops = {
        .get_config     = ifcvf_vdpa_get_config,
        .set_config     = ifcvf_vdpa_set_config,
        .set_config_cb  = ifcvf_vdpa_set_config_cb,
+       .get_vq_notification = ifcvf_get_vq_notification,
 };
 
 static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)