On 5/31/2021 3:56 PM, Jason Wang wrote:
在 2021/5/31 下午3:33, Zhu Lingshan 写道:
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@xxxxxxxxx>
---
drivers/vdpa/ifcvf/ifcvf_main.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c
b/drivers/vdpa/ifcvf/ifcvf_main.c
index ab0ab5cf0f6e..effb0e549135 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -413,6 +413,22 @@ 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_adapter *adapter = vdpa_to_adapter(vdpa_dev);
+ struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
+ struct pci_dev *pdev = adapter->pdev;
+ struct vdpa_notification_area area;
+
+ area.addr = vf->vring[idx].notify_pa;
+ area.size = PAGE_SIZE;
+ if (area.addr % PAGE_SIZE)
+ IFCVF_DBG(pdev, "vq %u doorbell address is not PAGE_SIZE
aligned\n", idx);
Let's leave the decision to upper layer by: (see
vp_vdpa_get_vq_notification)
area.addr = notify_pa;
area.size = notify_offset_multiplier;
Thanks
Hi Jason,
notify_offset_multiplier can be zero, means vqs share the same doorbell
address, distinguished by qid.
and in vdpa.c:
if (vma->vm_end - vma->vm_start != notify.size)
return -ENOTSUPP;
so a zero size would cause this feature failure.
mmap should work on at least a page, so if we really want "area.size =
notify_offset_multiplier;"
I think we should add some code in vdpa.c, like:
if(!notify.size)
notify.size = PAGE_SIZE;
sounds good?
Thanks
Zhu Lingshan
+
+ return area;
+}
+
/*
* IFCVF currently does't have on-chip IOMMU, so not
* implemented set_map()/dma_map()/dma_unmap()
@@ -440,6 +456,7 @@ 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)
