在 2021/4/28 下午6:20, Zhu, Lingshan 写道:
On 4/28/2021 6:03 PM, Jason Wang wrote:
在 2021/4/28 下午5:56, Zhu, Lingshan 写道:
On 4/28/2021 5:21 PM, Jason Wang wrote:
在 2021/4/28 下午4:59, Zhu, Lingshan 写道:
On 4/28/2021 4:42 PM, Jason Wang wrote:
在 2021/4/28 下午4:21, 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 | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c
b/drivers/vdpa/ifcvf/ifcvf_main.c
index e48e6b74fe2e..afcb71bc0f51 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -413,6 +413,23 @@ 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;
+
+ if (vf->notify_pa % PAGE_SIZE) {
+ area.addr = 0;
+ area.size = 0;
We don't need this since:
1) there's a check in the vhost vDPA
I think you mean this code block in vdpa.c
notify = ops->get_vq_notification(vdpa, index);
if (notify.addr & (PAGE_SIZE - 1))
return -EINVAL;
This should work, however, I think the parent driver should ensure
it passes a PAGE_SIZE aligned address to userspace, to be robust,
to be reliable.
The point is parent is unaware of whether or not there's a userspace.
when calling this, I think it targets a usersapce program, why
kernel space need it, so IMHO no harm if we check this to keep the
parent driver robust.
Again, vDPA device is unaware of what driver that is bound. It could
be virtio-vpda, vhost-vdpa or other in the future. It's only the vDPA
bus driver know how it is actually used.
2) device is unaware of the bound driver, non page aligned
doorbell doesn't necessarily meant it can be used
Yes, non page aligned doorbell can not be used, so there is a check.
Typo, what I meant is "it can't be used". That is to say, we should
let the vDPA bus driver to decide whether or not it can be used.
If it is not page aligned, there would be extra complexities for
vhost/qemu, I see it as a hardware defect,
It is allowed by the virtio spec, isn't it?
The spec does not require the doorbell to be page size aligned,
however it still a hardware defect if non page size aligned notify
base present, I will leave a warning message here instead of the 0 value.
Another note is that, using PAGE_SIZE is wrong here since it varies
among archs (at most 64K on some one).
Thanks
Thanks
Zhu Lingshan
Thanks
why adapt to this kind of defects?
Thanks
Zhu Lingshan
Thanks
Thanks
Zhu Lingshan
Let's leave those polices to the driver.
Thanks
+ } else {
+ area.addr = vf->notify_pa;
+ area.size = PAGE_SIZE;
+ }
+
+ return area;
+}
+
/*
* IFCVF currently does't have on-chip IOMMU, so not
* implemented set_map()/dma_map()/dma_unmap()
@@ -440,6 +457,7 @@ 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)
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