Re: [PATCH v1] vdpa/vdpa_sim: Use the negotiated features when calling vringh_init_iotlb

From
Stefano Garzarella <sgarzare@redhat.com>
Date
2021-07-20 08:16:36
Also in
lkml
On Tue, Jul 20, 2021 at 10:14:35AM +0300, Eli Cohen wrote:
On Tue, Jul 20, 2021 at 08:57:40AM +0200, Stefano Garzarella wrote:
quoted
On Tue, Jul 20, 2021 at 08:25:33AM +0300, Eli Cohen wrote:
quoted
When calling vringh_init_iotlb(), use the negotiated features which
might be different than the supported features.

Fixes: 2c53d0f64c06f ("vdpasim: vDPA device simulator")
Signed-off-by: Eli Cohen <redacted>
---
v0 --> v1:
Update "Fixes" line

drivers/vdpa/vdpa_sim/vdpa_sim.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 14e024de5cbf..89a474c7a096 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -66,7 +66,7 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
{
	struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];

-	vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features,
+	vringh_init_iotlb(&vq->vring, vdpasim->features,
			  VDPASIM_QUEUE_MAX, false,
			  (struct vring_desc *)(uintptr_t)vq->desc_addr,
			  (struct vring_avail *)
@@ -86,7 +86,7 @@ static void vdpasim_vq_reset(struct vdpasim *vdpasim,
	vq->device_addr = 0;
	vq->cb = NULL;
	vq->private = NULL;
-	vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features,
+	vringh_init_iotlb(&vq->vring, vdpasim->features,
vdpasim_vq_reset() is called while resetting the device in vdpasim_reset()
where we also set `vdpasim->features = 0` after resetting the vqs, so maybe
it's better to use the supported features here, since the negotiated ones
are related to the previous instance.
I don't think using supported features is valid. Better to make sure
vringh_init_iotlb() is called after the features have been negotiated.
I think the vringh_init_iotlb() call in vdpasim_vq_reset() is just used to clean up the `struct vringh`, then it will be initialized in vdpasim_queue_ready() when features have already been negotiated.

Maybe here we can pass 0 (to the features parameter) if we don't want to use the features supported by the device.

Thanks,
Stefano

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Thread (2 messages) 2 messages, 2 authors, last reply 2021-08-10
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