On Thu, 30 Jun 2022 14:35:38 +0800, Jason Wang [off-list ref] wrote:

On Wed, Jun 29, 2022 at 2:57 PM Xuan Zhuo [off-list ref] wrote:

quoted

Record the maximum queue num supported by the device.

virtio-net can display the maximum (supported by hardware) ring size in
ethtool -g eth0.

When the subsequent patch implements vring reset, it can judge whether
the ring size passed by the driver is legal based on this.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 arch/um/drivers/virtio_uml.c             |  1 +
 drivers/platform/mellanox/mlxbf-tmfifo.c |  2 ++
 drivers/remoteproc/remoteproc_virtio.c   |  2 ++
 drivers/s390/virtio/virtio_ccw.c         |  3 +++
 drivers/virtio/virtio_mmio.c             |  2 ++
 drivers/virtio/virtio_pci_legacy.c       |  2 ++
 drivers/virtio/virtio_pci_modern.c       |  2 ++
 drivers/virtio/virtio_ring.c             | 14 ++++++++++++++
 drivers/virtio/virtio_vdpa.c             |  2 ++
 include/linux/virtio.h                   |  2 ++
 10 files changed, 32 insertions(+)

diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index 82ff3785bf69..e719af8bdf56 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c

@@ -958,6 +958,7 @@ static struct virtqueue *vu_setup_vq(struct virtio_device *vdev,
                goto error_create;
        }
        vq->priv = info;
+       vq->num_max = num;
        num = virtqueue_get_vring_size(vq);

        if (vu_dev->protocol_features &

diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c
index 38800e86ed8a..1ae3c56b66b0 100644
--- a/drivers/platform/mellanox/mlxbf-tmfifo.c
+++ b/drivers/platform/mellanox/mlxbf-tmfifo.c

@@ -959,6 +959,8 @@ static int mlxbf_tmfifo_virtio_find_vqs(struct virtio_device *vdev,
                        goto error;
                }

+               vq->num_max = vring->num;
+
                vqs[i] = vq;
                vring->vq = vq;
                vq->priv = vring;

diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index d43d74733f0a..0f7706e23eb9 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c

@@ -125,6 +125,8 @@ static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
                return ERR_PTR(-ENOMEM);
        }

+       vq->num_max = num;
+
        rvring->vq = vq;
        vq->priv = rvring;

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 161d3b141f0d..6b86d0280d6b 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c

@@ -530,6 +530,9 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
                err = -ENOMEM;
                goto out_err;
        }
+
+       vq->num_max = info->num;
+
        /* it may have been reduced */
        info->num = virtqueue_get_vring_size(vq);

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 083ff1eb743d..a20d5a6b5819 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c

@@ -403,6 +403,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
                goto error_new_virtqueue;
        }

+       vq->num_max = num;
+
        /* Activate the queue */
        writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
        if (vm_dev->version == 1) {

diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
index a5e5721145c7..2257f1b3d8ae 100644
--- a/drivers/virtio/virtio_pci_legacy.c
+++ b/drivers/virtio/virtio_pci_legacy.c

@@ -135,6 +135,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
        if (!vq)
                return ERR_PTR(-ENOMEM);

+       vq->num_max = num;
+
        q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
        if (q_pfn >> 32) {
                dev_err(&vp_dev->pci_dev->dev,

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 623906b4996c..e7e0b8c850f6 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c

@@ -218,6 +218,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
        if (!vq)
                return ERR_PTR(-ENOMEM);

+       vq->num_max = num;
+
        /* activate the queue */
        vp_modern_set_queue_size(mdev, index, virtqueue_get_vring_size(vq));
        vp_modern_queue_address(mdev, index, virtqueue_get_desc_addr(vq),

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index a5ec724c01d8..4cac600856ad 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c

@@ -2385,6 +2385,20 @@ void vring_transport_features(struct virtio_device *vdev)
 }
 EXPORT_SYMBOL_GPL(vring_transport_features);

+/**
+ * virtqueue_get_vring_max_size - return the max size of the virtqueue's vring
+ * @_vq: the struct virtqueue containing the vring of interest.
+ *
+ * Returns the max size of the vring.
+ *
+ * Unlike other operations, this need not be serialized.
+ */
+unsigned int virtqueue_get_vring_max_size(struct virtqueue *_vq)
+{
+       return _vq->num_max;
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_vring_max_size);
+
 /**
  * virtqueue_get_vring_size - return the size of the virtqueue's vring
  * @_vq: the struct virtqueue containing the vring of interest.

diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
index c40f7deb6b5a..9670cc79371d 100644
--- a/drivers/virtio/virtio_vdpa.c
+++ b/drivers/virtio/virtio_vdpa.c

@@ -183,6 +183,8 @@ virtio_vdpa_setup_vq(struct virtio_device *vdev, unsigned int index,
                goto error_new_virtqueue;
        }

+       vq->num_max = max_num;
+
        /* Setup virtqueue callback */
        cb.callback = callback ? virtio_vdpa_virtqueue_cb : NULL;
        cb.private = info;

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index d8fdf170637c..a82620032e43 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h

@@ -31,6 +31,7 @@ struct virtqueue {
        struct virtio_device *vdev;
        unsigned int index;
        unsigned int num_free;
+       unsigned int num_max;

A question, since we export virtqueue to drivers, this means they can
access vq->num_max directly.

So we probably don't need a helper here.

I think you are right.

Thanks.

Thanks

quoted

        void *priv;
 };

@@ -80,6 +81,7 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *vq);

 void *virtqueue_detach_unused_buf(struct virtqueue *vq);

+unsigned int virtqueue_get_vring_max_size(struct virtqueue *vq);
 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);

 bool virtqueue_is_broken(struct virtqueue *vq);
--

2.31.0