On Fri, Jul 29, 2022 at 05:35:09PM +0800, Zhu, Lingshan wrote:

On 7/29/2022 5:23 PM, Michael S. Tsirkin wrote:

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On Fri, Jul 29, 2022 at 05:20:17PM +0800, Zhu, Lingshan wrote:

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On 7/29/2022 5:17 PM, Michael S. Tsirkin wrote:

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On Fri, Jul 29, 2022 at 05:07:11PM +0800, Zhu, Lingshan wrote:

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On 7/29/2022 4:53 PM, Michael S. Tsirkin wrote:

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On Fri, Jul 01, 2022 at 09:28:26PM +0800, Zhu Lingshan wrote:

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This commit fixes spars warnings: cast to restricted __le16
in function vdpa_dev_net_config_fill() and
vdpa_fill_stats_rec()

Signed-off-by: Zhu Lingshan <redacted>
---
    drivers/vdpa/vdpa.c | 6 +++---
    1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 846dd37f3549..ed49fe46a79e 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c

@@ -825,11 +825,11 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
    		    config.mac))
    		return -EMSGSIZE;
-	val_u16 = le16_to_cpu(config.status);
+	val_u16 = __virtio16_to_cpu(true, config.status);
    	if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, val_u16))
    		return -EMSGSIZE;
-	val_u16 = le16_to_cpu(config.mtu);
+	val_u16 = __virtio16_to_cpu(true, config.mtu);
    	if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16))
    		return -EMSGSIZE;

Wrong on BE platforms with legacy interface, isn't it?
We generally don't handle legacy properly in VDPA so it's
not a huge deal, but maybe add a comment at least?

Sure, I can add a comment here: this is for modern devices only.

Thanks,
Zhu Lingshan

Hmm. what "this" is for modern devices only here?

this cast, for LE modern devices.

I think status existed in legacy for sure, and it's possible that
some legacy devices backported mtu and max_virtqueue_pairs otherwise
we would have these fields as __le not as __virtio, right?

yes, that's the reason why it is virtio_16 than just le16.

I may find a better solution to detect whether it is LE, or BE without a
virtio_dev structure.
Check whether vdpa_device->get_device_features() has VIRTIO_F_VERISON_1. If
the device offers _F_VERSION_1, then it is a LE device,
or it is a BE device, then we use __virtio16_to_cpu(false, config.status).

Does this look good?

No since the question is can be a legacy driver with a transitional
device.  I don't have a good idea yet. vhost has VHOST_SET_VRING_ENDIAN
and maybe we need something like this for config as well?

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@@ -911,7 +911,7 @@ static int vdpa_fill_stats_rec(struct vdpa_device *vdev, struct sk_buff *msg,
    	}
    	vdpa_get_config_unlocked(vdev, 0, &config, sizeof(config));
-	max_vqp = le16_to_cpu(config.max_virtqueue_pairs);
+	max_vqp = __virtio16_to_cpu(true, config.max_virtqueue_pairs);
    	if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP, max_vqp))
    		return -EMSGSIZE;

-- 
2.31.1