Re: [PATCH v7 2/4] vdpa: Allow for printing negotiated features of a device

On 3/15/22 5:35 AM, Eli Cohen wrote:

quoted

quoted

+};
+
+#define VIRTIO_F_IN_ORDER 35
+#define VIRTIO_F_NOTIFICATION_DATA 38
+#define VDPA_EXT_FEATURES_SZ (VIRTIO_TRANSPORT_F_END - \
+			      VIRTIO_TRANSPORT_F_START + 1)
+
+static const char * const ext_feature_strs[VDPA_EXT_FEATURES_SZ] = {
+	[VIRTIO_RING_F_INDIRECT_DESC - VIRTIO_TRANSPORT_F_START] = "RING_INDIRECT_DESC",
+	[VIRTIO_RING_F_EVENT_IDX - VIRTIO_TRANSPORT_F_START] = "RING_EVENT_IDX",
+	[VIRTIO_F_VERSION_1 - VIRTIO_TRANSPORT_F_START] = "VERSION_1",
+	[VIRTIO_F_ACCESS_PLATFORM - VIRTIO_TRANSPORT_F_START] = "ACCESS_PLATFORM",
+	[VIRTIO_F_RING_PACKED - VIRTIO_TRANSPORT_F_START] = "RING_PACKED",
+	[VIRTIO_F_IN_ORDER - VIRTIO_TRANSPORT_F_START] = "IN_ORDER",
+	[VIRTIO_F_ORDER_PLATFORM - VIRTIO_TRANSPORT_F_START] = "ORDER_PLATFORM",
+	[VIRTIO_F_SR_IOV - VIRTIO_TRANSPORT_F_START] = "SR_IOV",
+	[VIRTIO_F_NOTIFICATION_DATA - VIRTIO_TRANSPORT_F_START] = "NOTIFICATION_DATA",

and the entries here should be a macro to handle the
VIRTIO_TRANSPORT_F_START  offset with column aligned strings.

I guess I could define a macro here if all the flags would start with "VIRTIO_F_ =" but unfortunately,
the first two flags don't follow this pattern.
I could send kernel patches to replace VIRTIO_RING_F_INDIRECT_DESC and
VIRTIO_RING_F_EVENT_IDX to VIRTIO_F_RING_INDIRECT_DESC and VIRTIO_F_RING_EVENT_IDX
and then fix the format here.

If you meant something else, please be more specific.

It can still work with the existing naming - it's the redundant use of
VIRTIO_TRANSPORT_F_START as an offset that is hidden by the macro
allowing the feature to string conversion to be easier to read.