Re: [PATCH v8 05/12] virtio-sound: handle VIRTIO_SND_R_PCM_INFO request

[Philippe Mathieu-Daudé]

On 28/8/23 21:55, Emmanouil Pitsidianakis wrote:

Respond to the VIRTIO_SND_R_PCM_INFO control request with the parameters
of each requested PCM stream.

Based-on: 
https://github.com/OpenSynergy/qemu/commit/5a2f350eec5d157b90d9c7b40a8e603f4da92471
Signed-off-by: Igor Skalkin <igor.skal...@opensynergy.com>
Signed-off-by: Anton Yakovlev <anton.yakov...@opensynergy.com>
Signed-off-by: Emmanouil Pitsidianakis <manos.pitsidiana...@linaro.org>
---
  hw/virtio/trace-events |  1 +
  hw/virtio/virtio-snd.c | 76 ++++++++++++++++++++++++++++++++++++++++++
  2 files changed, 77 insertions(+)

+/*
+ * Handle the VIRTIO_SND_R_PCM_INFO request.
+ * The function writes the info structs to the request element.
+ *
+ * @s: VirtIOSound device
+ * @cmd: The request command queue element from VirtIOSound cmdq field
+ */
+static void virtio_snd_handle_pcm_info(VirtIOSound *s,
+                                       virtio_snd_ctrl_command *cmd)
+{
+    virtio_snd_query_info req;
+    VirtIOSoundPCMStream *stream = NULL;
+    g_autofree virtio_snd_pcm_info *pcm_info = NULL;
+    size_t sz = iov_to_buf(cmd->elem->out_sg,
+                           cmd->elem->out_num,
+                           0,
+                           &req,
+                           sizeof(req));
+    if (sz != sizeof(virtio_snd_query_info)) {
+        cmd->resp.code = VIRTIO_SND_S_BAD_MSG;
+        return;
+    }
+
+    if (iov_size(cmd->elem->in_sg, cmd->elem->in_num) <
+        sizeof(virtio_snd_hdr) + req.size * req.count) {
+        error_report("pcm info: buffer too small, got: %zu, needed: %zu",
+                iov_size(cmd->elem->in_sg, cmd->elem->in_num),
+                sizeof(virtio_snd_pcm_info));
+        cmd->resp.code = VIRTIO_SND_S_BAD_MSG;
+        return;
+    }
+
+    pcm_info = g_new0(virtio_snd_pcm_info, req.count);
+    for (uint32_t i = req.start_id; i < req.start_id + req.count; i++) {

Starting from req.start_id seems to increase this code complexity.

+        trace_virtio_snd_handle_pcm_info(i);
+        stream = virtio_snd_pcm_get_stream(s, i);
+
+        if (!stream) {
+            error_report("Invalid stream id: %"PRIu32, i);
+            cmd->resp.code = VIRTIO_SND_S_BAD_MSG;
+            return;
+        }
+
+        pcm_info[i - req.start_id].hdr.hda_fn_nid = 
stream->info.hdr.hda_fn_nid;
+        pcm_info[i - req.start_id].features = stream->features;
+        pcm_info[i - req.start_id].formats = stream->formats;
+        pcm_info[i - req.start_id].rates = stream->rates;
+        pcm_info[i - req.start_id].direction = stream->direction;
+        pcm_info[i - req.start_id].channels_min = stream->channels_min;
+        pcm_info[i - req.start_id].channels_max = stream->channels_max;
+    }
+
+    cmd->resp.code = VIRTIO_SND_S_OK;
+
+    iov_from_buf(cmd->elem->in_sg,
+                 cmd->elem->in_num,
+                 sizeof(virtio_snd_hdr),
+                 pcm_info,
+                 sizeof(virtio_snd_pcm_info) * req.count);
+}