Suspect TX infinite loop root cause

The reason is that the number of payload is arbitrary.

Author: Cuda-Chen

virtio-snd.c

@@ -2,6 +2,7 @@
 #include <pthread.h>
 #include <stdio.h>
 #include <string.h>
+#include <inttypes.h>
 
 #define CNFA_IMPLEMENTATION
 #include "CNFA_sf.h"
@@ -679,19 +680,27 @@ static int virtio_snd_tx_desc_handler(virtio_snd_state_t *vsnd,
     struct virtq_desc vq_desc[VSND_DESC_CNT];
 
     /* Collect the descriptors */
-    for (int i = 0; i < VSND_DESC_CNT; i++) {
+    int i = 0;
+    while(true) {
         /* The size of the `struct virtq_desc` is 4 words */
         const uint32_t *desc = &vsnd->ram[queue->QueueDesc + desc_idx * 4];
 
         /* Retrieve the fields of current descriptor */
+        if(i < VSND_DESC_CNT) {
         vq_desc[i].addr = desc[0];
         vq_desc[i].len = desc[2];
         vq_desc[i].flags = desc[3];
+        }
         desc_idx = desc[3] >> 16; /* vq_desc[desc_cnt].next */
 
+        i++;
+        sleep(1);
+
         /* Leave the loop if next-flag is not set */
-        if (!(vq_desc[i].flags & VIRTIO_DESC_F_NEXT))
+        if (!(desc[3] & VIRTIO_DESC_F_NEXT)) {
+            fprintf(stderr, "index %" PRIu32 " no next flag\n", i);
             break;
+        }
     }
 
     fprintf(stderr, "TX process header\n");
@@ -701,18 +710,18 @@ static int virtio_snd_tx_desc_handler(virtio_snd_state_t *vsnd,
     uint32_t stream_id = request->stream_id;
     void *payload = (void *) ((uintptr_t) vsnd->ram + vq_desc[1].addr);
     virtio_snd_pcm_status_t *response =
-        (virtio_snd_pcm_status_t *) (uintptr_t) vsnd->ram + vq_desc[2].addr;
+        (virtio_snd_pcm_status_t *) ((uintptr_t) vsnd->ram + vq_desc[2].addr);
 
     /* Process the data */
     fprintf(stderr, "TX process header\n");
-    size_t sz = vsnd_props[stream_id].pp.buffer_bytes;
+    uint32_t sz = vsnd_props[stream_id].pp.buffer_bytes;
     memcpy(vsnd_props[stream_id].buf, payload, sz);
 
     /* Return the device status */
     fprintf(stderr, "TX return device status\n");
     response->status = VIRTIO_SND_S_OK;
     response->latency_bytes = 0; /* TODO: show the actual latency bytes */
-    *plen = sz;
+    *plen = vq_desc[1].len + sizeof(*response);
 
     return 0;
 }
@@ -896,8 +905,8 @@ static bool virtio_snd_reg_write(virtio_snd_state_t *vsnd,
                 break;
             case VSND_QUEUE_TX:
                 fprintf(stderr, "TX start\n");
-                /*virtio_queue_notify_handler(vsnd, value,
-                                            virtio_snd_tx_desc_handler);*/
+                virtio_queue_notify_handler(vsnd, value,
+                                            virtio_snd_tx_desc_handler);
                 fprintf(stderr, "TX end\n");
                 break;
             case VSND_QUEUE_EVT: