fix(iodispatcher): initialize virtio_requests_lock and hypercall context fields

Initialize client->virtio_requests_lock in bao_io_client_create().
Without explicitly initializing this mutex, the first lock operation
can trigger a breakpoint (BKP) exception on RISC-V due to operating
on an uninitialized lock structure.

Also explicitly initialize ctx.access_width and ctx.npend_req in
bao_dispatch_io() before issuing the hypercall. This avoids passing
uninitialized stack data to the hypervisor and makes the hypercall
context state fully defined.

These changes improve robustness and prevent runtime exceptions on
RISC-V systems.

Signed-off-by: João Peixoto <joaopeixotooficial@gmail.com>

Author: joaopeixoto13

iodispatcher/io_client.c

@@ -279,6 +279,7 @@ struct bao_io_client* bao_io_client_create(struct bao_dm* dm, bao_io_client_hand
     }
 
     INIT_LIST_HEAD(&client->virtio_requests);
+    mutex_init(&client->virtio_requests_lock);
     init_rwsem(&client->range_lock);
     INIT_LIST_HEAD(&client->range_list);
     init_waitqueue_head(&client->wq);

iodispatcher/io_dispatcher.c

@@ -63,6 +63,8 @@ int bao_dispatch_io(struct bao_dm* dm)
     ctx.addr = 0;
     ctx.value = 0;
     ctx.request_id = 0;
+    ctx.access_width = 0;
+    ctx.npend_req = 0;
 
     if (bao_remio_hypercall(&ctx)) {
         return -EFAULT;