Delete virtio_sound_counts, whose count host scheduling sets

issues/soundservers-virtio-sound-stream-is-played-by-no-guest-test.md

@@ -0,0 +1,30 @@
+---
+status: open
+kind: tooling
+opened: 2026-10-10
+---
+
+# soundserver's virtio-sound stream is played by no guest test
+
+No guest test plays a stream through soundserver's own virtio-sound driver
+(`userland/soundserver/src/virtio.rs`, driven by the device loop in
+`userland/soundserver/src/mix.rs`). `iommu_virtio_platform` reaches its
+bring-up and stops there; `toyos-virtio-sound`'s host tests reach the driver
+crate, not the interrupt-driven loop. Three behaviours of that path go unseen:
+
+- the order of its lines: `virtio-sound: stream 0 started` once, after the
+  client connects, then `virtio-sound: stream 0 stopped` once, then
+  `soundserver: suspended`;
+- the suspend comes only once every submitted period has completed
+  (`unplayed == 0` in the suspend block of `mix.rs`);
+- the suspend is reached through the claim's interrupts: with no client the
+  loop's wait has no timeout, so a transmit queue with no vector leaves the
+  stream `running`.
+
+`virtio_sound_counts` asserted all three, beside a count of submitted against
+filled periods that host scheduling sets; it was deleted whole for the count.
+
+Owner: the orchestrator, which dispatches it. Exit: a QEMU guest test plays a
+stream through soundserver's virtio-sound driver and asserts only the three
+behaviours above, by order and completion, never a count or a time beyond a
+hang ceiling; and the test reds when the transmit queue's vector is withheld.

tests/toyos.rs

@@ -186,10 +186,6 @@ const RUST_SKIP: &[&str] = &[
     // It claims QEMU's virtio NIC, which the T14 has none of: `bar_map_again`
     // runs it.
     "bar_map_again",
-    // It plays through soundserver's virtio-sound driver, which the T14 has no
-    // device for, and its counts are judged beside soundserver's lines:
-    // `virtio_sound_counts` runs it.
-    "virtio_sound_counts",
     // It claims the NVMe controller a boot off that disk starts no server
     // for, and reads the inventory: `block_grants_reach_their_partitions`
     // runs it on tests/blockgrantcase.
@@ -384,10 +380,6 @@ const MACHINE_TESTS: &[&str] = &[
     // function is its I219, and a kernel that dies on this takes the bench's
     // machine down with it.
     "bar_map_again",
-    // A stream through soundserver's own virtio-sound driver, counted and
-    // ordered: the device exists only on a QEMU machine — the T14's sound is
-    // HDA — and its audio goes nowhere, since no guest test plays any.
-    "virtio_sound_counts",
     // `console/system.toml`'s image, which runs no job and hands no machine
     // back: a metal boot of it ends with a hand on the power button.
     "console_image_boots",
@@ -3758,7 +3750,6 @@ fn run_machine_test(name: &str, test_config: &Path) -> Result<(), String> {
         "machine_shutdown_wire_kept" => power::machine_shutdown_wire_held(test_config, true),
         "machine_shutdown_wire_at_the_seal" => power::machine_shutdown_wire_at_the_seal(test_config),
         "bar_map_again" => bar_map_again(test_config),
-        "virtio_sound_counts" => virtio_sound_counts(test_config),
         "console_image_boots" => console_image_boots(),
         "nvme_disk_keeps_log_and_home" => nvme_disk_keeps_log_and_home(test_config),
         "block_grants_reach_their_partitions" => block_grants_reach_their_partitions(),
@@ -4236,69 +4227,6 @@ fn bar_map_again(test_config: &Path) -> Result<(), String> {
     Ok(())
 }
 
-/// soundserver brings the virtio-sound function up itself, behind the unit, and
-/// plays one stream through it to the end: the job's counts (`inspect`'s), and
-/// soundserver's lines in their order — the stream started once after the
-/// client connected, and stopped once, before soundserver suspended, with no
-/// refusal on the way.
-fn virtio_sound_counts(test_config: &Path) -> Result<(), String> {
-    const JOB: &str = "virtio_sound_counts";
-    /// soundserver's bring-up, which it says before any client is accepted.
-    const BROUGHT_UP: [&str; 3] = [
-        "virtio-sound: configured stream 0: 44100Hz 2ch s16le",
-        "soundserver: ready, 8 buffers, 44100Hz 2ch, 512 bytes/period, 128 frames/period",
-        "soundserver: suspended",
-    ];
-    /// The stream's lines, in the order they are owed, each once.
-    const IN_ORDER: [&str; 6] = [
-        " connected (id=",
-        "soundserver: resumed",
-        "virtio-sound: stream 0 started",
-        " removed (",
-        "virtio-sound: stream 0 stopped",
-        "soundserver: suspended",
-    ];
-    let bin = qemu::build_toyos_bin(qemu::SUITE_ARCH, &compile::repo_root().join("tests/toyos-rust-tests"), JOB);
-    let mut qemu =
-        QemuInstance::boot_with_options(test_config, &[], &[(JOB.to_string(), bin)], BootOptions::default());
-    let mut console = qemu.boot_log().to_string();
-    await_guest(&mut qemu, &mut console, "soundserver's bring-up", |c| BROUGHT_UP.iter().all(|l| c.contains(l)))
-        .map_err(|e| format!("{e}\n{console}"))?;
-    let boot = serial::Serial::named("the boot", console);
-    boot.must_be_clean()?;
-    boot.must_say("soundserver: VirtIO: PCI ")?;
-    boot.must_say("access_platform=y")?;
-    boot.must_not_say(audio::NULL_SINK)?;
-
-    let result = qemu.run_test(&format!("test_rs_{JOB}"), Duration::from_secs(120));
-    if let Some(why) = &result.error {
-        return Err(format!("{why}\nthe job said:\n{}", result.stdout));
-    }
-    if result.exit_code != Some(0) {
-        return Err(format!("the job ended {:?}:\n{}", result.exit_code, result.stdout));
-    }
-    let said = &result.stdout;
-    let Some(counted) = said.lines().find(|l| l.contains("virtio_sound_counts: ")) else {
-        return Err(format!("the job never said what it counted:\n{said}"));
-    };
-    if said.contains("cannot be driven on") {
-        return Err(format!("soundserver refused its device mid-stream:\n{said}"));
-    }
-    let mut from = 0;
-    for line in IN_ORDER {
-        let times = said.matches(line).count();
-        let Some(at) = said[from..].find(line) else {
-            return Err(format!("`{line}` is not after the line before it in the window:\n{said}"));
-        };
-        if times != 1 {
-            return Err(format!("`{line}` said {times} times in one stream's window:\n{said}"));
-        }
-        from += at + line.len();
-    }
-    eprintln!("  [sound] {}", counted.trim());
-    Ok(())
-}
-
 /// Every device delivery is still cpu0's, and no CPU took a shootdown IPI the
 /// issuer did not count.
 ///