Run performance tests with userspace bounce buffers

Now that we have userspace bounce buffers, we can run secret freedom
tests (including perf tests!) with then, which additionally allows us to
run them on x86 too.

Remove the swiotlb test cases from the performance tests, as the
performance impact here was shown too significant.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

tests/conftest.py

@@ -376,16 +376,12 @@ def io_engine(request):
     return request.param
 
 
-# 4MiB is the smallest swiotlb size that seems to generally work for all
-# perf tests. 2MiB makes the vsock throughput test consistently fail, and 1MiB makes
-# the network throughput test occasionally fail (both due to connection issues).
-# The block test passes even with the minimum of 1MiB. We pick 8 to have enough
-# buffer to the failing cases.
 secret_free_test_cases = [None]
-if platform.machine() == "aarch64":
-    secret_free_test_cases.append((8, False))
-    if global_props.instance != "m6g.metal":
-        secret_free_test_cases.append((8, True))
+if (
+    global_props.host_linux_version_metrics == "next"
+    and global_props.instance != "m6g.metal"
+):
+    secret_free_test_cases.append((0, True))
 
 
 @pytest.fixture(params=secret_free_test_cases)

tests/integration_tests/functional/test_secret_freedom.py

@@ -2,8 +2,6 @@
 # SPDX-License-Identifier: Apache-2.0
 """Test secret-freedom related functionality."""
 
-import platform
-
 import pytest
 
 from framework import defs
@@ -23,17 +21,16 @@
 ]
 
 
-@pytest.mark.skipif(
-    platform.machine() != "aarch64",
-    reason="only ARM can boot secret free VMs with I/O devices",
-)
 def test_secret_free_boot(microvm_factory, guest_kernel_linux_6_1, rootfs):
     """Tests that a VM can boot if all virtio devices are bound to a swiotlb region, and
     that this swiotlb region is actually discovered by the guest."""
     vm = microvm_factory.build(guest_kernel_linux_6_1, rootfs)
     vm.spawn()
     vm.memory_monitor = None
-    vm.basic_config(memory_config={"initial_swiotlb_size": 8, "secret_free": True})
+    vm.basic_config(
+        memory_config={"secret_free": True},
+        boot_args="console=ttyS0 reboot=k panic=1 pci=off no-kvmclock",
+    )
     vm.add_net_iface()
     vm.start()
 
@@ -54,7 +51,7 @@ def test_secret_free_initrd(microvm_factory, guest_kernel):
         vcpu_count=1,
         boot_args="console=ttyS0 reboot=k panic=1 pci=off no-kvmclock",
         use_initrd=True,
-        memory_config={"initial_swiotlb_size": 64, "secret_free": True},
+        memory_config={"secret_free": True},
     )
 
     uvm.start()
@@ -65,16 +62,15 @@ def test_secret_free_initrd(microvm_factory, guest_kernel):
     serial.rx(token=f"rootfs on / type {INITRD_FILESYSTEM}")
 
 
-@pytest.mark.skipif(
-    platform.machine() != "aarch64",
-    reason="only ARM can boot secret free VMs with I/O devices",
-)
 def test_secret_free_snapshot_creation(microvm_factory, guest_kernel_linux_6_1, rootfs):
     """Test that snapshot creation works for secret hidden VMs"""
     vm = microvm_factory.build(guest_kernel_linux_6_1, rootfs)
     vm.spawn()
     vm.memory_monitor = None
-    vm.basic_config(memory_config={"initial_swiotlb_size": 8, "secret_free": True})
+    vm.basic_config(
+        memory_config={"secret_free": True},
+        boot_args="console=ttyS0 reboot=k panic=1 pci=off no-kvmclock",
+    )
     vm.add_net_iface()
     vm.start()
 

tests/integration_tests/performance/test_block_ab.py

@@ -154,9 +154,12 @@ def test_block_performance(
     """
     Execute block device emulation benchmarking scenarios.
     """
-    if memory_config is not None and "6.1" not in guest_kernel_acpi.name:
+    if memory_config[0] != 0 and "6.1" not in guest_kernel_acpi.name:
         pytest.skip("swiotlb only supported on aarch64/6.1")
 
+    if memory_config is not None and io_engine == "Async":
+        pytest.skip("userspace bounce buffers not supported with async block engine")
+
     vm = microvm_factory.build(guest_kernel_acpi, rootfs, monitor_memory=False)
     vm.spawn(log_level="Info", emit_metrics=True)
     vm.basic_config(