Miscellaneous PCI fixes and more test coverage

tests/integration_tests/functional/test_balloon.py

@@ -449,11 +449,11 @@ def test_stats_update(uvm_plain_any):
     assert next_stats["available_memory"] != final_stats["available_memory"]
 
 
-def test_balloon_snapshot(microvm_factory, guest_kernel, rootfs):
+def test_balloon_snapshot(uvm_plain_any, microvm_factory):
     """
     Test that the balloon works after pause/resume.
     """
-    vm = microvm_factory.build(guest_kernel, rootfs)
+    vm = uvm_plain_any
     vm.spawn()
     vm.basic_config(
         vcpu_count=2,
@@ -531,11 +531,11 @@ def test_balloon_snapshot(microvm_factory, guest_kernel, rootfs):
     assert stats_after_snap["available_memory"] > latest_stats["available_memory"]
 
 
-def test_memory_scrub(microvm_factory, guest_kernel, rootfs):
+def test_memory_scrub(uvm_plain_any):
     """
     Test that the memory is zeroed after deflate.
     """
-    microvm = microvm_factory.build(guest_kernel, rootfs)
+    microvm = uvm_plain_any
     microvm.spawn()
     microvm.basic_config(vcpu_count=2, mem_size_mib=256)
     microvm.add_net_iface()

tests/integration_tests/functional/test_cpu_template_helper.py

@@ -261,9 +261,7 @@ def get_guest_msrs(microvm, msr_index_list):
     ),
 )
 def test_cpu_config_dump_vs_actual(
-    microvm_factory,
-    guest_kernel,
-    rootfs,
+    uvm_plain_any,
     cpu_template_helper,
     tmp_path,
 ):
@@ -277,7 +275,7 @@ def test_cpu_config_dump_vs_actual(
     dump_cpu_config = build_cpu_config_dict(cpu_config_path)
 
     # Retrieve actual CPU config from guest
-    microvm = microvm_factory.build(guest_kernel, rootfs)
+    microvm = uvm_plain_any
     microvm.spawn()
     microvm.basic_config(vcpu_count=1)
     microvm.add_net_iface()

tests/integration_tests/functional/test_feat_parity.py

@@ -28,16 +28,11 @@ def inst_set_cpu_template_fxt(request):
 
 
 @pytest.fixture(name="vm")
-def vm_fxt(
-    microvm_factory,
-    inst_set_cpu_template,
-    guest_kernel,
-    rootfs,
-):
+def vm_fxt(uvm_plain_any, inst_set_cpu_template):
     """
     Create a VM, using the normal CPU templates
     """
-    vm = microvm_factory.build(guest_kernel, rootfs)
+    vm = uvm_plain_any
     vm.spawn()
     vm.basic_config(vcpu_count=1, mem_size_mib=1024, cpu_template=inst_set_cpu_template)
     vm.add_net_iface()

tests/integration_tests/functional/test_snapshot_basic.py

@@ -115,9 +115,8 @@ def test_snapshot_current_version(uvm_nano):
 def test_cycled_snapshot_restore(
     bin_vsock_path,
     tmp_path,
+    uvm_plain_any,
     microvm_factory,
-    guest_kernel,
-    rootfs,
     snapshot_type,
     use_snapshot_editor,
     cpu_template_any,
@@ -133,7 +132,7 @@ def test_cycled_snapshot_restore(
     logger = logging.getLogger("snapshot_sequence")
     diff_snapshots = snapshot_type == SnapshotType.DIFF
 
-    vm = microvm_factory.build(guest_kernel, rootfs)
+    vm = uvm_plain_any
     vm.spawn()
     vm.basic_config(
         vcpu_count=2,
@@ -249,7 +248,7 @@ def test_load_snapshot_failure_handling(uvm_plain):
     vm.mark_killed()
 
 
-def test_cmp_full_and_first_diff_mem(microvm_factory, guest_kernel, rootfs):
+def test_cmp_full_and_first_diff_mem(uvm_plain_any):
     """
     Compare memory of 2 consecutive full and diff snapshots.
 
@@ -260,7 +259,7 @@ def test_cmp_full_and_first_diff_mem(microvm_factory, guest_kernel, rootfs):
     """
     logger = logging.getLogger("snapshot_sequence")
 
-    vm = microvm_factory.build(guest_kernel, rootfs)
+    vm = uvm_plain_any
     vm.spawn()
     vm.basic_config(
         vcpu_count=2,
@@ -430,12 +429,12 @@ def test_create_large_diff_snapshot(uvm_plain):
     # process would have been taken down.
 
 
-def test_diff_snapshot_overlay(guest_kernel, rootfs, microvm_factory):
+def test_diff_snapshot_overlay(uvm_plain_any, microvm_factory):
     """
     Tests that if we take a diff snapshot and direct firecracker to write it on
     top of an existing snapshot file, it will successfully merge them.
     """
-    basevm = microvm_factory.build(guest_kernel, rootfs)
+    basevm = uvm_plain_any
     basevm.spawn()
     basevm.basic_config(track_dirty_pages=True)
     basevm.add_net_iface()
@@ -467,15 +466,15 @@ def test_diff_snapshot_overlay(guest_kernel, rootfs, microvm_factory):
     # Check that the restored VM works
 
 
-def test_snapshot_overwrite_self(guest_kernel, rootfs, microvm_factory):
+def test_snapshot_overwrite_self(uvm_plain_any, microvm_factory):
     """Tests that if we try to take a snapshot that would overwrite the
     very file from which the current VM is stored, nothing happens.
 
     Note that even though we map the file as MAP_PRIVATE, the documentation
     of mmap does not specify what should happen if the file is changed after being
     mmap'd (https://man7.org/linux/man-pages/man2/mmap.2.html). It seems that
     these changes can propagate to the mmap'd memory region."""
-    base_vm = microvm_factory.build(guest_kernel, rootfs)
+    base_vm = uvm_plain_any
     base_vm.spawn()
     base_vm.basic_config()
     base_vm.add_net_iface()

tests/integration_tests/performance/test_huge_pages.py

@@ -68,13 +68,13 @@ def test_hugetlbfs_boot(uvm_plain):
     )
 
 
-def test_hugetlbfs_snapshot(microvm_factory, guest_kernel_linux_5_10, rootfs):
+def test_hugetlbfs_snapshot(microvm_factory, uvm_plain):
     """
     Test hugetlbfs snapshot restore via uffd
     """
 
     ### Create Snapshot ###
-    vm = microvm_factory.build(guest_kernel_linux_5_10, rootfs)
+    vm = uvm_plain
     vm.memory_monitor = None
     vm.spawn()
     vm.basic_config(huge_pages=HugePagesConfig.HUGETLBFS_2MB, mem_size_mib=128)
@@ -138,8 +138,7 @@ def test_hugetlbfs_diff_snapshot(microvm_factory, uvm_plain):
 @pytest.mark.parametrize("huge_pages", HugePagesConfig)
 def test_ept_violation_count(
     microvm_factory,
-    guest_kernel_linux_5_10,
-    rootfs,
+    uvm_plain,
     metrics,
     huge_pages,
 ):
@@ -149,7 +148,7 @@ def test_ept_violation_count(
     """
 
     ### Create Snapshot ###
-    vm = microvm_factory.build(guest_kernel_linux_5_10, rootfs)
+    vm = uvm_plain
     vm.memory_monitor = None
     vm.spawn()
     vm.basic_config(huge_pages=huge_pages, mem_size_mib=256)

tests/integration_tests/performance/test_snapshot.py

@@ -255,15 +255,13 @@ def test_population_latency(
 
 @pytest.mark.nonci
 def test_snapshot_create_latency(
-    microvm_factory,
-    guest_kernel_linux_5_10,
-    rootfs,
+    uvm_plain,
     metrics,
     snapshot_type,
 ):
     """Measure the latency of creating a Full snapshot"""
 
-    vm = microvm_factory.build(guest_kernel_linux_5_10, rootfs, monitor_memory=False)
+    vm = uvm_plain
     vm.spawn()
     vm.basic_config(
         vcpu_count=2,