diff --git a/libos/test/abi/x86_64/manifest.template b/libos/test/abi/x86_64/manifest.template
index c130d46db0..9c1608dd2e 100644
--- a/libos/test/abi/x86_64/manifest.template
+++ b/libos/test/abi/x86_64/manifest.template
@@ -7,6 +7,7 @@ fs.mounts = [
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '4' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ binary_dir }}/{{ entrypoint }}",
diff --git a/libos/test/abi/x86_64/stack_arg.manifest.template b/libos/test/abi/x86_64/stack_arg.manifest.template
index bc8658be3c..0b22a45104 100644
--- a/libos/test/abi/x86_64/stack_arg.manifest.template
+++ b/libos/test/abi/x86_64/stack_arg.manifest.template
@@ -12,6 +12,7 @@ fs.mounts = [
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '4' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ binary_dir }}/{{ entrypoint }}",
diff --git a/libos/test/abi/x86_64/stack_env.manifest.template b/libos/test/abi/x86_64/stack_env.manifest.template
index ef892f68f8..c0d075a36c 100644
--- a/libos/test/abi/x86_64/stack_env.manifest.template
+++ b/libos/test/abi/x86_64/stack_env.manifest.template
@@ -12,6 +12,7 @@ fs.mounts = [
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '4' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ binary_dir }}/{{ entrypoint }}",
diff --git a/libos/test/fs/manifest.template b/libos/test/fs/manifest.template
index 612873c068..f8d74543e6 100644
--- a/libos/test/fs/manifest.template
+++ b/libos/test/fs/manifest.template
@@ -22,6 +22,7 @@ fs.insecure__keys.default = "ffeeddccbbaa99887766554433221100"
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '16' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.allowed_files = [
   "file:tmp/",
diff --git a/libos/test/ltp/manifest.template b/libos/test/ltp/manifest.template
index 40d17ea3b4..f1909baa89 100644
--- a/libos/test/ltp/manifest.template
+++ b/libos/test/ltp/manifest.template
@@ -26,6 +26,7 @@ sys.brk.max_size = "32M"
 sys.stack.size = "4M"
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 # for tests that require SIGSEGV handling (e.g., setrlimit01, mmap03)
 sgx.use_exinfo = true
diff --git a/libos/test/regression/argv_from_file.manifest.template b/libos/test/regression/argv_from_file.manifest.template
index bc086bd4ec..072ff027d3 100644
--- a/libos/test/regression/argv_from_file.manifest.template
+++ b/libos/test/regression/argv_from_file.manifest.template
@@ -12,6 +12,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.allowed_files = [
   "file:argv_test_input",
diff --git a/libos/test/regression/argv_from_manifest.manifest.template b/libos/test/regression/argv_from_manifest.manifest.template
index 147ba14946..bd32c44292 100644
--- a/libos/test/regression/argv_from_manifest.manifest.template
+++ b/libos/test/regression/argv_from_manifest.manifest.template
@@ -19,6 +19,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/attestation.manifest.template b/libos/test/regression/attestation.manifest.template
index 54c86c1ef3..38ecd43454 100644
--- a/libos/test/regression/attestation.manifest.template
+++ b/libos/test/regression/attestation.manifest.template
@@ -12,6 +12,7 @@ fs.insecure__keys.default = "ffeeddccbbaa99887766554433221100"
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.remote_attestation = "{{ env.get('RA_TYPE', 'none') }}"
 sgx.ra_client_spid = "{{ env.get('RA_CLIENT_SPID', '') }}"
diff --git a/libos/test/regression/bootstrap_cpp.manifest.template b/libos/test/regression/bootstrap_cpp.manifest.template
index ba5b53f9fa..9893a42808 100644
--- a/libos/test/regression/bootstrap_cpp.manifest.template
+++ b/libos/test/regression/bootstrap_cpp.manifest.template
@@ -15,6 +15,7 @@ fs.mounts = [
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '8' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/debug_log_file.manifest.template b/libos/test/regression/debug_log_file.manifest.template
index af4976c2ed..a99e343edd 100644
--- a/libos/test/regression/debug_log_file.manifest.template
+++ b/libos/test/regression/debug_log_file.manifest.template
@@ -14,6 +14,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/debug_log_inline.manifest.template b/libos/test/regression/debug_log_inline.manifest.template
index 44ed734dc9..bf05bb07e5 100644
--- a/libos/test/regression/debug_log_inline.manifest.template
+++ b/libos/test/regression/debug_log_inline.manifest.template
@@ -13,6 +13,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/device_passthrough.manifest.template b/libos/test/regression/device_passthrough.manifest.template
index 2c056bccac..181141110e 100644
--- a/libos/test/regression/device_passthrough.manifest.template
+++ b/libos/test/regression/device_passthrough.manifest.template
@@ -10,6 +10,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/env_from_file.manifest.template b/libos/test/regression/env_from_file.manifest.template
index dbb9eb3da7..aeca295e9e 100644
--- a/libos/test/regression/env_from_file.manifest.template
+++ b/libos/test/regression/env_from_file.manifest.template
@@ -12,6 +12,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.allowed_files = [
   "file:env_test_input",
diff --git a/libos/test/regression/env_from_host.manifest.template b/libos/test/regression/env_from_host.manifest.template
index ba450019af..0fa6625735 100644
--- a/libos/test/regression/env_from_host.manifest.template
+++ b/libos/test/regression/env_from_host.manifest.template
@@ -12,6 +12,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/env_passthrough.manifest.template b/libos/test/regression/env_passthrough.manifest.template
index 95d054f186..64a7eb60d2 100644
--- a/libos/test/regression/env_passthrough.manifest.template
+++ b/libos/test/regression/env_passthrough.manifest.template
@@ -17,6 +17,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/eventfd_fork.manifest.template b/libos/test/regression/eventfd_fork.manifest.template
index 6c9887e436..86b8def2aa 100644
--- a/libos/test/regression/eventfd_fork.manifest.template
+++ b/libos/test/regression/eventfd_fork.manifest.template
@@ -11,6 +11,7 @@ sys.insecure__allow_eventfd = true
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/eventfd_fork_allowed_failing.manifest.template b/libos/test/regression/eventfd_fork_allowed_failing.manifest.template
index ba50648401..858af8c29a 100644
--- a/libos/test/regression/eventfd_fork_allowed_failing.manifest.template
+++ b/libos/test/regression/eventfd_fork_allowed_failing.manifest.template
@@ -17,6 +17,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/fcntl_lock_child_only.manifest.template b/libos/test/regression/fcntl_lock_child_only.manifest.template
index 202bfe59ed..090622ce2a 100644
--- a/libos/test/regression/fcntl_lock_child_only.manifest.template
+++ b/libos/test/regression/fcntl_lock_child_only.manifest.template
@@ -13,6 +13,7 @@ fs.insecure__keys.default = "ffeeddccbbaa99887766554433221100"
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/file_check_policy_allow_all_but_log.manifest.template b/libos/test/regression/file_check_policy_allow_all_but_log.manifest.template
index c2639b80e7..f67eb3160e 100644
--- a/libos/test/regression/file_check_policy_allow_all_but_log.manifest.template
+++ b/libos/test/regression/file_check_policy_allow_all_but_log.manifest.template
@@ -14,6 +14,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.file_check_policy = "allow_all_but_log"
 
diff --git a/libos/test/regression/file_check_policy_strict.manifest.template b/libos/test/regression/file_check_policy_strict.manifest.template
index 927c148671..34e96d2ccf 100644
--- a/libos/test/regression/file_check_policy_strict.manifest.template
+++ b/libos/test/regression/file_check_policy_strict.manifest.template
@@ -14,6 +14,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.file_check_policy = "strict"
 
diff --git a/libos/test/regression/fork_and_access_file.manifest.template b/libos/test/regression/fork_and_access_file.manifest.template
index 8f63bf4106..30cdaadfbf 100644
--- a/libos/test/regression/fork_and_access_file.manifest.template
+++ b/libos/test/regression/fork_and_access_file.manifest.template
@@ -10,6 +10,7 @@ fs.mounts = [
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '16' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 # this is only to test that `sgx.enable_stats` works (it can only be specified for debug-mode tests)
 sgx.enable_stats = true
diff --git a/libos/test/regression/fork_disallowed.manifest.template b/libos/test/regression/fork_disallowed.manifest.template
index 6cdb30edb3..03b0047546 100644
--- a/libos/test/regression/fork_disallowed.manifest.template
+++ b/libos/test/regression/fork_disallowed.manifest.template
@@ -15,6 +15,7 @@ sys.disallow_subprocesses = true
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/host_root_fs.manifest.template b/libos/test/regression/host_root_fs.manifest.template
index 12f4f9442f..8277c98141 100644
--- a/libos/test/regression/host_root_fs.manifest.template
+++ b/libos/test/regression/host_root_fs.manifest.template
@@ -12,6 +12,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/hostname_extra_runtime_conf.manifest.template b/libos/test/regression/hostname_extra_runtime_conf.manifest.template
index 2cdb1c9aa4..664fbec5ae 100644
--- a/libos/test/regression/hostname_extra_runtime_conf.manifest.template
+++ b/libos/test/regression/hostname_extra_runtime_conf.manifest.template
@@ -12,6 +12,7 @@ sys.enable_extra_runtime_domain_names_conf = true
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/init_fail.manifest.template b/libos/test/regression/init_fail.manifest.template
index 755f8b1c0a..a2c3462ac2 100644
--- a/libos/test/regression/init_fail.manifest.template
+++ b/libos/test/regression/init_fail.manifest.template
@@ -11,6 +11,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/init_fail2.manifest.template b/libos/test/regression/init_fail2.manifest.template
index 2222af6dbd..eedec259a2 100644
--- a/libos/test/regression/init_fail2.manifest.template
+++ b/libos/test/regression/init_fail2.manifest.template
@@ -11,6 +11,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 # this is an impossible combination of options, LibOS must fail very early in init process
 sgx.enclave_size = "256M"
diff --git a/libos/test/regression/large_mmap.manifest.template b/libos/test/regression/large_mmap.manifest.template
index 324b5a0097..dda3cfd712 100644
--- a/libos/test/regression/large_mmap.manifest.template
+++ b/libos/test/regression/large_mmap.manifest.template
@@ -14,6 +14,7 @@ fs.mounts = [
 sgx.enclave_size = "8G"
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.allowed_files = [
   "file:testfile",
diff --git a/libos/test/regression/madvise.manifest.template b/libos/test/regression/madvise.manifest.template
index 185365c189..b2cac3b6a1 100644
--- a/libos/test/regression/madvise.manifest.template
+++ b/libos/test/regression/madvise.manifest.template
@@ -10,6 +10,7 @@ fs.mounts = [
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '4' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 # `use_exinfo = true` is needed because `madvise(MADV_DONTNEED)` is used in this test. When EDMM is
 # enabled, it will free the committed pages but automatically recommit them on subsequent accesses
diff --git a/libos/test/regression/manifest.template b/libos/test/regression/manifest.template
index ab236b1cf2..51e8cf8528 100644
--- a/libos/test/regression/manifest.template
+++ b/libos/test/regression/manifest.template
@@ -24,6 +24,7 @@ sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '16' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
 sgx.use_exinfo = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.allowed_files = [
   "file:tmp/",
diff --git a/libos/test/regression/mmap_map_noreserve.manifest.template b/libos/test/regression/mmap_map_noreserve.manifest.template
index 372e485ed9..ee3cf8075e 100644
--- a/libos/test/regression/mmap_map_noreserve.manifest.template
+++ b/libos/test/regression/mmap_map_noreserve.manifest.template
@@ -16,6 +16,7 @@ sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '20' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
 sgx.use_exinfo = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.allowed_files = [
   "file:testfile_map_noreserve",
diff --git a/libos/test/regression/mock_syscalls.manifest.template b/libos/test/regression/mock_syscalls.manifest.template
index a6b042f19d..c85d1b3dd8 100644
--- a/libos/test/regression/mock_syscalls.manifest.template
+++ b/libos/test/regression/mock_syscalls.manifest.template
@@ -33,6 +33,7 @@ sys.debug__mock_syscalls = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.libos }}",
diff --git a/libos/test/regression/multi_pthread.manifest.template b/libos/test/regression/multi_pthread.manifest.template
index 2c6240bd7a..884c234811 100644
--- a/libos/test/regression/multi_pthread.manifest.template
+++ b/libos/test/regression/multi_pthread.manifest.template
@@ -12,6 +12,7 @@ sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '8' }}
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/multi_pthread_exitless.manifest.template b/libos/test/regression/multi_pthread_exitless.manifest.template
index f2f92753db..64216c24d1 100644
--- a/libos/test/regression/multi_pthread_exitless.manifest.template
+++ b/libos/test/regression/multi_pthread_exitless.manifest.template
@@ -13,6 +13,7 @@ sgx.insecure__rpc_thread_num = 8
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/openmp.manifest.template b/libos/test/regression/openmp.manifest.template
index cfcc63bb41..26e4bf8e5b 100644
--- a/libos/test/regression/openmp.manifest.template
+++ b/libos/test/regression/openmp.manifest.template
@@ -24,6 +24,7 @@ fs.mounts = [
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '32' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/rlimit_nofile_4k.manifest.template b/libos/test/regression/rlimit_nofile_4k.manifest.template
index 6f6fe02396..31ce232140 100644
--- a/libos/test/regression/rlimit_nofile_4k.manifest.template
+++ b/libos/test/regression/rlimit_nofile_4k.manifest.template
@@ -15,6 +15,7 @@ sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '4' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
 sgx.use_exinfo = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/rwlock.manifest.template b/libos/test/regression/rwlock.manifest.template
index 3900ba9dba..a7aac5b7a6 100644
--- a/libos/test/regression/rwlock.manifest.template
+++ b/libos/test/regression/rwlock.manifest.template
@@ -11,6 +11,7 @@ fs.mounts = [
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '200' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/shadow_pseudo_fs.manifest.template b/libos/test/regression/shadow_pseudo_fs.manifest.template
index b0ab21ac02..ff00ed6437 100644
--- a/libos/test/regression/shadow_pseudo_fs.manifest.template
+++ b/libos/test/regression/shadow_pseudo_fs.manifest.template
@@ -15,6 +15,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ binary_dir }}/{{ entrypoint }}",
diff --git a/libos/test/regression/shebang_test_script.manifest.template b/libos/test/regression/shebang_test_script.manifest.template
index 1b3b4e3b55..2abfe305cc 100644
--- a/libos/test/regression/shebang_test_script.manifest.template
+++ b/libos/test/regression/shebang_test_script.manifest.template
@@ -12,6 +12,7 @@ fs.mounts = [
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '16' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/shm.manifest.template b/libos/test/regression/shm.manifest.template
index 0d980681d0..8677c4899b 100644
--- a/libos/test/regression/shm.manifest.template
+++ b/libos/test/regression/shm.manifest.template
@@ -10,6 +10,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.allowed_files = [
   "dev:/dev/shm/shm_test",
diff --git a/libos/test/regression/sigterm_multithread.manifest.template b/libos/test/regression/sigterm_multithread.manifest.template
index 16bf962025..620050e0f1 100644
--- a/libos/test/regression/sigterm_multithread.manifest.template
+++ b/libos/test/regression/sigterm_multithread.manifest.template
@@ -12,6 +12,7 @@ fs.mounts = [
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '16' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/socket_ioctl.manifest.template b/libos/test/regression/socket_ioctl.manifest.template
index 33201f5b38..7459b71337 100644
--- a/libos/test/regression/socket_ioctl.manifest.template
+++ b/libos/test/regression/socket_ioctl.manifest.template
@@ -10,6 +10,7 @@ fs.mounts = [
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '4' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/sysfs_common.manifest.template b/libos/test/regression/sysfs_common.manifest.template
index 6850246587..15f9af4cea 100644
--- a/libos/test/regression/sysfs_common.manifest.template
+++ b/libos/test/regression/sysfs_common.manifest.template
@@ -9,6 +9,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/libos/test/regression/test_libos.py b/libos/test/regression/test_libos.py
index 73a5f5f300..acb102539e 100644
--- a/libos/test/regression/test_libos.py
+++ b/libos/test/regression/test_libos.py
@@ -10,6 +10,7 @@
 import tomli
 
 from graminelibos.regression import (
+    HAS_AEXNOTIFY,
     HAS_AVX,
     HAS_EDMM,
     HAS_SGX,
@@ -1391,6 +1392,8 @@ def test_080_close_range(self):
         stdout, _ = self.run_binary(['close_range'])
         self.assertIn('TEST OK', stdout)
 
+@unittest.skipIf(HAS_AEXNOTIFY,
+    'AEX-Notify HW feature conflicts with debugging tools (in particular, with #BP exceptions)')
 class TC_50_GDB(RegressionTestCase):
     def setUp(self):
         if not self.has_debug():
diff --git a/libos/test/regression/toml_parsing.manifest.template b/libos/test/regression/toml_parsing.manifest.template
index a8d99e77d2..84f826c429 100644
--- a/libos/test/regression/toml_parsing.manifest.template
+++ b/libos/test/regression/toml_parsing.manifest.template
@@ -19,6 +19,7 @@ libos.check_invalid_pointers = false
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 # the manifest options below added only so that they have any test coverage
 sgx.seal_key.flags_mask = "0xffffffffffffffff"
diff --git a/libos/test/regression/uid_gid.manifest.template b/libos/test/regression/uid_gid.manifest.template
index be1afc1a00..04e0d4f969 100644
--- a/libos/test/regression/uid_gid.manifest.template
+++ b/libos/test/regression/uid_gid.manifest.template
@@ -12,6 +12,7 @@ fs.mounts = [
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.trusted_files = [
   "file:{{ gramine.runtimedir(libc) }}/",
diff --git a/pal/regression/Bootstrap6.manifest.template b/pal/regression/Bootstrap6.manifest.template
index 08bda1f2b3..a5852e7375 100644
--- a/pal/regression/Bootstrap6.manifest.template
+++ b/pal/regression/Bootstrap6.manifest.template
@@ -6,3 +6,4 @@ loader.log_level = "debug"
 sgx.enclave_size = "8192M"
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
diff --git a/pal/regression/Bootstrap7.manifest.template b/pal/regression/Bootstrap7.manifest.template
index 177285ef56..0505c7dc09 100644
--- a/pal/regression/Bootstrap7.manifest.template
+++ b/pal/regression/Bootstrap7.manifest.template
@@ -2,6 +2,7 @@ loader.entrypoint.uri = "file:{{ binary_dir }}/{{ entrypoint }}"
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 loader.env.key1 = "na"
 loader.env.key2 = "na"
diff --git a/pal/regression/File.manifest.template b/pal/regression/File.manifest.template
index 59eb3e3c07..9d366b1f31 100644
--- a/pal/regression/File.manifest.template
+++ b/pal/regression/File.manifest.template
@@ -3,6 +3,7 @@ loader.log_level = "debug"
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 sgx.allowed_files = [
   "file:{{ entrypoint }}.manifest",
diff --git a/pal/regression/Thread2.manifest.template b/pal/regression/Thread2.manifest.template
index 8e9926f044..4d3fb9a1f5 100644
--- a/pal/regression/Thread2.manifest.template
+++ b/pal/regression/Thread2.manifest.template
@@ -3,3 +3,4 @@ loader.entrypoint.uri = "file:{{ binary_dir }}/{{ entrypoint }}"
 sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '2' }}
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
diff --git a/pal/regression/Thread2_edmm.manifest.template b/pal/regression/Thread2_edmm.manifest.template
index 0efd657eea..b8a06c33ea 100644
--- a/pal/regression/Thread2_edmm.manifest.template
+++ b/pal/regression/Thread2_edmm.manifest.template
@@ -5,3 +5,4 @@ loader.entrypoint.uri = "file:{{ binary_dir }}/{{ entrypoint }}"
 sgx.max_threads = 1
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
diff --git a/pal/regression/Thread2_exitless.manifest.template b/pal/regression/Thread2_exitless.manifest.template
index d416edd8d2..b65a2dc3d9 100644
--- a/pal/regression/Thread2_exitless.manifest.template
+++ b/pal/regression/Thread2_exitless.manifest.template
@@ -6,3 +6,4 @@ sgx.max_threads = {{ '1' if env.get('EDMM', '0') == '1' else '2' }}
 sgx.insecure__rpc_thread_num = 2
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
diff --git a/pal/regression/manifest.template b/pal/regression/manifest.template
index 2a388e510a..4761bfa92f 100644
--- a/pal/regression/manifest.template
+++ b/pal/regression/manifest.template
@@ -4,6 +4,7 @@ loader.insecure__use_cmdline_argv = true
 
 sgx.debug = true
 sgx.edmm_enable = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
+sgx.experimental_enable_aex_notify = {{ 'true' if env.get('AEXNOTIFY', '0') == '1' else 'false' }}
 
 # for Exception test (memfault handler)
 sgx.use_exinfo = {{ 'true' if env.get('EDMM', '0') == '1' else 'false' }}
diff --git a/pal/src/host/linux-sgx/enclave_entry.S b/pal/src/host/linux-sgx/enclave_entry.S
index faeb468db2..c9cdec8a85 100644
--- a/pal/src/host/linux-sgx/enclave_entry.S
+++ b/pal/src/host/linux-sgx/enclave_entry.S
@@ -41,7 +41,12 @@
 # Its sole purpose is to prepare the stage-2 handler by:
 #   - copying the interrupted SSA[0] context on the stack ("CPU context")
 #   - rewiring the SSA[0] context to point to _PalExceptionHandler()
-#   - invoking EEXIT (so that untrusted runtime can perform ERESUME)
+#   - handing over control to the SSA[0] context, in one of two ways:
+#       - AEX-Notify disabled or unavailable (legacy default flows): invoke EEXIT (so that untrusted
+#         runtime can perform ERESUME which will resume enclave execution in the SSA[0] context)
+#       - AEX-Notify enabled (explicit opt-in flows): manually restore SSA[0] context, invoke
+#         EDECCSSA instruction to go from SSA[1] to SSA[0] without exiting the enclave, and jump to
+#         SSA[0].GPRSGX.RIP to resume enclave execution
 
 #include "sgx_arch.h"
 #include "asm-offsets.h"
@@ -251,8 +256,9 @@ enclave_entry:
     je .Lcssa1_exception_during_enclave_run
 
     # We are interrupted during the never-returning OCALL_EXIT. Because the thread is going to exit
-    # anyway, we can ignore this exception.
-    jmp .Lcssa1_exception_eexit
+    # anyway, we can ignore this exception. We also don't care about AEX-Notify mitigations at this
+    # point, that's why we don't jump to the .Lcssa1_exception_eexit label.
+    jmp .Lcssa1_exception_eexit_legacy
 
 .Lcssa1_exception_during_ocall_flows:
     # At this point, we are in the stage-1 exception handler (CSSA=1) and
@@ -544,6 +550,12 @@ enclave_entry:
     movq %r10, %rdx
 
 .Lcssa1_exception_eexit:
+    cmpq $0, %gs:SGX_READY_FOR_AEX_NOTIFY
+    jne .Lcssa1_exception_eexit_aexnotify
+
+.Lcssa1_exception_eexit_legacy:
+    # AEX-Notify is disabled/unavailable, stage-1 exception handler follows the normal EEXIT flow
+
     # .Lcssa0_ocall_or_cssa1_exception_eexit has an ABI that uses RSI, RDI, RSP; clear the relevant
     # regs (note that stage-1 handler didn't clobber RSP -- which contains an untrusted pointer to
     # untrusted-runtime stack -- but this flow doesn't read/write RSP at all so there is no need to
@@ -555,6 +567,70 @@ enclave_entry:
     movq %rdx, %rbx
     jmp .Lcssa0_ocall_or_cssa1_exception_eexit
 
+.Lcssa1_exception_eexit_aexnotify:
+    # AEX-Notify is enabled, stage-1 exception handler doesn't invoke EEXIT but instead the new
+    # EDECCSSA instruction (before this, need to manually restore SSA[0] context)
+
+    # After restoring SSA[0] context into GPRs, we'll need to jump to the stage-2 handler, so
+    # memorize SSA[0].GPRSGX.RIP in an otherwise-unused R11. There is a corner case of the stage-1
+    # handler's final jmp instruction, see comment at .Lcssa1_exception_eexit_aexnotify_finaljmp.
+    leaq .Lcssa1_exception_eexit_aexnotify_finaljmp(%rip), %r11
+    cmpq %r11, SGX_GPR_RIP(%rbx)
+    je 1f
+
+    # not at the stage-1 handler's final jmp instruction, use SSA0's RIP directly
+    movq SGX_GPR_RIP(%rbx), %r11
+    jmp 2f
+
+1:
+    # at the stage-1 handler's final jmp instruction, skip over this jmp instruction by directly
+    # jumping to the previously-saved SSA0's RIP (which was saved in R11)
+    movq SGX_GPR_R11(%rbx), %r11
+
+2:
+    # Clear bit 0 within SSA[0].GPRSGX.AEXNOTIFY (so that ERESUME actually resumes stage-2
+    # handler if it was interrupted by yet another AEX). The stage-2 handler, _PalExceptionHandler()
+    # func, will re-instate this bit before applying mitigations.
+    movb $0, SGX_GPR_AEXNOTIFY(%rbx)
+
+    # restore context from SSA[0] (which was already modified above to jump to stage-2 C handler);
+    # note that XSAVE area (xregs) was already restored above, so only need to restore GPRs;
+    # note that we don't care about SSA[0].GPRSGX.{URSP,URBP,EXITINFO,RESERVED,GSBASE}
+
+    leaq SGX_GPR_RFLAGS(%rbx), %rsp     # trick to restore RFLAGS directly from SSA[0].GPRSGX.RFLAGS
+    popfq
+
+    movq SGX_GPR_FSBASE(%rbx), %rdi
+    .byte 0xf3, 0x48, 0x0f, 0xae, 0xd7  # WRFSBASE %RDI
+
+    movq SGX_GPR_RDI(%rbx), %rdi     # 1st arg to _PalExceptionHandler()
+    movq SGX_GPR_RSI(%rbx), %rsi     # 2nd arg to _PalExceptionHandler()
+    movq SGX_GPR_RDX(%rbx), %rdx     # 3rd arg to _PalExceptionHandler()
+    movq SGX_GPR_RCX(%rbx), %rcx     # 4th arg to _PalExceptionHandler()
+    movq SGX_GPR_R8(%rbx),  %r8      # 5th arg to _PalExceptionHandler()
+    movq SGX_GPR_R9(%rbx),  %r9      # not strictly needed
+    movq SGX_GPR_R10(%rbx), %r10     # not strictly needed
+    movq SGX_GPR_R12(%rbx), %r12     # not strictly needed
+    movq SGX_GPR_R13(%rbx), %r13     # not strictly needed
+    movq SGX_GPR_R14(%rbx), %r14     # not strictly needed
+    movq SGX_GPR_R15(%rbx), %r15     # not strictly needed
+    movq SGX_GPR_RBP(%rbx), %rbp     # not strictly needed
+    movq SGX_GPR_RSP(%rbx), %rsp
+    xorq %rbx, %rbx                  # for sanity
+
+    # go from SSA[1] to SSA[0] (more specifically, simply decrement CSSA from 1 to 0);
+    # must be careful after this ENCLU instruction because may be interrupted by new exceptions
+    movq $EDECCSSA, %rax
+    enclu
+
+    # Finally jump to the stage-2 C exception handler. An async signal can arrive at this exact jmp
+    # instruction. At this point, SSA0 has the correct internally-consistent context for the
+    # "stage-2 exception handler", so in this corner case the stage-1 exception handler can skip
+    # over this jmp and rewire SSA0's RIP directly to _PalExceptionHandler(), which at this point is
+    # stored in SSA[0].GPRSGX.R11. See also code at .Lcssa1_exception_eexit_aexnotify.
+.Lcssa1_exception_eexit_aexnotify_finaljmp:
+    jmp *%r11
+
     .cfi_endproc
 
 
@@ -590,6 +666,15 @@ sgx_ocall:
     pushq %rbx
     .cfi_offset %rbx, -24
 
+    # disable AEX-Notify during the ocall-exit assembly logic, as (1) there is no security benefit
+    # in mitigating AEX events during the ocall asm, and (2) AEX-Notify would otherwise clash with
+    # ocall-exit and return-from-ocall corner case flows (see .Lcssa1_exception_during_ocall_flows)
+    cmpq $0, %gs:SGX_READY_FOR_AEX_NOTIFY
+    je 1f
+    movq %gs:SGX_GPR, %rax
+    movb $0, SGX_GPR_AEXNOTIFY(%rax)
+
+1:
     CHECK_IF_SIGNAL_STACK_IS_USED %rsp, .Lon_signal_stack_ocall, .Lout_of_signal_stack_ocall
 
 .Lout_of_signal_stack_ocall:
@@ -745,6 +830,13 @@ sgx_ocall:
     cmpq $PAL_EVENT_NUM_BOUND, %rsi
     jb 2f
 
+1:
+    # re-enable AEX-Notify after return-from-ocall; see .Lcssa0_ocall for details
+    cmpq $0, %gs:SGX_READY_FOR_AEX_NOTIFY
+    je 1f
+    movq %gs:SGX_GPR, %rdi
+    movb $1, SGX_GPR_AEXNOTIFY(%rdi)
+
 1:
     # there was no event, simply call _restore_sgx_context(uc, xsave_area)
     movq %rsp, %rdi
diff --git a/pal/src/host/linux-sgx/generated_offsets.c b/pal/src/host/linux-sgx/generated_offsets.c
index 8ff89d06ec..d2c313df0f 100644
--- a/pal/src/host/linux-sgx/generated_offsets.c
+++ b/pal/src/host/linux-sgx/generated_offsets.c
@@ -56,6 +56,7 @@ const struct generated_offset generated_offsets[] = {
     OFFSET_T(SGX_GPR_RIP, sgx_pal_gpr_t, rip),
     OFFSET_T(SGX_GPR_EXITINFO, sgx_pal_gpr_t, exitinfo),
     OFFSET_T(SGX_GPR_AEXNOTIFY, sgx_pal_gpr_t, aexnotify),
+    OFFSET_T(SGX_GPR_FSBASE, sgx_pal_gpr_t, fsbase),
     DEFINE(SGX_GPR_SIZE, sizeof(sgx_pal_gpr_t)),
 
     /* sgx_cpu_context_t */
@@ -169,6 +170,7 @@ const struct generated_offset generated_offsets[] = {
 
     /* pal.h */
     DEFINE(PAL_EVENT_NO_EVENT, PAL_EVENT_NO_EVENT),
+    DEFINE(PAL_EVENT_INTERRUPTED, PAL_EVENT_INTERRUPTED),
     DEFINE(PAL_EVENT_NUM_BOUND, PAL_EVENT_NUM_BOUND),
 
     /* errno */
diff --git a/pal/src/host/linux-sgx/host_entry.S b/pal/src/host/linux-sgx/host_entry.S
index a6b24ab6df..72916a8533 100644
--- a/pal/src/host/linux-sgx/host_entry.S
+++ b/pal/src/host/linux-sgx/host_entry.S
@@ -134,6 +134,20 @@ async_exit_pointer:
     movb $0, %gs:PAL_HOST_TCB_IN_AEX
     .cfi_endproc
 
+    # In case of non-AEX-Notify flows, ERESUME never morphs into EENTER, so the values in RDI and
+    # RDX are ignored. Below code snippet becomes a no-op.
+    # In case of AEX-Notify flows, ERESUME will morph into EENTER. The only way we could arrive to
+    # this line of code is that there was no pending signal to handle inside the SGX enclave, i.e.,
+    # maybe_raise_pending_signal() didn't do anything. Since there was no real pending signal (but
+    # AEX happened, so AEX-Notify must react to this), we put a dummy PAL_EVENT_INTERRUPTED (aka
+    # SIGCONT). By putting this dummy signal, we survive all checks inside Gramine's in-enclave
+    # logic, because SIGCONT can always arrive and is benign and side-effect-free. Additionally,
+    # we put a print-error-and-terminate EEXIT target for EENTER (into which ERESUME morphs) to
+    # improve error diagnostics (such flows must end with EDECCSSA instead of EEXIT, otherwise it
+    # indicates a bug in Gramine's AEX-Notify flows).
+    movq $PAL_EVENT_INTERRUPTED, %rdi
+    leaq .Lsgx_fail_on_morphed_eresume(%rip), %rdx
+
     # fall-through to ERESUME
 
     .global eresume_pointer
@@ -209,3 +223,19 @@ sgx_raise:
     # RSI - external event
     jmp .Ldo_ecall
     .cfi_endproc
+
+
+.Lsgx_fail_on_morphed_eresume:
+    .cfi_startproc
+
+    pushq %rbp
+    .cfi_adjust_cfa_offset 8
+    movq %rsp, %rbp
+    .cfi_offset %rbp, -16
+    .cfi_def_cfa_register %rbp
+
+    andq $~0xF, %rsp  # Required by System V AMD64 ABI.
+    callq fail_on_morphed_eresume
+    ud2
+
+    .cfi_endproc
diff --git a/pal/src/host/linux-sgx/host_exception.c b/pal/src/host/linux-sgx/host_exception.c
index 5a2c5a2022..388fe3bd02 100644
--- a/pal/src/host/linux-sgx/host_exception.c
+++ b/pal/src/host/linux-sgx/host_exception.c
@@ -391,3 +391,9 @@ void maybe_raise_pending_signal(void) {
         return;
     }
 }
+
+noreturn void fail_on_morphed_eresume(void) {
+    log_error("Bug in AEX-Notify flows: ERESUME morphed into EENTER but then the enclave performed "
+              "EEXIT instead of EDECCSSA. Please debug.");
+    BUG();
+}
diff --git a/pal/src/host/linux-sgx/pal_exception.c b/pal/src/host/linux-sgx/pal_exception.c
index 6f004491df..af7cf79488 100644
--- a/pal/src/host/linux-sgx/pal_exception.c
+++ b/pal/src/host/linux-sgx/pal_exception.c
@@ -23,6 +23,7 @@
 #define ADDR_IN_PAL(addr) ((void*)(addr) > TEXT_START && (void*)(addr) < TEXT_END)
 
 bool g_aex_notify_enabled = false;
+uint64_t g_aex_notify_counter = 0;
 
 void init_aex_notify_for_thread(void) {
     if (!g_aex_notify_enabled)
@@ -30,25 +31,46 @@ void init_aex_notify_for_thread(void) {
 
     SET_ENCLAVE_TCB(ready_for_aex_notify, 1UL);
     MB();
-#if 0
-    /*
-     * FIXME: Re-enable in the following commit, when all AEX-Notify flows are added.
-     *        Currently this would fail, as the untrusted runtime expects AEX-Notify flows but
-     *        in-enclave runtime doesn't yet implement AEX-Notify flows.
-     */
     GET_ENCLAVE_TCB(gpr)->aexnotify = 1U;
     MB();
-#endif
 }
 
 void fini_aex_notify_for_thread(void) {
     if (!g_aex_notify_enabled)
         return;
 
-    SET_ENCLAVE_TCB(ready_for_aex_notify, 0UL);
+    /*
+     * Order is important: first the stage-2 signal handler must be informed to *not* re-enable
+     * AEX-Notify for this thread, then AEX-Notify must be disabled for this thread from the HW
+     * perspective (so that it doesn't morph ERESUME into EENTER), and finally AEX-Notify must be
+     * disabled from the SW perspective (so that it doesn't try EDECCSSA instead of EEXIT).
+     *
+     * Without `stopping_aex_notify`, a signal could arrive and force `restore_sgx_context()` to
+     * re-enable AEX-Notify, even if unsetting `aexnotify` was executed in the meantime.
+     *
+     * If `ready_for_aex_notify` would be unset before unsetting `aexnotify`, then the HW could
+     * morph ERESUME into EENTER, and the flow enclave_entry.S:Lcssa1_exception_eexit would choose
+     * the no-AEX-Notify path and perform EEXIT, which is unsupported in Gramine (Gramine assumes
+     * that ERESUME never returns).
+     */
+    SET_ENCLAVE_TCB(stopping_aex_notify, 1UL);
     MB();
     GET_ENCLAVE_TCB(gpr)->aexnotify = 0U;
     MB();
+    SET_ENCLAVE_TCB(ready_for_aex_notify, 0UL);
+    MB();
+}
+
+static void apply_aex_notify_mitigations(sgx_cpu_context_t* uc, PAL_XREGS_STATE* xregs_state) {
+    /*
+     * TODO: introduce mitigations like atomic prefetching of the working set, see proposed
+     *        mitigations in academic paper "AEX-Notify: Thwarting Precise Single-Stepping
+     *        Attacks through Interrupt Awareness for Intel SGX Enclaves"
+     */
+    __UNUSED(uc);
+    __UNUSED(xregs_state);
+
+    __atomic_fetch_add(&g_aex_notify_counter, 1, __ATOMIC_RELAXED);
 }
 
 /* Restore an sgx_cpu_context_t as generated by .Lhandle_exception. Execution will
@@ -58,13 +80,32 @@ noreturn static void restore_sgx_context(sgx_cpu_context_t* uc, PAL_XREGS_STATE*
     if (xregs_state == NULL)
         xregs_state = (PAL_XREGS_STATE*)g_xsave_reset_state;
 
-#ifdef ASAN
-    /* Unpoison the signal stack before leaving it */
     uintptr_t sig_stack_low = GET_ENCLAVE_TCB(sig_stack_low);
     uintptr_t sig_stack_high = GET_ENCLAVE_TCB(sig_stack_high);
+    bool restored_context_is_sighandler = (uc->rsp >= sig_stack_low && uc->rsp < sig_stack_high);
+
+#ifdef ASAN
+    /* Unpoison the signal stack before leaving it */
     asan_unpoison_current_stack(sig_stack_low, sig_stack_high - sig_stack_low);
 #endif
 
+    if (g_aex_notify_enabled && GET_ENCLAVE_TCB(ready_for_aex_notify)
+            && !GET_ENCLAVE_TCB(stopping_aex_notify) && !restored_context_is_sighandler) {
+        /*
+         * AEX-Notify must be re-enabled for this enclave thread before applying any mitigations
+         * (and consequently before restoring the regular execution of the enclave thread). For
+         * details, see e.g. the official whitepaper on AEX-Notify from Intel.
+         *
+         * Note that we re-enable AEX-Notify only in the outermost signal handler (the one that will
+         * jump to the application code and stack). Otherwise, AEX-Notify would be enabled while
+         * inside this Gramine-internal signal handler, and exceptions like #PF would result in
+         * nested invocations of this signal handler, thus overflowing the signal stack. This is
+         * especially true for the EDMM flows where #PF exceptions are a norm.
+         */
+        GET_ENCLAVE_TCB(gpr)->aexnotify = 1;
+        apply_aex_notify_mitigations(uc, xregs_state);
+    }
+
     _restore_sgx_context(uc, xregs_state);
 }
 
diff --git a/pal/src/host/linux-sgx/pal_linux.h b/pal/src/host/linux-sgx/pal_linux.h
index 97060e7bc3..59adc5281e 100644
--- a/pal/src/host/linux-sgx/pal_linux.h
+++ b/pal/src/host/linux-sgx/pal_linux.h
@@ -96,6 +96,7 @@ void restore_xregs(const PAL_XREGS_STATE* xsave_area);
 noreturn void _restore_sgx_context(sgx_cpu_context_t* uc, PAL_XREGS_STATE* xsave_area);
 
 extern bool g_aex_notify_enabled;
+extern uint64_t g_aex_notify_counter;
 void init_aex_notify_for_thread(void);
 void fini_aex_notify_for_thread(void);
 
diff --git a/pal/src/host/linux-sgx/pal_process.c b/pal/src/host/linux-sgx/pal_process.c
index 9f060b9519..9fde9fa00f 100644
--- a/pal/src/host/linux-sgx/pal_process.c
+++ b/pal/src/host/linux-sgx/pal_process.c
@@ -246,6 +246,16 @@ int init_child_process(int parent_stream_fd, PAL_HANDLE* out_parent_handle,
 noreturn void _PalProcessExit(int exitcode) {
     if (exitcode)
         log_debug("PalProcessExit: Returning exit code %d", exitcode);
+
+    /*
+     * FIXME: remove this when proper AEX-Notify mitigations are implemented;
+     *        see pal_exception.c:apply_aex_notify_mitigations()
+     */
+    if (g_aex_notify_enabled) {
+        uint64_t aex_notify_counter = __atomic_load_n(&g_aex_notify_counter, __ATOMIC_RELAXED);
+        log_warning("AEX-Notify counter at process exit: %lu", aex_notify_counter);
+    }
+
     ocall_exit(exitcode, /*is_exitgroup=*/true);
     /* Unreachable. */
 }
diff --git a/pal/src/host/linux-sgx/pal_tcb.h b/pal/src/host/linux-sgx/pal_tcb.h
index fa6886c029..c746082609 100644
--- a/pal/src/host/linux-sgx/pal_tcb.h
+++ b/pal/src/host/linux-sgx/pal_tcb.h
@@ -43,6 +43,7 @@ struct pal_enclave_tcb {
     uint64_t  thread_started;
     uint64_t  ready_for_exceptions;
     uint64_t  ready_for_aex_notify;
+    uint64_t  stopping_aex_notify;
     uint64_t  manifest_size;
     void*     heap_min;
     void*     heap_max;
@@ -126,4 +127,6 @@ void maybe_dump_and_reset_stats(void);
 
 void maybe_raise_pending_signal(void);
 
+noreturn void fail_on_morphed_eresume(void);
+
 #endif /* IN_ENCLAVE */
diff --git a/python/graminelibos/regression.py b/python/graminelibos/regression.py
index 5a966dbd6b..b7f9870ad0 100644
--- a/python/graminelibos/regression.py
+++ b/python/graminelibos/regression.py
@@ -16,6 +16,7 @@
 
 # pylint: disable=subprocess-popen-preexec-fn,subprocess-run-check
 
+HAS_AEXNOTIFY = os.environ.get('AEXNOTIFY') == '1'
 HAS_AVX = os.environ.get('AVX') == '1'
 HAS_EDMM = os.environ.get('EDMM') == '1'
 HAS_SGX = os.environ.get('SGX') == '1'