test: Reintroduce unrestorable MSRs for AMD

MSR_F15H_PERF_CTR5 and MSR_AMD64_DE_CFG are not restored correctly.
Although they were in the exceptionn list, no valid reasons are
assocaited [1]. Reintroduce them to the snapshot-specific exception list
for now but with TODOs. I'll come back to them soon.

[1]: cfc9619
Signed-off-by: Takahiro Itazuri <[email protected]>

Author: zulinx86

tests/integration_tests/functional/test_cpu_features_x86_64.py

@@ -258,6 +258,17 @@ def test_brand_string(uvm_plain_any):
     # - https://github.com/torvalds/linux/commit/7131636e7ea5b50ca910f8953f6365ef2d1f741c
     # - https://github.com/torvalds/linux/commit/b9846a698c9aff4eb2214a06ac83638ad098f33f
     "0x122",
+    # MSR_F15H_PERF_CTR5 is a performance counter MSR.
+    #
+    # TODO: Dive deep into kernel behavior.
+    "0xc001020b",
+    # MSR_AMD64_DE_CFG contains the LFENCE serializing bit.
+    #
+    # TODO: Dive deep into kernel behavior.
+    # - https://github.com/torvalds/linux/commit/e4d0e84e490790798691aaa0f2e598637f1867ec
+    # - https://github.com/torvalds/linux/commit/d1d93fa90f1afa926cb060b7f78ab01a65705b4d
+    # - https://github.com/torvalds/linux/commit/2632daebafd04746b4b96c2f26a6021bc38f6209
+    "0xc0011029",
 ]
 # fmt: on