Uncorrectable MCE invoked during REP MOVSB operation causes system crash

Issue

• Uncorrectable MCE invoked during REP MOVSB operation causes a Hyper-V guest to crash

[6994673.353939] mce: [Hardware Error]: CPU 20: Machine Check Exception: 7 Bank 0: bd80000000000134
[6994673.197005] mce: [Hardware Error]: Machine check events logged
[6994673.353939] mce: [Hardware Error]: RIP 10:<ffffffffb0393d89> {copy_user_enhanced_fast_string+0x9/0x20}
[6994673.353939] mce: [Hardware Error]: TSC 340ff8ec6027e1 ADDR 35d46c9000 MISC 8c 
[6994673.353939] mce: [Hardware Error]: PROCESSOR 0:50654 TIME 1638016546 SOCKET 0 APIC 14 microcode ffffffff
[6994673.353939] mce: [Hardware Error]: Run the above through 'mcelog --ascii'
[6994673.353939] mce: [Hardware Error]: Machine check: Action required: unknown MCACOD
[6994673.353939] Kernel panic - not syncing: Fatal machine check

PID: 13184  TASK: ffff93b7cfbb1070  CPU: 20  COMMAND: "mc:auxIO_3"
 #0 [ffff93881fd08e48] crash_nmi_callback at ffffffffb0058467
 #1 [ffff93881fd08e58] nmi_handle at ffffffffb078a93c
 #2 [ffff93881fd08eb0] do_nmi at ffffffffb078ab5d
 #3 [ffff93881fd08ef0] end_repeat_nmi at ffffffffb0789d9c
    [exception RIP: delay_tsc+42]
    RIP: ffffffffb039421a  RSP: ffff93881fd0bde8  RFLAGS: 00000287
    RAX: 0000000000000214  RBX: 0000000000484d21  RCX: 00340ff9102f5e0d
    RDX: 00340ff9102f6021  RSI: 0000000000000014  RDI: 0000000000000830
    RBP: ffff93881fd0bde8   R8: 0000000000000001   R9: 0000000000000000
    R10: 0000000000000001  R11: 0000000000000001  R12: 0000000000000001
    R13: ffff93881fd0bf58  R14: 0100000000000001  R15: 0000000000000001
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
--- <NMI exception stack> ---
 #4 [ffff93881fd0bde8] delay_tsc at ffffffffb039421a
 #5 [ffff93881fd0bdf0] __const_udelay at ffffffffb039416d
 #6 [ffff93881fd0be00] wait_for_panic at ffffffffb0777f76
 #7 [ffff93881fd0be18] mce_timed_out at ffffffffb004b2ce
 #8 [ffff93881fd0be30] do_machine_check at ffffffffb004cff3
 #9 [ffff93881fd0bf40] do_mce at ffffffffb004d4e5
#10 [ffff93881fd0bf50] machine_check at ffffffffb07897ce
    [exception RIP: copy_user_enhanced_fast_string+9]
    RIP: ffffffffb0393d89  RSP: ffff93b7f9cefc70  RFLAGS: 00050206
    RAX: ffff937f8699a279  RBX: ffff93b7f9cefd28  RCX: 0000000000000f40
    RDX: 0000000000001000  RSI: ffff938dd46c90c0  RDI: 00007ff3f68170c0
    RBP: ffff93b7f9cefca0   R8: 0000000000000002   R9: 0000000000000000
    R10: ffff93b7f9ceffd8  R11: ffff938a9b4e7580  R12: 0000000000001000
    R13: 0000000000001000  R14: ffff938dd46c9000  R15: 00007ff3f6817000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
--- <MCE exception stack> ---
    ...