Host kernel panics with "unexpected #NM exception" at restore_fpregs_from_fpstate, the exception is handled by exc_device_not_available

Issue

• Kernel panic with the following messages:

  unexpected #NM exception: 0000 [#1] PREEMPT SMP NOPTI
  

• A kernel warning can be observed prior to crash:

  WARNING: CPU: 67 PID: 2438139 at arch/x86/kernel/traps.c:1300 handle_xfd_event+0xb4/0xc0
  

• The exc_device_not_available exception was triggered when trying to load FPU context before returning to user space:

  PID: 1234  TASK: ff12f940f561a380  CPU: 7   COMMAND: "CPU 1/KVM"
   #0 [ff2556567473bad0] machine_kexec at ffffffffa58780f7
   #1 [ff2556567473bb28] __crash_kexec at ffffffffa59efdfa
   #2 [ff2556567473bbe8] crash_kexec at ffffffffa59f1088
   #3 [ff2556567473bbf0] oops_end at ffffffffa582f98b
   #4 [ff2556567473bc10] exc_device_not_available at ffffffffa64848b4
   #5 [ff2556567473bc30] asm_exc_device_not_available at ffffffffa6600a16
      [exception RIP: restore_fpregs_from_fpstate+0x3f]
      RIP: ffffffffa583abaf  RSP: ff2556567473bce0  RFLAGS: 00010046
      RAX: 00000000000604e7  RBX: 00000000000604ff  RCX: ff25565650d63000
      RDX: 0000000000000000  RSI: 00000000000604ff  RDI: ff25565650d63040
      RBP: ff12f940f561bc80   R8: ff12fc3abf540000   R9: 00007f1638bfe640
      R10: 0000000000181caa  R11: 0000000000000000  R12: 0000000000040000
      R13: 0000000000000000  R14: ff12fb81b38d4900  R15: 0000000000000000
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
   #6 [ff2556567473bcf8] switch_fpu_return at ffffffffa583ad5c
   #7 [ff2556567473bd18] vcpu_enter_guest.constprop.0 at ffffffffc1a648c8 [kvm]
   #8 [ff2556567473bd88] vcpu_run at ffffffffc1a65010 [kvm]
   #9 [ff2556567473bda8] kvm_arch_vcpu_ioctl_run at ffffffffc1a6539a [kvm]
  #10 [ff2556567473bdd8] kvm_vcpu_ioctl at ffffffffc1a353e1 [kvm]
  #11 [ff2556567473be88] __x64_sys_ioctl at ffffffffa5c4dec7
  #12 [ff2556567473beb8] do_syscall_64 at ffffffffa6483459
  #13 [ff2556567473bf50] entry_SYSCALL_64_after_hwframe at ffffffffa660012f
      RIP: 00007f1643a5659b  RSP: 00007f1638bfd3e8  RFLAGS: 00000246
      RAX: ffffffffffffffda  RBX: 000055d866d8d3b0  RCX: 00007f1643a5659b
      RDX: 0000000000000000  RSI: 000000000000ae80  RDI: 0000000000000028
      RBP: 000000000000ae80   R8: 000055d86860fb90   R9: 000055d86537f485
      R10: 00007f16393ffdb8  R11: 0000000000000246  R12: 00007f16393ffe50
      R13: 92d44c3e08aaef00  R14: 0000000000000000  R15: fffffffffffffd00
      ORIG_RAX: 0000000000000010  CS: 0033  SS: 002b