Hello,

syzbot has tested the proposed patch but the reproducer still triggered  
crash:
WARNING in kvm_arch_vcpu_ioctl_run

VMExit: intr_info=00000000 errcode=00000000 ilen=00000000
         reason=80000021 qualification=0000000000000000
IDTVectoring: info=00000000 errcode=00000000
TSC Offset = 0xffffffeeb46bc6ac
EPT pointer = 0x00000001ce37601e
WARNING: CPU: 0 PID: 3023 at arch/x86/kvm/x86.c:7293  
kvm_arch_vcpu_ioctl_run+0x213/0x5d20
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 3023 Comm: syz-executor4 Not tainted 4.14.0-next-20171117+ #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  dump_stack+0x173/0x237
  panic+0x1e4/0x41c
  __warn+0x1d9/0x1f0
  report_bug+0x20a/0x2d0
  fixup_bug.part.10+0x32/0x80
  do_error_trap+0x29c/0x370
  invalid_op+0x18/0x20
RIP: 0010:kvm_arch_vcpu_ioctl_run+0x213/0x5d20
RSP: 0018:ffff8801ce197680 EFLAGS: 00010293
RAX: ffff8801ce588440 RBX: ffff8801d5b8f000 RCX: ffffffff810d4003
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801ce0e02b8
RBP: ffff8801ce197a50 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffff8801ce0e0168 R14: ffff8801cec10980 R15: ffff8801ce0e0080
  kvm_vcpu_ioctl+0x619/0xf80
  do_vfs_ioctl+0x18b/0x13e0
  SyS_ioctl+0x7e/0xb0
  entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452879
RSP: 002b:00007f4bc97fdbe8 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000082 RCX: 0000000000452879
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000004
RBP: 00007ffce1993510 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
R13: 00007ffce199348f R14: 00007f4bc97fe9c0 R15: 0000000000000006
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


Tested on commit ee92513eae0107795fb27ce25b6bc3dfb14dd866
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
Patch is attached.
Kernel config is attached.
Raw console output is attached.