x86-urgent-2020-07-19

 - Fix the I/O bitmap invalidation on XEN PV, which was overlooked in the
   recent ioperm/iopl rework. This caused the TSS and XEN's I/O bitmap to
   get out of sync.

 - Use the proper vectors for HYPERV.

 - Make disabling of stack protector for the entry code work with GCC
   builds which enable stack protector by default. Removing the option is
   not sufficient, it needs an explicit -fno-stack-protector to shut it
   off.

 - Mark check_user_regs() noinstr as it is called from noinstr code. The
   missing annotation causes it to be placed in the text section which
   makes it instrumentable.

 - Add the missing interrupt disable in exc_alignment_check()

 - Fixup a XEN_PV build dependency in the 32bit entry code

 - A few fixes to make the Clang integrated assembler happy

 - Move EFI stub build to the right place for out of tree builds

 - Make prepare_exit_to_usermode() static. It's not longer called from ASM
   code.