[stable-3.4] possibly revert "KVM: X86 emulator: fix source operand decoding..."

[Paul Gortmaker <paul.gortmaker@windriver.com>]

Hi Greg,

The 3.4.44+ cherry pick:

  ----------------
  commit 5b5b30580218eae22609989546bac6e44d0eda6e
  Author: Gleb Natapov <gleb@redhat.com>
  Date:   Wed Apr 24 13:38:36 2013 +0300

    KVM: X86 emulator: fix source operand decoding for 8bit mov[zs]x instructions
    
    commit 660696d1d16a71e15549ce1bf74953be1592bcd3 upstream.
    
    Source operand for one byte mov[zs]x is decoded incorrectly if it is in
    high byte register. Fix that.
    
    Signed-off-by: Gleb Natapov <gleb@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  ----------------

introduces the following:

arch/x86/kvm/emulate.c: In function ‘decode_operand’:
arch/x86/kvm/emulate.c:3974:4: warning: passing argument 1 of ‘decode_register’ makes integer from pointer without a cast [enabled by default]
arch/x86/kvm/emulate.c:789:14: note: expected ‘u8’ but argument is of type ‘struct x86_emulate_ctxt *’
arch/x86/kvm/emulate.c:3974:4: warning: passing argument 2 of ‘decode_register’ makes pointer from integer without a cast [enabled by default]
arch/x86/kvm/emulate.c:789:14: note: expected ‘long unsigned int *’ but argument is of type ‘u8’

Based on the severity of the warnings above, I'm reasonably sure there will
be some kind of runtime regressions due to this, but I stopped to investigate
the warnings as soon as I saw them, before any run time testing.

It happens because mainline v3.7-rc1~113^2~40 (dd856efafe60) does this:

-static void *decode_register(u8 modrm_reg, unsigned long *regs,
+static void *decode_register(struct x86_emulate_ctxt *ctxt, u8 modrm_reg,

Since 660696d1d16a71e1 was only applied to stable 3.4, 3.8, and 3.9 -- and
the prerequisite above is in 3.7+, the issue should be limited to 3.4.44+

Thanks,
Paul.