• Greg Kroah-Hartman's avatar
    Revert "KVM: X86 emulator: fix source operand decoding for 8bit mov[zs]x instructions" · 5e1f777d
    Greg Kroah-Hartman authored
    This reverts commit 5b5b3058, which was
    commit 660696d1 upstream.
    
    Paul Gortmaker <paul.gortmaker@windriver.com> writes:
    
    [this patch] 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 (dd856efa) 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 660696d1
    
     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+
    Reported-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
    Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    Cc: Gleb Natapov <gleb@redhat.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    5e1f777d
emulate.c 111 KB