Messages in this thread Patch in this message |  | | From | Greg Kroah-Hartman <> | | Subject | [ 23/23] Revert "KVM: X86 emulator: fix source operand decoding for 8bit mov[zs]x instructions" | | Date | Thu, 12 Sep 2013 10:45:19 -0700 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 5b5b30580218eae22609989546bac6e44d0eda6e, which was commit 660696d1d16a71e15549ce1bf74953be1592bcd3 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 (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+
Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/x86/kvm/emulate.c | 4 ---- 1 file changed, 4 deletions(-)
--- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3737,10 +3737,6 @@ static int decode_operand(struct x86_emu break; case OpMem8: ctxt->memop.bytes = 1; - if (ctxt->memop.type == OP_REG) { - ctxt->memop.addr.reg = decode_register(ctxt, ctxt->modrm_rm, 1); - fetch_register_operand(&ctxt->memop); - } goto mem_common; case OpMem16: ctxt->memop.bytes = 2;
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