On Thu, Oct 31, 2013 at 11:29:42AM +0100, Paolo Bonzini wrote:
> Yet another instruction that we fail to emulate, this time found
> in Windows 2008R2 32-bit.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> Testcase on its way. BTW, lahf/sahf is another candidate for
> #UD emulation.
>
> arch/x86/kvm/emulate.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 8e2a07bd8eac..ef750e75c930 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -3296,6 +3296,18 @@ static int em_cpuid(struct x86_emulate_ctxt *ctxt)
> return X86EMUL_CONTINUE;
> }
>
> +static int em_sahf(struct x86_emulate_ctxt *ctxt)
> +{
> + u32 flags;
> +
Shouldn't we check CPUID.80000001H.ECX[0] = 1 in 64 bit mode?
> + flags = EFLG_CF | EFLG_PF | EFLG_AF | EFLG_ZF | EFLG_SF;
> + flags &= *reg_rmw(ctxt, VCPU_REGS_RAX) >> 8;
> +
> + ctxt->eflags &= ~0xffUL;
> + ctxt->eflags |= flags | X86_EFLAGS_FIXED;
> + return X86EMUL_CONTINUE;
> +}
> +
> static int em_lahf(struct x86_emulate_ctxt *ctxt)
> {
> *reg_rmw(ctxt, VCPU_REGS_RAX) &= ~0xff00UL;
> @@ -3788,7 +3800,7 @@ static const struct opcode opcode_table[256] = {
> DI(SrcAcc | DstReg, pause), X7(D(SrcAcc | DstReg)),
> /* 0x98 - 0x9F */
> D(DstAcc | SrcNone), I(ImplicitOps | SrcAcc, em_cwd),
> - I(SrcImmFAddr | No64, em_call_far), N,
> + I(SrcImmFAddr | No64, em_call_far), I(ImplicitOps, em_sahf),
> II(ImplicitOps | Stack, em_pushf, pushf),
> II(ImplicitOps | Stack, em_popf, popf), N, I(ImplicitOps, em_lahf),
> /* 0xA0 - 0xA7 */
> --
> 1.8.3.1
--
Gleb.
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