Re: [Qemu-devel] [PATCH] target-i386: n270 can MOVBE

[Andreas Färber]

Hi,

Am 08.02.2013 10:30, schrieb Borislav Petkov:
> From: Borislav Petkov <address@hidden>
> 
> The Atom core (cpu name "n270" in QEMU speak) supports MOVBE. This is
> needed when booting 3.8 and later linux kernels built with the MATOM
> target because we require MOVBE in order to boot properly now.
> 
> Cc: "H. Peter Anvin" <address@hidden>
> Cc: Richard Henderson <address@hidden>
> Signed-off-by: Borislav Petkov <address@hidden>

Please CC me on cpu.c changes (cf. MAINTAINERS).

> ---
> 
> Right, so I was playing with booting MATOM kernels in QEMU.
> As it turns out, QEMU's n270 model doesn't advertize MOVBE
> although the real hardware supports it. Quick search pointed me to
> http://lists.nongnu.org/archive/html/qemu-devel/2013-01/msg04317.html
> which adds that support, among other things. I've merged Richard's
> patchset with qemu's current master and after applying this patch below,
> I can report success booting an MATOM kernel with QEMU. The same kernel
> boots on the real n270 hardware, btw.
> 
>  target-i386/cpu.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 9f38e4435e53..83816edd8410 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -610,7 +610,8 @@ static x86_def_t builtin_x86_defs[] = {
>              CPUID_ACPI | CPUID_SS | CPUID_HT | CPUID_TM | CPUID_PBE,
>              /* Some CPUs got no CPUID_SEP */
>          .ext_features = CPUID_EXT_SSE3 | CPUID_EXT_MONITOR | CPUID_EXT_SSSE3 
> |
> -            CPUID_EXT_DSCPL | CPUID_EXT_EST | CPUID_EXT_TM2 | CPUID_EXT_XTPR,
> +            CPUID_EXT_DSCPL | CPUID_EXT_EST | CPUID_EXT_TM2 | CPUID_EXT_XTPR 
> |
> +         CPUID_EXT_MOVBE,

Tab. Please use scripts/checkpatch.pl to verify before sending.

>          .ext2_features = (PPRO_FEATURES & CPUID_EXT2_AMD_ALIASES) |
>              CPUID_EXT2_NX,
>          .ext3_features = CPUID_EXT3_LAHF_LM,

Otherwise if someone can ack (or if you can point me to a manual), this
looks like a good bugfix for v1.4. CC'ing some more CPU'ish people.

Regards,
Andreas

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