CPU emulated != host CPU

[Pierre Dupond]

Hi All,
      I would to install qemu to compile software for
a small machine pcengines APU (https://www.pcengines.ch).

This machine has the following CPU "AMD Embedded G series GX-412TC"
which is similar to the Qemu CPU "Opteron_G5".

Unfortunately my compile machine (where qemu is run) is
a Mac Pro 2010 with 8 Xeons core. I use the following command
to launch qemu:
    qemu-system-x86_64 -m 24576 \
    -smp 8 \
    -cpu Opteron_G5 \
    -nographic      \
    -serial tcp::${SERIAL_CONSOLE_PORT},server,nowait \
    -hda "${BASE_DISK_DIR}/netbsd9_wd0.img" \
    -hdb "${BASE_DISK_DIR}/netbsd9_wd1.img" \
    -cdrom "${BASE_DISK_DIR}/../../ISO/NetBSD-9.0-amd64-com.iso" \
    -net user,hostfwd=tcp::2222-:22

I get a lot of warnings similar to this one:
     qemu-system-x86_64: warning: TCG doesn't support requested feature: 
CPUID.01H:ECX.avx [bit 28]

I have more or less the same warnings when I use kvm.

My question is to know if it is possible to run a such configuration
which will be very convenient since my compile machine will have
the same architecture as the target machine.

Thanks for your help.

Best regards
--
Pierre Dupond <address@hidden>