Re: [Qemu-devel] [PATCH v2 15/16] target-s390x: use softmmu functions for mvcp/mvcs

[Richard Henderson <rth@twiddle.net>]

On 06/03/2015 02:09 PM, Aurelien Jarno wrote:
> mvcp and mvcs helper get access to the physical memory by a call to
> mmu_translate for the virtual to real conversion and then using ldb_phys
> and stb_phys to physically access the data. In practice this is quite
> slow because it bypasses the QEMU softmmu TLB and because stb_phys calls
> try to invalidate the corresponding memory for each access.
>
> Instead use cpu_ldb_{primary,secondary} for the loads and
> cpu_stb_{primary,secondary} for the stores. Ideally this should be
> further optimized by a call to memcpy, but that already improves the
> boot time of a guest by a factor 1.8.
>
> Cc: Alexander Graf<agraf@suse.de>
> Cc: Richard Henderson<rth@twiddle.net>
> Signed-off-by: Aurelien Jarno<aurelien@aurel32.net>
> ---
>   target-s390x/mem_helper.c | 53 ++++++++++++++++++-----------------------------
>   1 file changed, 20 insertions(+), 33 deletions(-)

Reviewed-by: Richard Henderson <rth@twiddle.net>


r~