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


From: Richard Henderson
Subject: Re: [Qemu-devel] [PATCH v2 15/16] target-s390x: use softmmu functions for mvcp/mvcs
Date: Wed, 03 Jun 2015 15:06:04 -0700
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0

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<address@hidden>
Cc: Richard Henderson<address@hidden>
Signed-off-by: Aurelien Jarno<address@hidden>
---
  target-s390x/mem_helper.c | 53 ++++++++++++++++++-----------------------------
  1 file changed, 20 insertions(+), 33 deletions(-)

Reviewed-by: Richard Henderson <address@hidden>


r~



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