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Re: [Qemu-devel] [PATCH v2] target-s390x: fix LOAD MULTIPLE instruction
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH v2] target-s390x: fix LOAD MULTIPLE instruction on page boundary |
Date: |
Tue, 26 May 2015 09:15:16 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
On 05/26/2015 02:09 AM, Aurelien Jarno wrote:
> This is an important detail in case the base register is in the list
> of registers to be loaded. If a page fault occurs this register might be
> overwritten and when the instruction is later restarted the wrong
> base register value is useD.
>
> Fix this by first loading the first and last value from memory, hence
> triggering all possible page faults, and then the remaining registers.
>
> This fixes random segmentation faults seen in the guest.
>
> Cc: Alexander Graf <address@hidden>
> Cc: Richard Henderson <address@hidden>
> Signed-off-by: Aurelien Jarno <address@hidden>
> ---
> target-s390x/translate.c | 128
> ++++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 99 insertions(+), 29 deletions(-)
>
> Changes v1->v2:
> - Do the load in two steps: first and last registers, and then the remaining
> ones
Reviewed-by: Richard Henderson <address@hidden>
r~