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Re: [Qemu-devel] [PATCH v2 3/8] s390x: improve error handling for SSCH a
From: |
Halil Pasic |
Subject: |
Re: [Qemu-devel] [PATCH v2 3/8] s390x: improve error handling for SSCH and RSCH |
Date: |
Tue, 10 Oct 2017 16:36:41 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 |
On 10/10/2017 03:07 PM, Cornelia Huck wrote:
> On Wed, 4 Oct 2017 17:41:39 +0200
> Halil Pasic <address@hidden> wrote:
>
>> Simplify the error handling of the SSCH and RSCH handler avoiding
>> arbitrary and cryptic error codes being used to tell how the instruction
>> is supposed to end. Let the code detecting the condition tell how it's
>> to be handled in a less ambiguous way. It's best to handle SSCH and RSCH
>> in one go as the emulation of the two shares a lot of code.
>>
>> For passthrough this change isn't pure refactoring, but changes the
>> way kernel reported EFAULT is handled. After clarifying the kernel
>> interface we decided that EFAULT shall be mapped to unit exception.
>> Same goes for unexpected error codes.
>>
>> Signed-off-by: Halil Pasic <address@hidden>
>> ---
>>
>> AFAIR we decided in the previous round to rather do transformation
>> and fixing in one patch than touch stuff twice. Hence this patch
>> ain't pure transformation any more.
>> ---
>> hw/s390x/css.c | 83
>> +++++++++++++--------------------------------
>> hw/s390x/s390-ccw.c | 11 +++---
>> hw/vfio/ccw.c | 30 ++++++++++++----
>> include/hw/s390x/css.h | 24 +++++++++----
>> include/hw/s390x/s390-ccw.h | 2 +-
>> target/s390x/ioinst.c | 53 ++++-------------------------
>> 6 files changed, 77 insertions(+), 126 deletions(-)
>
> After browsing through this patch, I think the change will work just as
> well if you use e.g. #defines instead of the structure, won't it?
>
Sure. We just loose type safety. For example if someone ever should try to
propagate a normal errno via return do_something() the compiler won't
catch it we effectively use int for both.
Re: [Qemu-devel] [PATCH v2 3/8] s390x: improve error handling for SSCH and RSCH, Dong Jia Shi, 2017/10/10
[Qemu-devel] [PATCH v2 5/8] s390x: refactor error handling for CSCH handler, Halil Pasic, 2017/10/04
[Qemu-devel] [PATCH v2 2/8] s390x/css: IO instr handler ending control, Halil Pasic, 2017/10/04