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From: Richard Henderson <rth@twiddle.net>
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Date: Thu, 16 Feb 2017 08:53:41 +1100
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Subject: Re: [Qemu-devel] [PATCH v12 12/24] tcg: handle EXCP_ATOMIC
 exception for system emulation
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To: =?UTF-8?Q?Alex_Benn=c3=a9e?= <alex.bennee@linaro.org>
Cc: mttcg@greensocs.com, peter.maydell@linaro.org, nikunj@linux.vnet.ibm.com, Peter Crosthwaite <crosthwaite.peter@gmail.com>, jan.kiszka@siemens.com, mark.burton@greensocs.com, a.rigo@virtualopensystems.com, qemu-devel@nongnu.org, cota@braap.org, serge.fdrv@gmail.com, pbonzini@redhat.com, bobby.prani@gmail.com, bamvor.zhangjian@linaro.org, fred.konrad@greensocs.com

On 02/14/2017 09:50 PM, Alex Bennée wrote:
>
> Richard Henderson <rth@twiddle.net> writes:
>
>> On 02/13/2017 11:10 PM, Alex Bennée wrote:
>>> @@ -239,9 +240,16 @@ static void cpu_exec_step(CPUState *cpu)
> <snip>
>>> +                } else if (r == EXCP_ATOMIC) {
>>> +                    qemu_mutex_unlock_iothread();
>>> +                    cpu_exec_step_atomic(cpu);
>>> +                    qemu_mutex_lock_iothread();
>> ...
>>> +            case EXCP_ATOMIC:
>>> +                qemu_mutex_unlock_iothread();
>>> +                cpu_exec_step_atomic(cpu);
>>> +                qemu_mutex_lock_iothread();
>>
>>
>> I just noticed this, but if you have to do a v13, it might be best to
>> move these locks inside cpu_exec_step_atomic, as with tcg_cpu_exec.
>> Otherwise leave it for later.
>
> Will that work given cpu_exec_step_atomic() is common between linux-user
> and system emulation?

Ug.  No, you're right.


r~