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Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling
From: |
Alex Bennée |
Subject: |
Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR |
Date: |
Wed, 14 Jun 2017 13:35:35 +0100 |
User-agent: |
mu4e 0.9.19; emacs 25.2.50.3 |
Paolo Bonzini <address@hidden> writes:
> On 14/06/2017 14:14, Alex Bennée wrote:
>>> Then Emilio's patch, if a bit of a heavy hammer, is correct. After
>>> aa64_daif_write needs you need an exit_tb so that arm_cpu_exec_interrupt
>>> is executed again.
>>
>> This is a case of cpu->interrupt_request being pending but not having
>> set cpu->icount_decr yet to signal the exit.
>
> Rather than "yet", "anymore". So far it has always been an invariant
> that anything that re-enabled an interrupt had to do exit_tb.
>
>> Wouldn't another approach
>> (that didn't involve futzing with each front-end) to be to check
>> cpu->interrupt_request and force the exit in lookup_tb_ptr?
>
> That would cause an unnecessary slowdown in code that runs with
> interrupts disabled but does a lot of indirect jumps... ppc's SLOF
> firmware probably qualifies.
Really? I'd have to measure the change it makes. Is there a benchmark
stanza for measuring the PPC slof firmware time?
I have 3 patches now which all fix the same thing so we can pick and
choose which we should apply. Patches incoming...
--
Alex Bennée
- Re: [Qemu-arm] [RFC DEBUG PATCH 3/3] translate-a64: fix lookup_tb_ptr hang (DEBUG!), (continued)
- Re: [Qemu-arm] [RFC DEBUG PATCH 3/3] translate-a64: fix lookup_tb_ptr hang (DEBUG!), Emilio G. Cota, 2017/06/11
- Re: [Qemu-arm] [RFC DEBUG PATCH 3/3] translate-a64: fix lookup_tb_ptr hang (DEBUG!), Alex Bennée, 2017/06/12
- [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR, Emilio G. Cota, 2017/06/13
- Re: [Qemu-arm] [Qemu-devel] [PATCH] target/aarch64: exit to main loop after handling MSR, no-reply, 2017/06/13
- Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR, Richard Henderson, 2017/06/14
- Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR, Paolo Bonzini, 2017/06/14
- Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR, Alex Bennée, 2017/06/14
- Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR, Paolo Bonzini, 2017/06/14
- Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR, Alex Bennée, 2017/06/14
- Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR, Paolo Bonzini, 2017/06/14
- Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR,
Alex Bennée <=
- Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR, Paolo Bonzini, 2017/06/14
- Re: [Qemu-arm] [PATCH] target/aarch64: exit to main loop after handling MSR, Alex Bennée, 2017/06/14