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From: Richard Henderson <rth@twiddle.net>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Sergey Fedorov <serge.fdrv@gmail.com>,
	sergey.fedorov@linaro.org, qemu-devel@nongnu.org
Cc: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Subject: Re: [Qemu-devel] [PATCH 4/5] tcg: reorder removal from lists in tb_phys_invalidate
Date: Mon, 28 Mar 2016 17:17:41 -0700	[thread overview]
Message-ID: <56F9C9A5.4040904@twiddle.net> (raw)
In-Reply-To: <56F99AE0.5080008@redhat.com>

On 03/28/2016 01:58 PM, Paolo Bonzini wrote:
>
>
> On 28/03/2016 20:42, Sergey Fedorov wrote:
>> On 17/03/16 16:46, sergey.fedorov@linaro.org wrote:
>>> First the translation block is invalidated, for which a simple write
>>> to tb->pc is enough.  This means that cpu-exec will not pick up anymore
>>> the block, though it may still execute it through chained jumps.  This
>>> also replaces the NULLing out of the pointer in the CPUs' local cache.
>>
>> Although, using 'tb->pc' to mark a TB as invalid is probably not such a
>> good idea. There may be some cases when PC could become equal to -1. For
>> example, ARMv6-M uses PC >= 0xFFFFFFF0 to perform exception return. So
>> we'd better introduce a separate 'tb->valid' or 'tb->invalid' flag.
>
> It is also possible to use tb->flags for that.  I suspect that all-ones
> tb flags is never valid, but it could also be a #define.

That might work by accident, but it might not.  You'd need to reserve a bit 
across all of the targets.


r~

  reply	other threads:[~2016-03-29  0:17 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-17 13:46 [Qemu-devel] [PATCH 0/5] tcg: Misc clean-up patches from Paolo sergey.fedorov
2016-03-17 13:46 ` [Qemu-devel] [PATCH 1/5] tcg: code_bitmap is not used by user-mode emulation sergey.fedorov
2016-03-17 14:56   ` Peter Maydell
2016-03-17 15:03     ` Sergey Fedorov
2016-03-17 13:46 ` [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop sergey.fedorov
2016-03-17 14:59   ` Peter Maydell
2016-03-22 14:59   ` Alex Bennée
2016-03-22 15:00     ` Paolo Bonzini
2016-03-29 13:19     ` Sergey Fedorov
2016-03-29 13:26       ` Paolo Bonzini
2016-03-29 14:05         ` Sergey Fedorov
2016-03-29 14:26           ` Alex Bennée
2016-03-29 14:37             ` Sergey Fedorov
2016-03-17 13:46 ` [Qemu-devel] [PATCH 3/5] tcg: always keep jump target and tb->jmp_next consistent sergey.fedorov
2016-03-17 17:57   ` Richard Henderson
2016-03-17 19:31     ` Paolo Bonzini
2016-03-17 20:45       ` Sergey Fedorov
2016-03-17 20:46         ` Richard Henderson
2016-03-18 10:29           ` Sergey Fedorov
2016-03-18 10:32         ` Sergey Fedorov
2016-03-17 13:46 ` [Qemu-devel] [PATCH 4/5] tcg: reorder removal from lists in tb_phys_invalidate sergey.fedorov
2016-03-17 15:09   ` Paolo Bonzini
2016-03-17 15:14     ` Sergey Fedorov
2016-03-28 15:18       ` Sergey Fedorov
2016-03-28 21:21         ` Paolo Bonzini
2016-03-29 10:03           ` Sergey Fedorov
2016-03-29 10:37             ` Paolo Bonzini
2016-03-29 12:31               ` Sergey Fedorov
2016-03-29 13:43                 ` Alex Bennée
2016-04-14 14:45               ` Sergey Fedorov
2016-04-14 15:13                 ` Paolo Bonzini
2016-04-14 15:36                   ` Sergey Fedorov
2016-04-14 17:27                     ` Paolo Bonzini
2016-04-14 18:29                   ` Sergey Fedorov
2016-04-14 18:37                   ` Sergey Fedorov
2016-03-28 18:42   ` Sergey Fedorov
2016-03-28 20:58     ` Paolo Bonzini
2016-03-29  0:17       ` Richard Henderson [this message]
2016-03-17 13:46 ` [Qemu-devel] [PATCH 5/5] tcg: move tb_invalidated_flag to CPUState sergey.fedorov
2016-03-22 15:07   ` Alex Bennée
2016-03-22 15:11     ` Sergey Fedorov

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