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Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire |
Date: |
Thu, 26 Jan 2017 15:28:44 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 |
On 26/01/2017 14:37, Pavel Dovgalyuk wrote:
>> Simpler:
>>
>> use_icount &&
>> ((int32_t)cpu->icount_decr.u32 < 0 ||
>> cpu->icount_decr.u16.low + cpu->icount_extra == 0)
> Right.
>
>> But I'm not sure that you need to test u32. After all you're not
> Checking u32 is needed, because sometimes it is less than zero.
If cpu->icount_decr.u32 is less than zero, the next translation block
would immediately exit with TB_EXIT_ICOUNT_EXPIRED, causing
cpu->exception_index = EXCP_INTERRUPT;
*last_tb = NULL;
cpu_loop_exit(cpu);
from cpu_loop_exec_tb's "case TB_EXIT_ICOUNT_EXPIRED".
And the same is true for cpu->icount_decr.u16.low + cpu->icount_extra ==
0, so I don't understand why this part of the patch is necessary.
Paolo
- [Qemu-devel] [PATCH v8 0/9] replay additions, Pavel Dovgalyuk, 2017/01/26
- [Qemu-devel] [PATCH v8 1/9] replay: exception replay fix, Pavel Dovgalyuk, 2017/01/26
- [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Pavel Dovgalyuk, 2017/01/26
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Paolo Bonzini, 2017/01/26
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Pavel Dovgalyuk, 2017/01/26
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Pavel Dovgalyuk, 2017/01/26
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Paolo Bonzini, 2017/01/26
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Pavel Dovgalyuk, 2017/01/27
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Paolo Bonzini, 2017/01/27
[Qemu-devel] [PATCH v8 3/9] apic: save apic_delivered flag, Pavel Dovgalyuk, 2017/01/26
[Qemu-devel] [PATCH v8 4/9] integratorcp: adding vmstate for save/restore, Pavel Dovgalyuk, 2017/01/26