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Re: [Qemu-devel] pause_all_vcpus() TCG bug?
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] pause_all_vcpus() TCG bug? |
Date: |
Thu, 02 May 2013 10:44:35 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2013-05-01 15:47, Peter Maydell wrote:
> On 1 May 2013 14:33, Andreas Färber <address@hidden> wrote:
>> Hello,
>>
>> This is today's function, with annotations and question inline:
>>
>> void pause_all_vcpus(void)
>> {
>> CPUArchState *penv = first_cpu;
>>
>> qemu_clock_enable(vm_clock, false);
>> while (penv) {
>> CPUState *pcpu = ENV_GET_CPU(penv);
>> pcpu->stop = true;
>> qemu_cpu_kick(pcpu);
>> penv = penv->next_cpu;
>> }
>>
>> /* So, at this point penv == NULL. */
>>
>> if (qemu_in_vcpu_thread()) {
>> cpu_stop_current();
>> if (!kvm_enabled()) {
>> while (penv) {
>>
>> /* Looks like this can never be true then? */
>> /* Is penv = first_cpu; missing? */
Yeah, obviously. It practically didn't matter so far for the use case of
pause/resume_all_vcpus over a vcpu itself (kvmvapic). Feel free to fix.
>>
>> CPUState *pcpu = ENV_GET_CPU(penv);
>> pcpu->stop = 0;
>>
>> /* 0 instead of false may hint at a mismerge... */
Nope, stop was uint32_t at that time.
Jan
>>
>> pcpu->stopped = true;
>> penv = penv->next_cpu;
>> }
>> return;
>> }
>> }
>
> This certainly looks odd. This bug seems to have
> been present since this patch was first committed
> (d798e9745, January last year, by Jan.)
>
> -- PMM
>
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