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From: Andi Kleen <ak@linux.intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Subject: Re: qemu polling KVM_IRQ_LINE_STATUS when stopped
Date: Thu, 19 Oct 2017 17:34:49 -0700	[thread overview]
Message-ID: <20171020003449.GG5109@tassilo.jf.intel.com> (raw)
In-Reply-To: <3d37ef15-932a-1492-3068-9ef0b8cd5794@redhat.com>

On Wed, Oct 18, 2017 at 09:24:33PM +0200, Paolo Bonzini wrote:
> On 18/10/2017 19:49, Andi Kleen wrote:
> > 
> > The ioctl appears to be the PIC timer
> > 
> >   - 6.36% __GI___ioctl                                                                                                                                ▒
> >            kvm_vm_ioctl                                                                                                                                   ▒
> >            kvm_set_irq                                                                                                                                    ▒
> >            kvm_pic_set_irq   
> 
> PIC is the interrupt controller, why do you say the timer?  What is the
> QEMU side of the call stack?


I did some more sampling in gdb this time.

All the timer call backs I caught are rtc_period_timer.

Perhaps that needs to be stopped when the guest is stopped?

It also calls the ioctl:

#0  0x00007f73d97175e0 in ioctl () from target:/lib64/libc.so.6
#1  0x000055ed03c7ec82 in kvm_vm_ioctl (s=s@entry=0x55ed06ba2000, type=<optimized out>) at /usr/src/debug/qemu-2.9.1/kvm-all.c:2136
#2  0x000055ed03c7fb15 in kvm_set_irq (s=0x55ed06ba2000, irq=<optimized out>, level=<optimized out>) at /usr/src/debug/qemu-2.9.1/kvm-all.c:1001
#3  0x000055ed03cef2c0 in kvm_pic_set_irq (opaque=<optimized out>, irq=<optimized out>, level=<optimized out>)
    at /usr/src/debug/qemu-2.9.1/hw/i386/kvm/i8259.c:114
#4  0x000055ed03cba196 in qemu_irq_raise (irq=<optimized out>) at /usr/src/debug/qemu-2.9.1/include/hw/irq.h:16
#5  rtc_periodic_timer (opaque=0x55ed06f88580) at /usr/src/debug/qemu-2.9.1/hw/timer/mc146818rtc.c:198
#6  0x000055ed03faf1f0 in timerlist_run_timers (timer_list=0x55ed06aafa40) at /usr/src/debug/qemu-2.9.1/util/qemu-timer.c:536
#7  0x000055ed03faf3f7 in qemu_clock_run_timers (type=QEMU_CLOCK_HOST) at /usr/src/debug/qemu-2.9.1/util/qemu-timer.c:547
#8  qemu_clock_run_all_timers () at /usr/src/debug/qemu-2.9.1/util/qemu-timer.c:662
#9  0x000055ed03faf8da in main_loop_wait (nonblocking=<optimized out>) at /usr/src/debug/qemu-2.9.1/util/main-loop.c:525
#10 0x000055ed03c2f0e3 in main_loop () at /usr/src/debug/qemu-2.9.1/vl.c:1898

-Andi

  reply	other threads:[~2017-10-20  0:34 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-17 21:34 qemu polling KVM_IRQ_LINE_STATUS when stopped Andi Kleen
2017-10-18  7:47 ` Paolo Bonzini
2017-10-18 17:49   ` Andi Kleen
2017-10-18 19:24     ` Paolo Bonzini
2017-10-20  0:34       ` Andi Kleen [this message]
2017-10-20  8:32         ` Paolo Bonzini
2017-10-20 14:09           ` Andi Kleen
2017-10-20 15:12             ` Paolo Bonzini
2017-10-20 20:50               ` Andi Kleen
2017-10-20 22:51                 ` Paolo Bonzini
2020-06-25 14:26                   ` Kevin Locke
2020-06-25 16:28                     ` Andi Kleen
2020-06-25 18:41                     ` Paolo Bonzini
2020-06-25 18:56                       ` Kevin Locke
2020-06-25 19:17                         ` Paolo Bonzini
2020-06-25 20:10                           ` Kevin Locke
2020-06-26 15:14                       ` Kevin Locke

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