Re: [Qemu-devel] BUG: RTC issue when Windows guest is idle

Hi:

I have met the same bug that windows2008 guest stop receive the RTC ticks when it in idle status by fortuitous.

When vnc connect, guest will resume to receive RTC ticks and the time run fast because of the coalesced timer

HPET is diabled, and RTC is set “catchup”, as following:

</clock>

My kvm module is version3.6. Should I upgrade it to latest version. Any suggestion is welcome !

Thanks!

--xiangyouxie

On Thu, Feb 21, 2013 at 06:16:10PM +0000, Matthew Anderson wrote:

> If this isn't the correct list just let me know,

> I've run into a bug whereby a Windows guest (tested on Server 2008R2 and

> 2012) no longer receives RTC ticks when it has been idle for a random amount

> of time. HPET is disabled and the guest is running Hyper-V relaxed timers

> (same situation without hv_relaxed). The guest clock stands still and the

> qemu process uses very little CPU (<0.5%, normally it's >5% when the guest is

> idle) . Eventually the guest stops responding to network requests but if you

> open the guest console via VNC and move the mouse around it comes back to

> life and QEMU replays the lost RTC ticks and the guest recovers. I've also

> been able to make it recover by querying the clock over the network via the

> net time command, you can see the clock stand still for 30 seconds then it

> replays the ticks and catches up.

> I've tried to reproduce the issue but it seems fairly illusive, the only way

> I've been able to reproduce it is by letting the VM's idle and waiting.

> Sometimes it's hours and sometimes minutes. Can anyone suggest a way to

> narrow the issue down?

> Qemu command line is-

> /usr/bin/kvm -name SQL01 -S -M pc-0.14 -cpu qemu64,hv_relaxed -enable-kvm -m

> 2048 -smp 2,sockets=2,cores=1,threads=1 -uuid

> 5f54333b-c250-aa72-c979-39d156814b85 -no-user-config -nodefaults -chardev

> socket,id=charmonitor,path=/var/lib/libvirt/qemu/iHost-SQL01.monitor,server,nowait

> -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime

> -no-hpet -no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2

> -drive

> file=/mnt/gluster1-norep/iHost/SQL01.qed,if=none,id=drive-virtio-disk0,format=qed,cache=writeback

> -device

> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0

> -drive

> file=/mnt/gluster1-norep/iHost/SQL01-Data.qed,if=none,id=drive-virtio-disk2,format=qed,cache=writeback

> -device

> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virtio-disk2,id=virtio-disk2

> -drive if=none,id=drive-ide0-1-0,readonly=on,format=raw -device

> ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0,bootindex=1 -netdev

> tap,fd=29,id=hostnet0,vhost=on,vhostfd=39 -device

> virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:2c:8d:23,bus=pci.0,addr=0x3

> -chardev pty,id=charserial0 -device

> isa-serial,chardev=charserial0,id=serial0 -device usb-tablet,id=input0 -vnc

> 127.0.0.1:22 -vga cirrus -device

> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4

> Environment is -

> Mainline 3.7.5 and 3.8.0

> Qemu 1.2.2, 1.3.1 and 1.4.0

From:	Xiexiangyou
Subject:	Re: [Qemu-devel] BUG: RTC issue when Windows guest is idle
Date:	Tue, 8 Oct 2013 09:38:48 +0000