Re: io_uring possibly the culprit for qemu hang (linux-5.4.y)
Hi Jens. On Sat, Oct 17, 2020 at 3:07 AM Jens Axboe wrote: > > Would be great if you could try 5.4.71 and see if that helps for your > issue. > Oh wow, yeah it did fix the issue. I'm able to reliably turn off and start the VM multiple times in a row. Double checked by confirming QEMU is dynamically linked to liburing.so.1. Looks like those 4 io_uring fixes helped. Thanks!
Re: io_uring possibly the culprit for qemu hang (linux-5.4.y)
A small update:
As per Stefano's suggestion, disabling io_uring support from QEMU from
the configuration step did fix the problem and I'm no longer having
hangs.
Looks like it __is__ an io_uring issue :(
Btw, I used liburing fe50048 for linking QEMU.
Thanks.
On Fri, Oct 2, 2020 at 4:35 PM Stefano Garzarella wrote:
>
> Hi Ju,
>
> On Thu, Oct 01, 2020 at 11:30:14PM +0900, Ju Hyung Park wrote:
> > Hi Stefano,
> >
> > On Thu, Oct 1, 2020 at 5:59 PM Stefano Garzarella
> > wrote:
> > > Please, can you share the qemu command line that you are using?
> > > This can be useful for the analysis.
> >
> > Sure.
>
> Thanks for sharing.
>
> The issue seems related to io_uring and the new io_uring fd monitoring
> implementation available from QEMU 5.0.
>
> I'll try to reproduce.
>
> For now, as a workaround, you can rebuild qemu by disabling io-uring support:
>
> ../configure --disable-linux-io-uring ...
>
>
> Thanks,
> Stefano
>
> >
> > QEMU:
> > /usr/bin/qemu-system-x86_64 -name guest=win10,debug-threads=on -S
> > -object
> > secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-1-win10/master-key.aes
> > -blockdev
> > {"driver":"file","filename":"/usr/share/OVMF/OVMF_CODE.fd","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}
> > -blockdev
> > {"node-name":"libvirt-pflash0-format","read-only":true,"driver":"raw","file":"libvirt-pflash0-storage"}
> > -blockdev
> > {"driver":"file","filename":"/var/lib/libvirt/qemu/nvram/win10_VARS.fd","node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}
> > -blockdev
> > {"node-name":"libvirt-pflash1-format","read-only":false,"driver":"raw","file":"libvirt-pflash1-storage"}
> > -machine
> > pc-q35-5.0,accel=kvm,usb=off,vmport=off,dump-guest-core=off,mem-merge=off,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format
> > -cpu
> > Skylake-Client-IBRS,ss=on,vmx=on,hypervisor=on,tsc-adjust=on,clflushopt=on,umip=on,md-clear=on,stibp=on,arch-capabilities=on,ssbd=on,xsaves=on,pdpe1gb=on,ibpb=on,amd-ssbd=on,fma=off,avx=off,f16c=off,rdrand=off,bmi1=off,hle=off,avx2=off,bmi2=off,rtm=off,rdseed=off,adx=off,hv-time,hv-relaxed,hv-vapic,hv-spinlocks=0x1fff,hv-vpindex,hv-runtime,hv-synic,hv-stimer,hv-reset
> > -m 8192 -mem-prealloc -mem-path /dev/hugepages/libvirt/qemu/1-win10
> > -overcommit mem-lock=off -smp 4,sockets=1,dies=1,cores=2,threads=2
> > -uuid 7ccc3031-1dab-4267-b72a-d60065b5ff7f -display none
> > -no-user-config -nodefaults -chardev
> > socket,id=charmonitor,fd=32,server,nowait -mon
> > chardev=charmonitor,id=monitor,mode=control -rtc
> > base=localtime,driftfix=slew -global kvm-pit.lost_tick_policy=delay
> > -no-hpet -no-shutdown -global ICH9-LPC.disable_s3=1 -global
> > ICH9-LPC.disable_s4=1 -boot menu=off,strict=on -device
> > pcie-root-port,port=0x8,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x1
> > -device pcie-root-port,port=0x9,chassis=2,id=pci.2,bus=pcie.0,addr=0x1.0x1
> > -device pcie-root-port,port=0xa,chassis=3,id=pci.3,bus=pcie.0,addr=0x1.0x2
> > -device pcie-root-port,port=0xb,chassis=4,id=pci.4,bus=pcie.0,addr=0x1.0x3
> > -device pcie-pci-bridge,id=pci.5,bus=pci.2,addr=0x0 -device
> > qemu-xhci,id=usb,bus=pci.1,addr=0x0 -blockdev
> > {"driver":"host_device","filename":"/dev/disk/by-partuuid/05c3750b-060f-4703-95ea-6f5e546bf6e9","node-name":"libvirt-1-storage","cache":{"direct":false,"no-flush":true},"auto-read-only":true,"discard":"unmap"}
> > -blockdev
> > {"node-name":"libvirt-1-format","read-only":false,"discard":"unmap","detect-zeroes":"unmap","cache":{"direct":false,"no-flush":true},"driver":"raw","file":"libvirt-1-storage"}
> > -device
> > virtio-blk-pci,scsi=off,bus=pcie.0,addr=0xa,drive=libvirt-1-format,id=virtio-disk0,bootindex=1,write-cache=on
> > -netdev tap,fd=34,id=hostnet0 -device
> > e1000,netdev=hostnet0,id=net0,mac=52:54:00:c6:bb:bc,bus=pcie.0,add
Re: io_uring possibly the culprit for qemu hang (linux-5.4.y)
Hi Stefano,
On Thu, Oct 1, 2020 at 5:59 PM Stefano Garzarella wrote:
> Please, can you share the qemu command line that you are using?
> This can be useful for the analysis.
Sure.
QEMU:
/usr/bin/qemu-system-x86_64 -name guest=win10,debug-threads=on -S
-object
secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-1-win10/master-key.aes
-blockdev
{"driver":"file","filename":"/usr/share/OVMF/OVMF_CODE.fd","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}
-blockdev
{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"raw","file":"libvirt-pflash0-storage"}
-blockdev
{"driver":"file","filename":"/var/lib/libvirt/qemu/nvram/win10_VARS.fd","node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}
-blockdev
{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"raw","file":"libvirt-pflash1-storage"}
-machine
pc-q35-5.0,accel=kvm,usb=off,vmport=off,dump-guest-core=off,mem-merge=off,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format
-cpu
Skylake-Client-IBRS,ss=on,vmx=on,hypervisor=on,tsc-adjust=on,clflushopt=on,umip=on,md-clear=on,stibp=on,arch-capabilities=on,ssbd=on,xsaves=on,pdpe1gb=on,ibpb=on,amd-ssbd=on,fma=off,avx=off,f16c=off,rdrand=off,bmi1=off,hle=off,avx2=off,bmi2=off,rtm=off,rdseed=off,adx=off,hv-time,hv-relaxed,hv-vapic,hv-spinlocks=0x1fff,hv-vpindex,hv-runtime,hv-synic,hv-stimer,hv-reset
-m 8192 -mem-prealloc -mem-path /dev/hugepages/libvirt/qemu/1-win10
-overcommit mem-lock=off -smp 4,sockets=1,dies=1,cores=2,threads=2
-uuid 7ccc3031-1dab-4267-b72a-d60065b5ff7f -display none
-no-user-config -nodefaults -chardev
socket,id=charmonitor,fd=32,server,nowait -mon
chardev=charmonitor,id=monitor,mode=control -rtc
base=localtime,driftfix=slew -global kvm-pit.lost_tick_policy=delay
-no-hpet -no-shutdown -global ICH9-LPC.disable_s3=1 -global
ICH9-LPC.disable_s4=1 -boot menu=off,strict=on -device
pcie-root-port,port=0x8,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x1
-device pcie-root-port,port=0x9,chassis=2,id=pci.2,bus=pcie.0,addr=0x1.0x1
-device pcie-root-port,port=0xa,chassis=3,id=pci.3,bus=pcie.0,addr=0x1.0x2
-device pcie-root-port,port=0xb,chassis=4,id=pci.4,bus=pcie.0,addr=0x1.0x3
-device pcie-pci-bridge,id=pci.5,bus=pci.2,addr=0x0 -device
qemu-xhci,id=usb,bus=pci.1,addr=0x0 -blockdev
{"driver":"host_device","filename":"/dev/disk/by-partuuid/05c3750b-060f-4703-95ea-6f5e546bf6e9","node-name":"libvirt-1-storage","cache":{"direct":false,"no-flush":true},"auto-read-only":true,"discard":"unmap"}
-blockdev
{"node-name":"libvirt-1-format","read-only":false,"discard":"unmap","detect-zeroes":"unmap","cache":{"direct":false,"no-flush":true},"driver":"raw","file":"libvirt-1-storage"}
-device
virtio-blk-pci,scsi=off,bus=pcie.0,addr=0xa,drive=libvirt-1-format,id=virtio-disk0,bootindex=1,write-cache=on
-netdev tap,fd=34,id=hostnet0 -device
e1000,netdev=hostnet0,id=net0,mac=52:54:00:c6:bb:bc,bus=pcie.0,addr=0x3
-device ich9-intel-hda,id=sound0,bus=pcie.0,addr=0x4 -device
hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -device
vfio-pci,host=:00:02.0,id=hostdev0,bus=pcie.0,addr=0x2,rombar=0
-device virtio-balloon-pci,id=balloon0,bus=pcie.0,addr=0x8 -object
rng-random,id=objrng0,filename=/dev/urandom -device
virtio-rng-pci,rng=objrng0,id=rng0,bus=pcie.0,addr=0x9 -msg
timestamp=on
And I use libvirt 6.3.0 to manage the VM. Here's an xml of my VM.
win10
7ccc3031-1dab-4267-b72a-d60065b5ff7f
http://libosinfo.org/xmlns/libvirt/domain/1.0;>
http://microsoft.com/win/10"/>
8388608
8388608
4
hvm
/usr/share/OVMF/OVMF_CODE.fd
/var/lib/libvirt/qemu/nvram/win10_VARS.fd
destroy
restart
destroy
/usr/bin/qemu-system-x86_64
/dev/urandom
