- Users - libvirt List Archives

DOS
by Tomas By 02 Nov '22

02 Nov '22

Hi all, I am trying to set up an `isolated virtual network' with two or more MS-DOS guests, all on one single Linux box. The aim is for them to share a disk (or just one directory on one disk). As I could not get it to work with IPX, am now trying TCP/IP. However, I suspect the MS tools are still attempting to use IPX as well. Is there some simple solution that I am missing? Does libvirt support IPX at all? Any other easy way to do DOS file sharing? (I believe I can use any version of DOS, and any sort of tool as long as I get a `remote' directory available as some drive letter.) /Tomas

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hook script for changing disk definition before guest start
by Gionatan Danti 31 Oct '22

31 Oct '22

Hi all, due to this [1] I am trying to change a guest's disk definition from "pool volume" to "file" via hook scripts. This seems an easy task via virsh detach-disk and virsh attach-disk, but virsh can not be called inside libvirt hook scripts. The best approach would be to change the disk definition right when a disk is attached, but I can not find any event calling a hook script when a disk is attache/detached. Do you have any suggestion short of monitoring the directory /etc/libvirt/qemu itself for changed files? Thanks. [1] https://github.com/cockpit-project/cockpit-machines/issues/815 -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti(a)assyoma.it - info(a)assyoma.it GPG public key ID: FF5F32A8

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Re: How to check tap device for sndbuf when I set sndbuf=0 in the interface xml
by Yalan Zhang 31 Oct '22

31 Oct '22

cc libvirt-users for more inputs Hi, I'm trying to find out how to check sndbuf for a tap device, could you please help to check it? In kernel 2.6.18, the tap device's default sndbuf is 1MB. There is a RFE bug[1] and patch[2] to introduce the option below in libvirt to adjust the sndbuf. <tune> <sndbuf>1600</sndbuf> </tune> It is said in the patch[2] that when we set sndbuf=0, we actually set it to 0xffffffff. How to check if it is set successfully? I have checked the below files, the value didn't change after I start a vm with sndbuf=0 # grep . /proc/sys/net/core/*mem_default /proc/sys/net/core/rmem_default:212992 /proc/sys/net/core/wmem_default:212992 And from the doc[3]: "The default value is set by the /proc/sys/net/core/wmem_default file and the maximum allowed value is set by the /proc/sys/net/core/wmem_max file." Current kernel 5.14.0-177.el9 has some updates about sndbuf: # cat /proc/sys/net/core/wmem_default 212992 # cat /proc/sys/net/core/wmem_max 212992 Thank you! [1] Bug 665293 <https://bugzilla.redhat.com/show_bug.cgi?id=665293> - RFE: Allow setting size of send buffer per TAP device in QEMU driver [2] https://listman.redhat.com/archives/libvir-list/2011-January/032763.html [3] https://man7.org/linux/man-pages/man7/socket.7.html Yalan

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Video device model set resolution does not work
by 陈新隆 31 Oct '22

31 Oct '22

Hi team, I've add a resolution sub-element to vga video device model, and the x attribute is 1920, y attribute is 1080. Dumped domain xml as follow : bash-4.4# virsh list > Authorization not available. Check if polkit service is running or see > debug message for more information. > Id Name State > ----------------------------------- > 1 proj1_vm-4uaz57bh running > bash-4.4# virsh dumpxml proj1_vm-4uaz57bh | grep -i -10 vga > Authorization not available. Check if polkit service is running or see > debug message for more information. > <alias name='input1'/> > </input> > <input type='keyboard' bus='ps2'> > <alias name='input2'/> > </input> > <graphics type='vnc' > socket='/var/run/kubevirt-private/dfe7d514-63f1-4e97-b642-f93109d5aa2f/virt-vnc'> > <listen type='socket' > socket='/var/run/kubevirt-private/dfe7d514-63f1-4e97-b642-f93109d5aa2f/virt-vnc'/> > </graphics> > <audio id='1' type='none'/> > <video> > <model type='vga' vram='65536' heads='1' primary='yes'> > <resolution x='1920' y='1080'/> > </model> > <alias name='video0'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x01' > function='0x0'/> > </video> > <memballoon model='virtio-non-transitional'> > <stats period='10'/> > <alias name='balloon0'/> > <address type='pci' domain='0x0000' bus='0x07' slot='0x00' > function='0x0'/> > </memballoon> It does work on my ubuntu guest, but it doesn't work on centos / windows guest. Is there any way to solve this problem ?

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Booting from USB device
by Simon Fairweather 28 Oct '22

28 Oct '22

I have a hooks file to hotplug a USB device at the prepare stage. Using OVMF version 2.6 this works fine, but using OVMF 2.7 the guest no longer boots from the USB device. Option 1) For it to work I have to set the boot order on the USB device and once the OVMF Shell appears I can reset it and it will find the USB device and boot. Option 2) Another setup which works if I remove all boot order settings from the guest and have a boot dev = 'fd' and this works every time.but I cannot add multiple entries. <os> <type arch='x86_64' machine='pc-q35-5.1'>hvm</type> <loader readonly='yes' type='pflash'>/usr/share/qemu/ovmf-x64/OVMF_CODE-pure-efi-tpm.fd</loader> <nvram>/etc/libvirt/qemu/nvram/b96bfc99-3612-0daa-9d8c-69e9d550d05a_VARS-pure-efi-tpm.fd</nvram> <boot dev='fd'/> <boot dev='hd'/> Any thoughts on how to get option 1) to working without having to do a reset.

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failed to load seccomp syscall filter in kernel: Operation canceled
by Jiatong Shen 28 Oct '22

28 Oct '22

Hello community, I am operating an openstack cluster where applications (libvirt/nova etc) are running using containers. The compute node's arch is aarch64 (phytium 2500), when there are virtual machines around 60 or 70, I failed to boot new virtual machines and faced with following error message, error: internal error: qemu unexpectedly closed the monitor: 2022-10-24T06:23:54.545685Z qemu-system-aarch64: -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny: failed to load seccomp syscall filter in kernel: Operation canceled Interestingly, if I virsh stop one virtual machine, I am able to boot another. Besides, I managed to manually boot a virtual machine without any issue. So my question is what could be the potential cause of this behavior and how can I deal with it? Thank you very much in advance for the help. -- Best Regards, Jiatong Shen

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Virtual Networking
by Armin Lepir 26 Oct '22

26 Oct '22

Hi I am using libvrt for the first time. Im building a KVM for multiple Virtual OS instances. The problem i have is with your official documentation for Virtual Networking. https://wiki.libvirt.org/page/VirtualNetworking The following is wrong: The default mode is BRIDGE + NAT. Optional mode is ROUTING. It should be: The default mode is ROUTING + NAT. Optional mode is BRIDGE. As far as i know a bridge operates on the Layer2. IP and NAT operate on the Layer3. NAT can not operate on the L2. Please tell me that im wrong and explain how am i wrong. Best Regards

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Re: MemoryBacking options
by Michal Prívozník 24 Oct '22

24 Oct '22

[Once again, I ask you to keep the list on the CC. In gmail's web UI it's the 'Reply to all' button]. On 10/22/22 11:19, Simon Fairweather wrote: > Is there a way to limit the shared memory allocated via Libvirt to > memory backing? > Yes, there is. On the top level there's /domain/memoryBacking [1] that serves as the default value for the guest. Then, under /domain/cpu/numa/cell [2] individual guest NUMA nodes are configured and each can have @memAccess attribute which overrides the top level setting (=memoryBacking). And finally, under /domain/devices/memory [3] individual RAM modules can be configured, and each one can have @access attribute which overrides both top level AND guest NUMA node setting. For instance: <domain> <maxMemory slots='16' unit='GiB'>8</maxMemory> <memory unit='GiB'>5</memory> <memoryBacking> <access mode='private'/> </memoryBacking> ... <cpu> <numa> <cell id='0' memory='2' unit='GiB' memAccess='shared'/> <cell id='1' memory='2' unit='GiB' /> </numa> </cpu> ... <devices> <memory model='dimm' access='private'> <target> <size unit='GiB'>1</size> <node>0</node> </target> </memory> </device> </domain> Here, the guest NUMA node 0 is going to be shared, except for DIMM module attached to it (which is going to be private) and NUMA node 1 is going to be private again. Michal 1: https://libvirt.org/formatdomain.html#memory-backing 2: https://libvirt.org/formatdomain.html#cpu-model-and-topology 3: https://libvirt.org/formatdomain.html#memory-devices > > > On Mon, Oct 17, 2022 at 9:06 AM Michal Prívozník <mprivozn(a)redhat.com > <mailto:mprivozn@redhat.com>> wrote: > > [please keep the list on CC for benefit of the community] > On 10/16/22 09:58, Simon Fairweather wrote: > > Thanks Michal, Are there any known issues with Memory Backing. We have > > QEMU 7.1 and libvirt 8.7. > > > > If just Memory Backing is set the VM Freezes after a couple of > hours and > > the allocated CPUs show 100% on the host. > > > > Seems to happen more on AMD Platforms than Intel. > > > > Please advise on any info you need, likely this is a QEMU issue. > > > > <memoryBacking> > > <source type='memfd'/> > > <access mode='shared'/> > > </memoryBacking> > > Agreed, this smells like QEMU issue. There's nothing obviously wrong > with this snipped. I have a VM with just that and run it just fine. > Although, I run it for couple of hours max. > > Michal >

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Cannot create vm with machine type raspi2b
by Niccolò Belli 22 Oct '22

22 Oct '22

Hi, I'm trying to use virt-manager to create a Raspberry Pi 2 virtual machine on my Talos 2 ppc64le workstation. In virt-manager I click on "New", then "Manual install", architecture "arm" and machine type "raspi2b". Next I set either "Generic or unknown OS" or "Debian 11" as operating system, I keep the default 1024 memory and 1 cpu and then I disable storage for this virtual machine (because I want to use an existing image with direct kernel boot, see https://raspi.debian.net/tested-images/) I check "Customize configuration before install" and I click "Finish". Unfortunately I get the following error: Error starting installation: Did not find any UEFI binary path for arch 'armv7l' So I've decided to start from scratch and select "virt" as machine type instead of "raspi2b" and change it back later. With "virt" I manage to reach the configuration overview before the installation begins. At this point I have three options for Firmware: Default UEFI UEFI armv7l:/usr/share/qemu/edk2-arm-code.fd UEFI is the default and if I change the machine type to raspi2b I still have the same three options (/usr/share/qemu/edk2-arm-code.fd does indeed exist in my file system). Unfortunately clicking on "Begin Installation" leads me to yet another error: Unable to complete install: 'internal error: Required option 'modelName' is not set for PCI controller with index '1', model 'pcie-root-port' and modelName 'none'' If I change the machine type back to "virt" I don't get any error. I'm using app-emulation/qemu 7.1.0, app-emulation/libvirt-8.8.0 and virt-manager-4.1.0 on Gentoo Linux ppc64le with a 4K page size kernel. Thanks, Niccolo' Belli

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How to merge incremental backups generated with virsh backup-begin?
by Jorge Luiz Correa 19 Oct '22

19 Oct '22

I'm trying to create incremental backups that I could restore when necessary. All backups are being generated fine but I couldn't find a way to recreate an image using all or some of the backup files. For example, my domain is called jammy and is running. jammy-backup.xml: <domainbackup> <incremental></incremental> </domainbackup> jammy-checkpoint.xml <domaincheckpoint> <disks> <disk name="vda" checkpoint="bitmap"/> </disks> </domaincheckpoint> ~# virsh backup-begin jammy jammy-backup.xml jammy-checkpoint.xml * This command with these files generates backup file in /var/lib/libvirt/images appending the checkpoint timestamp in file name (jammy.qcow2 -> jammy.qcow2.TIMESTAMP). ~# virsh checkpoint-list jammy Name Creation Time ----------------------------------------- 1666006874 2022-10-17 08:41:14 -0300 ~# ls -lh /var/lib/libvirt/images -rw-r--r-- 1 libvirt-qemu kvm 2,6G out 18 14:38 jammy.qcow2 -rw------- 1 root root 1,5G out 17 08:41 jammy.qcow2.1666006874 If I create a new domain using jammy.qcow2.1666006874 as disk, everything works good. Then, I've created some incremental backups. jammy-backup.xml: <domainbackup> <incremental>1666006874</incremental> </domainbackup> ~# virsh backup-begin jammy jammy-backup.xml jammy-checkpoint.xml ~# ls -lh /var/lib/libvirt/images -rw-r--r-- 1 libvirt-qemu kvm 2,6G out 18 14:38 jammy.qcow2 -rw------- 1 root root 1,5G out 17 08:41 jammy.qcow2.1666006874 -rw------- 1 root root 247M out 17 14:42 jammy.qcow2.1666010735 At this point, if I need to restore the backup with checkpoint 1666010735, how can I create a new image using jammy.qcow2.1666010735 and jammy.qcow2.1666006874? I would like to merge the incremental backup jammy.qcow2.1666010735 into the full backup jammy.qcow2.1666006874, to get a new image so I can create a new domain using it as disk. Am I doing it the right way? Ubuntu 22.04 LTS KVM libvirt 8.0.0-1ubuntu7.1 qemu 1:6.2+dfsg-2ubuntu6.4 Thank you! -- Jorge Luiz Corrêa Embrapa Agricultura Digital echo "CkpvcmdlIEx1aXogQ29ycmVhCkFu YWxpc3RhIGRlIFJlZGVzIGUgU2VndXJhbm NhCkVtYnJhcGEgQWdyaWN1bHR1cmEgRGln aXRhbCAtIE5USQpBdi4gQW5kcmUgVG9zZW xsbywgMjA5IChCYXJhbyBHZXJhbGRvKQpD RVAgMTMwODMtODg2IC0gQ2FtcGluYXMsIF NQClRlbGVmb25lOiAoMTkpIDMyMTEtNTg4 Mgpqb3JnZS5sLmNvcnJlYUBlbWJyYXBhLm JyCgo="|base64 -d -- __________________________ Aviso de confidencialidade Esta mensagem da Empresa Brasileira de Pesquisa Agropecuaria (Embrapa), empresa publica federal regida pelo disposto na Lei Federal no. 5.851, de 7 de dezembro de 1972, e enviada exclusivamente a seu destinatario e pode conter informacoes confidenciais, protegidas por sigilo profissional. Sua utilizacao desautorizada e ilegal e sujeita o infrator as penas da lei. Se voce a recebeu indevidamente, queira, por gentileza, reenvia-la ao emitente, esclarecendo o equivoco. Confidentiality note This message from Empresa Brasileira de Pesquisa Agropecuaria (Embrapa), a government company established under Brazilian law (5.851/72), is directed exclusively to its addressee and may contain confidential data, protected under professional secrecy rules. Its unauthorized use is illegal and may subject the transgressor to the law's penalties. If you are not the addressee, please send it back, elucidating the failure.

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Re: MemoryBacking options
by Michal Prívozník 17 Oct '22

17 Oct '22

[please keep the list on CC for benefit of the community] On 10/16/22 09:58, Simon Fairweather wrote: > Thanks Michal, Are there any known issues with Memory Backing. We have > QEMU 7.1 and libvirt 8.7. > > If just Memory Backing is set the VM Freezes after a couple of hours and > the allocated CPUs show 100% on the host. > > Seems to happen more on AMD Platforms than Intel. > > Please advise on any info you need, likely this is a QEMU issue. > > <memoryBacking> > <source type='memfd'/> > <access mode='shared'/> > </memoryBacking> Agreed, this smells like QEMU issue. There's nothing obviously wrong with this snipped. I have a VM with just that and run it just fine. Although, I run it for couple of hours max. Michal

1 0

Qeustion about how to use domsetlaunchsecstate command correctly.
by 贺培轩 14 Oct '22

14 Oct '22

Hello, I'm new to libvirt. I have tried to launch a sev vm with secret injection recently, and I found the command domsetlaunchsecstate is what I need. But I had some problem to make it work. Here is what I did to use this command. 1. run command: virsh create sev-guest.xml 2. create secret header file and secret file. 3. run command: virsh domsetlaunchsecstate sev-guest-1 --secrethdr <hdr-filename> --secret <secret-filename> . But it will report this error: SEV: not in correct state. I think it is because the vm is not in a paused state. So how can I launch a sev vm which is in a paused state? How should I revise my xml file? The sev-guest.xml I use is as follows: <domain type="kvm"> <name>sev-guest-1</name> <uuid>d50a4205-40e0-4482-b0dc-f26bb4a1a9ff</uuid> <metadata> <libosinfo:libosinfo xmlns:libosinfo=" http://libosinfo.org/xmlns/libvirt/domain/1.0"> <libosinfo:os id="http://ubuntu.com/ubuntu/16.04"/> </libosinfo:libosinfo> </metadata> <memory>4194304</memory> <currentMemory>4194304</currentMemory> <memtune> <hard_limit>4563402</hard_limit> </memtune> <vcpu>32</vcpu> <cpu mode='custom' match='exact' check='partial'> <model fallback='forbid'>EPYC</model> </cpu> <os> <type arch="x86_64" machine="q35">hvm</type> <loader readonly="yes" type="pflash">/data01/OVMF.fd</loader> <nvram template="/data01/OVMF.fd">/var/lib/libvirt/qemu/nvram/sev-guest-1_VARS.fd</nvram> <boot dev="hd"/> </os> <features> <acpi/> <apic/> </features> <clock offset="utc"> <timer name="rtc" tickpolicy="catchup"/> <timer name="pit" tickpolicy="delay"/> <timer name="hpet" present="no"/> </clock> <pm> <suspend-to-mem enabled="no"/> <suspend-to-disk enabled="no"/> </pm> <devices> <emulator>/usr/local/bin/qemu-system-x86_64</emulator> <disk type="file" device="disk"> <driver name="qemu" type="qcow2"/> <source file="/data01/AMDSEV/sev-guest-1.qcow2"/> <target dev="sda" bus="scsi"/> </disk> <controller type="scsi" index="0" model="virtio-scsi"> <driver iommu="on"/> </controller> <controller type="virtio-serial" index="0"> <driver iommu="on"/> </controller> <controller type="usb" index="0" model="ich9-ehci1"/> <controller type="usb" index="0" model="ich9-uhci1"> <master startport="0"/> </controller> <controller type="usb" index="0" model="ich9-uhci2"> <master startport="2"/> </controller> <controller type="usb" index="0" model="ich9-uhci3"> <master startport="4"/> </controller> <controller type='pci' index='1' model='pcie-root-port'> <model name='pcie-root-port'/> <target chassis='1' port='0x8'/> <alias name='pci.1'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0' multifunction='on'/> </controller> <controller type='pci' index='2' model='pcie-root-port'> <model name='pcie-root-port'/> <target chassis='2' port='0x9'/> <alias name='pci.2'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x1'/> </controller> <controller type='pci' index='3' model='pcie-root-port'> <model name='pcie-root-port'/> <target chassis='3' port='0xa'/> <alias name='pci.3'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x2'/> </controller> <controller type='pci' index='4' model='pcie-root-port'> <model name='pcie-root-port'/> <target chassis='4' port='0xb'/> <alias name='pci.4'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x3'/> </controller> <console type="pty"/> <input type="tablet" bus="usb"/> <graphics type="vnc" port="-1" listen="127.0.0.1"/> <video> <model type="vga"/> <address type='pci' slot='0x07'/> </video> <memballoon model="virtio"> <driver iommu="on"/> </memballoon> </devices> <launchSecurity type="sev"> <cbitpos>51</cbitpos> <reducedPhysBits>1</reducedPhysBits> <policy>0x05</policy> <dhCert>XXXXXXXXX</dhCert> <session>XXXXXXXXXXXXXXXXx</session> </launchSecurity> </domain> Thank you in advance, Peixuan

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Caching qemu capabilities and KubeVirt
by Roman Mohr 13 Oct '22

13 Oct '22

Hi, I have a question regarding capability caching in the context of KubeVirt. Since we start in KubeVirt one libvirt instance per VM, libvirt has to re-discover on every VM start the qemu capabilities which leads to a 1-2s+ delay in startup. We already discover the features in a dedicated KubeVirt pod on each node. Therefore I tried to copy the capabilities over to see if that would work. It looks like in general it could work, but libvirt seems to detect a mismatch in the exposed KVM CPU ID in every pod. Therefore it invalidates the cache. The recreated capability cache looks esctly like the original one though ... The check responsible for the invalidation is this: ``` Outdated capabilities for '%s': host cpuid changed ``` So the KVM_GET_SUPPORTED_CPUID call seems to return slightly different values in different containers. After trying out the attached golang scripts in different containers, I could indeed see differences. I can however not really judge what the differences in these KVM function registers mean and I am curious if someone else knows. The files are attached too (as json for easy diffing). Best regards, Roman

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MemoryBacking options
by Simon Fairweather 10 Oct '22

10 Oct '22

Hi, Is there any documentation that states which options can be used together with each other. <domain> ... <memoryBacking> <hugepages> <page size="1" unit="G" nodeset="0-3,5"/> <page size="2" unit="M" nodeset="4"/> </hugepages> <nosharepages/> <locked/> <source type="file|anonymous|memfd"/> <access mode="shared|private"/> <allocation mode="immediate|ondemand" threads='8'/> <discard/> </memoryBacking> ... </domain>

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Re: Why host device disappear in libvirt doman xml?
by Michal Prívozník 29 Sep '22

29 Sep '22

[Once again, please keep the list on CC] On 9/29/22 04:59, 陈新隆 wrote: > Thanks for the detail explanation, it's very helpful. > > I guess : > 1. virsh dumpxml <domain> outputs the live xml(or active xml) Yes, if domain is running then it outputs the live XML, otherwise it outputs the inactive XML. For running domains you can use --inactive flag to get the inactive XML. > 2. virsh edit <domain> edits the inactive xml, so I should cold boot > domain to take effect Correct. Michal

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Re: Why host device disappear in libvirt doman xml?
by Michal Prívozník 28 Sep '22

28 Sep '22

[Please, keep the list on CC for benefit of others] On 9/28/22 10:13, 陈新隆 wrote: > I'm using the `virsh dumpxml <domain name>` to check the xml. When I > first execute this command, there's two hostdev(GPU) in the xml, but > next time I execute the same command these two hostdev elements > disappeared. During this time, the vm didn't restart or stop. Also, > within the vm `lspci | grep -i nvidia` command did not print GPU infos. > > So I was wondering if there's a mechanism in libvirtd detach the hostdev > element without the vm stop or restart. This problem doesn't happen > often, so I am looking a way to reproduce it. > > Can you help me with these questions : > > 1. If I edit the xml manually then detached the hostdev elements from > xml by invoke libvirtd apis, will the vm apply it immediately without > stop or restart? Or I must restart the vm to apply the latest xml ? I'm not sure what you mean. Editing XML manually is different to using libvirt APIs to detach hostdevs. Here's how it works: 1) a domain is defined (say using virsh define file.xml), libvirt parses this XML, keeps it in a memory and stores it "somewhere" (it's under /etc/libvirt/qemu/ but we do not want users to hand edit those files manually as libvirt reads them only on libvirtd/virtqemud restart). This is called inactive XML, because it reflects the inactive state of domain. Sometimes it's also called config XML. 2) when the domain is started (e.g. virsh start), libvirt creates a copy of inactive XML, populates it with runtime information and saves it elsewhere (/run/libvirt/qemu/, but again, we do not want users to hand edit those files). This copy is referred to as live XML. 3) users can alter the live XML using APIs (e.g. to hotplug a device or hotunplug it). The inactive XML can be altered by providing altered XML and defining it again (here, domain name and UUID must match already existing domain). 4) upon domain shutoff, the live XML is thrown away, and finally 5) the inactive XML is never thrown away, until virsh undefine is called. Now, you can see that there's no real connection between live and inactive XMLs and changing one has no affect on the other, except when the domain is cold booted again. Live and inactive XMLs can vary wildly. Therefore, you can have inactive XML with two <hostdev/>-s, and active XML with no <hostdev> at all. NB, hotplug APIs can also be used to alter inactive XML (virsh attach-device --config / virsh detach-device --config / ...) or both at the same time (virsh attach-device --config --live / virsh attach-device --config --live / ...). And what you describe sounds as if those two <hostdev/>-s you saw at domain startup were hotunplugged. The fact that even 'lspci' ran from inside the domain can't find them only supports this theory. And no, libvirt never tries to bring inactive and live XMLs together. It has no intelligence built in to do that and we, developers, do not want such thing either. We might change something that user specifically wanted and I believe nobody likes those "smart" tools that get in your way. > 2. After a host device is hot-unplugged, will libvirtd aware of it then > remove the related `hostdev` element from xml ? Yes. I believe the reasoning is seen in the previous block of my reply. > > On Mon, Sep 26, 2022 at 10:10 PM Michal Prívozník <mprivozn(a)redhat.com > <mailto:mprivozn@redhat.com>> wrote: > > On 9/26/22 15:06, 陈新隆 wrote: > > > > <https://stackoverflow.com/posts/73854544/timeline > <https://stackoverflow.com/posts/73854544/timeline>> > > > > I'm using Kubevirt to manage my virtual machine instances. When I > using > > Kubevirt to create a vm(with two GPUs), kubevirt will generate a > libvirt > > guest domain xml for this vm which includes two GPUs, the domain > xml as > > follow : > > > > |<hostdev mode='subsystem' type='pci' managed='no'> <driver > > name='vfio'/> <source> <address domain='0x0000' bus='0x83' slot='0x00' > > function='0x0'/> </source> <alias name='ua-gpu-gpu0'/> <address > > type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'/> > > </hostdev> <hostdev mode='subsystem' type='pci' managed='no'> <driver > > name='vfio'/> <source> <address domain='0x0000' bus='0x84' slot='0x00' > > function='0x0'/> </source> <alias name='ua-gpu-gpu1'/> <address > > type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/> > > </hostdev> | > > > > No one ever edit this domain xml, but these two |hostdev| element > > disappeared in the domain xml. During this time, I've run > > the |gpu_burn| command to do a stress test for these two GPUs. > > > > My question is : > > > > * when will libvirtd change the guest domain xml ? > > * why libvirtd delete these two |hostdev| from domain xml ? > > > > Libvirt does not remove anything from domain XML (except for the > elements it does not understand, but this is not the case). My suspicion > is that you're looking at live XML instead of inactive XML or vice > versa. Libvirt allows guests to be defined (i.e. libvirt manages their > inactive definition). However, a guest can be started with wildly > different configuration (e.g. without those two <hostdev/>-s). OR, they > might have been hot-unplugged. > > I still recommend reading this link: > This article can explain more details: > https://wiki.libvirt.org/page/VM_lifecycle > <https://wiki.libvirt.org/page/VM_lifecycle> Michal

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[Question] Should libvirt update live xml accordingly when guest mac is changed?
by Fangge Jin 26 Sep '22

26 Sep '22

Hi I met an issue when testing trustGuestRxFilters: Attach a macvtap interface with trustGuestRxFilters=’yes’ to vm, then change interface mac address in vm. Should libvirt update interface mac in live vm xml accordingly? If not, vm network will be broken after managedsaving and restoring vm. BR, Fangge Jin Steps: 1. Start a vm 2. Attach a macvtap interface with trustGuestRxFilters=’yes’ to vm <interface type='direct' trustGuestRxFilters='yes'> <source dev='enp175s0v0' mode='passthrough'/> <target dev='macvtap0'/> <model type='virtio'/> <alias name='net1'/> </interface> 3. Check vm xml: # virsh dumpxml uefi --xpath //interface <interface type="direct" trustGuestRxFilters="yes"> <mac address="52:54:00:46:88:8b"/> <source dev="enp175s0v0" mode="passthrough"/> <target dev="macvtap2"/> <model type="virtio"/> <alias name="net0"/> <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/> </interface> 4. Change interface mac in guest: # ip link set dev enp1s0 address 52:54:00:9d:a1:1e # ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 4: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 52:54:00:9d:a1:1e brd ff:ff:ff:ff:ff:ff permaddr 52:54:00:46:88:8b inet 192.168.124.5/24 scope global enp1s0 valid_lft forever preferred_lft forever # ping 192.168.124.4 PING 192.168.124.4 (192.168.124.4) 56(84) bytes of data. 64 bytes from 192.168.124.4: icmp_seq=1 ttl=64 time=0.240 ms 64 bytes from 192.168.124.4: icmp_seq=2 ttl=64 time=0.138 ms --- 192.168.124.4 ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1001ms 5. Check vm xml: # virsh dumpxml uefi --xpath //interface <interface type="direct" trustGuestRxFilters="yes"> <mac address="52:54:00:46:88:8b"/> <source dev="enp175s0v0" mode="passthrough"/> <target dev="macvtap2"/> <model type="virtio"/> <alias name="net0"/> <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/> </interface> 6. Check on host: 16: macvtap1@enp175s0v0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 500 link/ether 52:54:00:9d:a1:1e brd ff:ff:ff:ff:ff:ff inet6 fe80::5054:ff:fe46:888b/64 scope link valid_lft forever preferred_lft forever 7. Do managedsave and restore # virsh managedsave uefi Domain 'uefi' state saved by libvirt # virsh start uefi Domain 'uefi' started 8. Check vm network function: # ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 4: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 52:54:00:9d:a1:1e brd ff:ff:ff:ff:ff:ff permaddr 52:54:00:46:88:8b inet 192.168.124.5/24 scope global enp1s0 valid_lft forever preferred_lft forever # ping 192.168.124.4 PING 192.168.124.4 (192.168.124.4) 56(84) bytes of data. --- 192.168.124.4 ping statistics --- 3 packets transmitted, 0 received, 100% packet loss, time 2036ms

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Why host device disappear in libvirt doman xml?
by 陈新隆 26 Sep '22

26 Sep '22

<https://stackoverflow.com/posts/73854544/timeline> I'm using Kubevirt to manage my virtual machine instances. When I using Kubevirt to create a vm(with two GPUs), kubevirt will generate a libvirt guest domain xml for this vm which includes two GPUs, the domain xml as follow : <hostdev mode='subsystem' type='pci' managed='no'> <driver name='vfio'/> <source> <address domain='0x0000' bus='0x83' slot='0x00' function='0x0'/> </source> <alias name='ua-gpu-gpu0'/> <address type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'/> </hostdev> <hostdev mode='subsystem' type='pci' managed='no'> <driver name='vfio'/> <source> <address domain='0x0000' bus='0x84' slot='0x00' function='0x0'/> </source> <alias name='ua-gpu-gpu1'/> <address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/> </hostdev> No one ever edit this domain xml, but these two hostdev element disappeared in the domain xml. During this time, I've run the gpu_burn command to do a stress test for these two GPUs. My question is : - when will libvirtd change the guest domain xml ? - why libvirtd delete these two hostdev from domain xml ?

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Backup KVM Guest VM in OVA or VMDK format
by Kaushal Shriyan 22 Sep '22

22 Sep '22

Hi, Is there a way to backup KVM Guest VM in kvmguestosimage.ova or kvmguestosimage.vmdk format as I am trying to restore it in AWS by referring to https://aws.amazon.com/ec2/vm-import/ article as per the below supported file format. [1] Open Virtualization Archive (OVA) [2] Virtual Machine Disk (VMDK) [3] Virtual Hard Disk (VHD/VHDX) [4] raw Also any method to take full and incremental backup of KVM Guest VM. Any help will be highly appreciated. I look forward to hearing from you. Thanks in Advance. Best Regards, Kaushal

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How can I check the history of all console logs starting from the first second of bootup
by Lucas Liu 22 Sep '22

22 Sep '22

Gratings: Recently, I got an error while installing a guest, the error message is this,: [image: image.png] Is there a method to get the full log? I have tried to use virt-install --console, or attach <log file="/var/log/libvirt/qemu/guestname-serial0.log" append="off"/> to get the full log, but they didn't work.

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Re: Help in porting smack related patches to meson build system
by Peter Krempa 20 Sep '22

20 Sep '22

On Mon, Sep 19, 2022 at 16:31:25 +0000, Vishal Gupta (vishagu2) wrote: > Hi Peter , Hi, I firstly want to ask you to avoid top-posting on technical mailing lists. > > > > Thanks for ur reply . > > > > Kirkstone is the latest release from Yocto foundation . details https://docs.yoctoproject.org/dev/migration-guides/migration-4.0.html > > > > Kirkstone support libvirt 8.10 https://layers.openembedded.org/layerindex/recipe/3052/ > > > > We are trying to port 2016 smack patch " https://listman.redhat.com/archives/libvir-list/2016-July/msg00456.html" for libvirt which is based on automake make file Okay so that is quite an old patch which was never finished and merged. > But above patch is incompatible with libvirt 8.10 .as libvirt 8.1 supports only meson > > > I was just wondering if above smack patch is already ported for meson based libvirt 8.10? > > We have issue in porting m4/virt-smack.m4 to meson.build file . virt-smack.m4 is define in 2016 smack patch No it is not ported. I want to warn you though that porting the build system part to meson will not be biggest of the problems. 1) The patch is more than 6 years old at this point There's quite a lot of change in libvirt during that time. Many helpers and internal APIs were refactored. The patch even once you port the build system will require *significant* rework to actually even compile. 2) libsmack (smack-utils) used by the new security module is not present in distros The library it requires doesn't seem to be adopted much: https://repology.org/project/smack-utils/versions Did you make sure that it's present in your environment? Additionally if you want to get the patch accepted upstream note that there were outstanding problems with the patch in the last version which is on the mailing list. I can see that there are definitely problems with coding style and the patch will need to be split to logical chunks as it's now just a big blob of code. Also given that the library is simply not present in distros it will require a justification why upstream should cary the patch. Carying code which is not compiled because of lack of dependencies is a burden to upstream and still can bitrot in the future. Even if you are not striving for upstreaming the patch, be prepared for more work than just porting the build system.

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Help in porting smack related patches to meson build system
by Akash Bhaskaran (akabhask) 19 Sep '22

19 Sep '22

Hi, We are trying to port some patches pertaining to files like Makefile.am ,configure.ac and .m4’s to libvirt kirkstone release. We see that latest kirskstone now uses meson build architecture. We have difficulties in porting the changes in the above-mentioned files to meson. Is there any script or reference you can provide for helping us port these files to meson? Thanks, Akash

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virt-manager alt-click passthrough?
by Alex 10 Sep '22

10 Sep '22

Hi, I'm using virt-manager to connect to a Windows 10 virtual machine, where I'm using photoshop. I need to send an alt-click key for some functions, but virt-manager is instead interpreting them. It isn't among the pre-configured options that can be sent. Is there a way to remap the alt key or alt-click combination so I can send it through to the virtual machine? I've also tried the RealVNC client/server trial, and I can't get that to connect at all. It does appear qemu/realvnc server is listening on 5900: tcp 0 0 127.0.0.1:5900 0.0.0.0:* LISTEN - qemu is also configured to listen (-spice port=5900,addr=127.0.0.1). I've also verified I can connect to port 5900 manually, so a Windows firewall is not the problem. Any ideas greatly appreciated.

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[libvirt-users] [virtual interface] detach interface during boot succeed with no changes
by Yalan Zhang 08 Sep '22

08 Sep '22

Hi guys, when I detach an interface from vm during boot (vm boot not finished), it always fail. I'm not sure if there is an existing bug. I have confirmed with someone that for disk, there is similar behavior, if this is also acceptable? # virsh destroy rhel7.2; virsh start rhel7.2 ;sleep 2; virsh detach-interface rhel7.2 network 52:54:00:98:c4:a0; sleep 2; virsh dumpxml rhel7.2 |grep /interface -B9 Domain rhel7.2 destroyed Domain rhel7.2 started Interface detached successfully <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/> </controller> <interface type='network'> <mac address='52:54:00:98:c4:a0'/> <source network='default' bridge='virbr0'/> <target dev='vnet0'/> <model type='rtl8139'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> When I detach after the vm boot, expand the sleep time to 10, it will succeed. # virsh destroy rhel7.2; virsh start rhel7.2 ;sleep 10; virsh detach-interface rhel7.2 network 52:54:00:98:c4:a0; sleep 2; virsh dumpxml rhel7.2 |grep /interface -B9 Domain rhel7.2 destroyed Domain rhel7.2 started Interface detached successfully ------- Best Regards, Yalan Zhang IRC: yalzhang Internal phone: 8389413

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CPU features/flags - host vs. guest (Libvirt/QEMU/KVM)
by kAja Ziegler 07 Sep '22

07 Sep '22

Hello, does anyone know of any list/table (ideally as up-to-date as possible) with individual CPU features/flags for x86_64 (preferably Intel), which would state: - description of individual features/flags - dependencies between individual features/flags - e.g. avx on xsave - what features/flags are checked on the hypervisor (host), but are not propagated to the guest - e.g. acpi, ds, monitor, pbe, tm, etc. - some are masked/disabled [(not) supported] by Libvirt, others by KVM/QEMU - what features/flags active for/in the guest limit certain virtualization behavior/options such as live migration - e.g. invtsc, xsaves - so far I only found https://github.com/libvirt/libvirt/blob/master/src/cpu_map/x86_features.xml - features with migratable='no' I would like to tweak the CPU configuration for the virtual servers ie. choose the basic CPU model and turn on/off the necessary or appropriate features/flags while maintaining the possibility of live migration. But I miss the above-mentioned contexts, because not all the mentioned features within the cpu element in the VM definition (domains in Libvirt) are then visible inside the VM in /proc/cpuinfo. Of course, I know about other related commands, registers, etc. like "virsh capabilities|cpu-baseline|cpu-compare", MSR, fixes in CPU microcode, host-model or host-passthrough CPU... but I'm still not sure about setting the match, check and fallback attributes and the resulting behavior of Libvirt and QEMU/KVM. Many thanks in advance for any response K. Ziegler

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