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Questions on device-added and device-removed events
by Han Han 23 Nov '21

23 Nov '21

Hi developers, When the guest OS is booting, the event for live attachment could be caught by libvirt, while the event for live detachment could not. Version: libvirt-7.9 qemu-kvm-6.1 Steps: Terminal 1: ➜ ~ virsh event --loop --all Terminal 2: ➜ ~ virsh start avocado-vt-vm1; qemu-img create /tmp/vdb 10M; virsh attach-disk avocado-vt-vm1 /tmp/vdb vdb; virsh detach-disk avocado-vt-vm1 vdb The outputs from terminal 1: event 'agent-lifecycle' for domain 'avocado-vt-vm1': state: 'disconnected' reason: 'domain started' event 'lifecycle' for domain 'avocado-vt-vm1': Resumed Unpaused event 'lifecycle' for domain 'avocado-vt-vm1': Started Booted event 'device-added' for domain 'avocado-vt-vm1': virtio-disk1 event 'agent-lifecycle' for domain 'avocado-vt-vm1': state: 'connected' reason: 'channel event' As you can see, the device live attachment and the device detachment are both executed when the guest OS is booting, but there is only the event 'device-added' is recorded. So my questions are: 1. Is it the expected results for the results above? 2. If so, what is the internal difference between 'device-added' and 'device-removed'? 3. I notice there is the DEVICE_DELETED event in qmp? Any relation between the 'device-removed' of libvirt and the DEVICE_DELETED of qmp?

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how to use vhost-user-vsock
by Jiatong Shen 23 Nov '21

23 Nov '21

Hello community, I am looking for a way to configure vhost-user-vsock using libvirt, but looks like it is not written in doc. How can I use vhost-user-vsock using libvirt? Thank you. -- Best Regards, Jiatong Shen

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configure path name of ebtables executable
by Michael Ströder 17 Nov '21

17 Nov '21

HI! Is it possible to configure the full path name of the ebtables executable used somewhere in libvirt's config? Background: I'd like to avoid automatic alternatives implementation to mess up libvirt installation. See also: https://bugzilla.opensuse.org/show_bug.cgi?id=1192799 Ciao, Michael.

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Cannot access KVM using virsh console after KVM rebooted or shut off
by Yifei Liu 16 Nov '21

16 Nov '21

Dear all, I used ssh with -X option to connect to an Ubuntu remote server where I applied virsh (libvirt) to manage my KVM virtual machines, and my local machine is MacOS. Then, I used virt-install to install a Tiny Core Linux VM, and I got a pop-up Virt Viewer window (via XQuartz) which is the console for my Tiny Core VM. However, if I rebooted my VM, then I checked the VM state by virsh list --all which was running. Then, I tried `virsh console my_vm_domain` but this command got stuck on: > Connected to domain my_vm_domain > Escape character is ^] The `virsh console` command hung without any response. This issue also happened when I used virsh console after I shut down and later started the VM. Even the VM was already started, I cannot return to the VM console by `virsh console`. I can get the VM console in Virt Viewer at the first boot (using virt-install). But, if I shutdown the VM once, I can never access the VM console by virsh console even the VM state is running. Any idea about how to use virsh console? Thanks, Yifei

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can't connect to virtlogd: Unable to open system token /run/libvirt/common/system.token: Permission denied
by 梁朝军 16 Nov '21

16 Nov '21

Hi all, I have encountered a new issue when start a VM with new builded libvirt. I failed to start VM from defined xml and hit the error like "can't connect to virtlogd: Unable to open system token /run/libvirt/common/system.token: Permission denied” Any inputs are appreciated. The libvit version: libvirtd -V setlocale: No such file or directory libvirtd (libvirt) 7.6.0 Os : cat /etc/redhat-release Red Hat Enterprise Linux release 8.4 (Ootpa) Linux kernel: uname -a Linux localhost.localdomain 4.18.0-305.el8.x86_64 #1 SMP Thu Apr 29 08:54:30 EDT 2021 x86_64 x86_64 x86_64 GNU/Linux QEMU version: usr/libexec/qemu-kvm --help QEMU emulator version 5.1.0 (qemu-kvm-5.1.0-1.el8) Copyright (c) 2003-2020 Fabrice Bellard and the QEMU Project developers Thanks!

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CPU vendor_id handling
by Toolybird 15 Nov '21

15 Nov '21

Hello, There are times when spoofing the CPU vendor_id is convenient. For example, some x86 guest OS's only run on Intel and refuse to run on an AMD host. Libvirt does support this in the "host-model" case, but it doesn't work for CPU "host-passthrough". On the QEMU command line it's as easy as: $ qemu-system-x86_64 -cpu host,vendor=GenuineIntel This works fine in libvirt XML: <cpu mode='host-model'> <model vendor_id='GenuineIntel'/> </cpu> This doesn't: <cpu mode='host-passthrough'> <model vendor_id='GenuineIntel'/> </cpu> Libvirt silently strips out the model line after saving "virsh edit ..." Is there any reason why libvirt cannot support this in the host-passthrough case? The status quo means that some folks end up resorting to <qemu:arg value='-cpu'/> hacks which of course causes all sorts of confusion with multiple -cpu lines getting passed to QEMU. Thanks

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creating specific cpu model
by daggs 13 Nov '21

13 Nov '21

Greetings, I want to create a new cpu model which is a cross section of cpu flags of 2 different cpus and libvirt capabilites. I've extracted the supported cpu flags of each cpu using lscpu. I've created a cross section of both. I've pulled the suppored cpu flags from libvirt and created a cross section of it with the subset from above. now I want to create a new cpu model out of it. I assume that creating a xml file at /usr/share/libvirt/cpu_map/ with the x86_ prefix that matches the format listed there will suffice for libvirt and later for qemu? Thanks, Dagg.

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another upgrade another vm issue
by daggs 31 Oct '21

31 Oct '21

Greetings, so I've upgraded my server and yet again, one of my vm lost a functionally. there is no usable sound card. xml: https://dpaste.com/CVR5M75VH in vm: https://snipboard.io/aZ7Dcf.jpg outputs: utils_server /home/igor # qemu-system-x86_64 --version QEMU emulator version 6.0.0 Copyright (c) 2003-2021 Fabrice Bellard and the QEMU Project developers utils_server /home/igor # libvirtd --version libvirtd (libvirt) 7.8.0 utils_server /home/igor # any ideas? Thanks.

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Iptables, et al best practices for protecting KVM host sharing "hostdev" (ixgbe-vf) interfaces with guests
by Philip Prindeville 29 Oct '21

29 Oct '21

Hi, I'm a developer and I use VM's for testing patches before submitting them (for various linux-* projects, as well as downstream things like OpenWrt, EPEL, etc). I have a trunked 10Gb/s Ethernet connection coming into my KVM servers (all of which are Supermicro x86_servers running CentOS 8) that have igb and ixgbe NIC's, so SR-IOV capable. Here's the situation: * the host is on a secured internal network, called "sandbox", which is VLAN 4. * the "external" network (i.e. public facing on my ISP) is "dirty", and is VLAN 66. * the main subnet that laptops, WAPs, desktops, etc. sit on is "main", and is VLAN 1. The KVM hosts sit wholly inside "sandbox". They host, however, several guests some of which sit on "main", and some of which sit on "main" and "external" (for instance, if I'm testing an OpenWrt firewall configuration with patches and it needs to be publicly accessible so that my testers can peer with it via IPsec). Oh, and one production guest which hosts "git" and sits only on "sandbox". Guests can be CentOS 8S, Windows 11, Ubuntu 20, Debian whatever, Fedora 33 or 34, OpenWrt, etc. My question is this: what's best practices for making sure that a switch VLAN misconfiguration issue, a cabling to the wrong port, etc. doesn't compromise the KVM server itself? How do I allow my KVM server to *not* be on "external", but some of its guests to be, without compromising security? Being the paranoid sort, I'd like to use defense-in-depth so I'm not counting on any single step to protect me. For instance, I might use ebtables or iptables rules to block VLAN traffic on hosts/guests that I don't want to see certain VLAN's under any circumstances. But I might also add interfaces to the list of things that NetworkManager ignores as /etc/NetworkManager/NetworkManager.conf lines like: [keyfile] unmanaged-devices=interface-name:eno*,except:interface-name:eno1 unmanaged-devices=interface-name:enp* Thinking about that, I'm wondering what the notation is for telling NetworkManager to ignore all interfaces except those on VLAN 3, for instance. Would that be: unmanaged-devices=interface-name:eno*.*,except:interface-name:eno*.3 Or something else? And what else can I do to further secure my KVM host? I thought about using one untagged (non VLAN'd) Ethernet for the host, and another tagged Ethernet for the guests, but that just seemed like a false sense of security... Apologies for the cross posting... these questions seems to touch on iptables, libvirt, and NetworkManager all at the same time... Thanks, -Philip

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RE: apt libvirt package
by admin＠foundryserver.com 26 Oct '21

26 Oct '21

Hello again, So I have been struggling to compile the libvirt newest version 7.8.0. I am running CentOS 8 and during the meson build process I am getting non stop dependency fails. I keep installing the necessary packages and slowly progressing. Now the last one that stopped was gnutls. When I go to install that package via yum install gnutls -y it says that it is already complete and installed. Sigh... I am very surprised that there is no package for libvirt via rpm,yum etc. the lastest one installed via yum was 6.0.0. Can someone help by pointing to some where that has these latest packages? Or how best to compile this from source. It is amazing how much is missing from this distro. Thanks again. Brad From: admin(a)foundryserver.com <admin(a)foundryserver.com> Sent: October 23, 2021 12:54 PM To: 'libvirt-users(a)redhat.com' <libvirt-users(a)redhat.com> Subject: apt libvirt package Hello, I am new to kvm/qemu/libvirt. I am loving it. I am working on setting my first vm with shared file system with virtio-fs. I got an error, and google foo said, my version was too old. When I checked it said. libvirt version: 6.0.0, package: 0ubuntu8.14 (Matthew Ruffell matthew.ruffell(a)canonical.com <mailto:matthew.ruffell@canonical.com> Tue, 14 Sep 2021 14:00:49 +1200) I used apt package manager to install libvirt. I am running on ubuntu 20.04. I have tried apt update libvirt and I get..no updates available. What do I do at this point? Do I have to build it from source? Any help would be greatly appreciated. Brad

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