我刚刚在我的 Ubuntu 21.04 上启动了“virt-manager”，令我惊讶的是我看到了错误“kvm 不可用。这可能意味着 kvm 软件包未安装等等“；这不是真的。我已经安装了 kvm 并且它工作得很好，如下图所示：
看看终端正在说什么：“/dev/kvm 存在；可以使用kvm加速“。我应该相信什么？缺少什么？
# apt install qemu-kvm libvirt-clients libvirt-daemon-system
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Note, selecting 'qemu-system-x86' instead of 'qemu-kvm'
qemu-system-x86 is already the newest version (1:5.2+dfsg-9ubuntu3.1).
libvirt-clients is already the newest version (7.0.0-2ubuntu2).
libvirt-daemon-system is already the newest version (7.0.0-2ubuntu2).
0 upgraded, 0 newly installed, 0 to remove and 11 not upgraded.
# virt-host-validate
QEMU: Checking for hardware virtualization : PASS
QEMU: Checking if device /dev/kvm exists : PASS
QEMU: Checking if device /dev/kvm is accessible : PASS
QEMU: Checking if device /dev/vhost-net exists : PASS
QEMU: Checking if device /dev/net/tun exists : PASS
QEMU: Checking for cgroup 'cpu' controller support : PASS
QEMU: Checking for cgroup 'cpuacct' controller support : PASS
QEMU: Checking for cgroup 'cpuset' controller support : PASS
QEMU: Checking for cgroup 'memory' controller support : PASS
QEMU: Checking for cgroup 'devices' controller support : PASS
QEMU: Checking for cgroup 'blkio' controller support : PASS
QEMU: Checking for device assignment IOMMU support : PASS
QEMU: Checking if IOMMU is enabled by kernel : PASS
QEMU: Checking for secure guest support : WARN (Unknown if this platform has Secure Guest support)
LXC: Checking for Linux >= 2.6.26 : PASS
LXC: Checking for namespace ipc : PASS
LXC: Checking for namespace mnt : PASS
LXC: Checking for namespace pid : PASS
LXC: Checking for namespace uts : PASS
LXC: Checking for namespace net : PASS
LXC: Checking for namespace user : PASS
LXC: Checking for cgroup 'cpu' controller support : PASS
LXC: Checking for cgroup 'cpuacct' controller support : PASS
LXC: Checking for cgroup 'cpuset' controller support : PASS
LXC: Checking for cgroup 'memory' controller support : PASS
LXC: Checking for cgroup 'devices' controller support : PASS
LXC: Checking for cgroup 'freezer' controller support : PASS
LXC: Checking for cgroup 'blkio' controller support : PASS
LXC: Checking if device /sys/fs/fuse/connections exists : PASS
再次 ：
● libvirtd.service - Virtualization daemon
Loaded: loaded (/lib/systemd/system/libvirtd.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2021-07-28 13:18:31 CEST; 41min ago
TriggeredBy: ● libvirtd-admin.socket
● libvirtd-ro.socket
● libvirtd.socket
Docs: man:libvirtd(8)
https://libvirt.org
Main PID: 2091 (libvirtd)
Tasks: 21 (limit: 32768)
Memory: 49.3M
CGroup: /system.slice/libvirtd.service
├─2091 /usr/sbin/libvirtd
├─2405 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
└─2406 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
Jul 28 12:45:30 Z390-AORUS-PRO libvirtd[2091]: internal error: Failed to start QEMU binary /usr/local/bin/qemu-system-x86_64 for probing: libvirt: error : cannot execute binary /usr/local/bin/qemu-system-x86_64: Permission denied
Jul 28 12:45:30 Z390-AORUS-PRO libvirtd[2091]: Failed to probe capabilities for /usr/local/bin/qemu-system-x86_64: internal error: Failed to start QEMU binary /usr/local/bin/qemu-system-x86_64 for probing: libvirt: error : cannot execute binary /usr/local/bin/qemu-system-x86_64: Permission denied
Jul 28 13:58:54 Z390-AORUS-PRO libvirtd[2091]: internal error: libxenlight state driver is not active
Jul 28 13:58:54 Z390-AORUS-PRO libvirtd[2091]: End of file while reading data: Input/output error
Jul 28 13:58:54 Z390-AORUS-PRO libvirtd[2091]: invalid argument: could not find capabilities for arch=x86_64 domaintype=qemu
Jul 28 13:58:54 Z390-AORUS-PRO libvirtd[2091]: internal error: Cannot find suitable emulator for x86_64
Jul 28 13:58:54 Z390-AORUS-PRO libvirtd[2091]: internal error: Failed to start QEMU binary /usr/local/bin/qemu-system-x86_64 for probing: libvirt: error : cannot execute binary /usr/local/bin/qemu-system-x86_64: Permission denied
Jul 28 13:58:54 Z390-AORUS-PRO libvirtd[2091]: Failed to probe capabilities for /usr/local/bin/qemu-system-x86_64: internal error: Failed to start QEMU binary /usr/local/bin/qemu-system-x86_64 for probing: libvirt: error : cannot execute binary /usr/local/bin/qemu-system-x86_64: Permission denied
Jul 28 13:59:06 Z390-AORUS-PRO libvirtd[2091]: internal error: Failed to start QEMU binary /usr/local/bin/qemu-system-x86_64 for probing: libvirt: error : cannot execute binary /usr/local/bin/qemu-system-x86_64: Permission denied
Jul 28 13:59:06 Z390-AORUS-PRO libvirtd[2091]: Failed to probe capabilities for /usr/local/bin/qemu-system-x86_64: internal error: Failed to start QEMU binary /usr/local/bin/qemu-system-x86_64 for probing: libvirt: error : cannot execute binary /usr/local/bin/qemu-system-x86_64: Permission denied
答案1
让我们从显而易见的事情开始。
cannot execute binary /usr/local/bin/qemu-system-x86_64: Permission denied
尝试停止 AppArmor，然后重新启动libvirtd并重新启动virt-manager
sudo systemctl stop apparmor