Bug 1720213
| Summary: | Couldn't boot L2 guest on L1 when boot L1 with -cpu $model_name,vmx | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux Advanced Virtualization | Reporter: | Li Xiaohui <xiaohli> |
| Component: | qemu-kvm | Assignee: | Paolo Bonzini <pbonzini> |
| qemu-kvm sub component: | General | QA Contact: | Qinghua Cheng <qcheng> |
| Status: | CLOSED CURRENTRELEASE | Docs Contact: | |
| Severity: | unspecified | ||
| Priority: | high | CC: | bsd, chayang, coli, hhei, jinzhao, juzhang, knoel, pbonzini, ribarry, virt-maint, vkuznets, xiaohli |
| Version: | 8.1 | Keywords: | TestOnly |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2021-01-08 16:53:03 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 1559846, 1791648, 1794843 | ||
| Bug Blocks: | 1771318 | ||
Since it is limited to named machine types, I think we can delay it to 8.2 and fix it together with bug 1559846 ("Nested KVM: limit VMX features according to CPU models") and bug 1689270 ("https://bugzilla.redhat.com/show_bug.cgi?id=1689270"). Since it works with "-cpu host", it should not be a kernel issue. Also, since we are not limiting VMX features in named CPU models, live migration would _not_ work across hosts with different CPU. Therefore, now that live migration is going to be supported for nested virtualization, it's arguably better if "-cpu foo,vmx" is broken. (In reply to Paolo Bonzini from comment #2) > Since it is limited to named machine types, I think we can delay it to 8.2 > and fix it together with bug 1559846 ("Nested KVM: limit VMX features > according to CPU models") and bug 1689270 > ("https://bugzilla.redhat.com/show_bug.cgi?id=1689270"). Since it works > with "-cpu host", it should not be a kernel issue. Thanks. I've moved this to 8.2 and added dependencies on 1559846/1689270. QEMU has been recently split into sub-components and as a one-time operation to avoid breakage of tools, we are setting the QEMU sub-component of this BZ to "General". Please review and change the sub-component if necessary the next time you review this BZ. Thanks Verified on RHEL8.2 Kernel: 4.18.0-180.el8.x86_64 qemu-kvm: qemu-kvm-4.2.0-13.module+el8.2.0+5898+fb4bceae.x86_64 This bug is not reproduced. Changing this TestOnly BZ as CLOSED CURRENTRELEASE. Please reopen if the issue is not resolved. |
Description of problem: Could not access KVM kernel module and qemu-kvm: failed to initialize KVM when boot L2 guest. Only occured when boot L1 guest with -cpu $module_name,vmx Version-Release number of selected component (if applicable): host info: (1)cpu info [root@dhcp-12-148 qemu-sh]# virsh capabilities | grep model <model>IvyBridge-IBRS</model> <secmodel> <model>selinux</model> </secmodel> <secmodel> <model>dac</model> </secmodel> (2)version info: kernel-4.18.0-103.el8.x86_64 & qemu-img-4.0.0-4.module+el8.1.0+3356+cda7f1ee.x86_64 guest info: kernel-4.18.0-100.el8.x86_64 & qemu-img-4.0.0-4.module+el8.1.0+3356+cda7f1ee.x86_64 How reproducible: 5/5 Steps to Reproduce: 1.enable nested on L0 host: [root@dhcp-12-148 ~]# cat /sys/module/kvm_intel/parameters/nested Y 2.boot L1 guest with commands on L0: /usr/libexec/qemu-kvm \ -enable-kvm \ -machine q35 \ -m 4096 \ -smp 2 \ -cpu "Nehalem",vmx \ -device pcie-root-port,id=pcie.0-root-port-2,slot=2,chassis=2,addr=0x2,bus=pcie.0 \ -device pcie-root-port,id=pcie.0-root-port-3,slot=3,chassis=3,addr=0x3,bus=pcie.0 \ -device pcie-root-port,id=pcie.0-root-port-4,slot=4,chassis=4,addr=0x4,bus=pcie.0 \ -blockdev node-name=back_image,driver=file,cache.direct=on,cache.no-flush=off,filename=/mnt/nfs/rhel8-1-0-blk.qcow2,aio=threads \ -blockdev node-name=drive-virtio-disk0,driver=qcow2,cache.direct=on,cache.no-flush=off,file=back_image \ -device virtio-blk-pci,drive=drive-virtio-disk0,id=disk0,bus=pcie.0-root-port-2 \ -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown,queues=4 \ -device virtio-net-pci,netdev=hostnet0,id=net0,mac=00:1b:21:7a:76:1c,bus=pcie.0-root-port-3,vectors=10,mq=on \ -vnc :0 \ -device VGA \ -monitor stdio \ -qmp tcp:0:1234,server,nowait \ 3.in L1 guest, install qemu-kvm and config switch network. 4.boot L2 guest in L1 with commands: /usr/libexec/qemu-kvm \ -enable-kvm \ -machine q35 \ -m 4096 \ -smp 2 \ -cpu "Nehalem",vmx \ -device pcie-root-port,id=pcie.0-root-port-2,slot=2,chassis=2,addr=0x2,bus=pcie.0 \ -device pcie-root-port,id=pcie.0-root-port-3,slot=3,chassis=3,addr=0x3,bus=pcie.0 \ -device pcie-root-port,id=pcie.0-root-port-4,slot=4,chassis=4,addr=0x4,bus=pcie.0 \ -blockdev node-name=back_image,driver=file,cache.direct=on,cache.no-flush=off,filename=rhel8-1-0-blk.qcow2,aio=threads \ -blockdev node-name=drive-virtio-disk0,driver=qcow2,cache.direct=on,cache.no-flush=off,file=back_image \ -device virtio-blk-pci,drive=drive-virtio-disk0,id=disk0,bus=pcie.0-root-port-2 \ -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown,queues=4 \ -device virtio-net-pci,netdev=hostnet0,id=net0,mac=00:1b:21:7a:76:e1,bus=pcie.0-root-port-3,vectors=10,mq=on \ -vnc :0 \ -device VGA \ -monitor stdio \ -qmp tcp:0:1234,server,nowait \ Actual results: when execute step4, qemu couldn't start, get error prompts: Could not access KVM kernel module: No such file or directory qemu-kvm: failed to initialize KVM: No such file or directory and found kvm module loaded in L1 failed: [root@dhcp-12-206 work]# lsmod | grep kvm kvm 749568 0 irqbypass 16384 1 kvm Expected results: L2 guest could start successfully in L1. Additional info: 1.when boot L1 with "-cpu host", L2 guest could start successfully in L1, and kvm module loaded succeeded. 2.test on the latest rhel7.7 host using same guest rhel8.1, L2 guest started successfully in L1.