https://bugzilla.kernel.org/show_bug.cgi?id=205441 Bug ID: 205441 Summary: Enabling KVM causes any Linux VM reboot on kernel boot Product: Virtualization Version: unspecified Kernel Version: 4.19.81 Hardware: Intel OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: kvm Assignee: virtualization_kvm@xxxxxxxxxxxxxxxxxxxx Reporter: hawk@xxxxxxxxxxxxx Regression: No Created attachment 285801 --> https://bugzilla.kernel.org/attachment.cgi?id=285801&action=edit Kernel .config file I'm unable to run any Linux VM on host running kernel 4.19.81. VM starts fine, boot loader works fine, both kernel and initramfs images are loaded and when kernel boot should occur, VM simply reboots itself. This happens only when -enable-kvm is added on command line. Disabling KVM makes it working again (but slow). Problem appears only on one of my two physical hosts, the one with Intel Core 2 Quad 9500 CPU. KVM works fine on Intel Xeon E3-1246 CPU (same packages, same versions, same configs). I tried different guest kernel versions and systems and VM will always reboot when trying to boot kernel. If I downgrade to 4.19.73 KVM is working fine again. I may test kernels from 4.19.74 to 4.19.79 to see which one introduces the problem, but it will take some time as I must build these packages manually. I'm starting my test VM with below command, but started via libvirt have same problem. qemu-system-x86_64 -m 2048M -smp 1 -k en-us -drive file=/tmp/cri-tld-x64-20190916.iso,media=cdrom,format=raw,if=ide -cpu kvm64 -vnc 127.0.0.1:0 -enable-kvm I tried changing -cpu parameter including host passthrough option, but problems persists. Kernel version (distribution package): Linux version 4.19.81-4.19-vanilla-1 (builder@x64) (gcc version 9.2.0 20190830 (release) (TLD-Linux)) #1 SMP Wed Oct 30 20:56:24 CET 2019 Kernel config is attached. CPU on host where problem exists (limited output to single core) processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 23 model name : Intel(R) Core(TM)2 Quad CPU Q9500 @ 2.83GHz stepping : 10 microcode : 0xa0b cpu MHz : 2015.344 cache size : 3072 KB physical id : 0 siblings : 4 core id : 0 cpu cores : 4 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl cpuid aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm pti tpr_shadow vnmi flexpriority dtherm bugs : cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf mds swapgs bogomips : 5652.52 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: -- You are receiving this mail because: You are watching the assignee of the bug.
