Hi, OK, lets see: kvm_put_msrs: ret=18 expected=105
so I think it's one of the MSRs around 18 that it's upset at: kvm_msr_entry_add: @17 index=4b564d03 value=0 41:#define MSR_KVM_STEAL_TIME 0x4b564d03 kvm_msr_entry_add: @18 index=38d value=0 #define MSR_CORE_PERF_FIXED_CTR_CTRL 0x38d So my guess is it's the steal time thing. 1) You didn't say what kernel your host was running - please tell me I think that steal time thing went into the kernel ~3.0 2) try starting qemu with -cpu host,-kvm_steal_time and/or -cpu host,-perfctr_core 3) If those don't work, in kvm_put_msrs try hacking out the lines: if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_STEAL_TIME)) { kvm_msr_entry_add(cpu, MSR_KVM_STEAL_TIME, env->steal_time_msr); } and turning the : if (has_msr_architectural_pmu) { into if (0) { Dave -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1661386 Title: Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed Status in QEMU: New Bug description: Hello, I see the following when try to run qemu from master as the following: # ./x86_64-softmmu/qemu-system-x86_64 --version QEMU emulator version 2.8.50 (v2.8.0-1006-g4e9f524) Copyright (c) 2003-2016 Fabrice Bellard and the QEMU Project developers # ./x86_64-softmmu/qemu-system-x86_64 -machine accel=kvm -nodefaults -no-reboot -nographic -cpu host -vga none -kernel .build.kernel.kvm -initrd .build.initrd.kvm -append 'panic=1 no-kvmclock console=ttyS0 loglevel=7' -m 1024 -serial stdio qemu-system-x86_64: /home/matwey/lab/qemu/target/i386/kvm.c:1849: kvm_put_msrs: Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed. First broken commit has been bisected: commit 48e1a45c3166d659f781171a47dabf4a187ed7a5 Author: Paolo Bonzini <pbonz...@redhat.com> Date: Wed Mar 30 22:55:29 2016 +0200 target-i386: assert that KVM_GET/SET_MSRS can set all requested MSRs This would have caught the bug in the previous patch. Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> My cpuinfo is the following: processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 44 model name : Intel(R) Xeon(R) CPU X5675 @ 3.07GHz stepping : 2 microcode : 0x14 cpu MHz : 3066.775 cache size : 12288 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 11 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts mmx fxsr sse sse2 ss ht syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliable nonstop_tsc aperfmperf pni pclmulqdq vmx ssse3 cx16 sse4_1 sse4_2 popcnt aes hypervisor lahf_lm ida arat epb dtherm tpr_shadow vnmi ept vpid bugs : bogomips : 6133.55 clflush size : 64 cache_alignment : 64 address sizes : 40 bits physical, 48 bits virtual power management: To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1661386/+subscriptions