From mboxrd@z Thu Jan 1 00:00:00 1970 From: zhanghailiang Subject: [BUG/RFC] Two cpus are not brought up normally in SLES11 sp3 VM after reboot Date: Mon, 6 Jul 2015 15:54:20 +0800 Message-ID: <559A342C.6020207@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: , "qemu-devel@nongnu.org" To: Return-path: Received: from szxga01-in.huawei.com ([58.251.152.64]:59417 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753018AbbGFHye (ORCPT ); Mon, 6 Jul 2015 03:54:34 -0400 Sender: kvm-owner@vger.kernel.org List-ID: Hi, Recently we encountered a problem in our project: 2 CPUs in VM are not = brought up normally after reboot. Our host is using KVM kmod 3.6 and QEMU 2.1. A SLES 11 sp3 VM configured with 8 vcpus, cpu model is configured with 'host-passthrough'. After VM's first time started up, everything seems to be OK. and then VM is paniced and rebooted. After reboot, only 6 cpus are brought up in VM, cpu1 and cpu7 are not o= nline. This is the only message we can get from VM: VM dmesg shows: [ 0.069867] Booting Node 0, Processors #1 [ 5.060042] CPU1: Stuck ?? [ 5.060499] #2 [ 5.088322] kvm-clock: cpu 2, msr 6:3fc90901, secondary cpu clock [ 5.088335] KVM setup async PF for cpu 2 [ 5.092967] NMI watchdog enabled, takes one hw-pmu counter. [ 5.094405] #3 [ 5.108324] kvm-clock: cpu 3, msr 6:3fcd0901, secondary cpu clock [ 5.108333] KVM setup async PF for cpu 3 [ 5.113553] NMI watchdog enabled, takes one hw-pmu counter. [ 5.114970] #4 [ 5.128325] kvm-clock: cpu 4, msr 6:3fd10901, secondary cpu clock [ 5.128336] KVM setup async PF for cpu 4 [ 5.134576] NMI watchdog enabled, takes one hw-pmu counter. [ 5.135998] #5 [ 5.152324] kvm-clock: cpu 5, msr 6:3fd50901, secondary cpu clock [ 5.152334] KVM setup async PF for cpu 5 [ 5.154764] NMI watchdog enabled, takes one hw-pmu counter. [ 5.156467] #6 [ 5.172327] kvm-clock: cpu 6, msr 6:3fd90901, secondary cpu clock [ 5.172341] KVM setup async PF for cpu 6 [ 5.180738] NMI watchdog enabled, takes one hw-pmu counter. [ 5.182173] #7 Ok. [ 10.170815] CPU7: Stuck ?? [ 10.171648] Brought up 6 CPUs [ 10.172394] Total of 6 processors activated (28799.97 BogoMIPS). From host, we found that QEMU vcpu1 thread and vcpu7 thread were not c= onsuming any cpu (Should be in idle state), All of VCPUs' stacks in host is like bellow: [] kvm_vcpu_block+0x65/0xa0 [kvm] [] __vcpu_run+0xd1/0x260 [kvm] [] kvm_arch_vcpu_ioctl_run+0x68/0x1a0 [kvm] [] kvm_vcpu_ioctl+0x38e/0x580 [kvm] [] do_vfs_ioctl+0x8b/0x3b0 [] sys_ioctl+0xa1/0xb0 [] system_call_fastpath+0x16/0x1b [<00002ab9fe1f99a7>] 0x2ab9fe1f99a7 [] 0xffffffffffffffff We looked into the kernel codes that could leading to the above 'Stuck'= warning, and found that the only possible is the emulation of 'cpuid' instruct i= n kvm/qemu has something wrong. But since we can=E2=80=99t reproduce this problem, we are not quite sur= e. Is there any possible that the cupid emulation in kvm/qemu has some bug= ? Has anyone come across these problem before? Or any idea? Thanks, zhanghailiang