Re: [nVMX] With 3.20.0-0.rc0.git5.1 on L0, booting L2 guest results in L1 *rebooting*

[Kashyap Chamarthy <kchamart@redhat.com>]

On Tue, Feb 17, 2015 at 07:07:21PM +0100, Jan Kiszka wrote:
> On 2015-02-17 19:00, Bandan Das wrote:
> > Kashyap Chamarthy <kchamart@redhat.com> writes:
> > ..
> >>>
> >>> Does enable_apicv make a difference?
> >>
> >> Actually, I did perform a test (on Paolo's suggestion on IRC) with
> >> enable_apicv=0 on physical host, and it didn't make any difference:
> >>
> >> $ cat /proc/cmdline 
> >> BOOT_IMAGE=/vmlinuz-3.20.0-0.rc0.git5.1.fc23.x86_64 root=/dev/mapper/fedora--server_dell--per910--02-root ro console=ttyS1,115200n81 rd.lvm.lv=fedora-server_dell-per910-02/swap rd.lvm.lv=fedora-server_dell-per910-02/root LANG=en_US.UTF-8 enable_apicv=0
> > 
> > I am not sure if this works ? enable_apicv is a kvm_intel module parameter
> 
> Good point. Has to be kvm_intel.enable_apicv=0 (if the module is built in).

Hmm, yeah, I should have just added "options kvm-intel enable_apicv=n"
(without quotes) to  /etc/modprobe.d/dist.conf.

I just rebooted the host with "kvm_intel.enable_apicv=0" on Kernel command
line:

$ dmesg | grep apicv
[    0.000000] Command line: BOOT_IMAGE=/vmlinuz-3.20.0-0.rc0.git5.1.fc23.x86_64 root=/dev/mapper/fedora--server_dell--per910--02-root ro console=ttyS1,115200n81 rd.lvm.lv=fedora-server_dell-per910-02/swap rd.lvm.lv=fedora-server_dell-per910-02/root LANG=en_US.UTF-8 kvm_intel.enable_apicv=0
[    0.000000] Kernel command line: BOOT_IMAGE=/vmlinuz-3.20.0-0.rc0.git5.1.fc23.x86_64 root=/dev/mapper/fedora--server_dell--per910--02-root ro console=ttyS1,115200n81 rd.lvm.lv=fedora-server_dell-per910-02/swap rd.lvm.lv=fedora-server_dell-per910-02/root LANG=en_US.UTF-8 kvm_intel.enable_apicv=0

$ cat /sys/module/kvm_intel/parameters/enable_apicv
N
 

Then, booted an L2 guest over L1's serial console, while observing
host's `dmesg -w`, I can see the same traceback:

. . .
[  918.327553] ------------[ cut here ]------------
[  918.332196] WARNING: CPU: 13 PID: 2201 at arch/x86/kvm/vmx.c:9190 nested_vmx_vmexit+0x96e/0xb00 [kvm_intel]()
[  918.342162] Modules linked in: vhost_net vhost macvtap macvlan xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack tun bridge stp llc ip6table_filter ip6_tables cfg80211 rfkill iTCO_wdt ipmi_devintf iTCO_vendor_support gpio_ich dcdbas coretemp kvm_intel kvm crc32c_intel serio_raw ipmi_ssif ipmi_si tpm_tis tpm ipmi_msghandler acpi_power_meter i7core_edac lpc_ich edac_core acpi_cpufreq mfd_core shpchp wmi mgag200 i2c_algo_bit drm_kms_helper ttm drm ata_generic pata_acpi megaraid_sas bnx2
[  918.396548] CPU: 13 PID: 2201 Comm: qemu-system-x86 Not tainted 3.20.0-0.rc0.git5.1.fc23.x86_64 #1
[  918.405605] Hardware name: Dell Inc. PowerEdge R910/0P658H, BIOS 2.8.2 10/25/2012
[  918.413138]  0000000000000000 00000000651bc665 ffff883f619ebc18 ffffffff818760f7
[  918.420790]  0000000000000000 0000000000000000 ffff883f619ebc58 ffffffff810ab80a
[  918.428336]  ffff887f5b838000 ffff883f3f8c8000 0000000000000000 0000000000000014
[  918.435865] Call Trace:
[  918.438390]  [<ffffffff818760f7>] dump_stack+0x4c/0x65
[  918.443590]  [<ffffffff810ab80a>] warn_slowpath_common+0x8a/0xc0
[  918.449596]  [<ffffffff810ab93a>] warn_slowpath_null+0x1a/0x20
[  918.455494]  [<ffffffffa100857e>] nested_vmx_vmexit+0x96e/0xb00 [kvm_intel]
[  918.462455]  [<ffffffffa100b5f7>] ? vmx_handle_exit+0x1e7/0xcb2 [kvm_intel]
[  918.469444]  [<ffffffffa0236972>] ? kvm_arch_vcpu_ioctl_run+0x6d2/0x1b50 [kvm]
[  918.476731]  [<ffffffffa100892a>] vmx_queue_exception+0x10a/0x150 [kvm_intel]
[  918.483870]  [<ffffffffa023730b>] kvm_arch_vcpu_ioctl_run+0x106b/0x1b50 [kvm]
[  918.491078]  [<ffffffffa0236972>] ? kvm_arch_vcpu_ioctl_run+0x6d2/0x1b50 [kvm]
[  918.498302]  [<ffffffff8110760d>] ? trace_hardirqs_on+0xd/0x10
[  918.504203]  [<ffffffffa021edf6>] ? vcpu_load+0x26/0x70 [kvm]
[  918.510012]  [<ffffffff81103c0f>] ? lock_release_holdtime.part.29+0xf/0x200
[  918.516973]  [<ffffffffa021f203>] kvm_vcpu_ioctl+0x383/0x7e0 [kvm]
[  918.523157]  [<ffffffff81027b9d>] ? native_sched_clock+0x2d/0xa0
[  918.529167]  [<ffffffff810d5fc6>] ? creds_are_invalid.part.1+0x16/0x50
[  918.535701]  [<ffffffff810d6021>] ? creds_are_invalid+0x21/0x30
[  918.541678]  [<ffffffff813a61da>] ? inode_has_perm.isra.48+0x2a/0xa0
[  918.548097]  [<ffffffff8128c7b8>] do_vfs_ioctl+0x2e8/0x530
[  918.553579]  [<ffffffff8128ca81>] SyS_ioctl+0x81/0xa0
[  918.558635]  [<ffffffff8187f8e9>] system_call_fastpath+0x12/0x17
[  918.564640] ---[ end trace b07d41c569219c46 ]---
[ 1092.389383 <  173.824743>] kvm [2168]: vcpu0 unhandled rdmsr: 0x1c9
[ 1092.394374 <    0.004991>] kvm [2168]: vcpu0 unhandled rdmsr: 0x1a6
[ 1092.399399 <    0.005025>] kvm [2168]: vcpu0 unhandled rdmsr: 0x3f6
. . .

-- 
/kashyap