Description of problem: rhel6 guest system time does not correct after reboot when adjusting host time Version-Release number of selected component (if applicable): host: kernel-2.6.32-392.el6.x86_64 qemu-kvm-0.12.1.2-2.377.el6.x86_64 guest: kernel-2.6.32-358.14.1.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1. in host, ntpdate clock.redhat.com and check time # ntpdate clock.redhat.com 4 Jul 19:21:41 ntpdate[7739]: adjust time server 10.5.26.10 offset 0.055313 sec 2. boot the guest with "-rtc base=utc,clock=host" /usr/libexec/qemu-kvm \ -name 'vm1' \ -chardev socket,id=serial_id_serial1,path=/tmp/serial-serial1-20130702-093138-pSivbSG8,server,nowait \ -device isa-serial,chardev=serial_id_serial1 \ -drive file='/root/staf-kvm-devel/autotest-devel/client/tests/virt/shared/data/images/RHEL-Server-6.4-64-virtio.qcow2',if=none,id=drive-virtio-disk1,media=disk,cache=none,snapshot=off,format=qcow2,aio=native \ -device virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk1 \ -net none \ -m 4096 \ -smp 1,maxcpus=1,cores=1,threads=1,sockets=2 \ -cpu 'Penryn' \ -M rhel6.5.0 \ -vnc :0 \ -vga cirrus \ -rtc base=utc,clock=host,driftfix=slew \ -boot order=cdn,once=c,menu=off \ -no-kvm-pit-reinjection \ -enable-kvm \ -monitor stdio 3. in guest check time # date Thu Jul 4 19:24:34 CST 2013 # hwclock Thu 04 Jul 2013 07:24:38 PM CST -0.433308 seconds 4. in host, adjust system time # date -s 21:00:00 Thu Jul 4 21:00:00 CST 2013 5. reboot the guest and check time in guest Actual results: # date Thu Jul 4 19:26:51 CST 2013 # hwclock Thu 04 Jul 2013 07:26:55 PM CST -0.365013 seconds guest system time can not adjust time to host Expected results: guest time should be adjust with host Additional info: 1 host cpuinfo processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 23 model name : Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz stepping : 10 cpu MHz : 2992.051 cache size : 6144 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 apicid : 1 initial apicid : 1 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 aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm dts tpr_shadow vnmi flexpriority bogomips : 5984.10 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: 2. in guest # cat /sys/devices/system/clocksource/clocksource0/current_clocksource kvm-clock 3. i tried the following scenarios: 1). Sync the host time to ntp server 2). boot the guest with host system clockA 3). Adjust host time forward or backward by using "date -s" to system clockB 4). reboot guest --Results-- +--------------------------+----------------------------------+ | RHEL6 boot with | guest system and hardware clock | | -rtc base=utc,clock=host | not sync to host clockB | +--------------------------+----------------------------------+ | RHEL6 boot with | guest system and hardware clock | | -rtc base=utc,clock=vm | not sync to host clockB | +--------------------------+----------------------------------+ | RHEL7 boot with | guest system and hardware clock | | -rtc base=utc,clock=host | sync to host clockB | +--------------------------+----------------------------------+ | RHEL7 boot with | guest system and hardware clock | | -rtc base=utc,clock=vm | not sync to host clockB | +--------------------------+----------------------------------+
ShupingCui, This is the same issue as discussed here: https://bugzilla.redhat.com/show_bug.cgi?id=978120 And the conclusion was: there is no known strong reason to have the emulated RTC be initialized from the host time on system reset. Closing.
Description of problem: rhel6 guest system time does not correct after reboot when adjusting host time Version-Release number of selected component (if applicable): host: kernel-2.6.32-392.el6.x86_64 qemu-kvm-0.12.1.2-2.377.el6.x86_64 guest: kernel-2.6.32-358.14.1.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1. in host, ntpdate clock.redhat.com and check time # ntpdate clock.redhat.com 4 Jul 19:21:41 ntpdate[7739]: adjust time server 10.5.26.10 offset 0.055313 sec 2. boot the guest with "-rtc base=utc,clock=host" /usr/libexec/qemu-kvm \ -name 'vm1' \ -chardev socket,id=serial_id_serial1,path=/tmp/serial-serial1-20130702-093138-pSivbSG8,server,nowait \ -device isa-serial,chardev=serial_id_serial1 \ -drive file='/root/staf-kvm-devel/autotest-devel/client/tests/virt/shared/data/images/RHEL-Server-6.4-64-virtio.qcow2',if=none,id=drive-virtio-disk1,media=disk,cache=none,snapshot=off,format=qcow2,aio=native \ -device virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk1 \ -net none \ -m 4096 \ -smp 1,maxcpus=1,cores=1,threads=1,sockets=2 \ -cpu 'Penryn' \ -M rhel6.5.0 \ -vnc :0 \ -vga cirrus \ -rtc base=utc,clock=host,driftfix=slew \ -boot order=cdn,once=c,menu=off \ -no-kvm-pit-reinjection \ -enable-kvm \ -monitor stdio 3. in guest check time # date Thu Jul 4 19:24:34 CST 2013 # hwclock Thu 04 Jul 2013 07:24:38 PM CST -0.433308 seconds 4. in host, adjust system time # date -s 21:00:00 Thu Jul 4 21:00:00 CST 2013 5. reboot the guest and check time in guest Actual results: # date Thu Jul 4 19:26:51 CST 2013 # hwclock Thu 04 Jul 2013 07:26:55 PM CST -0.365013 seconds guest system time can not adjust time to host Expected results: guest time should be adjust with host Additional info: 1 host cpuinfo processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 23 model name : Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz stepping : 10 cpu MHz : 2992.051 cache size : 6144 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 apicid : 1 initial apicid : 1 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 aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm dts tpr_shadow vnmi flexpriority bogomips : 5984.10 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: 2. in guest # cat /sys/devices/system/clocksource/clocksource0/current_clocksource kvm-clock 3. i tried the following scenarios: 1). Sync the host time to ntp server 2). boot the guest with host system clockA 3). Adjust host time forward or backward by using "date -s" to system clockB 4). reboot guest --Results-- +--------------------------+----------------------------------+ | RHEL6 boot with | guest system and hardware clock | | -rtc base=utc,clock=host | not sync to host clockB | +--------------------------+----------------------------------+ | RHEL6 boot with | guest system and hardware clock | | -rtc base=utc,clock=vm | not sync to host clockB | +--------------------------+----------------------------------+ | RHEL7 boot with | guest system and hardware clock | | -rtc base=utc,clock=host | sync to host clockB | +--------------------------+----------------------------------+ | RHEL7 boot with | guest system and hardware clock | | -rtc base=utc,clock=vm | not sync to host clockB | +--------------------------+----------------------------------+