Bug 846479
| Summary: | KVM: x86: apply kvmclock offset to guest wall clock time (upstream backport) | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Marcelo Tosatti <mtosatti> |
| Component: | kernel | Assignee: | Marcelo Tosatti <mtosatti> |
| Status: | CLOSED DUPLICATE | QA Contact: | Red Hat Kernel QE team <kernel-qe> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 6.3 | ||
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2012-08-08 15:58:23 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
*** This bug has been marked as a duplicate of bug 817243 *** |
commit 4b6486659a7defef82ea51b276024b3aa357fefc Author: Bruce Rogers <brogers> Date: Fri Jul 20 10:44:24 2012 -0600 KVM: x86: apply kvmclock offset to guest wall clock time When a guest migrates to a new host, the system time difference from the previous host is used in the updates to the kvmclock system time visible to the guest, resulting in a continuation of correct kvmclock based guest timekeeping. The wall clock component of the kvmclock provided time is currently not updated with this same time offset. Since the Linux guest caches the wall clock based time, this discrepency is not noticed until the guest is rebooted. After reboot the guest's time calculations are off. This patch adjusts the wall clock by the kvmclock_offset, resulting in correct guest time after a reboot. --- Lack of this fix can result in application crashes in guests which are difficult to debug, when migration is used.