https://bugzilla.kernel.org/show_bug.cgi?id=115991 Bug ID: 115991 Summary: tsc_offset is error for hot-plugged vcpu. Product: Virtualization Version: unspecified Kernel Version: 4.5 Hardware: x86-64 OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: kvm Assignee: virtualization_kvm@xxxxxxxxxxxxxxxxxxxx Reporter: changlimin@xxxxxxx Regression: No 1. when hot plug vcpu, KVM will call kvm_write_tsc set the new vcpu's tsc_offset to current host tsc. The new vcpu's tsc_offsets is greatly different from existed vcpu's tsc_offset. 2. For redhat 6.x, the vm will show warning and turn off TSC clock. kernel: CPU 1 got hotplugged kernel: kvm-clock: cpu 1, msr 0:282367c1, secondary cpu clock kernel: TSC synchronization [CPU#0 -> CPU#1]: kernel: Measured 150076598781 cycles TSC warp between CPUs, turning off TSC clock. kernel: Marking TSC unstable due to check_tsc_sync_source failed 3. I think should set the new vcpu's tsc_offset to kvm->arch.cur_tsc_offset if host tsc is stable and use_master_clock is true. -- You are receiving this mail because: You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
