Re: [Qemu-devel] [PATCH RFC] KVM: X86: save and load PVCLOCK_TSC_UNSTABLE_BIT when migration

2017-06-13 Thread Radim Krčmář
2017-06-13 20:00+0800, Jay Zhou: > On 2017/6/13 3:52, Radim Krčmář wrote: > > If you get a timestamp from KVM_GET_CLOCK() and pass that to > > KVM_SET_CLOCK(), then kvmclock should not jump backwards anymore > > (it could before 4.9, but only if the host had stable tsc). > > If migrating from old

Re: [Qemu-devel] [PATCH RFC] KVM: X86: save and load PVCLOCK_TSC_UNSTABLE_BIT when migration

2017-06-13 Thread Jay Zhou
Hi Radim, On 2017/6/13 3:52, Radim Krčmář wrote: 2017-06-12 21:23+0800, Jay Zhou: Guest using kvmclock will be hanged when migrating from unstable tsc host to stable tsc host occasionally. Sometimes, the tsc timestamp saved at the source side will be backward when the guest stopped, and this va

Re: [Qemu-devel] [PATCH RFC] KVM: X86: save and load PVCLOCK_TSC_UNSTABLE_BIT when migration

2017-06-12 Thread Radim Krčmář
2017-06-12 21:23+0800, Jay Zhou: > Guest using kvmclock will be hanged when migrating from unstable > tsc host to stable tsc host occasionally. > Sometimes, the tsc timestamp saved at the source side will be > backward when the guest stopped, and this value is transferred > to the destination side.

[Qemu-devel] [PATCH RFC] KVM: X86: save and load PVCLOCK_TSC_UNSTABLE_BIT when migration

2017-06-12 Thread Jay Zhou
Guest using kvmclock will be hanged when migrating from unstable tsc host to stable tsc host occasionally. Sometimes, the tsc timestamp saved at the source side will be backward when the guest stopped, and this value is transferred to the destination side. The guest at the destination side thought