2016-07-07 16:10 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>: > > > On 07/07/2016 05:46, Wanpeng Li wrote: >> From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> >> >> We will go to vcpu_run() loop after L0 emulates VMRESUME which incurs >> kvm_sched_out and kvm_sched_in operations since cond_resched() will be >> called once need resched. Preemption timer will be reprogrammed if vCPU >> is scheduled to a different pCPU. Then the preemption timer bit of vmcs02 >> will be set if L0 enable preemption timer to run L1 even if L1 doesn't >> enable preemption timer to run L2. >> >> This patch fix it by don't reprogram preemption timer of vmcs02 if L1's >> vCPU is scheduled on diffent pCPU when we are in the way to vmresume >> nested guest. > > Again, this is wrong. There is no reason why L1's APIC timer cannot be > emulated through the vmcs12's preemption timer setting. The only issue > is getting the pin-based execution controls right. This patch doesn't intend to implement "L1 TSC deadline timer to trigger while L2 is running", it just solves why vmcs02 is set even if exec_control = vmcs12->pin_based_vm_exec_control; exec_control |= vmcs_config.pin_based_exec_ctrl; exec_control &= ~PIN_BASED_VMX_PREEMPTION_TIMER; We should set pin-based execution controls right to implement "L1 TSC deadline timer to trigger while L2 is running". Regards, Wanpeng Li -- 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
