On 2014-01-05 21:01, Paolo Bonzini wrote: > Il 04/01/2014 18:47, Jan Kiszka ha scritto: >> From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> >> >> Set guest activity state in L1's VMCS according to the VCPUs mp_state. >> This ensures we report the correct state in case we L2 executed HLT or >> if we put L2 into HLT state and it was now woken up by an event. >> >> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> >> --- >> arch/x86/kvm/vmx.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> index bde8ddd..1245ff1 100644 >> --- a/arch/x86/kvm/vmx.c >> +++ b/arch/x86/kvm/vmx.c >> @@ -8223,6 +8223,10 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, >> vmcs_read32(GUEST_INTERRUPTIBILITY_INFO); >> vmcs12->guest_pending_dbg_exceptions = >> vmcs_readl(GUEST_PENDING_DBG_EXCEPTIONS); >> + if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED) >> + vmcs12->guest_activity_state = GUEST_ACTIVITY_HLT; >> + else >> + vmcs12->guest_activity_state = GUEST_ACTIVITY_ACTIVE; >> >> if ((vmcs12->pin_based_vm_exec_control & PIN_BASED_VMX_PREEMPTION_TIMER) && >> (vmcs12->vm_exit_controls & VM_EXIT_SAVE_VMX_PREEMPTION_TIMER)) >> > > So, without this patch, CPU_BASED_HLT_EXITING should have been set in > nested_vmx_procbased_ctls_low (because disabling HLT exits means L2 can > go "spontaneously" to KVM_MP_STATE_HALTED and without this patch it > would exit the HLT on a subsequent unrelated vmexit). I guess so. I've no hardware around that does not support GUEST_ACTIVITY_HLT, but it makes most sense that those machines enforced HLT_EXITING that way - so should have we. But that inconsistency is fixed now, hopefully. > > I cannot think of any other control that we do not support disabling, > but perhaps I'm missing something. Yeah, I wouldn't be surprised to find a few more broken corner cases. As the number of hypervisor continue to increase, they may help to find them. Reminds me that I still want to run [1] over my queue. They claim to use the preemption timer extensively. Jan [1] http://muen.codelabs.ch/
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