On Sun, Sep 25, 2011 at 11:13:06AM +0300, Nadav Har'El wrote: > On Fri, Sep 23, 2011, Marcelo Tosatti wrote about "Re: [PATCH 1/2] nVMX: Add KVM_REQ_IMMEDIATE_EXIT": > > On Thu, Sep 22, 2011 at 01:52:56PM +0300, Nadav Har'El wrote: > > > This patch adds a new vcpu->requests bit, KVM_REQ_IMMEDIATE_EXIT. > > > This bit requests that when next entering the guest, we should run it only > > > for as little as possible, and exit again. > > > > > > We use this new option in nested VMX: When L1 launches L2, but L0 wishes L1 > >... > > > @@ -5647,6 +5648,8 @@ static int vcpu_enter_guest(struct kvm_v > > > } > > > if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu)) > > > record_steal_time(vcpu); > > > + req_immediate_exit = > > > + kvm_check_request(KVM_REQ_IMMEDIATE_EXIT, vcpu); > >... > > The immediate exit information can be lost if entry decides to bail out. > > You can do > > > > req_immediate_exit = kvm_check_request(KVM_REQ_IMMEDIATE_EXIT) > > after preempt_disable() > > and then transfer back the bit in the bail out case in > > if (vcpu->mode == EXITING_GUEST_MODE || vcpu->requests > > Thanks. > > But thinking about this a bit, it seems to me that in my case *losing* this > bit on a canceled entry is the correct thing to do, as turning on this bit was > decided in the injection phase (in enable_irq_window()), and next time, if > the reason to turn on this bit still exists (i.e., L0 has something to inject > to L1, but L2 needs to run), we will turn it on again. Correct, the loss is irrelevant. -- 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
