On Mon, Nov 26, 2018 at 12:18 PM Sean Christopherson
<sean.j.christopherson@xxxxxxxxx> wrote:
>
> On Mon, Nov 26, 2018 at 11:23:31AM -0800, Jim Mattson wrote:
> > According to the SDM, "interrupt-window exiting" VM-exits wake a
> > logical processor from the same inactive states as would an external
> > interrupt. Specifically, they wake a logical processor from the states
> > entered using the HLT and MWAIT instructions.
> >
> > Fixes: 6dfacadd5858 ("KVM: nVMX: Add support for activity state HLT")
> > Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
> > Reviewed-by: Peter Shier <pshier@xxxxxxxxxx>
> > ---
> > arch/x86/kvm/vmx.c | 17 ++++++++++++++---
> > 1 file changed, 14 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> > index 358e96f0c21d..a29921b216f5 100644
> > --- a/arch/x86/kvm/vmx.c
> > +++ b/arch/x86/kvm/vmx.c
> > @@ -13498,6 +13498,16 @@ static bool nested_vmx_nmi_window_exit(struct vmcs12 *vmcs12)
> > (GUEST_INTR_STATE_NMI | GUEST_INTR_STATE_MOV_SS));
> > }
> >
> > +static bool nested_vmx_intr_window_exit(struct vmcs12 *vmcs12)
> > +{
> > + return (vmcs12->cpu_based_vm_exec_control &
> > + CPU_BASED_VIRTUAL_INTR_PENDING) &&
> > + vmcs12->guest_activity_state != GUEST_ACTIVITY_WAIT_SIPI &&
>
> Technically this also needs to weed out GUEST_ACTIVITY_SHUTDOWN as
> INTR doesn't break shutdown. That being said, I wonder if it makes
> sense to remove the activity state and guest_interruptibility_info
> checks altogether from both the NMI and INTR helpers. The current use
> case is only for guest_activity_state==HLT, which makes both checks
> redundant since guest_activity_state obviously can't be two things at
> once and STI/MOVSS blocking are only legal when going to ACTIVE state.
> Event blocking and prioritization is so complex that it seems unlikely
> that a generic kitchen-sink helper will be useful, e.g.
> handle_invalid_guest_state() already has this code and more by way of
> vmx_interrupt_allowed().
>
> At that point it's probably easiest to just open code the checks, e.g.:
>
> exec_controls = vmcs12->cpu_based_vm_exec_control;
> if ((vmcs12->guest_activity_state == GUEST_ACTIVITY_HLT) &&
> !(vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK) &&
> !(exec_controls & CPU_BASED_VIRTUAL_NMI_PENDING) &&
> !((exec_controls & CPU_BASED_VIRTUAL_INTR_PENDING) &&
> (vmcs12->guest_rflags & X86_EFLAGS_IF))) {
> vmx->nested.nested_run_pending = 0;
> return kvm_vcpu_halt(vcpu);
> }
> return 1;
Sounds good to me. Let's call that v3.
