2018-11-26 12:34-0800, Jim Mattson:
> 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;
I have queued this patch. Let me know if you'd like to make any
amendments. (I deliberately made the lines over 80 characters.)
---8<---
From: Jim Mattson <jmattson@xxxxxxxxxx>
Subject: kvm: nVMX: NMI-window and interrupt-window exiting should
According to the SDM, "NMI-window exiting" VM-exits wake a logical
processor from the same inactive states as would an NMI and
"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 shutdown state and 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>
Suggested-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
[Squashed comments of two Jim's patches and used the simplified code
hunk provided by Sean. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
---
arch/x86/kvm/vmx/nested.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 3f019aa63341..adc8493132ee 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3156,11 +3156,15 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
nested_cache_shadow_vmcs12(vcpu, vmcs12);
/*
- * If we're entering a halted L2 vcpu and the L2 vcpu won't be woken
- * by event injection, halt vcpu.
+ * If we're entering a halted L2 vcpu and the L2 vcpu won't be
+ * awakened by event injection or by an NMI-window VM-exit or
+ * by an interrupt-window VM-exit, halt the vcpu.
*/
if ((vmcs12->guest_activity_state == GUEST_ACTIVITY_HLT) &&
- !(vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK)) {
+ !(vmcs12->vm_entry_intr_info_field & INTR_INFO_VALID_MASK) &&
+ !(vmcs12->cpu_based_vm_exec_control & CPU_BASED_VIRTUAL_NMI_PENDING) &&
+ !((vmcs12->cpu_based_vm_exec_control & CPU_BASED_VIRTUAL_INTR_PENDING) &&
+ (vmcs12->guest_rflags & X86_EFLAGS_IF))) {
vmx->nested.nested_run_pending = 0;
return kvm_vcpu_halt(vcpu);
}
--
2.20.1
