[PATCH] kvm: nVMX: add tracepoint for kvm:kvm_nested_vmrun

[PATCH] kvm: nVMX: add tracepoint for kvm:kvm_nested_vmrun

[Mingwei Zhang]

From: David Matlack <dmatlack@google.com>

This tracepoint is called by nested SVM during emulated VMRUN. Call
also during emulated VMLAUNCH and VMRESUME in nested VMX.

Attempt to use analagous VMCS fields to the VMCB fields that are
reported in the SVM case:

"int_ctl": 32-bit field of the VMCB that the CPU uses to deliver virtual
interrupts. The analagous VMCS field is the 16-bit "guest interrupt
status".

"event_inj": 32-bit field of VMCB that is used to inject events
(exceptions and interrupts) into the guest. The analagous VMCS field
is the "VM-entry interruption-information field".

"npt": 1 when the VCPU has enabled nested paging. The analagous VMCS
field is the enable-EPT execution control.

Signed-off-by: David Matlack <dmatlack@google.com>
[Move the code into the nested_vmx_enter_non_root_mode().]
Signed-off-by: Mingwei Zhang <mizhang@google.com>
---
 arch/x86/kvm/vmx/nested.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index f5cb18e00e78..29cc36cf2568 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3367,6 +3367,13 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
 	};
 	u32 failed_index;
 
+	trace_kvm_nested_vmrun(
+		kvm_rip_read(vcpu), vmx->nested.current_vmptr,
+		vmcs12->guest_rip,
+		vmcs12->guest_intr_status,
+		vmcs12->vm_entry_intr_info_field,
+		vmcs12->secondary_vm_exec_control & SECONDARY_EXEC_ENABLE_EPT);
+
 	kvm_service_local_tlb_flush_requests(vcpu);
 
 	evaluate_pending_interrupts = exec_controls_get(vmx) &

base-commit: 922d4578cfd017da67f545bfd07331bda86f795d
-- 
2.37.0.rc0.161.g10f37bed90-goog

Re: [PATCH] kvm: nVMX: add tracepoint for kvm:kvm_nested_vmrun

[Sean Christopherson]

On Sun, Jun 26, 2022, Mingwei Zhang wrote:
> From: David Matlack <dmatlack@google.com>
> 
> This tracepoint is called by nested SVM during emulated VMRUN. Call
> also during emulated VMLAUNCH and VMRESUME in nested VMX.
> 
> Attempt to use analagous VMCS fields to the VMCB fields that are
> reported in the SVM case:
> 
> "int_ctl": 32-bit field of the VMCB that the CPU uses to deliver virtual
> interrupts. The analagous VMCS field is the 16-bit "guest interrupt
> status".
> 
> "event_inj": 32-bit field of VMCB that is used to inject events
> (exceptions and interrupts) into the guest. The analagous VMCS field
> is the "VM-entry interruption-information field".
> 
> "npt": 1 when the VCPU has enabled nested paging. The analagous VMCS
> field is the enable-EPT execution control.
> 
> Signed-off-by: David Matlack <dmatlack@google.com>
> [Move the code into the nested_vmx_enter_non_root_mode().]
> Signed-off-by: Mingwei Zhang <mizhang@google.com>
> ---
>  arch/x86/kvm/vmx/nested.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index f5cb18e00e78..29cc36cf2568 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -3367,6 +3367,13 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
>  	};
>  	u32 failed_index;
>  
> +	trace_kvm_nested_vmrun(
> +		kvm_rip_read(vcpu), vmx->nested.current_vmptr,
> +		vmcs12->guest_rip,

Be consistent; either put each parameter on it's own line or wrap only when
necessary.

> +		vmcs12->guest_intr_status,
> +		vmcs12->vm_entry_intr_info_field,
> +		vmcs12->secondary_vm_exec_control & SECONDARY_EXEC_ENABLE_EPT);
> +

Align the parameters to the opening '(', that "rule" trumps the 80 char soft limit.

	trace_kvm_nested_vmrun(kvm_rip_read(vcpu),
			       vmx->nested.current_vmptr,
			       vmcs12->guest_rip,
			       vmcs12->guest_intr_status,
			       vmcs12->vm_entry_intr_info_field,
			       vmcs12->secondary_vm_exec_control & SECONDARY_EXEC_ENABLE_EPT);

And if we're going to add nVMX, we should clean up the tracepoint output.  E.g.
pass in KVM_ISA_{SVM,VMX} to different VMCB vs. VMCS and npt vs. ept (and maybe
print nNPT and nEPT to make it obvious it's the vmcs12 setting?).  The "nrip"
field is wrong even for SVM; the tracepoint prints the L2 rip, not the next_rip
field in vmcs12.  Maybe "L2 rip"?

Re: [PATCH] kvm: nVMX: add tracepoint for kvm:kvm_nested_vmrun

[Mingwei Zhang]

> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > index f5cb18e00e78..29cc36cf2568 100644
> > --- a/arch/x86/kvm/vmx/nested.c
> > +++ b/arch/x86/kvm/vmx/nested.c
> > @@ -3367,6 +3367,13 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
> >       };
> >       u32 failed_index;
> >
> > +     trace_kvm_nested_vmrun(
> > +             kvm_rip_read(vcpu), vmx->nested.current_vmptr,
> > +             vmcs12->guest_rip,
>
> Be consistent; either put each parameter on it's own line or wrap only when
> necessary.

will do.

>
> > +             vmcs12->guest_intr_status,
> > +             vmcs12->vm_entry_intr_info_field,
> > +             vmcs12->secondary_vm_exec_control & SECONDARY_EXEC_ENABLE_EPT);
> > +
>
> Align the parameters to the opening '(', that "rule" trumps the 80 char soft limit.

will do.

>
>         trace_kvm_nested_vmrun(kvm_rip_read(vcpu),
>                                vmx->nested.current_vmptr,
>                                vmcs12->guest_rip,
>                                vmcs12->guest_intr_status,
>                                vmcs12->vm_entry_intr_info_field,
>                                vmcs12->secondary_vm_exec_control & SECONDARY_EXEC_ENABLE_EPT);
>
> And if we're going to add nVMX, we should clean up the tracepoint output.  E.g.
> pass in KVM_ISA_{SVM,VMX} to different VMCB vs. VMCS and npt vs. ept (and maybe
> print nNPT and nEPT to make it obvious it's the vmcs12 setting?).  The "nrip"
> field is wrong even for SVM; the tracepoint prints the L2 rip, not the next_rip
> field in vmcs12.  Maybe "L2 rip"?

I can change the 'nrip' to 'nested rip', since it may not necessarily
the 'L2 rip'.

For the others, will do.