Re: [RESEND][patch V3 19/23] x86/kvm/vmx: Add hardirq tracing to guest enter/exit

[Thomas Gleixner]

Peter Zijlstra <peterz@xxxxxxxxxxxxx> writes:

> On Fri, Mar 20, 2020 at 07:00:15PM +0100, Thomas Gleixner wrote:
>> The VMX code does not track hard interrupt state correctly. The state in
>> tracing and lockdep is 'OFF' all the way during guest mode. From the host
>> point of view this is wrong because the VMENTER reenables interrupts like a
>> return to user space and VMENTER disables them again like an entry from
>> user space.
>> 
>> Make it do exactly the same thing as enter/exit user mode does.
>> 
>> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>
> This patch (and the SVM counterpart) result in:
>
> ERROR: "lockdep_hardirqs_on" [arch/x86/kvm/kvm-amd.ko] undefined!
> ERROR: "lockdep_hardirqs_off" [arch/x86/kvm/kvm-amd.ko] undefined!
> ERROR: "__trace_hardirqs_off" [arch/x86/kvm/kvm-amd.ko] undefined!
> ERROR: "lockdep_hardirqs_on_prepare" [arch/x86/kvm/kvm-amd.ko] undefined!
> ERROR: "__trace_hardirqs_on" [arch/x86/kvm/kvm-amd.ko] undefined!
> ERROR: "lockdep_hardirqs_on" [arch/x86/kvm/kvm-intel.ko] undefined!
> ERROR: "lockdep_hardirqs_off" [arch/x86/kvm/kvm-intel.ko] undefined!
> ERROR: "__trace_hardirqs_off" [arch/x86/kvm/kvm-intel.ko] undefined!
> ERROR: "lockdep_hardirqs_on_prepare" [arch/x86/kvm/kvm-intel.ko] undefined!
> ERROR: "__trace_hardirqs_on" [arch/x86/kvm/kvm-intel.ko] undefined!
>
> on allmodconfig.
>
> I suppose them things need an EXPORT_SYMBOL_GPL() on them.

Indeed.