Re: [PATCH v2 2/3] KVM: x86: introduce definitions to support static calls for kvm_x86_ops

[Paolo Bonzini]

On 15/01/21 10:26, Peter Zijlstra wrote:
> > +#define KVM_X86_OP(func)					     \
> > +	DEFINE_STATIC_CALL_NULL(kvm_x86_##func,			     \
> > +				*(((struct kvm_x86_ops *)0)->func));
> > +#define KVM_X86_OP_NULL KVM_X86_OP
> > +#include <asm/kvm-x86-ops.h>
> > +EXPORT_STATIC_CALL_GPL(kvm_x86_get_cs_db_l_bits);
> > +EXPORT_STATIC_CALL_GPL(kvm_x86_cache_reg);
> > +EXPORT_STATIC_CALL_GPL(kvm_x86_tlb_flush_current);
> Would something like:
>
>    https://lkml.kernel.org/r/20201110103909.GD2594@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> Be useful? That way modules can call the static_call() but not change
> it.

Maybe not in these cases, but in general there may be cases where we 
later want to change the static_call (for example replacing jump labels 
with static_calls).

Paolo