Re: [PATCH 7/8] KVM: arm64: Mark some header functions as inline

[Mark Rutland <mark.rutland@arm.com>]

On Wed, Feb 05, 2025 at 09:50:30PM +0000, Mark Brown wrote:
> On Tue, Feb 04, 2025 at 03:20:59PM +0000, Mark Rutland wrote:
> > The shared hyp swtich header has a number of static functions which
> > might not be used by all files that include the header, and when unused
> > they will provoke compiler warnings, e.g.
> 
> With at least LLVM 18 we still have some issues with unused statics
> arising from the aliased function definitions:
> 
> In file included from arch/arm64/kvm/hyp/nvhe/hyp-main.c:8:
> ./arch/arm64/kvm/hyp/include/hyp/switch.h:699:13: warning: unused function 'kvm_hyp_handle_iabt_low' [-Wunused-function]
>   699 | static bool kvm_hyp_handle_iabt_low(struct kvm_vcpu *vcpu, u64 *exit_code)
>       |             ^~~~~~~~~~~~~~~~~~~~~~~
> ./arch/arm64/kvm/hyp/include/hyp/switch.h:701:13: warning: unused function 'kvm_hyp_handle_watchpt_low' [-Wunused-function]
>   701 | static bool kvm_hyp_handle_watchpt_low(struct kvm_vcpu *vcpu, u64 *exit_code)
>       |             ^~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> The simplest thing would be to expand the alises into simple wrapper
> functions but that doesn't feel amazing, I don't know what people's
> taste is there?

Adding 'inline' seems to work, which seems simpler?

That said, I'm going to go with the below, adding 'inline' to
kvm_hyp_handle_memory_fault() and using CPP defines to alias the
function names:

| static inline bool kvm_hyp_handle_memory_fault(struct kvm_vcpu *vcpu,
|                                                u64 *exit_code)
| {
|         if (!__populate_fault_info(vcpu))
|                 return true;
| 
|         return false;
| }
| #define kvm_hyp_handle_iabt_low         kvm_hyp_handle_memory_fault
| #define kvm_hyp_handle_watchpt_low      kvm_hyp_handle_memory_fault

I think that's clearer, and it's more alisnged with how we usually alias
function names in headers. Other than these two cases, __alias() is only
used in C files to create a sesparate exprted symbol, and it's odd to
use it in a header anyhow.

Marc, please should if you'd prefer otherwise.

Mark.