Re: [PATCH V2 03/14] x86/set_memory: Add x86_set_memory_enc static call support

On 8/5/2021 10:29 PM, Dave Hansen wrote:

On 8/5/21 7:23 AM, Peter Zijlstra wrote:

quoted

This is assuming any of this is actually performance critical, based off
of this using static_call() to begin with.

This code is not performance critical.

I think I sent folks off on a wild goose chase when I asked that we make
an effort to optimize code that does:

	if (some_hyperv_check())
		foo();

	if (some_amd_feature_check())
		bar();

with checks that will actually compile away when Hyper-V or
some_amd_feature() is disabled.  That's less about performance and just
about good hygiene.  I *wanted* to see
cpu_feature_enabled(X86_FEATURE...) checks.

Someone suggested using static calls, and off we went...

Could we please just use cpu_feature_enabled()?

Yes, cpu_feature_enabled() works. The target is just to run platform 
code after platform check. I will update this in the next version.