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Re: [PATCH V2 03/14] x86/set_memory: Add x86_set_memory_enc static call support
- To: Peter Zijlstra <peterz@xxxxxxxxxxxxx>, Tianyu Lan <ltykernel@xxxxxxxxx>
- From: Dave Hansen <dave.hansen@xxxxxxxxx>
- Date: Thu, 5 Aug 2021 07:29:28 -0700
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- Delivery-date: Thu, 05 Aug 2021 14:29:44 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 8/5/21 7:23 AM, Peter Zijlstra wrote:
> 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()?
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