linux-kernel - Re: [PATCH hyperv-next v2] arch/x86: Provide the CPU number in the wakeup AP callback

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Message-ID: <877c31pgbm.ffs@tglx>
Date: Wed, 30 Apr 2025 22:03:41 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: Tom Lendacky <thomas.lendacky@....com>, Roman Kisel
 <romank@...ux.microsoft.com>, ardb@...nel.org, bp@...en8.de,
 dave.hansen@...ux.intel.com, decui@...rosoft.com,
 dimitri.sivanich@....com, haiyangz@...rosoft.com, hpa@...or.com,
 imran.f.khan@...cle.com, jacob.jun.pan@...ux.intel.com, jgross@...e.com,
 justin.ernst@....com, kprateek.nayak@....com, kyle.meyer@....com,
 kys@...rosoft.com, lenb@...nel.org, mingo@...hat.com, nikunj@....com,
 papaluri@....com, perry.yuan@....com, peterz@...radead.org,
 rafael@...nel.org, russ.anderson@....com, steve.wahl@....com,
 tim.c.chen@...ux.intel.com, tony.luck@...el.com, wei.liu@...nel.org,
 xin@...or.com, yuehaibing@...wei.com, linux-acpi@...r.kernel.org,
 linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org, x86@...nel.org
Cc: apais@...rosoft.com, benhill@...rosoft.com, bperkins@...rosoft.com,
 sunilmut@...rosoft.com
Subject: Re: [PATCH hyperv-next v2] arch/x86: Provide the CPU number in the
 wakeup AP callback

On Wed, Apr 30 2025 at 14:44, Tom Lendacky wrote:
> On 4/30/25 14:33, Thomas Gleixner wrote:
>> bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
>> {
>> 	return (u32)phys_id == cpu;
>> }
>
> There is an x86 version of this function in arch/x86/kernel/cpu/topology.c
> that overrides the __weak definition and does:
>
> bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
> {
> 	return phys_id == (u64)cpuid_to_apicid[cpu];
> }

Oops. I missed that somehow. So yes, aside of the signed/unsigned thing
this looks fine.

Thanks,

        tglx