linux-kernel - Re: [RFC PATCH v7 03/37] x86/apic: KVM: Deduplicate APIC vector => register+bit math

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Message-ID: <24675ed2-e3ae-4473-9d8e-acd378da220c@amd.com>
Date: Wed, 25 Jun 2025 06:51:05 +0530
From: Neeraj Upadhyay <Neeraj.Upadhyay@....com>
To: Borislav Petkov <bp@...en8.de>
Cc: linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
 dave.hansen@...ux.intel.com, Thomas.Lendacky@....com, nikunj@....com,
 Santosh.Shukla@....com, Vasant.Hegde@....com, Suravee.Suthikulpanit@....com,
 David.Kaplan@....com, x86@...nel.org, hpa@...or.com, peterz@...radead.org,
 seanjc@...gle.com, pbonzini@...hat.com, kvm@...r.kernel.org,
 kirill.shutemov@...ux.intel.com, huibo.wang@....com, naveen.rao@....com,
 francescolavra.fl@...il.com, tiala@...rosoft.com
Subject: Re: [RFC PATCH v7 03/37] x86/apic: KVM: Deduplicate APIC vector =>
 register+bit math



On 6/23/2025 5:19 PM, Borislav Petkov wrote:
> On Tue, Jun 10, 2025 at 11:23:50PM +0530, Neeraj Upadhyay wrote:
>> diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
>> index 23d86c9750b9..c84d4e86fe4e 100644
>> --- a/arch/x86/include/asm/apic.h
>> +++ b/arch/x86/include/asm/apic.h
>> @@ -488,11 +488,14 @@ static inline void apic_setup_apic_calls(void) { }
>>  
>>  extern void apic_ack_irq(struct irq_data *data);
>>  
>> +#define APIC_VECTOR_TO_BIT_NUMBER(v) ((unsigned int)(v) % 32)
>> +#define APIC_VECTOR_TO_REG_OFFSET(v) ((unsigned int)(v) / 32 * 0x10)
> 
> Dunno - I'd probably shorten those macro names:
> 
> APIC_VEC_TO_BITNUM()
> APIC_VEC_TO_REGOFF()
> 
> because this way of shortening those words is very common and is still very
> readable, even if not fully written out...
> 

Sounds good to me. Will change this in next version (will also wait for Sean's
comment on this).

> LGTM regardless.
> 

Thanks!

- Neeraj

> Thx.
>