Re: [PATCH v6 01/11] x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT

From: "Kuppuswamy, Sathyanarayanan"  <sathyanarayanan.kuppuswamy@linux.intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	Juergen Gross <jgross@suse.com>, Deep Shah <sdeep@vmware.com>,
	VMware Inc <pv-drivers@vmware.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Peter H Anvin <hpa@zytor.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Tony Luck <tony.luck@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Kirill Shutemov <kirill.shutemov@linux.intel.com>,
	Sean Christopherson <seanjc@google.com>,
	Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 01/11] x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT
Date: Fri, 3 Sep 2021 12:03:56 -0700	[thread overview]
Message-ID: <256d0f5b-3a6d-0912-2edc-44b4a0889c73@linux.intel.com> (raw)
In-Reply-To: <YTJn0HOkMd0thT+3@zn.tnic>

On 9/3/21 11:22 AM, Borislav Petkov wrote:
> On Fri, Sep 03, 2021 at 10:28:02AM -0700, Kuppuswamy Sathyanarayanan wrote:
>> diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
>> index c5ce9845c999..ddc77c95adc6 100644
>> --- a/arch/x86/include/asm/irqflags.h
>> +++ b/arch/x86/include/asm/irqflags.h
>> @@ -59,27 +59,8 @@ static inline __cpuidle void native_halt(void)
>>   
>>   #endif
>>   
>> -#ifdef CONFIG_PARAVIRT_XXL
>> -#include <asm/paravirt.h>
>> -#else
>> +#ifndef CONFIG_PARAVIRT
>>   #ifndef __ASSEMBLY__
>> -#include <linux/types.h>
>> -
>> -static __always_inline unsigned long arch_local_save_flags(void)
>> -{
>> -	return native_save_fl();
>> -}
>> -
>> -static __always_inline void arch_local_irq_disable(void)
>> -{
>> -	native_irq_disable();
>> -}
>> -
>> -static __always_inline void arch_local_irq_enable(void)
>> -{
>> -	native_irq_enable();
>> -}
>> -
>>   /*
>>    * Used in the idle loop; sti takes one instruction cycle
>>    * to complete:
>> @@ -97,6 +78,33 @@ static inline __cpuidle void halt(void)
>>   {
>>   	native_halt();
>>   }
>> +#endif /* __ASSEMBLY__ */
>> +#endif /* CONFIG_PARAVIRT */
>> +
>> +#ifdef CONFIG_PARAVIRT
>> +#ifndef __ASSEMBLY__
>> +#include <asm/paravirt.h>
>> +#endif /* __ASSEMBLY__ */
>> +#endif /* CONFIG_PARAVIRT */
> 
> I think the way we write those is like this:
> 
> #ifdef CONFIG_PARAVIRT
> 
> # ifndef __ASSEMBLY__
> # include <asm/paravirt.h>
> # endif
> 
> #else /* ! CONFIG_PARAVIRT */
> 
> # ifndef __ASSEMBLY__
> /*
>   * Used in the idle loop; sti takes one instruction cycle
>   * to complete:
>   */
> static inline __cpuidle void arch_safe_halt(void)
> {
> 	native_safe_halt();
> }
> 
> /*
>   * Used when interrupts are already enabled or to
>   * shutdown the processor:
>   */
> static inline __cpuidle void halt(void)
> {
> 	native_halt();
> }
> # endif /* __ASSEMBLY__ */
> 
> #endif /* CONFIG_PARAVIRT */

Yes, I can combine the #ifdef as you have mentioned. I can fix this
in next version.

> 
> Note the empty space after the '#' of the inner ifdef to show that it is
> an inner one.

Is this new convention? #ifdefs used in this file does not follow this
format.

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer