Re: [PATCH v2 4/9] KVM: arm/arm64: replace vcpu->arch.pause with a vcpu request

From: Marc Zyngier <marc.zyngier@arm.com>
To: Paolo Bonzini <pbonzini@redhat.com>, Andrew Jones <drjones@redhat.com>
Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
	cdall@linaro.org, rkrcmar@redhat.com
Subject: Re: [PATCH v2 4/9] KVM: arm/arm64: replace vcpu->arch.pause with a vcpu request
Date: Tue, 4 Apr 2017 16:05:22 +0100	[thread overview]
Message-ID: <d4b01586-4833-6759-6a1d-04c956718b0c@arm.com> (raw)
In-Reply-To: <f615bc88-0a18-47a3-1122-e7e6db38bf3d@redhat.com>

On 04/04/17 15:51, Paolo Bonzini wrote:
> 
> 
> On 04/04/2017 16:47, Andrew Jones wrote:
>>>> -#define KVM_REQ_VCPU_EXIT	8
>>>> +#define KVM_REQ_PAUSE		8
>>> Small nit: can we have a #define for this 8? KVM_REQ_ARCH_BASE, or
>>> something along those lines?
>> Sounds good to me.  Should I even do something like
>>
>>  #define KVM_REQ_ARCH_BASE 8
>>
>>  #define KVM_ARCH_REQ(bit) ({ \
>>      BUILD_BUG_ON(((bit) + KVM_REQ_ARCH_BASE) >= BITS_PER_LONG); \
> 
> Please make this 32 so that we don't fail on 32-bit machines.
> 
> or even
> 
> BUILD_BUG_ON((unsigned)(bit) >= BITS_PER_LONG - KVM_REQ_ARCH_BASE);
> 
> in case someone is crazy enough to pass a negative value!
> 
> Paolo
> 
>>      ((bit) + KVM_REQ_ARCH_BASE); \
>>  })
>>
>>  #define KVM_REQ_PAUSE KVM_ARCH_REQ(0)
>>
>> or would that be overkill?  Also, whether we switch to just the base
>> define, or the macro, I guess it would be good to do for all
>> architectures.
> 

Both suggestions look good to me.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...