linux-kernel - Re: [PATCH 3/4] KVM: VMX: Macrofy the MSR bitmap getters and setters

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Message-ID: <f4934b3e-4d5f-a242-e14f-ad5841079349@redhat.com>
Date:   Wed, 17 Mar 2021 14:15:07 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Alexander Graf <graf@...zon.com>,
        Yuan Yao <yaoyuan0329os@...il.com>
Subject: Re: [PATCH 3/4] KVM: VMX: Macrofy the MSR bitmap getters and setters

On 16/03/21 19:44, Sean Christopherson wrote:
> +	return (ret)true;						      \

I'm not sure if (void)true is amazing or disgusting, but anyway...

> +BUILD_VMX_MSR_BITMAP_HELPER(bool, test, read)
> +BUILD_VMX_MSR_BITMAP_HELPER(bool, test, write)
> +BUILD_VMX_MSR_BITMAP_HELPER(void, clear, read, __)
> +BUILD_VMX_MSR_BITMAP_HELPER(void, clear, write, __)
> +BUILD_VMX_MSR_BITMAP_HELPER(void, set, read, __)
> +BUILD_VMX_MSR_BITMAP_HELPER(void, set, write, __)

... I guess we have an armed truce where you let me do my bit 
manipulation magic and I let you do your macro magic.

Still, I think gluing the variadic arguments with ## is a bit too much. 
  This would be slightly less mysterious:

+BUILD_VMX_MSR_BITMAP_HELPER(bool, vmx_test_msr_bitmap_, read, test_bit)
+BUILD_VMX_MSR_BITMAP_HELPER(bool, vmx_test_msr_bitmap_, write, test_bit)
+BUILD_VMX_MSR_BITMAP_HELPER(void, vmx_clear_msr_bitmap_, read, __clear_bit)
+BUILD_VMX_MSR_BITMAP_HELPER(void, vmx_clear_msr_bitmap_, write, 
__clear_bit)
+BUILD_VMX_MSR_BITMAP_HELPER(void, vmx_set_msr_bitmap_, read, __set_bit)
+BUILD_VMX_MSR_BITMAP_HELPER(void, vmx_set_msr_bitmap_, write, __set_bit)

And I also wonder if we really need to expand all six functions one at a 
time.  You could remove the third argument and VMX_MSR_BITMAP_BASE_*, at 
the cost of expanding the inline functions' body twice in 
BUILD_VMX_MSR_BITMAP_HELPER.

Thanks,

Paolo