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

From: Paolo Bonzini
Date: Wed Mar 17 2021 - 09:16:15 EST


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