Re: [PATCH v3 10/12] KVM: x86/mmu: Use BUILD_BUG_ON_INVALID() for KVM_MMU_WARN_ON() stub

From: Philippe Mathieu-Daudé
Date: Wed Aug 02 2023 - 02:50:00 EST

On 2/8/23 01:41, Sean Christopherson wrote:
On Tue, Aug 01, 2023, Philippe Mathieu-Daudé wrote:
Hi Sean,

On 29/7/23 02:47, Sean Christopherson wrote:
Use BUILD_BUG_ON_INVALID() instead of an empty do-while loop to stub out
KVM_MMU_WARN_ON() when CONFIG_KVM_PROVE_MMU=n, that way _some_ build
issues with the usage of KVM_MMU_WARN_ON() will be dected even if the
kernel is using the stubs, e.g. basic syntax errors will be detected.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
arch/x86/kvm/mmu/mmu_internal.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 40e74db6a7d5..f1ef670058e5 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -9,7 +9,7 @@
-#define KVM_MMU_WARN_ON(x) do { } while (0)

No need to include <linux/build_bug.h> ?

It's indirectly included via

linux/kvm_host.h => linux/bug.h => linux/build_bug.h

Depending on the day, I might argue for explicitly including all dependencies, but
in this case build_bug.h is a "core" header, and IMO there's no value added by
including it directly.

OK, fine then, thanks!