From 8d862c270bf14cb3e63ca84a9a51be77c9fa4e2a Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 27 Nov 2024 17:33:54 -0800 Subject: [PATCH] KVM: x86: #undef SPEC_CTRL_SSBD in cpuid.c to avoid macro collisions Undefine SPEC_CTRL_SSBD, which is #defined by msr-index.h to represent the enable flag in MSR_IA32_SPEC_CTRL, to avoid issues with the macro being unpacked into its raw value when passed to KVM's F() macro. This will allow using multiple layers of macros in F() and friends, e.g. to harden against incorrect usage of F(). No functional change intended (cpuid.c doesn't consume SPEC_CTRL_SSBD). Link: https://lore.kernel.org/r/20241128013424.4096668-28-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/cpuid.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 2cd06155684e..cebb7314b9be 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -665,6 +665,12 @@ static __always_inline void kvm_cpu_cap_init(u32 leaf, u32 mask) feature_bit(name); \ }) +/* + * Undefine the MSR bit macro to avoid token concatenation issues when + * processing X86_FEATURE_SPEC_CTRL_SSBD. + */ +#undef SPEC_CTRL_SSBD + void kvm_set_cpu_caps(void) { memset(kvm_cpu_caps, 0, sizeof(kvm_cpu_caps)); -- 2.25.1