diff options
| author | Sean Christopherson <seanjc@google.com> | 2025-02-26 17:01:10 -0800 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2025-04-24 11:18:32 -0700 |
| commit | 3fa0fc95db6df904dc812fa806a55ea6bafa65c1 (patch) | |
| tree | 69f911b6384eb132da353a7fa8369077c87aa727 | |
| parent | 656d9624bd21d35499eaa5ee97fda6def62901c8 (diff) | |
x86/msr: Rename the WRMSRNS opcode macro to ASM_WRMSRNS (for KVM)
Rename the WRMSRNS instruction opcode macro so that it doesn't collide
with X86_FEATURE_WRMSRNS when using token pasting to generate references
to X86_FEATURE_WRMSRNS. KVM heavily uses token pasting to generate KVM's
set of support feature bits, and adding WRMSRNS support in KVM will run
will run afoul of the opcode macro.
arch/x86/kvm/cpuid.c:719:37: error: pasting "X86_FEATURE_" and "" "" does not
give a valid preprocessing token
719 | u32 __leaf = __feature_leaf(X86_FEATURE_##name); \
| ^~~~~~~~~~~~
KVM has worked around one such collision in the past by #undef'ing the
problematic macro in order to avoid blocking a KVM rework, but such games
are generally undesirable, e.g. requires bleeding macro details into KVM,
risks weird behavior if what KVM is #undef'ing changes, etc.
Reviewed-by: Xin Li (Intel) <xin@zytor.com>
Link: https://lore.kernel.org/r/20250227010111.3222742-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/include/asm/msr.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 9397a319d165..7b16501912ad 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -300,7 +300,7 @@ do { \ #endif /* !CONFIG_PARAVIRT_XXL */ /* Instruction opcode for WRMSRNS supported in binutils >= 2.40 */ -#define WRMSRNS _ASM_BYTES(0x0f,0x01,0xc6) +#define ASM_WRMSRNS _ASM_BYTES(0x0f,0x01,0xc6) /* Non-serializing WRMSR, when available. Falls back to a serializing WRMSR. */ static __always_inline void wrmsrns(u32 msr, u64 val) @@ -309,7 +309,7 @@ static __always_inline void wrmsrns(u32 msr, u64 val) * WRMSR is 2 bytes. WRMSRNS is 3 bytes. Pad WRMSR with a redundant * DS prefix to avoid a trailing NOP. */ - asm volatile("1: " ALTERNATIVE("ds wrmsr", WRMSRNS, X86_FEATURE_WRMSRNS) + asm volatile("1: " ALTERNATIVE("ds wrmsr", ASM_WRMSRNS, X86_FEATURE_WRMSRNS) "2: " _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_WRMSR) : : "c" (msr), "a" ((u32)val), "d" ((u32)(val >> 32))); } |