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h=Date:Subject:From:To:Cc:References:In-Reply-To:From; b=rnePR2hwJuXY5FmWXVv6sKakKb16gqY6la25fcNXD75cRQVpa2ZRcjCrKVOuukjCB hRqstDX2y33m5xXuD7NVQPXDQYLTAplDaBg1xcMyt+j959umpzmuK30mLTDge0cGXp bnvazkO/OsgotjsN+4A03SGz9l8AUI6QO/4BJ9vha8pm3FY247UsUaf91Izo6cffrQ olDvEOmJ3YNx2I/0aCLbw3SAefG82cytvU9inPCFtN7bbjw/fVGuZWrUfEKeWiHKih mJwYNN1fefggEc2XOBAauB3RKE/hvo3PoSnUZaFsHLKmVg/yGvEbQYRrnL4xbRkR89 uKCAqqVibBGfw== Message-ID: Date: Wed, 5 Mar 2025 16:29:26 -0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] x86/msr: Rename the WRMSRNS opcode macro to ASM_WRMSRNS (for KVM) From: Xin Li To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250227010111.3222742-1-seanjc@google.com> <20250227010111.3222742-2-seanjc@google.com> Content-Language: en-US Autocrypt: addr=xin@zytor.com; keydata= xsDNBGUPz1cBDACS/9yOJGojBFPxFt0OfTWuMl0uSgpwk37uRrFPTTLw4BaxhlFL0bjs6q+0 2OfG34R+a0ZCuj5c9vggUMoOLdDyA7yPVAJU0OX6lqpg6z/kyQg3t4jvajG6aCgwSDx5Kzg5 Rj3AXl8k2wb0jdqRB4RvaOPFiHNGgXCs5Pkux/qr0laeFIpzMKMootGa4kfURgPhRzUaM1vy bsMsL8vpJtGUmitrSqe5dVNBH00whLtPFM7IbzKURPUOkRRiusFAsw0a1ztCgoFczq6VfAVu raTye0L/VXwZd+aGi401V2tLsAHxxckRi9p3mc0jExPc60joK+aZPy6amwSCy5kAJ/AboYtY VmKIGKx1yx8POy6m+1lZ8C0q9b8eJ8kWPAR78PgT37FQWKYS1uAroG2wLdK7FiIEpPhCD+zH wlslo2ETbdKjrLIPNehQCOWrT32k8vFNEMLP5G/mmjfNj5sEf3IOKgMTMVl9AFjsINLHcxEQ 6T8nGbX/n3msP6A36FDfdSEAEQEAAc0WWGluIExpIDx4aW5Aenl0b3IuY29tPsLBDQQTAQgA NxYhBIUq/WFSDTiOvUIqv2u9DlcdrjdRBQJlD89XBQkFo5qAAhsDBAsJCAcFFQgJCgsFFgID AQAACgkQa70OVx2uN1HUpgv/cM2fsFCQodLArMTX5nt9yqAWgA5t1srri6EgS8W3F+3Kitge tYTBKu6j5BXuXaX3vyfCm+zajDJN77JHuYnpcKKr13VcZi1Swv6Jx1u0II8DOmoDYLb1Q2ZW v83W55fOWJ2g72x/UjVJBQ0sVjAngazU3ckc0TeNQlkcpSVGa/qBIHLfZraWtdrNAQT4A1fa sWGuJrChBFhtKbYXbUCu9AoYmmbQnsx2EWoJy3h7OjtfFapJbPZql+no5AJ3Mk9eE5oWyLH+ QWqtOeJM7kKvn/dBudokFSNhDUw06e7EoVPSJyUIMbYtUO7g2+Atu44G/EPP0yV0J4lRO6EA wYRXff7+I1jIWEHpj5EFVYO6SmBg7zF2illHEW31JAPtdDLDHYcZDfS41caEKOQIPsdzQkaQ oW2hchcjcMPAfyhhRzUpVHLPxLCetP8vrVhTvnaZUo0xaVYb3+wjP+D5j/3+hwblu2agPsaE vgVbZ8Fx3TUxUPCAdr/p73DGg57oHjgezsDNBGUPz1gBDAD4Mg7hMFRQqlzotcNSxatlAQNL MadLfUTFz8wUUa21LPLrHBkUwm8RujehJrzcVbPYwPXIO0uyL/F///CogMNx7Iwo6by43KOy g89wVFhyy237EY76j1lVfLzcMYmjBoTH95fJC/lVb5Whxil6KjSN/R/y3jfG1dPXfwAuZ/4N cMoOslWkfZKJeEut5aZTRepKKF54T5r49H9F7OFLyxrC/uI9UDttWqMxcWyCkHh0v1Di8176 jjYRNTrGEfYfGxSp+3jYL3PoNceIMkqM9haXjjGl0W1B4BidK1LVYBNov0rTEzyr0a1riUrp Qk+6z/LHxCM9lFFXnqH7KWeToTOPQebD2B/Ah5CZlft41i8L6LOF/LCuDBuYlu/fI2nuCc8d m4wwtkou1Y/kIwbEsE/6RQwRXUZhzO6llfoN96Fczr/RwvPIK5SVMixqWq4QGFAyK0m/1ap4 bhIRrdCLVQcgU4glo17vqfEaRcTW5SgX+pGs4KIPPBE5J/ABD6pBnUUAEQEAAcLA/AQYAQgA JhYhBIUq/WFSDTiOvUIqv2u9DlcdrjdRBQJlD89ZBQkFo5qAAhsMAAoJEGu9DlcdrjdR4C0L /RcjolEjoZW8VsyxWtXazQPnaRvzZ4vhmGOsCPr2BPtMlSwDzTlri8BBG1/3t/DNK4JLuwEj OAIE3fkkm+UG4Kjud6aNeraDI52DRVCSx6xff3bjmJsJJMb12mWglN6LjdF6K+PE+OTJUh2F dOhslN5C2kgl0dvUuevwMgQF3IljLmi/6APKYJHjkJpu1E6luZec/lRbetHuNFtbh3xgFIJx 2RpgVDP4xB3f8r0I+y6ua+p7fgOjDLyoFjubRGed0Be45JJQEn7A3CSb6Xu7NYobnxfkwAGZ Q81a2XtvNS7Aj6NWVoOQB5KbM4yosO5+Me1V1SkX2jlnn26JPEvbV3KRFcwV5RnDxm4OQTSk PYbAkjBbm+tuJ/Sm+5Yp5T/BnKz21FoCS8uvTiziHj2H7Cuekn6F8EYhegONm+RVg3vikOpn gao85i4HwQTK9/D1wgJIQkdwWXVMZ6q/OALaBp82vQ2U9sjTyFXgDjglgh00VRAHP7u1Rcu4 l75w1xInsg== In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2/26/2025 5:14 PM, Xin Li wrote: > On 2/26/2025 5:01 PM, Sean Christopherson wrote: >> 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. >> >> Signed-off-by: Sean Christopherson >> --- >>   arch/x86/include/asm/msr.h | 4 ++-- >>   1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h >> index 001853541f1e..60b80a36d045 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))); >>   } > > I hit the same build issue, thanks for fixing it. > > Reviewed-by: Xin Li (Intel) > Do we need an ack from x86 maintainers?