From nobody Tue Dec 2 01:26:24 2025 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 44D912E6CD9 for ; Fri, 21 Nov 2025 18:55:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=96.67.55.147 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763751344; cv=none; b=rM4aAx4+eSfKQQT8lZSmdVNJSZeYU0mxzgQ5SXwIsdgDSQ+lti4zewV6uNjpoogJHq+HZfJ+oOLGnGFIimF0hV0cmNZozC+SlBezDG/1sp6I3CEdjrxM913iqGecZGop/f9kcqZPFEs9AfQHUxKsdig9Y7s17DYngYmxmzsDUpg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763751344; c=relaxed/simple; bh=kyNvvX8d8Z10nF3LzBMwP9AHfpqra/BL93A1sYBNPAI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eggFHV5Kf6k+pdY60p+jc199pkLE33ITFhXcXHYLczDLWqhreYLGlfw4xRnhkVwU0dd2xYIMtyjTg1hFkuezpQyG0pSj5cRfRC4ylER6mUFumoxPyDjbWPdIv0V/5B4pfP9TKWn/dJMLIxI2K4gcRcOfoE6x2lHmKJjp+6RWuwc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com; spf=pass smtp.mailfrom=surriel.com; dkim=pass (2048-bit key) header.d=surriel.com header.i=@surriel.com header.b=nH76roIl; arc=none smtp.client-ip=96.67.55.147 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=surriel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=surriel.com header.i=@surriel.com header.b="nH76roIl" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=surriel.com ; s=mail; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=zO4x19k55VdNyjCXU0v5aeF8BxFoVMCPY3uuyYoVlXM=; b=nH76roIl0112QJWoy/rkGn3t87 EyFym6veATc3+d+Igg0TZTizEsouClhXPB2EyopQhBpAAqz7LwzcCiTEPleamTMdqxZ6mGoiatW6+ k7bF6Fm2q6udc5ch5aO9f2jrgPbatrR10bIV3Hvo9Xpc+pcAcXO43YjdYDYIGn20gRmRMLcwyicd7 oZxd1UmQsE/qPepAOJC7MIRLqaZIS4ptelmM7Dwf44BTBqGkxqg+WOMpLn1ZwGsPZQu3uFxG3qLdA p0NU7UCRHskoD7BSjnP4awN70aUY8lQEBZlHihf6FK7990sik6jch/OUi1X6KpGomsgKwGQ/JIVYo 0yHP3o6Q==; Received: from fangorn.home.surriel.com ([10.0.13.7]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.97.1) (envelope-from ) id 1vMWI9-000000003i4-1Es7; Fri, 21 Nov 2025 13:55:34 -0500 From: Rik van Riel To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, x86@kernel.org, dave.hansen@linux.intel.com, peterz@infradead.org, kernel-team@meta.com, bp@alien8.de, Yu-cheng Yu , Rik van Riel Subject: [RFC v5 1/8] x86/mm: Introduce Remote Action Request MSRs Date: Fri, 21 Nov 2025 13:54:22 -0500 Message-ID: <20251121185530.21876-2-riel@surriel.com> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251121185530.21876-1-riel@surriel.com> References: <20251121185530.21876-1-riel@surriel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Yu-cheng Yu Remote Action Request (RAR) is a model-specific feature to speed up inter-processor operations by moving parts of those operations from software to hardware. The current RAR implementation handles TLB flushes and MSR writes. This patch introduces RAR MSRs. RAR is introduced in later patches. There are five RAR MSRs: MSR_CORE_CAPABILITIES MSR_IA32_RAR_CTRL MSR_IA32_RAR_ACT_VEC MSR_IA32_RAR_PAYLOAD_BASE MSR_IA32_RAR_INFO Signed-off-by: Yu-cheng Yu Signed-off-by: Rik van Riel --- arch/x86/include/asm/msr-index.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-in= dex.h index 3d0a0950d20a..69d9e96e8324 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -110,6 +110,8 @@ =20 /* Abbreviated from Intel SDM name IA32_CORE_CAPABILITIES */ #define MSR_IA32_CORE_CAPS 0x000000cf +#define MSR_IA32_CORE_CAPS_RAR_BIT 1 +#define MSR_IA32_CORE_CAPS_RAR BIT(MSR_IA32_CORE_CAPS_RAR_BIT) #define MSR_IA32_CORE_CAPS_INTEGRITY_CAPS_BIT 2 #define MSR_IA32_CORE_CAPS_INTEGRITY_CAPS BIT(MSR_IA32_CORE_CAPS_INTEGRI= TY_CAPS_BIT) #define MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT_BIT 5 @@ -122,6 +124,17 @@ #define SNB_C3_AUTO_UNDEMOTE (1UL << 27) #define SNB_C1_AUTO_UNDEMOTE (1UL << 28) =20 +/* + * Remote Action Requests (RAR) MSRs + */ +#define MSR_IA32_RAR_CTRL 0x000000ed +#define MSR_IA32_RAR_ACT_VEC 0x000000ee +#define MSR_IA32_RAR_PAYLOAD_BASE 0x000000ef +#define MSR_IA32_RAR_INFO 0x000000f0 + +#define RAR_CTRL_ENABLE BIT(31) +#define RAR_CTRL_IGNORE_IF BIT(30) + #define MSR_MTRRcap 0x000000fe =20 #define MSR_IA32_ARCH_CAPABILITIES 0x0000010a --=20 2.51.1