From patchwork Mon May 6 18:35:55 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Reinette Chatre X-Patchwork-Id: 13655890 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.9]) (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 8C1B013E8BA; Mon, 6 May 2024 18:36:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.9 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715020586; cv=none; b=qFO32/aZMUZqMDs4edVxmS2GSWEdqThQ1N09idqoeQb4FDnxSJjG2TR+sfWNaGVkU97cVGzAY2LPl5tKTGXeWNIfMh3f3i8naBjFkaTZjCd1GJszwwn7J72YMYVW68oJd1dMHWis6LfcQB5g8QqRqVWoKBUboZRZFR24jrklQUI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715020586; c=relaxed/simple; bh=JCMdLmx7hIlCtOWjHewphvGoWCSoaO1qN1Iyo0V0rtg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=P/VM63ooTNJDRfxb1QtVGalRRE364RlInmva6CWASj0b2REvMEi3mlAo5zRcijC0GeZ75CKk/ZOBtOGJAslF+n/yzBf29IdbF7s+yQtBh0K2Y4wfmCcK8+3DyBX1T1/aGJmqlo/O/AK9jKxOYimzUZJFTKqx/EosK4wDrjhPKGU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Eb6HrA0+; arc=none smtp.client-ip=192.198.163.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Eb6HrA0+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1715020585; x=1746556585; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=JCMdLmx7hIlCtOWjHewphvGoWCSoaO1qN1Iyo0V0rtg=; b=Eb6HrA0+IVyp2sJhunKku6pJQbRR8xrl6Zgg7zCxqAwO5heq2Acf35QT wHnNLZ3LCkXhoIVTSlKu7agTZW95+2DvlaloTIAiCwJ1XeMya/FrS0CGc FlYUEu6Rrt48ogIfaq3CUkO/TmyodNYDyAxeJyjYelKjmJ5SdMa+EyMxv ymPfugqjKoqzAIQP9bvOEWP6ksEpdi7MQ3Z9PDbnxsID3pa/21J5SdbRg JQVBXhAaANKSnlxdALmVsaq4Fgll4CBlkOiO3IKP9Awih/tXxCyG/1DkC BegSd5YHSZZbjiE1MShVUyaSDTz5yAygonYBDPGd55v1hVdVj3jdPOb+E w==; X-CSE-ConnectionGUID: N5Fd4vAISRSm7VWeB3aOkA== X-CSE-MsgGUID: aKYfLx+TTbuy/Lgx8zaQ9w== X-IronPort-AV: E=McAfee;i="6600,9927,11065"; a="21455743" X-IronPort-AV: E=Sophos;i="6.07,259,1708416000"; d="scan'208";a="21455743" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 May 2024 11:36:10 -0700 X-CSE-ConnectionGUID: Dl22qp/lSiOB0TYBDYy6EA== X-CSE-MsgGUID: bStAaS47SbybSrCM0oz2qw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,259,1708416000"; d="scan'208";a="28237805" Received: from rchatre-ws.ostc.intel.com ([10.54.69.144]) by fmviesa008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 May 2024 11:36:09 -0700 From: Reinette Chatre To: isaku.yamahata@intel.com, pbonzini@redhat.com, erdemaktas@google.com, vkuznets@redhat.com, seanjc@google.com, vannapurve@google.com, jmattson@google.com, mlevitsk@redhat.com, xiaoyao.li@intel.com, chao.gao@intel.com, rick.p.edgecombe@intel.com, yuan.yao@intel.com Cc: reinette.chatre@intel.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V6 1/4] KVM: x86: hyper-v: Calculate APIC bus frequency for Hyper-V Date: Mon, 6 May 2024 11:35:55 -0700 Message-Id: X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Isaku Yamahata Remove APIC_BUS_FREQUENCY and calculate it based on nanoseconds per APIC bus cycle. APIC_BUS_FREQUENCY is used only for HV_X64_MSR_APIC_FREQUENCY. The MSR is not frequently read, calculate it every time. There are two constants related to the APIC bus frequency: APIC_BUS_FREQUENCY and APIC_BUS_CYCLE_NS. Only one value is required because one can be calculated from the other: APIC_BUS_CYCLES_NS = 1000 * 1000 * 1000 / APIC_BUS_FREQUENCY. Remove APIC_BUS_FREQUENCY and instead calculate it when needed. This prepares for support of configurable APIC bus frequency by requiring to change only a single variable. Suggested-by: Maxim Levitsky Signed-off-by: Isaku Yamahata Reviewed-by: Maxim Levitsky Reviewed-by: Xiaoyao Li Reviewed-by: Rick Edgecombe [reinette: rework changelog] Signed-off-by: Reinette Chatre --- Changes v5: - Add Rick's Reviewed-by tag. Changes v4: - Modify subject to match custom: "KVM: x86/hyperv:" -> "KVM: x86: hyper-v:" and use standard capitalization for Hyper-V ("hyper-v" -> "Hyper-V"). - Rework changelog to remove pronouns ("we"). - Change logic in commit log: "APIC bus cycles per NS" -> "nanoseconds per APIC bus cycle". - Fix typos. (Maxim and Xiaoyao) - Add Maxim and Xiaoyao's Reviewed-by tags. - Add Maxim's "Suggested-by". Changes v3: - Newly added according to Maxim Levitsky suggestion. --- arch/x86/kvm/hyperv.c | 2 +- arch/x86/kvm/lapic.h | 1 - 2 files changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 8a47f8541eab..1030701db967 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1737,7 +1737,7 @@ static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, data = (u64)vcpu->arch.virtual_tsc_khz * 1000; break; case HV_X64_MSR_APIC_FREQUENCY: - data = APIC_BUS_FREQUENCY; + data = div64_u64(1000000000ULL, APIC_BUS_CYCLE_NS); break; default: kvm_pr_unimpl_rdmsr(vcpu, msr); diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 0a0ea4b5dd8c..a20cb006b6c8 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -17,7 +17,6 @@ #define APIC_DEST_MASK 0x800 #define APIC_BUS_CYCLE_NS 1 -#define APIC_BUS_FREQUENCY (1000000000ULL / APIC_BUS_CYCLE_NS) #define APIC_BROADCAST 0xFF #define X2APIC_BROADCAST 0xFFFFFFFFul