From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D9E7F22EF8 for ; Fri, 5 Apr 2024 23:20:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712359245; cv=none; b=DJn+Zl5rwbRsflfEElvp25Ng1KZjMXn7hgMcX3ceS1rkNAXyjCvq4RhIhqkyz27eXIo2XIsCRhQDFGxTZUhGvmYzvTYwzfil24sDUelVKsNXwDO3Wj5vN0RCHcDL3zcEcB3vOWozPauuRcy+DzTh5dmc+dfnxLe55IrEz/C3FpM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712359245; c=relaxed/simple; bh=6JYCjL9C4AfaDryXf5XSZhrO2zWHCuIkX8eHeXELHqU=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=a6Y4Xr9NK0nrOFLQd3yQtEZTMoM7Px03QAMsqe09LD6MiZcS9JTprsZqEBbnTkO5moqcVxFar2dUOqDY1aluRKMhBIpJVcUXrGS1KPcwX8Eho+DUffIbIpM+ffrdrs8sOemesofWtuPc6qHmyZ+gMUHiI1XlPfXpdZY7lIFhEbk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=pfB410vd; arc=none smtp.client-ip=209.85.215.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="pfB410vd" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-5d8bcf739e5so2345514a12.1 for ; Fri, 05 Apr 2024 16:20:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1712359243; x=1712964043; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=12i/1U6e69lGZbnks+aFjU43EdHvF/EYY258ON1Z+QY=; b=pfB410vdjh/TM3n9ksMNXrl7zddiS1npxNi0FlxrlJ+4I8UZH6S/cnIEdSpZ1LiJAL 4WHMwlvY4lOHClZz2FUQxxVes3/dYRH7mXqcqUApf3WZfZvPOdeV/+9hOJXd38EY/xsn zD5l4RgUxVjuSeUejen4ULbnOSPfnxh19ACcnzvl7XsxsLNV29XNMIIrp9LK7mXgsPDe eArJO7kPEWqr52JX+ajKqX5KpVcnW1s0jGXDwdgxBd+IPNyUJRPxFOFuKPcuR1+PnQhy PWJ/GsmT2SZHWIp+jnkjEEYbbZ4muBuXe01OxGsjCOBbx9p9uKkNb1fZE3vwzFJ8BbYd ntQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1712359243; x=1712964043; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=12i/1U6e69lGZbnks+aFjU43EdHvF/EYY258ON1Z+QY=; b=KyUL/s9UzrSSwAJARQO15+zwRum5acS8bBzdp0vuhF9IhR/4MzuL5eqUT3qqkhXGRD l/p2LkLlqi3c8apOq6olNC9HXEKyrILRzn1RDH9e7AxQvu3zQDKFPTBrJTrksfKqM3zY Rb5bKzWqgMyizI8P9Ldt07FqC6sOhci4IuibOImXOwV4vVqo1UFjRh59hNH2jRyeTaGa EMry9vkfP8Y5x9DEmdZbrQMMfDD7aSiwhQ7qifkCpM8yBZ2dLxtgrsFvhc17G2NIc0zl yrszXrazUuhTjTJTftbVgdBfZFd5/whg5kubEjaxCwrv2SgGh/Ey/cJFX2dvv80aNjrZ iumg== X-Forwarded-Encrypted: i=1; AJvYcCVJkdjKnWh3f0ys/WbxU0vcaPgD4ia8K66QkAKMdbTRMaFc6/ASoBU4maDUKBjt9KqUrP9I+E6seWCFxmw0zaTmtW2kVaY5gdOK35DI X-Gm-Message-State: AOJu0YzyeG/OyvFwWuz4/T9CX8xEAJxI2GDXIvgUOj84E0YZPEBvnyCU QamSopS9gOr8lvd6456MQY4Xq1J+0E5qh9QezsWAbgxEHRuk4T9TLRrNtsjcCmVUfRikhKacLV6 z3A== X-Google-Smtp-Source: AGHT+IEUYFveyLiskfYb2sLUp535rDaaKamTXvVef0iSV4YFA3At2jAAYj0djH4lUTfne66XFXNLoy2e1Dc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a63:1115:0:b0:5f3:fddf:e819 with SMTP id g21-20020a631115000000b005f3fddfe819mr4204pgl.10.1712359243207; Fri, 05 Apr 2024 16:20:43 -0700 (PDT) Date: Fri, 5 Apr 2024 16:20:41 -0700 In-Reply-To: <20240323080541.10047-2-pmenzel@molgen.mpg.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240323080541.10047-2-pmenzel@molgen.mpg.de> Message-ID: Subject: Re: [PATCH] KVM: VMX: make vmx_init a late init call to get to init process faster From: Sean Christopherson To: Paul Menzel Cc: Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Colin Ian King , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Sat, Mar 23, 2024, Paul Menzel wrote: > From: Colin Ian King > > Making vmx_init a late initcall improves QEMU kernel boot times to > get to the init process. Average of 100 boots, QEMU boot average > reduced from 0.776 seconds to 0.622 seconds (~19.8% faster) on > Alder Lake i9-12900 and ~0.5% faster for non-QEMU UEFI boots. The changelog needs to better explain what "QEMU kernel boot times" means. I assume the test is a QEMU VM running a kernel KVM_INTEL built-in? This should also call out that late_initcall is #defined to module_init() when KVM is built as a module. > Signed-off-by: Colin Ian King > [Take patch > https://github.com/clearlinux-pkgs/linux/commit/797db35496031b19ba37b1639ac5fa5db9159a06 > and fix spelling of Alder Lake.] > Signed-off-by: Paul Menzel > --- > arch/x86/kvm/vmx/vmx.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index c37a89eda90f..0a9f4b20fbda 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -8783,4 +8783,4 @@ static int __init vmx_init(void) > kvm_x86_vendor_exit(); > return r; > } > -module_init(vmx_init); > +late_initcall(vmx_init); _If_ we do this, then we should also give svm_init() and kvm_x86_init() the same treatment. I see no reason for vmx_init() to be special. I'm not opposed to this, but I also have zero idea if this could have a negative impact userspace. E.g. what happens if some setup's init process expects /dev/kvm to exist? Will this break that?