From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELtpAH5PgASzaoNq1PoYRpH/CGFMCR8yLY0dvmxpNDCsmih0+Jf1XiBJAIk8A8xbBwwx8fKK ARC-Seal: i=1; a=rsa-sha256; t=1520257174; cv=none; d=google.com; s=arc-20160816; b=QR3vi6btguerfNwGMpDQlFcoR8L5kLB8t8NGIKDalAJvKHjMZm37EXjRgp6Ei05WV0 j+268aPCkvn83lW8wjgOpY2MtzGzwb01HNcq9xR+C26XR2Monl6OrHhioODeROIwK2TS aT1S15O8iUa9/wxRvHyA6VcxmGZkLQOAEA5DCeOAWJRoMZhaGfXV7Pr8MUnYd/NvaMji /cGcNkZ87zssEf8IIgLOKBe94tMbQ63DNl1qsGWKi5OgtjoW96dnKCYazosMv/vNrEQb P28QBhsWYQ+sr2C2JZi7k0W1aMDNhRUxJNHW83YiscE2igVzs/iigVBK2Lu9L8sOkHAt p3kg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-language:content-transfer-encoding:in-reply-to:mime-version :user-agent:date:message-id:organization:from:references:cc:to :subject:arc-authentication-results; bh=oleO6uIqKRxgciax9wsNzwK6Jl4Sl9EveCSbxNpaUq4=; b=Ywdlv7fARoeTehkkuMNMOISUYJQome1eluq+9MwlilaQl8ixtkhSkBiBx/+LVXnUFt vs/FOh+WGt5Rcvb1OKiXDDjL1MQiYeLPxIgDej91UjGkTYtNB/7q/lK2Ag2UcgiHuouM KbLOGoeZH31wO0UcvTSchVxXqBCFOg8snfEd8fA+xpkX4Zxn3+2iv0amEvE2w9gP6iWK iA90bqu8KTo14aMxHv49PueiP9jCag8BetcrstiBf92g8ib2alnXwX+RGBO5BJMXUMNk wl8z1oZv6zEwdv6zDEM1cFkMHODn2uTVh0OAFJFGt+eAtdhdInRzdJqVPhR7giAlIVeD mp0g== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of longman@redhat.com designates 66.187.233.73 as permitted sender) smtp.mailfrom=longman@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of longman@redhat.com designates 66.187.233.73 as permitted sender) smtp.mailfrom=longman@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Subject: Re: [PATCH 34/34] x86/mm/pti: Add Warning when booting on a PCIE capable CPU To: Joerg Roedel , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Andy Lutomirski , Dave Hansen , Josh Poimboeuf , Juergen Gross , Peter Zijlstra , Borislav Petkov , Jiri Kosina , Boris Ostrovsky , Brian Gerst , David Laight , Denys Vlasenko , Eduardo Valentin , Greg KH , Will Deacon , aliguori@amazon.com, daniel.gruss@iaik.tugraz.at, hughd@google.com, keescook@google.com, Andrea Arcangeli , Waiman Long , Pavel Machek , jroedel@suse.de References: <1520245563-8444-1-git-send-email-joro@8bytes.org> <1520245563-8444-35-git-send-email-joro@8bytes.org> From: Waiman Long Organization: Red Hat Message-ID: Date: Mon, 5 Mar 2018 08:39:28 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <1520245563-8444-35-git-send-email-joro@8bytes.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594093033976694451?= X-GMAIL-MSGID: =?utf-8?q?1594105186846531756?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 03/05/2018 05:26 AM, Joerg Roedel wrote: > From: Joerg Roedel > > Warn the user in case the performance can be significantly > improved by switching to a 64-bit kernel. > > Suggested-by: Andy Lutomirski > Signed-off-by: Joerg Roedel > --- > arch/x86/mm/pti.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c > index 3ffd923..8f5aa0d 100644 > --- a/arch/x86/mm/pti.c > +++ b/arch/x86/mm/pti.c > @@ -385,6 +385,22 @@ void __init pti_init(void) > > pr_info("enabled\n"); > > +#ifdef CONFIG_X86_32 > + if (boot_cpu_has(X86_FEATURE_PCID)) { > + /* Use printk to work around pr_fmt() */ > + printk(KERN_WARNING "\n"); > + printk(KERN_WARNING "************************************************************\n"); > + printk(KERN_WARNING "** WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! **\n"); > + printk(KERN_WARNING "** **\n"); > + printk(KERN_WARNING "** You are using 32-bit PTI on a 64-bit PCID-capable CPU. **\n"); > + printk(KERN_WARNING "** Your performance will increase dramatically if you **\n"); > + printk(KERN_WARNING "** switch to a 64-bit kernel! **\n"); > + printk(KERN_WARNING "** **\n"); > + printk(KERN_WARNING "** WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! **\n"); > + printk(KERN_WARNING "************************************************************\n"); > + } > +#endif > + > pti_clone_user_shared(); > pti_clone_entry_text(); > pti_setup_espfix64(); Typo in the patch title: PCIE => PCID. -Longman