From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x225R2b96S9j5jHeWZcwKBnyQ/OdmkWK+gYvaWaiPXNHxNZTchC3GtsrQhVo9HjHDGNQTnvzg ARC-Seal: i=1; a=rsa-sha256; t=1518198485; cv=none; d=google.com; s=arc-20160816; b=kUjL9TV0Z+S7lL4qxSkjqQcn4n3tGgdwHkJE6foC121sJC6NCI6lwftbkQCqOPFZqp JKd33M3FUA+X56WaBoMzrVZ+HMEGGjCM3oRkxLONz1k0ONv1G9jCv/VEUlEbEnCquUPN 9rBMaJqBwSwr5VpKUKrlPznnkWpekmpv3NN/VCqwMgNfpnvS18PNk4nj+TgtNV2so0OW 3paj7DAg1dCbLFgeVtW4T/ZxY8T1avp2OwQi7amlcstwoJrG3CUKO8gAKt33gMIP1O3x Id+qtj+6U9NEXdWY3wctGMEB487/M2shq7QJcoK8/BLh5wLzTfJO5aWiTDtdpcX3H0DY hOYQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:references:in-reply-to :mime-version:dmarc-filter:arc-authentication-results; bh=Jp02DY9Ua833tCIgfbeK9FnMXZHm+7uGrP5YA1AaxHg=; b=F0HxLyt5HIIlr0CI7AD3fTeeBFaVuVmmFnOXOPYmbgY24APESsuXXPA6HrqEu0tla8 DlilTkO4iVI1doCF8PHmoeIirnJ6ZkkkQ6clYuXbNNH8pW4pD6kvXHrFzcWW2Bf0n4Rn EIIhd2uZPfisKC21ZRJ+CPoE2yAcuBIlXC/h7YvfRULOJZ7tkeV9mOcBAdAPEqm8ANEB OVG/eM3OXGzxhZcBbyJgMpDuiANr3bGnobE+hJoA3pIT37EdLuEpTfEbp+nwdcHl4PQX nLKsZbsWo/ierjEtCHD9XRZmXK/RYoQBlt/8DYbvGSUfQdM3GTgH323f6B5/RWNtuOIJ MMeg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of luto@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=luto@kernel.org Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of luto@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=luto@kernel.org DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5A5B217B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=luto@kernel.org MIME-Version: 1.0 In-Reply-To: <1518168340-9392-1-git-send-email-joro@8bytes.org> References: <1518168340-9392-1-git-send-email-joro@8bytes.org> From: Andy Lutomirski Date: Fri, 9 Feb 2018 17:47:43 +0000 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 00/31 v2] PTI support for x86_32 To: Joerg Roedel Cc: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , X86 ML , LKML , Linux-MM , 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 , "Liguori, Anthony" , Daniel Gruss , Hugh Dickins , Kees Cook , Andrea Arcangeli , Waiman Long , Pavel Machek , Joerg Roedel Content-Type: text/plain; charset="UTF-8" X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1591914900490843452?= X-GMAIL-MSGID: =?utf-8?q?1591946494654213614?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Fri, Feb 9, 2018 at 9:25 AM, Joerg Roedel wrote: > Hi, > > here is the second version of my PTI implementation for > x86_32, based on tip/x86-pti-for-linus. It took a lot longer > than I had hoped, but there have been a number of obstacles > on the way. It also isn't the small patch-set anymore that v1 > was, but compared to it this one actually works :) One thing worth noting is that performance of this whole series is going to be abysmal due to the complete lack of 32-bit PCID. Maybe any kernel built with this option set that runs on a CPU that has the PCID bit set in CPUID should print a big fat warning like "WARNING: you are using 32-bit PTI on a 64-bit PCID-capable CPU. Your performance will increase dramatically if you switch to a 64-bit kernel."