From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f198.google.com (mail-qk0-f198.google.com [209.85.220.198]) by kanga.kvack.org (Postfix) with ESMTP id 3DD3B6B1B53 for ; Mon, 20 Aug 2018 18:02:52 -0400 (EDT) Received: by mail-qk0-f198.google.com with SMTP id v65-v6so16147952qka.23 for ; Mon, 20 Aug 2018 15:02:52 -0700 (PDT) Received: from smtp-fw-6002.amazon.com (smtp-fw-6002.amazon.com. [52.95.49.90]) by mx.google.com with ESMTPS id r22-v6si3228797qkr.338.2018.08.20.15.02.51 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 20 Aug 2018 15:02:51 -0700 (PDT) Content-Type: multipart/mixed; boundary="===============7676184271832597047==" MIME-Version: 1.0 From: "Woodhouse, David" Subject: Re: Redoing eXclusive Page Frame Ownership (XPFO) with isolated CPUs in mind (for KVM to isolate its guests per CPU) Date: Mon, 20 Aug 2018 21:52:19 +0000 Message-ID: <1534801939.10027.24.camel@amazon.co.uk> References: <20180820212556.GC2230@char.us.oracle.com> In-Reply-To: MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: "torvalds@linux-foundation.org" , "konrad.wilk@oracle.com" Cc: "juerg.haefliger@hpe.com" , "deepa.srinivasan@oracle.com" , "jmattson@google.com" , "andrew.cooper3@citrix.com" , "linux-kernel@vger.kernel.org" , "boris.ostrovsky@oracle.com" , "linux-mm@kvack.org" , "tglx@linutronix.de" , "joao.m.martins@oracle.com" , "pradeep.vincent@oracle.com" , "ak@linux.intel.com" , "khalid.aziz@oracle.com" , "kanth.ghatraju@oracle.com" , "liran.alon@oracle.com" , "keescook@google.com" , "jsteckli@os.inf.tu-dresden.de" , "kernel-hardening@lists.openwall.com" , "chris.hyser@oracle.com" , "tyhicks@canonical.com" , "john.haxby@oracle.com" , "jcm@redhat.com" --===============7676184271832597047== Content-Language: en-US Content-Type: multipart/signed; micalg=sha-256; protocol="application/x-pkcs7-signature"; boundary="=-fMMvEwHthOXPfEoyAeNK" --=-fMMvEwHthOXPfEoyAeNK Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2018-08-20 at 14:48 -0700, Linus Torvalds wrote: >=20 > Of course, after the long (and entirely unrelated) discussion about > the TLB flushing bug we had, I'm starting to worry about my own > competence, and maybe I'm missing something really fundamental, and > the XPFO patches do something else than what I think they do, or my > "hey, let's use our Meltdown code" idea has some fundamental weakness > that I'm missing. The interesting part is taking the user (and other) pages out of the kernel's 1:1 physmap. It's the *kernel* we don't want being able to access those pages, because of the multitude of unfixable cache load gadgets. --=-fMMvEwHthOXPfEoyAeNK Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCEE4w ggUuMIIEFqADAgECAhEApEtL31g6H7ROXdOiQnA9RjANBgkqhkiG9w0BAQsFADCBlzELMAkGA1UE BhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgG A1UEChMRQ09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhl bnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0EwHhcNMTcxMjIxMDAwMDAwWhcNMTgxMjIxMjM1 OTU5WjAiMSAwHgYJKoZIhvcNAQkBFhFkd213QGFtYXpvbi5jby51azCCASIwDQYJKoZIhvcNAQEB BQADggEPADCCAQoCggEBAKdGKgXuwKMg2r+i/4BZZC0ddRxNq3xIKTakie/VCSzoO7P17A36ZzUc VMEYPfqDt/65xoc6Tdih+qkY2pNDppZ1DZ8mVrAX6O2O60ZhmXB60wMoDvXPZInvkMOW4drqnje/ 7/NOypn/XQAY+ln4KT+3tHG3TfryyJFMedqC/r29KJlCeeCxIzdtq2j5mN42tvPVv4+p+Kr77uui 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