From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x22722DrtzbQRtASkmY5WmN0tP678x2xo49PJdCKKphxKnhNoxOLSShpFxFuuv1mCAo+K0+LM ARC-Seal: i=1; a=rsa-sha256; t=1516749321; cv=none; d=google.com; s=arc-20160816; b=ym2B7HPzjUuhtjd68Ujh3uyroK60XthmS+wNtWrMnGAmGV0yZtFJgw3ebuJgCVL2w5 FVEJ/6guoyDaYFTqxp1BC9vEnVQKzZiZDoBLVi/iJm+JcO03+aIyxOJ6mCUzfjGRFQUr 3I5mn6Y9CVSbDRK+ugRKBnYiDncUeuI02UnFKZK4/+bnfT5oOKgwzR0Rn2zTPRuz1laH 9CemEQ53dmrRs+Kc15AKKY/bqcboRLJbWqxhzYX5R0TeRDeg6qxjwe+nQ+AzlH3IgX5q 9W65uVaXYcXsiAA2oAJ1n1LC0UT6VjPd/ZVJHUpu1gnEZYQenQJstoFO78w/dxkFBkQr Fl6g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:accept-language:in-reply-to:references:message-id:date :thread-index:thread-topic:subject:cc:to:from:mime-version :dkim-signature:arc-authentication-results; bh=EBlKkcptkTUMRTKA5lAYiPW32UfWEWJARJ4MIvs8Qms=; b=cp0c0xoAZTctLbjj4UiGOsSbD4lgIsMvjdeUOjR4JN4gPCQ2bvVl+pQxzzc8ACECpY DmKzzKrUQcddDTP57IT/FJOHZ2f7eRfPygb2y6lx7euXJ2P1irCFDRbEJNK11wXZmyu9 rjoF5+FiD7+02tmxrZFGTj5hH5GHy6CojpDh+TdkGTrZbjE0nmLpix1j45OO1WqP00VO ze4TnFMo3cT6IYhmYjseqEGvVm4WuWRCgyVaUn/bUny5JbdXH4+1y0ztSSg9f9mye5tv gV8BE6IngJH7Njh0eq3QG83tTa+IRJfFNxFrnbTbuO3zDqvjyhx3xhLA90A9jRb+vZxW W0ew== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@amazon.co.uk header.s=amazon201209 header.b=fi7VVSP2; spf=pass (google.com: domain of prvs=5548949a8=dwmw@amazon.co.uk designates 207.171.184.29 as permitted sender) smtp.mailfrom=prvs=5548949a8=dwmw@amazon.co.uk; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=amazon.co.uk Authentication-Results: mx.google.com; dkim=pass header.i=@amazon.co.uk header.s=amazon201209 header.b=fi7VVSP2; spf=pass (google.com: domain of prvs=5548949a8=dwmw@amazon.co.uk designates 207.171.184.29 as permitted sender) smtp.mailfrom=prvs=5548949a8=dwmw@amazon.co.uk; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=amazon.co.uk X-Amazon-filename: smime.p7s X-IronPort-AV: E=Sophos;i="5.46,403,1511827200"; d="p7s'?scan'208";a="589303711" Content-Type: multipart/mixed; boundary="===============4185153328309937169==" MIME-Version: 1.0 From: "Woodhouse, David" To: "thomas.lendacky@amd.com" , "ak@linux.intel.com" CC: "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "peterz@infradead.org" , "ashok.raj@intel.com" , "Raslan, KarimAllah" , "arjan.van.de.ven@intel.com" , "arjan@linux.intel.com" , "bp@suse.de" , "tglx@linutronix.de" , "Janakarajan.Natarajan@amd.com" , "tim.c.chen@linux.intel.com" , "torvalds@linux-foundation.org" , "joro@8bytes.org" , "dan.j.williams@intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "aarcange@redhat.com" , "mingo@redhat.com" , "luto@kernel.org" , "pbonzini@redhat.com" , "gregkh@linuxfoundation.org" , "dave.hansen@intel.com" , "luto@amacapital.net" , "mhiramat@kernel.org" , "asit.k.mallick@intel.com" , "jun.nakajima@intel.com" , "labbott@redhat.com" , "rkrcmar@redhat.com" Subject: Re: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation Thread-Topic: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation Thread-Index: AQHTkiQ0iyjGMUW5uUybCpLmt+1puKN+s8qAgALx8gCAAAJHgIAAaTuAgAADcwCAAAblAA== Date: Tue, 23 Jan 2018 23:14:36 +0000 Message-ID: <1516749276.13558.25.camel@amazon.co.uk> References: <1516476182-5153-1-git-send-email-karahmed@amazon.de> <1516476182-5153-10-git-send-email-karahmed@amazon.de> <243BE571-AF73-44B3-8D17-193F9E07686A@amacapital.net> <4e01a7a9-29e4-adcc-3f53-550fb7f3d370@amd.com> <1516724457.9521.156.camel@amazon.co.uk> <20180123224956.GQ7844@tassilo.jf.intel.com> In-Reply-To: <20180123224956.GQ7844@tassilo.jf.intel.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: yes X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.43.60.116] MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1590140582166248265?= X-GMAIL-MSGID: =?utf-8?q?1590426936453413201?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: --===============4185153328309937169== Content-Language: en-US Content-Type: multipart/signed; micalg=sha-256; protocol="application/x-pkcs7-signature"; boundary="=-q+mZOhcj9cJaZ9CQ8Sfx" --=-q+mZOhcj9cJaZ9CQ8Sfx Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2018-01-23 at 14:49 -0800, Andi Kleen wrote: > > Not sure.=C2=A0 Maybe to start, the answer might be to allow it to be s= et for > > the ultra-paranoid, but in general don't enable it by default.=C2=A0 Ha= ving it > > enabled would be an alternative to someone deciding to disable SMT, sin= ce > > that would have even more of a performance impact. >=20 > I agree. A reasonable strategy would be to only enable it for > processes that have dumpable disabled. This should be already set for > high value processes like GPG, and allows others to opt-in if > they need to. That seems to make sense, and I think was the solution we were approaching for IBPB on context switch too, right? Are we generally agreed on dumpable as the criterion for both of those? --=-q+mZOhcj9cJaZ9CQ8Sfx 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 GOASNdFJbNdgx7UGF+il6kRGSle17LJZKMgRiLJXYjECwnGwdfLdN5SINWD5IC3yXY8d14Bq6DyD jNts1DFw+SKhW8kVFYRZpv7TE3/42QJKQVL6YWka5T4EJO7AD3gy2ypRsd8CAwEAAaOCAecwggHj MB8GA1UdIwQYMBaAFIKvbIz4xf6WYXzoHz0rcUhexIvAMB0GA1UdDgQWBBT/vhvBExl2wDr8f50u b+0yzFyZRjAOBgNVHQ8BAf8EBAMCBaAwDAYDVR0TAQH/BAIwADAgBgNVHSUEGTAXBggrBgEFBQcD BAYLKwYBBAGyMQEDBQIwEQYJYIZIAYb4QgEBBAQDAgUgMEYGA1UdIAQ/MD0wOwYMKwYBBAGyMQEC AQEBMCswKQYIKwYBBQUHAgEWHWh0dHBzOi8vc2VjdXJlLmNvbW9kby5uZXQvQ1BTMFoGA1UdHwRT MFEwT6BNoEuGSWh0dHA6Ly9jcmwuY29tb2RvY2EuY29tL0NPTU9ET1JTQUNsaWVudEF1dGhlbnRp Y2F0aW9uYW5kU2VjdXJlRW1haWxDQS5jcmwwgYsGCCsGAQUFBwEBBH8wfTBVBggrBgEFBQcwAoZJ aHR0cDovL2NydC5jb21vZG9jYS5jb20vQ09NT0RPUlNBQ2xpZW50QXV0aGVudGljYXRpb25hbmRT ZWN1cmVFbWFpbENBLmNydDAkBggrBgEFBQcwAYYYaHR0cDovL29jc3AuY29tb2RvY2EuY29tMBwG A1UdEQQVMBOBEWR3bXdAYW1hem9uLmNvLnVrMA0GCSqGSIb3DQEBCwUAA4IBAQCK2HofespbCaDu udwwfh8GxDpVUnVbZZVWScpZMxfYpXzLot7L6iZrr16oMQ+UOiDDAK6/D3+u2QN8u0lJ6yLKVmvh lGOzDywGsyG2Ohy8Dt5jcEK5sz84OsPtrRH7ahZHLxYPhWlUKOjOPN6sb9h6uMYlXmG/KmAr2rwF exN6Zrwh6YwF7ukuMs175YcNyYRdB8kVYq3WikfbTHOoRbJiu9Unw7LqnvPTfx+xUvD6aN2CKLtr mactWbk98swNgbI18UWjfEpugvAqw09CDLjeq7N1v0SkUkQEDqGSUE+hKFryTNXtZ6zOfl+MQfD8 U7T5oJa34DmWXK9+x7dl+MrqMIIFLjCCBBagAwIBAgIRAKRLS99YOh+0Tl3TokJwPUYwDQYJKoZI hvcNAQELBQAwgZcxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVhdGVyIE1hbmNoZXN0ZXIxEDAO BgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1pdGVkMT0wOwYDVQQDEzRDT01P RE8gUlNBIENsaWVudCBBdXRoZW50aWNhdGlvbiBhbmQgU2VjdXJlIEVtYWlsIENBMB4XDTE3MTIy MTAwMDAwMFoXDTE4MTIyMTIzNTk1OVowIjEgMB4GCSqGSIb3DQEJARYRZHdtd0BhbWF6b24uY28u dWswggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCnRioF7sCjINq/ov+AWWQtHXUcTat8 SCk2pInv1Qks6Duz9ewN+mc1HFTBGD36g7f+ucaHOk3YofqpGNqTQ6aWdQ2fJlawF+jtjutGYZlw etMDKA71z2SJ75DDluHa6p43v+/zTsqZ/10AGPpZ+Ck/t7Rxt0368siRTHnagv69vSiZQnngsSM3 bato+ZjeNrbz1b+Pqfiq++7rohjgEjXRSWzXYMe1BhfopepERkpXteyyWSjIEYiyV2IxAsJxsHXy 3TeUiDVg+SAt8l2PHdeAaug8g4zbbNQxcPkioVvJFRWEWab+0xN/+NkCSkFS+mFpGuU+BCTuwA94 MtsqUbHfAgMBAAGjggHnMIIB4zAfBgNVHSMEGDAWgBSCr2yM+MX+lmF86B89K3FIXsSLwDAdBgNV HQ4EFgQU/74bwRMZdsA6/H+dLm/tMsxcmUYwDgYDVR0PAQH/BAQDAgWgMAwGA1UdEwEB/wQCMAAw IAYDVR0lBBkwFwYIKwYBBQUHAwQGCysGAQQBsjEBAwUCMBEGCWCGSAGG+EIBAQQEAwIFIDBGBgNV HSAEPzA9MDsGDCsGAQQBsjEBAgEBATArMCkGCCsGAQUFBwIBFh1odHRwczovL3NlY3VyZS5jb21v ZG8ubmV0L0NQUzBaBgNVHR8EUzBRME+gTaBLhklodHRwOi8vY3JsLmNvbW9kb2NhLmNvbS9DT01P RE9SU0FDbGllbnRBdXRoZW50aWNhdGlvbmFuZFNlY3VyZUVtYWlsQ0EuY3JsMIGLBggrBgEFBQcB AQR/MH0wVQYIKwYBBQUHMAKGSWh0dHA6Ly9jcnQuY29tb2RvY2EuY29tL0NPTU9ET1JTQUNsaWVu dEF1dGhlbnRpY2F0aW9uYW5kU2VjdXJlRW1haWxDQS5jcnQwJAYIKwYBBQUHMAGGGGh0dHA6Ly9v Y3NwLmNvbW9kb2NhLmNvbTAcBgNVHREEFTATgRFkd213QGFtYXpvbi5jby51azANBgkqhkiG9w0B AQsFAAOCAQEAith6H3rKWwmg7rncMH4fBsQ6VVJ1W2WVVknKWTMX2KV8y6Ley+oma69eqDEPlDog wwCuvw9/rtkDfLtJSesiylZr4ZRjsw8sBrMhtjocvA7eY3BCubM/ODrD7a0R+2oWRy8WD4VpVCjo zjzerG/YerjGJV5hvypgK9q8BXsTema8IemMBe7pLjLNe+WHDcmEXQfJFWKt1opH20xzqEWyYrvV J8Oy6p7z038fsVLw+mjdgii7a5mnLVm5PfLMDYGyNfFFo3xKboLwKsNPQgy43quzdb9EpFJEBA6h klBPoSha8kzV7Weszn5fjEHw/FO0+aCWt+A5llyvfse3ZfjK6jCCBeYwggPOoAMCAQICEGqb4Tg7 /ytrnwHV2binUlYwDQYJKoZIhvcNAQEMBQAwgYUxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVh dGVyIE1hbmNoZXN0ZXIxEDAOBgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1p dGVkMSswKQYDVQQDEyJDT01PRE8gUlNBIENlcnRpZmljYXRpb24gQXV0aG9yaXR5MB4XDTEzMDEx MDAwMDAwMFoXDTI4MDEwOTIzNTk1OVowgZcxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVhdGVy IE1hbmNoZXN0ZXIxEDAOBgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1pdGVk MT0wOwYDVQQDEzRDT01PRE8gUlNBIENsaWVudCBBdXRoZW50aWNhdGlvbiBhbmQgU2VjdXJlIEVt YWlsIENBMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvrOeV6wodnVAFsc4A5jTxhh2 IVDzJXkLTLWg0X06WD6cpzEup/Y0dtmEatrQPTRI5Or1u6zf+bGBSyD9aH95dDSmeny1nxdlYCeX IoymMv6pQHJGNcIDpFDIMypVpVSRsivlJTRENf+RKwrB6vcfWlP8dSsE3Rfywq09N0ZfxcBa39V0 wsGtkGWC+eQKiz4pBZYKjrc5NOpG9qrxpZxyb4o4yNNwTqzaaPpGRqXB7IMjtf7tTmU2jqPMLxFN e1VXj9XB1rHvbRikw8lBoNoSWY66nJN/VCJv5ym6Q0mdCbDKCMPybTjoNCQuelc0IAaO4nLUXk0B OSxSxt8kCvsUtQIDAQABo4IBPDCCATgwHwYDVR0jBBgwFoAUu69+Aj36pvE8hI6t7jiY7NkyMtQw HQYDVR0OBBYEFIKvbIz4xf6WYXzoHz0rcUhexIvAMA4GA1UdDwEB/wQEAwIBhjASBgNVHRMBAf8E CDAGAQH/AgEAMBEGA1UdIAQKMAgwBgYEVR0gADBMBgNVHR8ERTBDMEGgP6A9hjtodHRwOi8vY3Js LmNvbW9kb2NhLmNvbS9DT01PRE9SU0FDZXJ0aWZpY2F0aW9uQXV0aG9yaXR5LmNybDBxBggrBgEF BQcBAQRlMGMwOwYIKwYBBQUHMAKGL2h0dHA6Ly9jcnQuY29tb2RvY2EuY29tL0NPTU9ET1JTQUFk ZFRydXN0Q0EuY3J0MCQGCCsGAQUFBzABhhhodHRwOi8vb2NzcC5jb21vZG9jYS5jb20wDQYJKoZI hvcNAQEMBQADggIBAHhcsoEoNE887l9Wzp+XVuyPomsX9vP2SQgG1NgvNc3fQP7TcePo7EIMERoh 42awGGsma65u/ITse2hKZHzT0CBxhuhb6txM1n/y78e/4ZOs0j8CGpfb+SJA3GaBQ+394k+z3ZBy WPQedXLL1OdK8aRINTsjk/H5Ns77zwbjOKkDamxlpZ4TKSDMKVmU/PUWNMKSTvtlenlxBhh7ETrN 543j/Q6qqgCWgWuMAXijnRglp9fyadqGOncjZjaaSOGTTFB+E2pvOUtY+hPebuPtTbq7vODqzCM6 ryEhNhzf+enm0zlpXK7q332nXttNtjv7VFNYG+I31gnMrwfHM5tdhYF/8v5UY5g2xANPECTQdu9v WPoqNSGDt87b3gXb1AiGGaI06vzgkejL580ul+9hz9D0S0U4jkhJiA7EuTecP/CFtR72uYRBcunw wH3fciPjviDDAI9SnC/2aPY8ydehzuZutLbZdRJ5PDEJM/1tyZR2niOYihZ+FCbtf3D9mB12D4ln 9icgc7CwaxpNSCPt8i/GqK2HsOgkL3VYnwtx7cJUmpvVdZ4ognzgXtgtdk3ShrtOS1iAN2ZBXFiR mjVzmehoMof06r1xub+85hFQzVxZx5/bRaTKTlL8YXLI8nAbR9HWdFqzcOoB/hxfEyIQpx9/s81r gzdEZOofSlZHynoSMYIDyjCCA8YCAQEwga0wgZcxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVh dGVyIE1hbmNoZXN0ZXIxEDAOBgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1p dGVkMT0wOwYDVQQDEzRDT01PRE8gUlNBIENsaWVudCBBdXRoZW50aWNhdGlvbiBhbmQgU2VjdXJl IEVtYWlsIENBAhEApEtL31g6H7ROXdOiQnA9RjANBglghkgBZQMEAgEFAKCCAe0wGAYJKoZIhvcN AQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTgwMTIzMjMxNDM2WjAvBgkqhkiG9w0B CQQxIgQgzrW60cZEmlAR78OLHT9HGlmZpQ+BMjgu5V27l1MzaYgwgb4GCSsGAQQBgjcQBDGBsDCB rTCBlzELMAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMH U2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0Eg Q2xpZW50IEF1dGhlbnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0ECEQCkS0vfWDoftE5d06JC cD1GMIHABgsqhkiG9w0BCRACCzGBsKCBrTCBlzELMAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0 ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0 ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhlbnRpY2F0aW9uIGFuZCBTZWN1cmUg RW1haWwgQ0ECEQCkS0vfWDoftE5d06JCcD1GMA0GCSqGSIb3DQEBAQUABIIBACatM//nTpZWvi8Y A8Mj40Q1ejg388yNGmqh44G2GKezURymesh0guJ1KuKmU6/Ud7EFdm4fCqruwT41pAqH2dtjfjdR JNZbk+Q/mcVR/HzSqogu1oUS3Wwjm5GZy9c8HkXSBcuUgA17iapHjnr06NZ8R5/3s5nBaE5lDDt5 zdpOAIty3UGg7mZwgdD1rn7QAjWUWnpDUXCNDMvb7mV10pkZtaGHrdnGV4Q+WG+rcYMNY7B2OZOQ Oc60dKApSa5HH9/o0qAsedSNpAmqvCYG+YtLLzWmoXjCrnSWi+4mRZsJvgI/WlPFtOuVI/brnHq5 oWzuwoFNa1JD+QdnHlIE/14AAAAAAAA= --=-q+mZOhcj9cJaZ9CQ8Sfx-- --===============4185153328309937169== Content-Type: multipart/alternative; boundary="===============4841900918607595045==" MIME-Version: 1.0 Content-Disposition: inline --===============4841900918607595045== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Amazon Web Services UK Limited. Registered in England and Wales with regist= ration number 08650665 and which has its registered office at 60 Holborn Vi= aduct, London EC1A 2FD, United Kingdom. --===============4841900918607595045== Content-Type: text/html; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Amazon Web Services UK Limited. Registered in England and Wales with regist= ration number 08650665 and which has its registered office at 60 Holborn Vi= aduct, London EC1A 2FD, United Kingdom. --===============4841900918607595045==-- --===============4185153328309937169==--