From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x225jUEcWwqDzyXm1hk8OHteEpwaxsxhKeuePc7CmKbSgg9dDUOQWPa3FSpZh3Dm9LUjsoOBY ARC-Seal: i=1; a=rsa-sha256; t=1517314204; cv=none; d=google.com; s=arc-20160816; b=0zilgkxR19sCC6FOK31i0eD2YfTIGK3wlZ5K2nzGjKSX+x7q0wno26qmn+bBRQ+AOt mryfpf0Nm1fKTchZKr1vfArMPF8IE9WXyg+unsz/xVIZwQBxZGMWF3Mdg4CPD2Mqb13V 6XJnCqLOxg8PT/UovXgSzUN6V7SMcINFAQYxIad5GGCkA0rTFuy0vu2a0vC+4bALrF8r xlhacKhZ2pySlO78Yv62AqKGhR+/sGsvNYKcPbTB5d3x+/n8/emrZjKVL11qqPtCy4Qc M2HcDQu8coCVnveYcV0lTct7yjG4d95BbVWyIK1mLF3eHC5NZA9hM2bCFrmK8jI5EcZU 9dEA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:date:face:references:in-reply-to:cc:to:from:subject :message-id:dkim-signature:arc-authentication-results; bh=p3rDq8lS6HSnIcrgFVtdyQd3/cztLsIF+zjg21nH9fY=; b=AuniJSvtEDLRBlsDRhCVy067rY4JrrwGjQMIuaYHXbQJtLGejff2A1uO8QLhizyGJr GGFbSFHcq+UYSzjQB0xTi10Xo66DBITZZ6oXRlEmzPxN/ziluwr0dLcMPXQRGZwD/1C6 X2D0Z9hISoGXrprjIOeLtKyBCsO1caetXOFySHAFXVjPnOVBT16U7wV6Gfy7nyBsYWmi NIETaz6X7scPeM5mt5WlYcON5oOcahP1hTNnGs45xKsROCuUbPoaRuWNBQGHDht003yW 0IM2uQHdRk5sb8DvR68mw/+Ws+6S0XvQPEOfDZGx0EawLgWiAAs3JotwXxZGMrdo5YUg ISZg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=twosheds.20170209 header.b=Kk/8WAl/; spf=pass (google.com: best guess record for domain of batv+1fe713f0495e48d9b4a9+5273+infradead.org+dwmw2@twosheds.srs.infradead.org designates 2001:8b0:10b:1:21d:7dff:fe04:dbe2 as permitted sender) smtp.mailfrom=BATV+1fe713f0495e48d9b4a9+5273+infradead.org+dwmw2@twosheds.srs.infradead.org Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=twosheds.20170209 header.b=Kk/8WAl/; spf=pass (google.com: best guess record for domain of batv+1fe713f0495e48d9b4a9+5273+infradead.org+dwmw2@twosheds.srs.infradead.org designates 2001:8b0:10b:1:21d:7dff:fe04:dbe2 as permitted sender) smtp.mailfrom=BATV+1fe713f0495e48d9b4a9+5273+infradead.org+dwmw2@twosheds.srs.infradead.org Message-ID: <1517314193.18619.115.camel@infradead.org> Subject: Re: [PATCH] x86/cpuid: Fix up "virtual" IBRS/IBPB/STIBP feature bits on Intel From: David Woodhouse To: Thomas Gleixner Cc: Borislav Petkov , arjan@linux.intel.com, karahmed@amazon.de, x86@kernel.org, linux-kernel@vger.kernel.org, tim.c.chen@linux.intel.com, peterz@infradead.org, pbonzini@redhat.com, ak@linux.intel.com, torvalds@linux-foundation.org, gregkh@linux-foundation.org In-Reply-To: References: <1517269773-16750-1-git-send-email-dwmw@amazon.co.uk> <20180130105814.m5zd43dyx2o2ius2@pd.tnic> <1517310230.18619.86.camel@infradead.org> <20180130111848.zjv2dngfzcz35lyt@pd.tnic> <1517311693.18619.102.camel@infradead.org> Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwBAMAAAClLOS0AAAAG1BMVEUHBwcUFBQpKSlGRkZhYWF9fX2Xl5eysrLMzMxFF+rXAAACaElEQVQ4y21UQXbbIBQE9wJALmAg6ToWON22FrhZthHgbvssUPathC7QWMful2JHSmtWwGg+zPxBCE0DU4QoJQgRgsg4w2gJjBNE8PjFBZgnQMBs+uZ1NQNQjZO3BV4AGDFC0f+l4DBG0VUAM4yv7SO8IgRdHXQ+A78HKL5OAeCfNQV5cHX8DsBUyIJKtYbt98BKaGNCKjfgFVkqYVLbkHKsRsbSCSa0T6npIqLrpRBgQKHUpQmgs9eEKaiUcooE8WWfCGVnBiUcn1uF2XhbfmN9apKnmMP2K4kizKkQWxuaVNOpU2cACIyxO1Po8ETHcXEDMVnozcejkAYA9iaD4pU0ZvNQ8VurNnTuFAYVtuIPUZW25PjDIjQAlGyffIiRQxoWAZBmJ0LTdW2Nyc0iP3DqRhxizvGJkBWZmyFVyZkddWzmBoIBVMpCCJ1CFzl98xav4VJKSSD45KbUT75ixikTphDSRh8+Uz7JLgUTAgAFwzqzjxc/nDY7WUApqY0OMdTwCKZSXplSKkgIRCHElCp8ZnhnKqXuwcNbk1L0VXE+I9alUXoHlLHl3mv7/dWQlJwtjREC7mu9L/U2jQyMUuO2EDS4q9Kl2ddm232bxIE5pjJuVwiljNn/Cfv25/T0cu5cZbwHGVq7h/zp0B4n3S99V/utD+Uo8BiGx9xCsOAV5z7/tjo4Z4z1Lvb90KZ7eFOoOeXOukqF2seo234YYuaQPpRP+cVZU5adT1Edun5Iz3z8fTz3+eSDh0Ip1c7zx1MaijGzTd/3MbRuBHz8cvcVgCMBRpOHvgu59WDhoat+nIZm+LWm9C/aaaGq5DCP9QAAAABJRU5ErkJggg== Content-Type: multipart/signed; micalg="sha-256"; protocol="application/x-pkcs7-signature"; boundary="=-hYPIrE/BrslpobO5+GuK" Date: Tue, 30 Jan 2018 12:09:53 +0000 Mime-Version: 1.0 X-Mailer: Evolution 3.18.5.2-0ubuntu3.2 X-SRS-Rewrite: SMTP reverse-path rewritten from by twosheds.infradead.org. See http://www.infradead.org/rpr.html X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1590972687399963990?= X-GMAIL-MSGID: =?utf-8?q?1591019257780568788?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: --=-hYPIrE/BrslpobO5+GuK Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2018-01-30 at 12:37 +0100, Thomas Gleixner wrote: > In any case, if there is ucode mismatch between CPUs the whole thing is > hosed anyway no matter what. So can you please agree on a solution so we > can unbreak the current state of affairs? If there is =C2=B5code mismatch between CPUs then the inconsistent bits should be filtered down to the lowest common denominator and we shouldn't use the features that are not consistently present. That much ought to work already with my patch. Boris's version uses setup_force_cpu_cap() and forces the bit to be set even on secondary CPUs which don't really have it, and thus it won't get filtered out. We'll try to use it, and it will fault on the CPUs which don't have it. That's the difference. --=-hYPIrE/BrslpobO5+GuK Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCEFQw ggUxMIIEGaADAgECAhBNRhEyk/HZ7naOeTHWrzuAMA0GCSqGSIb3DQEBCwUAMIGXMQswCQYDVQQG EwJHQjEbMBkGA1UECBMSR3JlYXRlciBNYW5jaGVzdGVyMRAwDgYDVQQHEwdTYWxmb3JkMRowGAYD VQQKExFDT01PRE8gQ0EgTGltaXRlZDE9MDsGA1UEAxM0Q09NT0RPIFJTQSBDbGllbnQgQXV0aGVu dGljYXRpb24gYW5kIFNlY3VyZSBFbWFpbCBDQTAeFw0xNzEyMjEwMDAwMDBaFw0xODEyMjEyMzU5 NTlaMCQxIjAgBgkqhkiG9w0BCQEWE2R3bXcyQGluZnJhZGVhZC5vcmcwggEiMA0GCSqGSIb3DQEB AQUAA4IBDwAwggEKAoIBAQDgzLNWa18DNpGUj/ZeH0Sgz53ESIbzdPw3OJeuNP6jZhxZojbyfxbM hETscxI/Hj6UZ4a7sHm5BkVjlsB1Af2Za/PXUt8MmLAcPMHkMPGunvkUibEvblDvpqMkQZlaZM+t 5PqFmWkbehLaEvbpNY7dmEAAeKh4klTzJzrr5AAzaCQ32cA2e3+DEIv5O5l9ViMIjy/JM+xMQrfX 3PZ0chY1PaVWjg59d4Uno+5LRDbgCnPkKJX4ysBGadibjBGQGJEZCjh94iiEebn2KsRLvtrJ72Ph 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