From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x2271ZH/sCocSvSg/ups+XqIebj8f5aLnUgq1lsJtSjYOL9JYjhghgAoMqSbiJMhk4jzYQwnK ARC-Seal: i=1; a=rsa-sha256; t=1516806549; cv=none; d=google.com; s=arc-20160816; b=BDImN8QVbjFVZpq6YsEKioxF0GoZZszE/jkXkI7WXvzhX1MLdnhZwqW11lCy/8aO6D 4V9E/XxDHkCtZfj3gR2e+XljIkOSc0OvVHRKHQXRGt54/ieYJ0x7JBIKqRKSdGewdefx lhpUpBtgqY1CgFW1GzY0igOBC0IH+h9BQa5L5bk6Ts9HMepaHcZMtTYk9yCvXYKrYIj4 tz2SO2G1dsaymZrdNkEfKbiemn3Ltd0BbSgWZ1hf3JKw0/EPH/VBDgdPw7K/Tv5Gc0gP ZzbuHzL9ayvnl+GZNtF1T+RoY0ZbM+6GrABH17GXOMvoq5OBq/76I5m40YkZUaZzNFtp 4kIQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :arc-authentication-results; bh=XWJ2PvXVCFHub9hSmNaYhNsmtUS1mTa7i+fdN9xcjwE=; b=VtvuZpFrA2YcI6ollsKliBn2ePJ2aN3FOPBDa9R3U/5NK/PYBOTk6aM/fVI0tUSdoO 2tRdzjDhNEbrZN4sy3E5U8z9ioNRlyBkpbh2OWbfyVOqlBkW8rWnDwlEolyDHGSm49LP kfYN0ZQUM7TtTI1euk0q62/hZpgbZHtyYe+wLNOxTvr9E4P6pjfcNe0og4beSBDEByYI x2DlEBfm63ImQDtBSpQUuDpfCxX2Z68AKl/fZhMsq3wamGtB5jOgzGIN3VLrUJ66Gd2D KkqZI4lX0XtjCbP+SZR1GQulhXj4D22sftyvCJI19L5AOrJI+vzITjSjwjF0ssQXSC2s eAHQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of arjan@linux.intel.com designates 134.134.136.100 as permitted sender) smtp.mailfrom=arjan@linux.intel.com Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of arjan@linux.intel.com designates 134.134.136.100 as permitted sender) smtp.mailfrom=arjan@linux.intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,408,1511856000"; d="scan'208";a="29134395" Subject: Re: [RFC 05/10] x86/speculation: Add basic IBRS support infrastructure To: Greg Kroah-Hartman , David Woodhouse Cc: Peter Zijlstra , Thomas Gleixner , KarimAllah Ahmed , linux-kernel@vger.kernel.org, Andi Kleen , Andrea Arcangeli , Andy Lutomirski , Ashok Raj , Asit Mallick , Borislav Petkov , Dan Williams , Dave Hansen , "H . Peter Anvin" , Ingo Molnar , Janakarajan Natarajan , Joerg Roedel , Jun Nakajima , Laura Abbott , Linus Torvalds , Masami Hiramatsu , Paolo Bonzini , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Tim Chen , Tom Lendacky , kvm@vger.kernel.org, x86@kernel.org References: <1516476182-5153-1-git-send-email-karahmed@amazon.de> <1516476182-5153-6-git-send-email-karahmed@amazon.de> <1516741116.13558.11.camel@infradead.org> <20180124084735.GM2228@hirez.programming.kicks-ass.net> <1516784541.13558.90.camel@infradead.org> <20180124091049.GB12100@kroah.com> From: Arjan van de Ven Message-ID: <68fc14f7-38b0-5127-5c7a-a11c27e3b166@linux.intel.com> Date: Wed, 24 Jan 2018 07:09:06 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <20180124091049.GB12100@kroah.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1590140581449802182?= X-GMAIL-MSGID: =?utf-8?q?1590486944521992215?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 1/24/2018 1:10 AM, Greg Kroah-Hartman wrote: > >> That means the whitelist ends up basically empty right now. Should I >> add a command line parameter to override it? Otherwise we end up having >> to rebuild the kernel every time there's a microcode release which >> covers a new CPU SKU (which is why I kind of hate the whitelist, but >> Arjan is very insistent...) > > Ick, no, whitelists are a pain for everyone involved. Don't do that > unless it is absolutely the only way it will ever work. > > Arjan, why do you think this can only be done as a whitelist? I suggested a minimum version list for those cpus that need it. microcode versions are tricky (and we've released betas etc etc with their own numbers) and as a result there might be several numbers that have those issues with their IBRS for the same F/M/S