From owner-freebsd-questions@freebsd.org Tue May 21 02:55:42 2019 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id DDDF9159F0B3 for ; Tue, 21 May 2019 02:55:42 +0000 (UTC) (envelope-from list_freebsd@bluerosetech.com) Received: from echo.brtsvcs.net (echo.brtsvcs.net [208.111.40.118]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 555637094E for ; Tue, 21 May 2019 02:55:41 +0000 (UTC) (envelope-from list_freebsd@bluerosetech.com) Received: from chombo.houseloki.net (catnip [73.240.250.185]) by echo.brtsvcs.net (Postfix) with ESMTPS id 9694D38D09; Mon, 20 May 2019 19:55:33 -0700 (PDT) Received: from [IPv6:2601:1c2:1402:1770:8827:268e:2026:877b] (unknown [IPv6:2601:1c2:1402:1770:8827:268e:2026:877b]) by chombo.houseloki.net (Postfix) with ESMTPSA id D053B2D9C; Mon, 20 May 2019 19:55:32 -0700 (PDT) Subject: Re: Unclear On The New MDS Patch To: Tim Daneliuk , freebsd-questions@freebsd.org References: <20190519230343.4340af09@gumby.homeunix.com> From: Mel Pilgrim Message-ID: <17c04ae2-9b32-3cbe-93c9-819af21b4ff8@bluerosetech.com> Date: Mon, 20 May 2019 19:55:32 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 555637094E X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; spf=pass (mx1.freebsd.org: domain of list_freebsd@bluerosetech.com designates 208.111.40.118 as permitted sender) smtp.mailfrom=list_freebsd@bluerosetech.com X-Spamd-Result: default: False [-3.83 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+mx]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[bluerosetech.com]; RCVD_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_SOME(0.00)[]; MX_GOOD(-0.01)[echo.brtsvcs.net,foxtrot.brtsvcs.net]; RCPT_COUNT_TWO(0.00)[2]; NEURAL_HAM_SHORT(-0.73)[-0.726,0]; IP_SCORE(-0.79)[asn: 36236(-3.89), country: US(-0.06)]; RECEIVED_SPAMHAUS_PBL(0.00)[185.250.240.73.zen.spamhaus.org : 127.0.0.10]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:36236, ipnet:208.111.40.0/24, country:US]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; FROM_EQ_ENVFROM(0.00)[] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 May 2019 02:55:43 -0000 On 2019-05-20 11:11, Tim Daneliuk wrote: > What about cloud based servers like Digital Ocean FreeBSD droplets? Does > microcode updating even make sense in that context since the underlying > system is actually what touches the hardware? Short answer: no. Longer answer: Microcode updates use the WRMSR (WRite Model Specific Register) instruction, which requires ring 0. Intel and AMD virtualization both emulate ring 0 for guests by pushing the physical ring 0 into a layer only accessible by the VMM and faking it for guests so they can operate without paravirtualization. This is visible with software like msr-tools, where the rdmsr tool works fine but wrmsr appears to have no effect when run on a guest.