From owner-freebsd-virtualization@freebsd.org Sun Oct 29 21:45:28 2017 Return-Path: Delivered-To: freebsd-virtualization@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 87E88E4D49D for ; Sun, 29 Oct 2017 21:45:28 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (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 74B0868436 for ; Sun, 29 Oct 2017 21:45:28 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from bugs.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id v9TLjSvH080652 for ; Sun, 29 Oct 2017 21:45:28 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-virtualization@FreeBSD.org Subject: [Bug 218662] bhyve exposes CPU feature SDBG to guests, causing guest panic on OpenBSD 6.1 Date: Sun, 29 Oct 2017 21:45:28 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: bin X-Bugzilla-Version: 10.3-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: freebsd@bdragon.rtk0.net X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-virtualization@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: cc attachments.created Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-virtualization@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Discussion of various virtualization techniques FreeBSD supports." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 29 Oct 2017 21:45:28 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D218662 Brandon Bergren changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |freebsd@bdragon.rtk0.net --- Comment #2 from Brandon Bergren --- Created attachment 187571 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D187571&action= =3Dedit VMM patch (from HardenedBSD) This affects me too. HardenedBSD has the most elegant fix at https://github.com/HardenedBSD/hardenedBSD/commit/e76fcb77ba82649bc6aed808a= f06d6d2184847d8 -- I have attached a copy of the patch. I can confirm that with just that p= atch I can successfully run OpenBSD 6.1 in bhyve on my machine that is otherwise affected by this problem. I believe it makes a lot more sense than emulating the MSR (i.e. what https://github.com/HardenedBSD/hardenedBSD/commit/cc91b57f4d1dabddfbf8b1e76= 55 does.) My SuperMicro C7Z170-OCE board actually has bios options for enabling and disabling the silicon debug status and lock bit, so if I were to misconfigu= re my bios, the countermeasure would have actually been effective (when applie= d to the host). I can verify though that with it disabled in the bios, it is indeed locked down, without needing the countermeasure. root@narwhal:~ # kldload cpuctl root@narwhal:~ # cpucontrol -m 0xc80 /dev/cpuctl0 MSR 0xc80: 0x00000000 0x40000000 I still think the countermeasure is a good idea though! https://github.com/HardenedBSD/hardenedBSD/commit/da28546280938e19e866d2e11= a9ccda3c4ca82fa is a version of the countermeasure that checks the virtualization flag too = so it will avoid tickling the bhyve limitation while still providing protectio= n. But at the very least, filter the SDBG feature flag. --=20 You are receiving this mail because: You are the assignee for the bug.=