From owner-freebsd-virtualization@freebsd.org Sun Apr 30 18:17:42 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 B15ACD57805 for ; Sun, 30 Apr 2017 18:17:42 +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 861BC10CB for ; Sun, 30 Apr 2017 18:17:42 +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 v3UIHgrZ042729 for ; Sun, 30 Apr 2017 18:17:42 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-virtualization@FreeBSD.org Subject: [Bug 203994] bhyve kernel module may need to relax some checks when running nested under KVM Date: Sun, 30 Apr 2017 18:17:42 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: grehan@FreeBSD.org 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: 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, 30 Apr 2017 18:17:42 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D203994 --- Comment #17 from Peter Grehan --- Just an update on this. I used Ubuntu since it was easy to get a range of L= inux kernel versions to test with. - Ubuntu 17.04 (kernel 4.10) works without any changes to bhyve - Ubuntu 15.10 doesn't advertize INVVPID capability. While it would be possible to modify bhyve to work in this mode, I'm loathe to do it since it= 's such a niche case - Ubuntu 16.04 seems to have the capabilities that most folk have reported. After modifying bhyve to ignore the unused INVVPID capabilities and to fall-back to the all-context INVEPT if single-context wasn't available, the next issue was that Linux/KVM wasn't setting the GLA on EPT faults. This is used by bhyve to verify the GLA that is also obtained through the instructi= on emulation path for guest MMIO operations. This verification path hasn't thr= own any errors for a few years now, so I relaxed this test when in this mode. (Of note, this bug was reported here https://lkml.org/lkml/2016/9/4/156, and the author has submitted a diff review to relax some of the INVVPID/INVEPT checks at https://reviews.freebsd.org/D10049) However, after doing all this, bhyve would still eventually panic with a ke= rnel trap-9 fault when issuing a vmread instruction, so there may still be some additional KVM bugs that are being hit on this kernel rev :( I'll do some more experimentation and then post the patch that I have. --=20 You are receiving this mail because: You are the assignee for the bug.=