[FreeBSD-Announce] FreeBSD Errata Notice FreeBSD-EN-19:16.bhyve

FreeBSD Errata Notices errata-notices at freebsd.org
Tue Aug 20 20:12:32 UTC 2019

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FreeBSD-EN-19:16.bhyve                                          Errata Notice
                                                          The FreeBSD Project

Topic:          Bhyve instruction emulation improvements (opcode 03H and F7H)

Category:       core
Module:         bhyve
Announced:      2019-08-20
Credits:        John Baldwin, Jason Tubnor
Affects:        All supported versions of FreeBSD.
Corrected:      2019-07-07 17:30:23 UTC (stable/12, 12.0-STABLE)
                2019-08-20 17:45:44 UTC (releng/12.0, 12.0-RELEASE-p10)
                2019-07-07 17:31:13 UTC (stable/11, 11.3-STABLE)
                2019-08-20 17:45:44 UTC (releng/11.3, 11.3-RELEASE-p3)

Note: This errata notice does not update FreeBSD 11.2.  FreeBSD 11.2
users affected by this update should upgrade to FreeBSD 11.3.

For general information regarding FreeBSD Errata Notices and Security
Advisories, including descriptions of the fields above, security
branches, and the following sections, please visit

I.   Background

bhyve(8) is a hypervisor that supports running a variety of guest operating
systems in virtual machines, using hardware virtualization in Intel and AMD
CPUs.  Some instructions are not handled by hardware virtualization and must
be emulated by the hypervisor.

II.  Problem Description

Some newer software uses instructions previously not handled by bhyve's
instruction emulation.  This errata notice adds emulation for two instruction
opcodes, to enable flash variable storage in OVMF and to support guest
operating systems compiled with Clang 8.0.0 that use the TEST instruction
against local APIC registers (such as OpenBSD 6.6).

III. Impact

Guest firmware or operating systems using unsupported instructions caused
bhyve to exit with a "Failed to emulate instruction" error.

IV.  Workaround

No workaround is available.

V.   Solution

Upgrade your system to a supported FreeBSD stable or release / security
branch (releng) dated after the correction date.

1) To update your system via a binary patch:

Systems running a RELEASE version of FreeBSD on the i386 or amd64
platforms can be updated via the freebsd-update(8) utility:

# freebsd-update fetch
# freebsd-update install

2) To update your system via a source code patch:

The following patches have been verified to apply to the applicable
FreeBSD release branches.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

[FreeBSD 11.3, FreeBSD 12.0]
# fetch https://security.FreeBSD.org/patches/EN-19:16/bhyve.patch
# fetch https://security.FreeBSD.org/patches/EN-19:16/bhyve.patch.asc
# gpg --verify bhyve.patch.asc

b) Apply the patch.  Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch

c) Recompile the operating system using buildworld and installworld as
described in <URL:https://www.FreeBSD.org/handbook/makeworld.html>.

Start the applicable virtual machines.

VI.  Correction details

The following list contains the correction revision numbers for each
affected branch.

Branch/path                                                      Revision
- -------------------------------------------------------------------------
stable/12/                                                        r349808
releng/12.0/                                                      r351256
stable/11/                                                        r349809
releng/11.3/                                                      r351256
- -------------------------------------------------------------------------

To see which files were modified by a particular revision, run the
following command, replacing NNNNNN with the revision number, on a
machine with Subversion installed:

# svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base

Or visit the following URL, replacing NNNNNN with the revision number:


VII. References


The latest revision of this advisory is available at


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