This is used as part of implementing run control in bhyve's debug server. The hypervisor now maintains a set of "debugged" CPUs. Attempting to run a debugged CPU will fail to execute any guest instructions and will instead report a VM_EXITCODE_DEBUG exit to the userland hypervisor. Virtual CPUs are placed into the debugged state via vm_suspend_cpu() (implemented via a new VM_SUSPEND_CPU ioctl). Virtual CPUs can be resumed via vm_resume_cpu() (VM_RESUME_CPU ioctl). The debug server suspends virtual CPUs when it wishes them to stop executing in the guest (for example, when a debugger attaches to the server). The debug server can choose to resume only a subset of CPUs (for example, when single stepping) or it can choose to resume all CPUs. The debug server must explicitly mark a CPU as resumed via vm_resume_cpu() before the virtual CPU will successfully execute any guest instructions. Reviewed by: avg, grehan Tested on: Intel (jhb), AMD (avg) Differential Revision: https://reviews.freebsd.org/D14466
FreeBSD Source:
This is the top level of the FreeBSD source directory. This file
was last revised on:
FreeBSD
For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information).
The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7) and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html for more information, including setting make(1) variables.
The buildkernel
and installkernel
targets build and install
the kernel and the modules (see below). Please see the top of
the Makefile in this directory for more information on the
standard build targets and compile-time flags.
Building a kernel is a somewhat more involved process. See build(7), config(8), and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information.
Note: If you want to build and install the kernel with the
buildkernel
and installkernel
targets, you might need to build
world before. More information is available in the handbook.
The kernel configuration files reside in the sys/<arch>/conf
sub-directory. GENERIC is the default configuration used in release builds.
NOTES contains entries and documentation for all possible
devices, not just those commonly used.
Source Roadmap:
bin System/user commands.
cddl Various commands and libraries under the Common Development
and Distribution License.
contrib Packages contributed by 3rd parties.
crypto Cryptography stuff (see crypto/README).
etc Template files for /etc.
gnu Various commands and libraries under the GNU Public License.
Please see gnu/COPYING* for more information.
include System include files.
kerberos5 Kerberos5 (Heimdal) package.
lib System libraries.
libexec System daemons.
release Release building Makefile & associated tools.
rescue Build system for statically linked /rescue utilities.
sbin System commands.
secure Cryptographic libraries and commands.
share Shared resources.
stand Boot loader sources.
sys Kernel sources.
tests Regression tests which can be run by Kyua. See tests/README
for additional information.
tools Utilities for regression testing and miscellaneous tasks.
usr.bin User commands.
usr.sbin System administration commands.
For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see:
https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/current-stable.html