65eefbe422
Currently most of the debug registers are not saved and restored during VM transitions allowing guest and host debug register values to leak into the opposite context. One result is that hardware watchpoints do not work reliably within a guest under VT-x. Due to differences in SVM and VT-x, slightly different approaches are used. For VT-x: - Enable debug register save/restore for VM entry/exit in the VMCS for DR7 and MSR_DEBUGCTL. - Explicitly save DR0-3,6 of the guest. - Explicitly save DR0-3,6-7, MSR_DEBUGCTL, and the trap flag from %rflags for the host. Note that because DR6 is "software" managed and not stored in the VMCS a kernel debugger which single steps through VM entry could corrupt the guest DR6 (since a single step trap taken after loading the guest DR6 could alter the DR6 register). To avoid this, explicitly disable single-stepping via the trace flag before loading the guest DR6. A determined debugger could still defeat this by setting a breakpoint after the guest DR6 was loaded and then single-stepping. For SVM: - Enable debug register caching in the VMCB for DR6/DR7. - Explicitly save DR0-3 of the guest. - Explicitly save DR0-3,6-7, and MSR_DEBUGCTL for the host. Since SVM saves the guest DR6 in the VMCB, the race with single-stepping described for VT-x does not exist. For both platforms, expose all of the guest DRx values via --get-drX and --set-drX flags to bhyvectl. Discussed with: avg, grehan Tested by: avg (SVM), myself (VT-x) MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D13229 |
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| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| stand | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| .gitattributes | ||
| .gitignore | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.libcompat | ||
| Makefile.sys.inc | ||
| ObsoleteFiles.inc | ||
| README | ||
| README.md | ||
| UPDATING | ||
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