freebsd-dev/usr.sbin/bhyve/gdb.h
John Baldwin cbd03a9df2 Support software breakpoints in the debug server on Intel CPUs.
- Allow the userland hypervisor to intercept breakpoint exceptions
  (BP#) in the guest.  A new capability (VM_CAP_BPT_EXIT) is used to
  enable this feature.  These exceptions are reported to userland via
  a new VM_EXITCODE_BPT that includes the length of the original
  breakpoint instruction.  If userland wishes to pass the exception
  through to the guest, it must be explicitly re-injected via
  vm_inject_exception().

- Export VMCS_ENTRY_INST_LENGTH as a VM_REG_GUEST_ENTRY_INST_LENGTH
  pseudo-register.  Injecting a BP# on Intel requires setting this to
  the length of the breakpoint instruction.  AMD SVM currently ignores
  writes to this register (but reports success) and fails to read it.

- Rework the per-vCPU state tracked by the debug server.  Rather than
  a single 'stepping_vcpu' global, add a structure for each vCPU that
  tracks state about that vCPU ('stepping', 'stepped', and
  'hit_swbreak').  A global 'stopped_vcpu' tracks which vCPU is
  currently reporting an event.  Event handlers for MTRAP and
  breakpoint exits loop until the associated event is reported to the
  debugger.

  Breakpoint events are discarded if the breakpoint is not present
  when a vCPU resumes in the breakpoint handler to retry submitting
  the breakpoint event.

- Maintain a linked-list of active breakpoints in response to the GDB
  'Z0' and 'z0' packets.

Reviewed by:	markj (earlier version)
MFC after:	2 months
Differential Revision:	https://reviews.freebsd.org/D20309
2019-12-13 19:21:58 +00:00

40 lines
1.6 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2017 John H. Baldwin <jhb@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef __GDB_H__
#define __GDB_H__
void gdb_cpu_add(int vcpu);
void gdb_cpu_breakpoint(int vcpu, struct vm_exit *vmexit);
void gdb_cpu_mtrap(int vcpu);
void gdb_cpu_suspend(int vcpu);
void init_gdb(struct vmctx *ctx, int sport, bool wait);
#endif /* !__GDB_H__ */