cd377eb369
This commit adds a new debug server to bhyve. Unlike the existing -g option which provides an efficient connection to a debug server running in the guest OS, this debug server permits inspection and control of the guest from within the hypervisor itself without requiring any cooperation from the guest. It is similar to the debug server provided by qemu. To avoid conflicting with the existing -g option, a new -G option has been added that accepts a TCP port. An IPv4 socket is bound to this port and listens for connections from debuggers. In addition, if the port begins with the character 'w', the hypervisor will pause the guest at the first instruction until a debugger attaches and explicitly continues the guest. Note that only a single debugger can attach to a guest at a time. Virtual CPUs are exposed to the remote debugger as threads. General purpose register values can be read for each virtual CPU. Other registers cannot currently be read, and no register values can be changed by the debugger. The remote debugger can read guest memory but not write to guest memory. To facilitate source-level debugging of the guest, memory addresses from the debugger are treated as virtual addresses (rather than physical addresses) and are resolved to a physical address using the active virtual address translation of the current virtual CPU. Memory reads should honor memory mapped I/O regions, though the debug server does not attempt to honor any alignment or size constraints when accessing MMIO. The debug server provides limited support for controlling the guest. The guest is suspended when a debugger is attached and resumes when a debugger detaches. A debugger can suspend a guest by sending a Ctrl-C request (e.g. via Ctrl-C in GDB). A debugger can also continue a suspended guest while remaining attached. Breakpoints are not yet supported. Single stepping is supported on Intel CPUs that support MTRAP VM exits, but is not available on other systems. While the current debug server has limited functionality, it should at least be usable for basic debugging now. It is also a useful checkpoint to serve as a base for adding additional features. Reviewed by: grehan Differential Revision: https://reviews.freebsd.org/D15022
66 lines
2.2 KiB
C
66 lines
2.2 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2012 NetApp, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _MEM_H_
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#define _MEM_H_
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#include <sys/linker_set.h>
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struct vmctx;
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typedef int (*mem_func_t)(struct vmctx *ctx, int vcpu, int dir, uint64_t addr,
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int size, uint64_t *val, void *arg1, long arg2);
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struct mem_range {
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const char *name;
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int flags;
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mem_func_t handler;
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void *arg1;
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long arg2;
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uint64_t base;
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uint64_t size;
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};
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#define MEM_F_READ 0x1
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#define MEM_F_WRITE 0x2
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#define MEM_F_RW 0x3
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#define MEM_F_IMMUTABLE 0x4 /* mem_range cannot be unregistered */
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void init_mem(void);
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int emulate_mem(struct vmctx *, int vcpu, uint64_t paddr, struct vie *vie,
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struct vm_guest_paging *paging);
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int read_mem(struct vmctx *ctx, int vcpu, uint64_t gpa, uint64_t *rval,
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int size);
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int register_mem(struct mem_range *memp);
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int register_mem_fallback(struct mem_range *memp);
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int unregister_mem(struct mem_range *memp);
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#endif /* _MEM_H_ */
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