This replaces the 'struct vm, int vcpuid' tuple passed to most API calls and is similar to the changes recently made in vmm(4) in the kernel. struct vcpu is an opaque type managed by libvmmapi. For now it stores a pointer to the VM context and an integer id. As an immediate effect this removes the divergence between the kernel and userland for the instruction emulation code introduced by the recent vmm(4) changes. Since this is a major change to the vmmapi API, bump VMMAPI_VERSION to 0x200 (2.0) and the shared library major version. While here (and since the major version is bumped), remove unused vcpu argument from vm_setup_pptdev_msi*(). Add new functions vm_suspend_all_cpus() and vm_resume_all_cpus() for use by the debug server. The underyling ioctl (which uses a vcpuid of -1) remains unchanged, but the userlevel API now uses separate functions for global CPU suspend/resume. Reviewed by: corvink, markj Differential Revision: https://reviews.freebsd.org/D38124
1918 lines
39 KiB
C
1918 lines
39 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2017-2018 John H. Baldwin <jhb@FreeBSD.org>
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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 THE AUTHOR AND CONTRIBUTORS ``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 THE AUTHOR 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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#ifndef WITHOUT_CAPSICUM
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#include <sys/capsicum.h>
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#endif
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#include <sys/endian.h>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <sys/queue.h>
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#include <sys/socket.h>
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#include <machine/atomic.h>
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#include <machine/specialreg.h>
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#include <machine/vmm.h>
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#include <netinet/in.h>
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#include <assert.h>
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#ifndef WITHOUT_CAPSICUM
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#include <capsicum_helpers.h>
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#endif
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <netdb.h>
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#include <pthread.h>
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#include <pthread_np.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sysexits.h>
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#include <unistd.h>
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#include <vmmapi.h>
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#include "bhyverun.h"
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#include "config.h"
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#include "gdb.h"
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#include "mem.h"
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#include "mevent.h"
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/*
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* GDB_SIGNAL_* numbers are part of the GDB remote protocol. Most stops
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* use SIGTRAP.
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*/
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#define GDB_SIGNAL_TRAP 5
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static void gdb_resume_vcpus(void);
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static void check_command(int fd);
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static struct mevent *read_event, *write_event;
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static cpuset_t vcpus_active, vcpus_suspended, vcpus_waiting;
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static pthread_mutex_t gdb_lock;
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static pthread_cond_t idle_vcpus;
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static bool first_stop, report_next_stop, swbreak_enabled;
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/*
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* An I/O buffer contains 'capacity' bytes of room at 'data'. For a
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* read buffer, 'start' is unused and 'len' contains the number of
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* valid bytes in the buffer. For a write buffer, 'start' is set to
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* the index of the next byte in 'data' to send, and 'len' contains
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* the remaining number of valid bytes to send.
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*/
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struct io_buffer {
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uint8_t *data;
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size_t capacity;
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size_t start;
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size_t len;
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};
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struct breakpoint {
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uint64_t gpa;
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uint8_t shadow_inst;
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TAILQ_ENTRY(breakpoint) link;
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};
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/*
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* When a vCPU stops to due to an event that should be reported to the
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* debugger, information about the event is stored in this structure.
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* The vCPU thread then sets 'stopped_vcpu' if it is not already set
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* and stops other vCPUs so the event can be reported. The
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* report_stop() function reports the event for the 'stopped_vcpu'
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* vCPU. When the debugger resumes execution via continue or step,
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* the event for 'stopped_vcpu' is cleared. vCPUs will loop in their
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* event handlers until the associated event is reported or disabled.
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*
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* An idle vCPU will have all of the boolean fields set to false.
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*
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* When a vCPU is stepped, 'stepping' is set to true when the vCPU is
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* released to execute the stepped instruction. When the vCPU reports
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* the stepping trap, 'stepped' is set.
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*
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* When a vCPU hits a breakpoint set by the debug server,
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* 'hit_swbreak' is set to true.
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*/
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struct vcpu_state {
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bool stepping;
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bool stepped;
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bool hit_swbreak;
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};
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static struct io_buffer cur_comm, cur_resp;
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static uint8_t cur_csum;
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static struct vmctx *ctx;
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static int cur_fd = -1;
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static TAILQ_HEAD(, breakpoint) breakpoints;
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static struct vcpu_state *vcpu_state;
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static struct vcpu **vcpus;
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static int cur_vcpu, stopped_vcpu;
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static bool gdb_active = false;
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static const int gdb_regset[] = {
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VM_REG_GUEST_RAX,
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VM_REG_GUEST_RBX,
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VM_REG_GUEST_RCX,
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VM_REG_GUEST_RDX,
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VM_REG_GUEST_RSI,
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VM_REG_GUEST_RDI,
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VM_REG_GUEST_RBP,
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VM_REG_GUEST_RSP,
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VM_REG_GUEST_R8,
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VM_REG_GUEST_R9,
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VM_REG_GUEST_R10,
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VM_REG_GUEST_R11,
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VM_REG_GUEST_R12,
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VM_REG_GUEST_R13,
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VM_REG_GUEST_R14,
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VM_REG_GUEST_R15,
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VM_REG_GUEST_RIP,
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VM_REG_GUEST_RFLAGS,
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VM_REG_GUEST_CS,
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VM_REG_GUEST_SS,
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VM_REG_GUEST_DS,
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VM_REG_GUEST_ES,
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VM_REG_GUEST_FS,
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VM_REG_GUEST_GS
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};
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static const int gdb_regsize[] = {
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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8,
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4,
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4,
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4,
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4,
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4,
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4,
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4
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};
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#ifdef GDB_LOG
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#include <stdarg.h>
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#include <stdio.h>
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static void __printflike(1, 2)
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debug(const char *fmt, ...)
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{
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static FILE *logfile;
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va_list ap;
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if (logfile == NULL) {
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logfile = fopen("/tmp/bhyve_gdb.log", "w");
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if (logfile == NULL)
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return;
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#ifndef WITHOUT_CAPSICUM
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if (caph_limit_stream(fileno(logfile), CAPH_WRITE) == -1) {
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fclose(logfile);
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logfile = NULL;
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return;
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}
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#endif
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setlinebuf(logfile);
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}
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va_start(ap, fmt);
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vfprintf(logfile, fmt, ap);
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va_end(ap);
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}
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#else
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#define debug(...)
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#endif
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static void remove_all_sw_breakpoints(void);
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static int
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guest_paging_info(struct vcpu *vcpu, struct vm_guest_paging *paging)
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{
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uint64_t regs[4];
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const int regset[4] = {
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VM_REG_GUEST_CR0,
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VM_REG_GUEST_CR3,
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VM_REG_GUEST_CR4,
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VM_REG_GUEST_EFER
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};
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if (vm_get_register_set(vcpu, nitems(regset), regset, regs) == -1)
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return (-1);
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/*
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* For the debugger, always pretend to be the kernel (CPL 0),
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* and if long-mode is enabled, always parse addresses as if
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* in 64-bit mode.
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*/
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paging->cr3 = regs[1];
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paging->cpl = 0;
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if (regs[3] & EFER_LMA)
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paging->cpu_mode = CPU_MODE_64BIT;
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else if (regs[0] & CR0_PE)
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paging->cpu_mode = CPU_MODE_PROTECTED;
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else
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paging->cpu_mode = CPU_MODE_REAL;
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if (!(regs[0] & CR0_PG))
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paging->paging_mode = PAGING_MODE_FLAT;
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else if (!(regs[2] & CR4_PAE))
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paging->paging_mode = PAGING_MODE_32;
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else if (regs[3] & EFER_LME)
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paging->paging_mode = (regs[2] & CR4_LA57) ?
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PAGING_MODE_64_LA57 : PAGING_MODE_64;
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else
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paging->paging_mode = PAGING_MODE_PAE;
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return (0);
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}
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/*
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* Map a guest virtual address to a physical address (for a given vcpu).
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* If a guest virtual address is valid, return 1. If the address is
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* not valid, return 0. If an error occurs obtaining the mapping,
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* return -1.
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*/
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static int
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guest_vaddr2paddr(struct vcpu *vcpu, uint64_t vaddr, uint64_t *paddr)
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{
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struct vm_guest_paging paging;
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int fault;
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if (guest_paging_info(vcpu, &paging) == -1)
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return (-1);
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/*
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* Always use PROT_READ. We really care if the VA is
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* accessible, not if the current vCPU can write.
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*/
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if (vm_gla2gpa_nofault(vcpu, &paging, vaddr, PROT_READ, paddr,
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&fault) == -1)
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return (-1);
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if (fault)
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return (0);
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return (1);
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}
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static void
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io_buffer_reset(struct io_buffer *io)
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{
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io->start = 0;
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io->len = 0;
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}
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/* Available room for adding data. */
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static size_t
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io_buffer_avail(struct io_buffer *io)
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{
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return (io->capacity - (io->start + io->len));
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}
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static uint8_t *
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io_buffer_head(struct io_buffer *io)
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{
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return (io->data + io->start);
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}
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static uint8_t *
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io_buffer_tail(struct io_buffer *io)
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{
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return (io->data + io->start + io->len);
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}
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static void
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io_buffer_advance(struct io_buffer *io, size_t amount)
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{
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assert(amount <= io->len);
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io->start += amount;
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io->len -= amount;
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}
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static void
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io_buffer_consume(struct io_buffer *io, size_t amount)
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{
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io_buffer_advance(io, amount);
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if (io->len == 0) {
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io->start = 0;
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return;
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}
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/*
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* XXX: Consider making this move optional and compacting on a
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* future read() before realloc().
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*/
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memmove(io->data, io_buffer_head(io), io->len);
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io->start = 0;
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}
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static void
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io_buffer_grow(struct io_buffer *io, size_t newsize)
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{
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uint8_t *new_data;
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size_t avail, new_cap;
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avail = io_buffer_avail(io);
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if (newsize <= avail)
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return;
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new_cap = io->capacity + (newsize - avail);
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new_data = realloc(io->data, new_cap);
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if (new_data == NULL)
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err(1, "Failed to grow GDB I/O buffer");
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io->data = new_data;
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io->capacity = new_cap;
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}
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static bool
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response_pending(void)
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{
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if (cur_resp.start == 0 && cur_resp.len == 0)
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return (false);
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if (cur_resp.start + cur_resp.len == 1 && cur_resp.data[0] == '+')
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return (false);
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return (true);
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}
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static void
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close_connection(void)
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{
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/*
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* XXX: This triggers a warning because mevent does the close
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* before the EV_DELETE.
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*/
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pthread_mutex_lock(&gdb_lock);
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mevent_delete(write_event);
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mevent_delete_close(read_event);
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write_event = NULL;
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read_event = NULL;
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io_buffer_reset(&cur_comm);
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io_buffer_reset(&cur_resp);
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cur_fd = -1;
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remove_all_sw_breakpoints();
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/* Clear any pending events. */
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memset(vcpu_state, 0, guest_ncpus * sizeof(*vcpu_state));
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/* Resume any stopped vCPUs. */
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gdb_resume_vcpus();
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pthread_mutex_unlock(&gdb_lock);
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}
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static uint8_t
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hex_digit(uint8_t nibble)
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{
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if (nibble <= 9)
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return (nibble + '0');
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else
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return (nibble + 'a' - 10);
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}
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static uint8_t
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parse_digit(uint8_t v)
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{
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if (v >= '0' && v <= '9')
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return (v - '0');
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if (v >= 'a' && v <= 'f')
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return (v - 'a' + 10);
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if (v >= 'A' && v <= 'F')
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return (v - 'A' + 10);
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return (0xF);
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}
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/* Parses big-endian hexadecimal. */
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static uintmax_t
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parse_integer(const uint8_t *p, size_t len)
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{
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uintmax_t v;
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v = 0;
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while (len > 0) {
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v <<= 4;
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v |= parse_digit(*p);
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p++;
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len--;
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}
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return (v);
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}
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static uint8_t
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parse_byte(const uint8_t *p)
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{
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return (parse_digit(p[0]) << 4 | parse_digit(p[1]));
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}
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static void
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send_pending_data(int fd)
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{
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ssize_t nwritten;
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if (cur_resp.len == 0) {
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mevent_disable(write_event);
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return;
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}
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nwritten = write(fd, io_buffer_head(&cur_resp), cur_resp.len);
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if (nwritten == -1) {
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warn("Write to GDB socket failed");
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close_connection();
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} else {
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io_buffer_advance(&cur_resp, nwritten);
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if (cur_resp.len == 0)
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mevent_disable(write_event);
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else
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mevent_enable(write_event);
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}
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}
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|
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/* Append a single character to the output buffer. */
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static void
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send_char(uint8_t data)
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{
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io_buffer_grow(&cur_resp, 1);
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*io_buffer_tail(&cur_resp) = data;
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cur_resp.len++;
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}
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|
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/* Append an array of bytes to the output buffer. */
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static void
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send_data(const uint8_t *data, size_t len)
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{
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io_buffer_grow(&cur_resp, len);
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memcpy(io_buffer_tail(&cur_resp), data, len);
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cur_resp.len += len;
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}
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static void
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format_byte(uint8_t v, uint8_t *buf)
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|
{
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buf[0] = hex_digit(v >> 4);
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buf[1] = hex_digit(v & 0xf);
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|
}
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|
|
/*
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|
* Append a single byte (formatted as two hex characters) to the
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|
* output buffer.
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|
*/
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|
static void
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send_byte(uint8_t v)
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{
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uint8_t buf[2];
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format_byte(v, buf);
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send_data(buf, sizeof(buf));
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}
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static void
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start_packet(void)
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{
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send_char('$');
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cur_csum = 0;
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}
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static void
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finish_packet(void)
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{
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send_char('#');
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send_byte(cur_csum);
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debug("-> %.*s\n", (int)cur_resp.len, io_buffer_head(&cur_resp));
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}
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/*
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|
* Append a single character (for the packet payload) and update the
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* checksum.
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*/
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static void
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append_char(uint8_t v)
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{
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|
|
send_char(v);
|
|
cur_csum += v;
|
|
}
|
|
|
|
/*
|
|
* Append an array of bytes (for the packet payload) and update the
|
|
* checksum.
|
|
*/
|
|
static void
|
|
append_packet_data(const uint8_t *data, size_t len)
|
|
{
|
|
|
|
send_data(data, len);
|
|
while (len > 0) {
|
|
cur_csum += *data;
|
|
data++;
|
|
len--;
|
|
}
|
|
}
|
|
|
|
static void
|
|
append_string(const char *str)
|
|
{
|
|
|
|
append_packet_data(str, strlen(str));
|
|
}
|
|
|
|
static void
|
|
append_byte(uint8_t v)
|
|
{
|
|
uint8_t buf[2];
|
|
|
|
format_byte(v, buf);
|
|
append_packet_data(buf, sizeof(buf));
|
|
}
|
|
|
|
static void
|
|
append_unsigned_native(uintmax_t value, size_t len)
|
|
{
|
|
size_t i;
|
|
|
|
for (i = 0; i < len; i++) {
|
|
append_byte(value);
|
|
value >>= 8;
|
|
}
|
|
}
|
|
|
|
static void
|
|
append_unsigned_be(uintmax_t value, size_t len)
|
|
{
|
|
char buf[len * 2];
|
|
size_t i;
|
|
|
|
for (i = 0; i < len; i++) {
|
|
format_byte(value, buf + (len - i - 1) * 2);
|
|
value >>= 8;
|
|
}
|
|
append_packet_data(buf, sizeof(buf));
|
|
}
|
|
|
|
static void
|
|
append_integer(unsigned int value)
|
|
{
|
|
|
|
if (value == 0)
|
|
append_char('0');
|
|
else
|
|
append_unsigned_be(value, (fls(value) + 7) / 8);
|
|
}
|
|
|
|
static void
|
|
append_asciihex(const char *str)
|
|
{
|
|
|
|
while (*str != '\0') {
|
|
append_byte(*str);
|
|
str++;
|
|
}
|
|
}
|
|
|
|
static void
|
|
send_empty_response(void)
|
|
{
|
|
|
|
start_packet();
|
|
finish_packet();
|
|
}
|
|
|
|
static void
|
|
send_error(int error)
|
|
{
|
|
|
|
start_packet();
|
|
append_char('E');
|
|
append_byte(error);
|
|
finish_packet();
|
|
}
|
|
|
|
static void
|
|
send_ok(void)
|
|
{
|
|
|
|
start_packet();
|
|
append_string("OK");
|
|
finish_packet();
|
|
}
|
|
|
|
static int
|
|
parse_threadid(const uint8_t *data, size_t len)
|
|
{
|
|
|
|
if (len == 1 && *data == '0')
|
|
return (0);
|
|
if (len == 2 && memcmp(data, "-1", 2) == 0)
|
|
return (-1);
|
|
if (len == 0)
|
|
return (-2);
|
|
return (parse_integer(data, len));
|
|
}
|
|
|
|
/*
|
|
* Report the current stop event to the debugger. If the stop is due
|
|
* to an event triggered on a specific vCPU such as a breakpoint or
|
|
* stepping trap, stopped_vcpu will be set to the vCPU triggering the
|
|
* stop. If 'set_cur_vcpu' is true, then cur_vcpu will be updated to
|
|
* the reporting vCPU for vCPU events.
|
|
*/
|
|
static void
|
|
report_stop(bool set_cur_vcpu)
|
|
{
|
|
struct vcpu_state *vs;
|
|
|
|
start_packet();
|
|
if (stopped_vcpu == -1) {
|
|
append_char('S');
|
|
append_byte(GDB_SIGNAL_TRAP);
|
|
} else {
|
|
vs = &vcpu_state[stopped_vcpu];
|
|
if (set_cur_vcpu)
|
|
cur_vcpu = stopped_vcpu;
|
|
append_char('T');
|
|
append_byte(GDB_SIGNAL_TRAP);
|
|
append_string("thread:");
|
|
append_integer(stopped_vcpu + 1);
|
|
append_char(';');
|
|
if (vs->hit_swbreak) {
|
|
debug("$vCPU %d reporting swbreak\n", stopped_vcpu);
|
|
if (swbreak_enabled)
|
|
append_string("swbreak:;");
|
|
} else if (vs->stepped)
|
|
debug("$vCPU %d reporting step\n", stopped_vcpu);
|
|
else
|
|
debug("$vCPU %d reporting ???\n", stopped_vcpu);
|
|
}
|
|
finish_packet();
|
|
report_next_stop = false;
|
|
}
|
|
|
|
/*
|
|
* If this stop is due to a vCPU event, clear that event to mark it as
|
|
* acknowledged.
|
|
*/
|
|
static void
|
|
discard_stop(void)
|
|
{
|
|
struct vcpu_state *vs;
|
|
|
|
if (stopped_vcpu != -1) {
|
|
vs = &vcpu_state[stopped_vcpu];
|
|
vs->hit_swbreak = false;
|
|
vs->stepped = false;
|
|
stopped_vcpu = -1;
|
|
}
|
|
report_next_stop = true;
|
|
}
|
|
|
|
static void
|
|
gdb_finish_suspend_vcpus(void)
|
|
{
|
|
|
|
if (first_stop) {
|
|
first_stop = false;
|
|
stopped_vcpu = -1;
|
|
} else if (report_next_stop) {
|
|
assert(!response_pending());
|
|
report_stop(true);
|
|
send_pending_data(cur_fd);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vCPU threads invoke this function whenever the vCPU enters the
|
|
* debug server to pause or report an event. vCPU threads wait here
|
|
* as long as the debug server keeps them suspended.
|
|
*/
|
|
static void
|
|
_gdb_cpu_suspend(struct vcpu *vcpu, bool report_stop)
|
|
{
|
|
int vcpuid = vcpu_id(vcpu);
|
|
|
|
debug("$vCPU %d suspending\n", vcpuid);
|
|
CPU_SET(vcpuid, &vcpus_waiting);
|
|
if (report_stop && CPU_CMP(&vcpus_waiting, &vcpus_suspended) == 0)
|
|
gdb_finish_suspend_vcpus();
|
|
while (CPU_ISSET(vcpuid, &vcpus_suspended))
|
|
pthread_cond_wait(&idle_vcpus, &gdb_lock);
|
|
CPU_CLR(vcpuid, &vcpus_waiting);
|
|
debug("$vCPU %d resuming\n", vcpuid);
|
|
}
|
|
|
|
/*
|
|
* Invoked at the start of a vCPU thread's execution to inform the
|
|
* debug server about the new thread.
|
|
*/
|
|
void
|
|
gdb_cpu_add(struct vcpu *vcpu)
|
|
{
|
|
int vcpuid;
|
|
|
|
if (!gdb_active)
|
|
return;
|
|
vcpuid = vcpu_id(vcpu);
|
|
debug("$vCPU %d starting\n", vcpuid);
|
|
pthread_mutex_lock(&gdb_lock);
|
|
assert(vcpuid < guest_ncpus);
|
|
assert(vcpus[vcpuid] == NULL);
|
|
vcpus[vcpuid] = vcpu;
|
|
CPU_SET(vcpuid, &vcpus_active);
|
|
if (!TAILQ_EMPTY(&breakpoints)) {
|
|
vm_set_capability(vcpu, VM_CAP_BPT_EXIT, 1);
|
|
debug("$vCPU %d enabled breakpoint exits\n", vcpu);
|
|
}
|
|
|
|
/*
|
|
* If a vcpu is added while vcpus are stopped, suspend the new
|
|
* vcpu so that it will pop back out with a debug exit before
|
|
* executing the first instruction.
|
|
*/
|
|
if (!CPU_EMPTY(&vcpus_suspended)) {
|
|
CPU_SET(vcpuid, &vcpus_suspended);
|
|
_gdb_cpu_suspend(vcpu, false);
|
|
}
|
|
pthread_mutex_unlock(&gdb_lock);
|
|
}
|
|
|
|
/*
|
|
* Invoked by vCPU before resuming execution. This enables stepping
|
|
* if the vCPU is marked as stepping.
|
|
*/
|
|
static void
|
|
gdb_cpu_resume(struct vcpu *vcpu)
|
|
{
|
|
struct vcpu_state *vs;
|
|
int error;
|
|
|
|
vs = &vcpu_state[vcpu_id(vcpu)];
|
|
|
|
/*
|
|
* Any pending event should already be reported before
|
|
* resuming.
|
|
*/
|
|
assert(vs->hit_swbreak == false);
|
|
assert(vs->stepped == false);
|
|
if (vs->stepping) {
|
|
error = vm_set_capability(vcpu, VM_CAP_MTRAP_EXIT, 1);
|
|
assert(error == 0);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Handler for VM_EXITCODE_DEBUG used to suspend a vCPU when the guest
|
|
* has been suspended due to an event on different vCPU or in response
|
|
* to a guest-wide suspend such as Ctrl-C or the stop on attach.
|
|
*/
|
|
void
|
|
gdb_cpu_suspend(struct vcpu *vcpu)
|
|
{
|
|
|
|
if (!gdb_active)
|
|
return;
|
|
pthread_mutex_lock(&gdb_lock);
|
|
_gdb_cpu_suspend(vcpu, true);
|
|
gdb_cpu_resume(vcpu);
|
|
pthread_mutex_unlock(&gdb_lock);
|
|
}
|
|
|
|
static void
|
|
gdb_suspend_vcpus(void)
|
|
{
|
|
|
|
assert(pthread_mutex_isowned_np(&gdb_lock));
|
|
debug("suspending all CPUs\n");
|
|
vcpus_suspended = vcpus_active;
|
|
vm_suspend_all_cpus(ctx);
|
|
if (CPU_CMP(&vcpus_waiting, &vcpus_suspended) == 0)
|
|
gdb_finish_suspend_vcpus();
|
|
}
|
|
|
|
/*
|
|
* Handler for VM_EXITCODE_MTRAP reported when a vCPU single-steps via
|
|
* the VT-x-specific MTRAP exit.
|
|
*/
|
|
void
|
|
gdb_cpu_mtrap(struct vcpu *vcpu)
|
|
{
|
|
struct vcpu_state *vs;
|
|
int vcpuid;
|
|
|
|
if (!gdb_active)
|
|
return;
|
|
vcpuid = vcpu_id(vcpu);
|
|
debug("$vCPU %d MTRAP\n", vcpuid);
|
|
pthread_mutex_lock(&gdb_lock);
|
|
vs = &vcpu_state[vcpuid];
|
|
if (vs->stepping) {
|
|
vs->stepping = false;
|
|
vs->stepped = true;
|
|
vm_set_capability(vcpu, VM_CAP_MTRAP_EXIT, 0);
|
|
while (vs->stepped) {
|
|
if (stopped_vcpu == -1) {
|
|
debug("$vCPU %d reporting step\n", vcpuid);
|
|
stopped_vcpu = vcpuid;
|
|
gdb_suspend_vcpus();
|
|
}
|
|
_gdb_cpu_suspend(vcpu, true);
|
|
}
|
|
gdb_cpu_resume(vcpu);
|
|
}
|
|
pthread_mutex_unlock(&gdb_lock);
|
|
}
|
|
|
|
static struct breakpoint *
|
|
find_breakpoint(uint64_t gpa)
|
|
{
|
|
struct breakpoint *bp;
|
|
|
|
TAILQ_FOREACH(bp, &breakpoints, link) {
|
|
if (bp->gpa == gpa)
|
|
return (bp);
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
void
|
|
gdb_cpu_breakpoint(struct vcpu *vcpu, struct vm_exit *vmexit)
|
|
{
|
|
struct breakpoint *bp;
|
|
struct vcpu_state *vs;
|
|
uint64_t gpa;
|
|
int error, vcpuid;
|
|
|
|
if (!gdb_active) {
|
|
fprintf(stderr, "vm_loop: unexpected VMEXIT_DEBUG\n");
|
|
exit(4);
|
|
}
|
|
vcpuid = vcpu_id(vcpu);
|
|
pthread_mutex_lock(&gdb_lock);
|
|
error = guest_vaddr2paddr(vcpu, vmexit->rip, &gpa);
|
|
assert(error == 1);
|
|
bp = find_breakpoint(gpa);
|
|
if (bp != NULL) {
|
|
vs = &vcpu_state[vcpuid];
|
|
assert(vs->stepping == false);
|
|
assert(vs->stepped == false);
|
|
assert(vs->hit_swbreak == false);
|
|
vs->hit_swbreak = true;
|
|
vm_set_register(vcpu, VM_REG_GUEST_RIP, vmexit->rip);
|
|
for (;;) {
|
|
if (stopped_vcpu == -1) {
|
|
debug("$vCPU %d reporting breakpoint at rip %#lx\n",
|
|
vcpuid, vmexit->rip);
|
|
stopped_vcpu = vcpuid;
|
|
gdb_suspend_vcpus();
|
|
}
|
|
_gdb_cpu_suspend(vcpu, true);
|
|
if (!vs->hit_swbreak) {
|
|
/* Breakpoint reported. */
|
|
break;
|
|
}
|
|
bp = find_breakpoint(gpa);
|
|
if (bp == NULL) {
|
|
/* Breakpoint was removed. */
|
|
vs->hit_swbreak = false;
|
|
break;
|
|
}
|
|
}
|
|
gdb_cpu_resume(vcpu);
|
|
} else {
|
|
debug("$vCPU %d injecting breakpoint at rip %#lx\n", vcpuid,
|
|
vmexit->rip);
|
|
error = vm_set_register(vcpu, VM_REG_GUEST_ENTRY_INST_LENGTH,
|
|
vmexit->u.bpt.inst_length);
|
|
assert(error == 0);
|
|
error = vm_inject_exception(vcpu, IDT_BP, 0, 0, 0);
|
|
assert(error == 0);
|
|
}
|
|
pthread_mutex_unlock(&gdb_lock);
|
|
}
|
|
|
|
static bool
|
|
gdb_step_vcpu(struct vcpu *vcpu)
|
|
{
|
|
int error, val, vcpuid;
|
|
|
|
vcpuid = vcpu_id(vcpu);
|
|
debug("$vCPU %d step\n", vcpuid);
|
|
error = vm_get_capability(vcpu, VM_CAP_MTRAP_EXIT, &val);
|
|
if (error < 0)
|
|
return (false);
|
|
|
|
discard_stop();
|
|
vcpu_state[vcpuid].stepping = true;
|
|
vm_resume_cpu(vcpu);
|
|
CPU_CLR(vcpuid, &vcpus_suspended);
|
|
pthread_cond_broadcast(&idle_vcpus);
|
|
return (true);
|
|
}
|
|
|
|
static void
|
|
gdb_resume_vcpus(void)
|
|
{
|
|
|
|
assert(pthread_mutex_isowned_np(&gdb_lock));
|
|
vm_resume_all_cpus(ctx);
|
|
debug("resuming all CPUs\n");
|
|
CPU_ZERO(&vcpus_suspended);
|
|
pthread_cond_broadcast(&idle_vcpus);
|
|
}
|
|
|
|
static void
|
|
gdb_read_regs(void)
|
|
{
|
|
uint64_t regvals[nitems(gdb_regset)];
|
|
|
|
if (vm_get_register_set(vcpus[cur_vcpu], nitems(gdb_regset),
|
|
gdb_regset, regvals) == -1) {
|
|
send_error(errno);
|
|
return;
|
|
}
|
|
start_packet();
|
|
for (size_t i = 0; i < nitems(regvals); i++)
|
|
append_unsigned_native(regvals[i], gdb_regsize[i]);
|
|
finish_packet();
|
|
}
|
|
|
|
static void
|
|
gdb_read_mem(const uint8_t *data, size_t len)
|
|
{
|
|
uint64_t gpa, gva, val;
|
|
uint8_t *cp;
|
|
size_t resid, todo, bytes;
|
|
bool started;
|
|
int error;
|
|
|
|
/* Skip 'm' */
|
|
data += 1;
|
|
len -= 1;
|
|
|
|
/* Parse and consume address. */
|
|
cp = memchr(data, ',', len);
|
|
if (cp == NULL || cp == data) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
gva = parse_integer(data, cp - data);
|
|
len -= (cp - data) + 1;
|
|
data += (cp - data) + 1;
|
|
|
|
/* Parse length. */
|
|
resid = parse_integer(data, len);
|
|
|
|
started = false;
|
|
while (resid > 0) {
|
|
error = guest_vaddr2paddr(vcpus[cur_vcpu], gva, &gpa);
|
|
if (error == -1) {
|
|
if (started)
|
|
finish_packet();
|
|
else
|
|
send_error(errno);
|
|
return;
|
|
}
|
|
if (error == 0) {
|
|
if (started)
|
|
finish_packet();
|
|
else
|
|
send_error(EFAULT);
|
|
return;
|
|
}
|
|
|
|
/* Read bytes from current page. */
|
|
todo = getpagesize() - gpa % getpagesize();
|
|
if (todo > resid)
|
|
todo = resid;
|
|
|
|
cp = paddr_guest2host(ctx, gpa, todo);
|
|
if (cp != NULL) {
|
|
/*
|
|
* If this page is guest RAM, read it a byte
|
|
* at a time.
|
|
*/
|
|
if (!started) {
|
|
start_packet();
|
|
started = true;
|
|
}
|
|
while (todo > 0) {
|
|
append_byte(*cp);
|
|
cp++;
|
|
gpa++;
|
|
gva++;
|
|
resid--;
|
|
todo--;
|
|
}
|
|
} else {
|
|
/*
|
|
* If this page isn't guest RAM, try to handle
|
|
* it via MMIO. For MMIO requests, use
|
|
* aligned reads of words when possible.
|
|
*/
|
|
while (todo > 0) {
|
|
if (gpa & 1 || todo == 1)
|
|
bytes = 1;
|
|
else if (gpa & 2 || todo == 2)
|
|
bytes = 2;
|
|
else
|
|
bytes = 4;
|
|
error = read_mem(vcpus[cur_vcpu], gpa, &val,
|
|
bytes);
|
|
if (error == 0) {
|
|
if (!started) {
|
|
start_packet();
|
|
started = true;
|
|
}
|
|
gpa += bytes;
|
|
gva += bytes;
|
|
resid -= bytes;
|
|
todo -= bytes;
|
|
while (bytes > 0) {
|
|
append_byte(val);
|
|
val >>= 8;
|
|
bytes--;
|
|
}
|
|
} else {
|
|
if (started)
|
|
finish_packet();
|
|
else
|
|
send_error(EFAULT);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
assert(resid == 0 || gpa % getpagesize() == 0);
|
|
}
|
|
if (!started)
|
|
start_packet();
|
|
finish_packet();
|
|
}
|
|
|
|
static void
|
|
gdb_write_mem(const uint8_t *data, size_t len)
|
|
{
|
|
uint64_t gpa, gva, val;
|
|
uint8_t *cp;
|
|
size_t resid, todo, bytes;
|
|
int error;
|
|
|
|
/* Skip 'M' */
|
|
data += 1;
|
|
len -= 1;
|
|
|
|
/* Parse and consume address. */
|
|
cp = memchr(data, ',', len);
|
|
if (cp == NULL || cp == data) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
gva = parse_integer(data, cp - data);
|
|
len -= (cp - data) + 1;
|
|
data += (cp - data) + 1;
|
|
|
|
/* Parse and consume length. */
|
|
cp = memchr(data, ':', len);
|
|
if (cp == NULL || cp == data) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
resid = parse_integer(data, cp - data);
|
|
len -= (cp - data) + 1;
|
|
data += (cp - data) + 1;
|
|
|
|
/* Verify the available bytes match the length. */
|
|
if (len != resid * 2) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
|
|
while (resid > 0) {
|
|
error = guest_vaddr2paddr(vcpus[cur_vcpu], gva, &gpa);
|
|
if (error == -1) {
|
|
send_error(errno);
|
|
return;
|
|
}
|
|
if (error == 0) {
|
|
send_error(EFAULT);
|
|
return;
|
|
}
|
|
|
|
/* Write bytes to current page. */
|
|
todo = getpagesize() - gpa % getpagesize();
|
|
if (todo > resid)
|
|
todo = resid;
|
|
|
|
cp = paddr_guest2host(ctx, gpa, todo);
|
|
if (cp != NULL) {
|
|
/*
|
|
* If this page is guest RAM, write it a byte
|
|
* at a time.
|
|
*/
|
|
while (todo > 0) {
|
|
assert(len >= 2);
|
|
*cp = parse_byte(data);
|
|
data += 2;
|
|
len -= 2;
|
|
cp++;
|
|
gpa++;
|
|
gva++;
|
|
resid--;
|
|
todo--;
|
|
}
|
|
} else {
|
|
/*
|
|
* If this page isn't guest RAM, try to handle
|
|
* it via MMIO. For MMIO requests, use
|
|
* aligned writes of words when possible.
|
|
*/
|
|
while (todo > 0) {
|
|
if (gpa & 1 || todo == 1) {
|
|
bytes = 1;
|
|
val = parse_byte(data);
|
|
} else if (gpa & 2 || todo == 2) {
|
|
bytes = 2;
|
|
val = be16toh(parse_integer(data, 4));
|
|
} else {
|
|
bytes = 4;
|
|
val = be32toh(parse_integer(data, 8));
|
|
}
|
|
error = write_mem(vcpus[cur_vcpu], gpa, val,
|
|
bytes);
|
|
if (error == 0) {
|
|
gpa += bytes;
|
|
gva += bytes;
|
|
resid -= bytes;
|
|
todo -= bytes;
|
|
data += 2 * bytes;
|
|
len -= 2 * bytes;
|
|
} else {
|
|
send_error(EFAULT);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
assert(resid == 0 || gpa % getpagesize() == 0);
|
|
}
|
|
assert(len == 0);
|
|
send_ok();
|
|
}
|
|
|
|
static bool
|
|
set_breakpoint_caps(bool enable)
|
|
{
|
|
cpuset_t mask;
|
|
int vcpu;
|
|
|
|
mask = vcpus_active;
|
|
while (!CPU_EMPTY(&mask)) {
|
|
vcpu = CPU_FFS(&mask) - 1;
|
|
CPU_CLR(vcpu, &mask);
|
|
if (vm_set_capability(vcpus[vcpu], VM_CAP_BPT_EXIT,
|
|
enable ? 1 : 0) < 0)
|
|
return (false);
|
|
debug("$vCPU %d %sabled breakpoint exits\n", vcpu,
|
|
enable ? "en" : "dis");
|
|
}
|
|
return (true);
|
|
}
|
|
|
|
static void
|
|
remove_all_sw_breakpoints(void)
|
|
{
|
|
struct breakpoint *bp, *nbp;
|
|
uint8_t *cp;
|
|
|
|
if (TAILQ_EMPTY(&breakpoints))
|
|
return;
|
|
|
|
TAILQ_FOREACH_SAFE(bp, &breakpoints, link, nbp) {
|
|
debug("remove breakpoint at %#lx\n", bp->gpa);
|
|
cp = paddr_guest2host(ctx, bp->gpa, 1);
|
|
*cp = bp->shadow_inst;
|
|
TAILQ_REMOVE(&breakpoints, bp, link);
|
|
free(bp);
|
|
}
|
|
TAILQ_INIT(&breakpoints);
|
|
set_breakpoint_caps(false);
|
|
}
|
|
|
|
static void
|
|
update_sw_breakpoint(uint64_t gva, int kind, bool insert)
|
|
{
|
|
struct breakpoint *bp;
|
|
uint64_t gpa;
|
|
uint8_t *cp;
|
|
int error;
|
|
|
|
if (kind != 1) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
|
|
error = guest_vaddr2paddr(vcpus[cur_vcpu], gva, &gpa);
|
|
if (error == -1) {
|
|
send_error(errno);
|
|
return;
|
|
}
|
|
if (error == 0) {
|
|
send_error(EFAULT);
|
|
return;
|
|
}
|
|
|
|
cp = paddr_guest2host(ctx, gpa, 1);
|
|
|
|
/* Only permit breakpoints in guest RAM. */
|
|
if (cp == NULL) {
|
|
send_error(EFAULT);
|
|
return;
|
|
}
|
|
|
|
/* Find any existing breakpoint. */
|
|
bp = find_breakpoint(gpa);
|
|
|
|
/*
|
|
* Silently ignore duplicate commands since the protocol
|
|
* requires these packets to be idempotent.
|
|
*/
|
|
if (insert) {
|
|
if (bp == NULL) {
|
|
if (TAILQ_EMPTY(&breakpoints) &&
|
|
!set_breakpoint_caps(true)) {
|
|
send_empty_response();
|
|
return;
|
|
}
|
|
bp = malloc(sizeof(*bp));
|
|
bp->gpa = gpa;
|
|
bp->shadow_inst = *cp;
|
|
*cp = 0xcc; /* INT 3 */
|
|
TAILQ_INSERT_TAIL(&breakpoints, bp, link);
|
|
debug("new breakpoint at %#lx\n", gpa);
|
|
}
|
|
} else {
|
|
if (bp != NULL) {
|
|
debug("remove breakpoint at %#lx\n", gpa);
|
|
*cp = bp->shadow_inst;
|
|
TAILQ_REMOVE(&breakpoints, bp, link);
|
|
free(bp);
|
|
if (TAILQ_EMPTY(&breakpoints))
|
|
set_breakpoint_caps(false);
|
|
}
|
|
}
|
|
send_ok();
|
|
}
|
|
|
|
static void
|
|
parse_breakpoint(const uint8_t *data, size_t len)
|
|
{
|
|
uint64_t gva;
|
|
uint8_t *cp;
|
|
bool insert;
|
|
int kind, type;
|
|
|
|
insert = data[0] == 'Z';
|
|
|
|
/* Skip 'Z/z' */
|
|
data += 1;
|
|
len -= 1;
|
|
|
|
/* Parse and consume type. */
|
|
cp = memchr(data, ',', len);
|
|
if (cp == NULL || cp == data) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
type = parse_integer(data, cp - data);
|
|
len -= (cp - data) + 1;
|
|
data += (cp - data) + 1;
|
|
|
|
/* Parse and consume address. */
|
|
cp = memchr(data, ',', len);
|
|
if (cp == NULL || cp == data) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
gva = parse_integer(data, cp - data);
|
|
len -= (cp - data) + 1;
|
|
data += (cp - data) + 1;
|
|
|
|
/* Parse and consume kind. */
|
|
cp = memchr(data, ';', len);
|
|
if (cp == data) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
if (cp != NULL) {
|
|
/*
|
|
* We do not advertise support for either the
|
|
* ConditionalBreakpoints or BreakpointCommands
|
|
* features, so we should not be getting conditions or
|
|
* commands from the remote end.
|
|
*/
|
|
send_empty_response();
|
|
return;
|
|
}
|
|
kind = parse_integer(data, len);
|
|
data += len;
|
|
len = 0;
|
|
|
|
switch (type) {
|
|
case 0:
|
|
update_sw_breakpoint(gva, kind, insert);
|
|
break;
|
|
default:
|
|
send_empty_response();
|
|
break;
|
|
}
|
|
}
|
|
|
|
static bool
|
|
command_equals(const uint8_t *data, size_t len, const char *cmd)
|
|
{
|
|
|
|
if (strlen(cmd) > len)
|
|
return (false);
|
|
return (memcmp(data, cmd, strlen(cmd)) == 0);
|
|
}
|
|
|
|
static void
|
|
check_features(const uint8_t *data, size_t len)
|
|
{
|
|
char *feature, *next_feature, *str, *value;
|
|
bool supported;
|
|
|
|
str = malloc(len + 1);
|
|
memcpy(str, data, len);
|
|
str[len] = '\0';
|
|
next_feature = str;
|
|
|
|
while ((feature = strsep(&next_feature, ";")) != NULL) {
|
|
/*
|
|
* Null features shouldn't exist, but skip if they
|
|
* do.
|
|
*/
|
|
if (strcmp(feature, "") == 0)
|
|
continue;
|
|
|
|
/*
|
|
* Look for the value or supported / not supported
|
|
* flag.
|
|
*/
|
|
value = strchr(feature, '=');
|
|
if (value != NULL) {
|
|
*value = '\0';
|
|
value++;
|
|
supported = true;
|
|
} else {
|
|
value = feature + strlen(feature) - 1;
|
|
switch (*value) {
|
|
case '+':
|
|
supported = true;
|
|
break;
|
|
case '-':
|
|
supported = false;
|
|
break;
|
|
default:
|
|
/*
|
|
* This is really a protocol error,
|
|
* but we just ignore malformed
|
|
* features for ease of
|
|
* implementation.
|
|
*/
|
|
continue;
|
|
}
|
|
value = NULL;
|
|
}
|
|
|
|
if (strcmp(feature, "swbreak") == 0)
|
|
swbreak_enabled = supported;
|
|
}
|
|
free(str);
|
|
|
|
start_packet();
|
|
|
|
/* This is an arbitrary limit. */
|
|
append_string("PacketSize=4096");
|
|
append_string(";swbreak+");
|
|
finish_packet();
|
|
}
|
|
|
|
static void
|
|
gdb_query(const uint8_t *data, size_t len)
|
|
{
|
|
|
|
/*
|
|
* TODO:
|
|
* - qSearch
|
|
*/
|
|
if (command_equals(data, len, "qAttached")) {
|
|
start_packet();
|
|
append_char('1');
|
|
finish_packet();
|
|
} else if (command_equals(data, len, "qC")) {
|
|
start_packet();
|
|
append_string("QC");
|
|
append_integer(cur_vcpu + 1);
|
|
finish_packet();
|
|
} else if (command_equals(data, len, "qfThreadInfo")) {
|
|
cpuset_t mask;
|
|
bool first;
|
|
int vcpu;
|
|
|
|
if (CPU_EMPTY(&vcpus_active)) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
mask = vcpus_active;
|
|
start_packet();
|
|
append_char('m');
|
|
first = true;
|
|
while (!CPU_EMPTY(&mask)) {
|
|
vcpu = CPU_FFS(&mask) - 1;
|
|
CPU_CLR(vcpu, &mask);
|
|
if (first)
|
|
first = false;
|
|
else
|
|
append_char(',');
|
|
append_integer(vcpu + 1);
|
|
}
|
|
finish_packet();
|
|
} else if (command_equals(data, len, "qsThreadInfo")) {
|
|
start_packet();
|
|
append_char('l');
|
|
finish_packet();
|
|
} else if (command_equals(data, len, "qSupported")) {
|
|
data += strlen("qSupported");
|
|
len -= strlen("qSupported");
|
|
check_features(data, len);
|
|
} else if (command_equals(data, len, "qThreadExtraInfo")) {
|
|
char buf[16];
|
|
int tid;
|
|
|
|
data += strlen("qThreadExtraInfo");
|
|
len -= strlen("qThreadExtraInfo");
|
|
if (*data != ',') {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
tid = parse_threadid(data + 1, len - 1);
|
|
if (tid <= 0 || !CPU_ISSET(tid - 1, &vcpus_active)) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
|
|
snprintf(buf, sizeof(buf), "vCPU %d", tid - 1);
|
|
start_packet();
|
|
append_asciihex(buf);
|
|
finish_packet();
|
|
} else
|
|
send_empty_response();
|
|
}
|
|
|
|
static void
|
|
handle_command(const uint8_t *data, size_t len)
|
|
{
|
|
|
|
/* Reject packets with a sequence-id. */
|
|
if (len >= 3 && data[0] >= '0' && data[0] <= '9' &&
|
|
data[0] >= '0' && data[0] <= '9' && data[2] == ':') {
|
|
send_empty_response();
|
|
return;
|
|
}
|
|
|
|
switch (*data) {
|
|
case 'c':
|
|
if (len != 1) {
|
|
send_error(EINVAL);
|
|
break;
|
|
}
|
|
|
|
discard_stop();
|
|
gdb_resume_vcpus();
|
|
break;
|
|
case 'D':
|
|
send_ok();
|
|
|
|
/* TODO: Resume any stopped CPUs. */
|
|
break;
|
|
case 'g': {
|
|
gdb_read_regs();
|
|
break;
|
|
}
|
|
case 'H': {
|
|
int tid;
|
|
|
|
if (data[1] != 'g' && data[1] != 'c') {
|
|
send_error(EINVAL);
|
|
break;
|
|
}
|
|
tid = parse_threadid(data + 2, len - 2);
|
|
if (tid == -2) {
|
|
send_error(EINVAL);
|
|
break;
|
|
}
|
|
|
|
if (CPU_EMPTY(&vcpus_active)) {
|
|
send_error(EINVAL);
|
|
break;
|
|
}
|
|
if (tid == -1 || tid == 0)
|
|
cur_vcpu = CPU_FFS(&vcpus_active) - 1;
|
|
else if (CPU_ISSET(tid - 1, &vcpus_active))
|
|
cur_vcpu = tid - 1;
|
|
else {
|
|
send_error(EINVAL);
|
|
break;
|
|
}
|
|
send_ok();
|
|
break;
|
|
}
|
|
case 'm':
|
|
gdb_read_mem(data, len);
|
|
break;
|
|
case 'M':
|
|
gdb_write_mem(data, len);
|
|
break;
|
|
case 'T': {
|
|
int tid;
|
|
|
|
tid = parse_threadid(data + 1, len - 1);
|
|
if (tid <= 0 || !CPU_ISSET(tid - 1, &vcpus_active)) {
|
|
send_error(EINVAL);
|
|
return;
|
|
}
|
|
send_ok();
|
|
break;
|
|
}
|
|
case 'q':
|
|
gdb_query(data, len);
|
|
break;
|
|
case 's':
|
|
if (len != 1) {
|
|
send_error(EINVAL);
|
|
break;
|
|
}
|
|
|
|
/* Don't send a reply until a stop occurs. */
|
|
if (!gdb_step_vcpu(vcpus[cur_vcpu])) {
|
|
send_error(EOPNOTSUPP);
|
|
break;
|
|
}
|
|
break;
|
|
case 'z':
|
|
case 'Z':
|
|
parse_breakpoint(data, len);
|
|
break;
|
|
case '?':
|
|
report_stop(false);
|
|
break;
|
|
case 'G': /* TODO */
|
|
case 'v':
|
|
/* Handle 'vCont' */
|
|
/* 'vCtrlC' */
|
|
case 'p': /* TODO */
|
|
case 'P': /* TODO */
|
|
case 'Q': /* TODO */
|
|
case 't': /* TODO */
|
|
case 'X': /* TODO */
|
|
default:
|
|
send_empty_response();
|
|
}
|
|
}
|
|
|
|
/* Check for a valid packet in the command buffer. */
|
|
static void
|
|
check_command(int fd)
|
|
{
|
|
uint8_t *head, *hash, *p, sum;
|
|
size_t avail, plen;
|
|
|
|
for (;;) {
|
|
avail = cur_comm.len;
|
|
if (avail == 0)
|
|
return;
|
|
head = io_buffer_head(&cur_comm);
|
|
switch (*head) {
|
|
case 0x03:
|
|
debug("<- Ctrl-C\n");
|
|
io_buffer_consume(&cur_comm, 1);
|
|
|
|
gdb_suspend_vcpus();
|
|
break;
|
|
case '+':
|
|
/* ACK of previous response. */
|
|
debug("<- +\n");
|
|
if (response_pending())
|
|
io_buffer_reset(&cur_resp);
|
|
io_buffer_consume(&cur_comm, 1);
|
|
if (stopped_vcpu != -1 && report_next_stop) {
|
|
report_stop(true);
|
|
send_pending_data(fd);
|
|
}
|
|
break;
|
|
case '-':
|
|
/* NACK of previous response. */
|
|
debug("<- -\n");
|
|
if (response_pending()) {
|
|
cur_resp.len += cur_resp.start;
|
|
cur_resp.start = 0;
|
|
if (cur_resp.data[0] == '+')
|
|
io_buffer_advance(&cur_resp, 1);
|
|
debug("-> %.*s\n", (int)cur_resp.len,
|
|
io_buffer_head(&cur_resp));
|
|
}
|
|
io_buffer_consume(&cur_comm, 1);
|
|
send_pending_data(fd);
|
|
break;
|
|
case '$':
|
|
/* Packet. */
|
|
|
|
if (response_pending()) {
|
|
warnx("New GDB command while response in "
|
|
"progress");
|
|
io_buffer_reset(&cur_resp);
|
|
}
|
|
|
|
/* Is packet complete? */
|
|
hash = memchr(head, '#', avail);
|
|
if (hash == NULL)
|
|
return;
|
|
plen = (hash - head + 1) + 2;
|
|
if (avail < plen)
|
|
return;
|
|
debug("<- %.*s\n", (int)plen, head);
|
|
|
|
/* Verify checksum. */
|
|
for (sum = 0, p = head + 1; p < hash; p++)
|
|
sum += *p;
|
|
if (sum != parse_byte(hash + 1)) {
|
|
io_buffer_consume(&cur_comm, plen);
|
|
debug("-> -\n");
|
|
send_char('-');
|
|
send_pending_data(fd);
|
|
break;
|
|
}
|
|
send_char('+');
|
|
|
|
handle_command(head + 1, hash - (head + 1));
|
|
io_buffer_consume(&cur_comm, plen);
|
|
if (!response_pending())
|
|
debug("-> +\n");
|
|
send_pending_data(fd);
|
|
break;
|
|
default:
|
|
/* XXX: Possibly drop connection instead. */
|
|
debug("-> %02x\n", *head);
|
|
io_buffer_consume(&cur_comm, 1);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
gdb_readable(int fd, enum ev_type event __unused, void *arg __unused)
|
|
{
|
|
size_t pending;
|
|
ssize_t nread;
|
|
int n;
|
|
|
|
if (ioctl(fd, FIONREAD, &n) == -1) {
|
|
warn("FIONREAD on GDB socket");
|
|
return;
|
|
}
|
|
assert(n >= 0);
|
|
pending = n;
|
|
|
|
/*
|
|
* 'pending' might be zero due to EOF. We need to call read
|
|
* with a non-zero length to detect EOF.
|
|
*/
|
|
if (pending == 0)
|
|
pending = 1;
|
|
|
|
/* Ensure there is room in the command buffer. */
|
|
io_buffer_grow(&cur_comm, pending);
|
|
assert(io_buffer_avail(&cur_comm) >= pending);
|
|
|
|
nread = read(fd, io_buffer_tail(&cur_comm), io_buffer_avail(&cur_comm));
|
|
if (nread == 0) {
|
|
close_connection();
|
|
} else if (nread == -1) {
|
|
if (errno == EAGAIN)
|
|
return;
|
|
|
|
warn("Read from GDB socket");
|
|
close_connection();
|
|
} else {
|
|
cur_comm.len += nread;
|
|
pthread_mutex_lock(&gdb_lock);
|
|
check_command(fd);
|
|
pthread_mutex_unlock(&gdb_lock);
|
|
}
|
|
}
|
|
|
|
static void
|
|
gdb_writable(int fd, enum ev_type event __unused, void *arg __unused)
|
|
{
|
|
|
|
send_pending_data(fd);
|
|
}
|
|
|
|
static void
|
|
new_connection(int fd, enum ev_type event __unused, void *arg)
|
|
{
|
|
int optval, s;
|
|
|
|
s = accept4(fd, NULL, NULL, SOCK_NONBLOCK);
|
|
if (s == -1) {
|
|
if (arg != NULL)
|
|
err(1, "Failed accepting initial GDB connection");
|
|
|
|
/* Silently ignore errors post-startup. */
|
|
return;
|
|
}
|
|
|
|
optval = 1;
|
|
if (setsockopt(s, SOL_SOCKET, SO_NOSIGPIPE, &optval, sizeof(optval)) ==
|
|
-1) {
|
|
warn("Failed to disable SIGPIPE for GDB connection");
|
|
close(s);
|
|
return;
|
|
}
|
|
|
|
pthread_mutex_lock(&gdb_lock);
|
|
if (cur_fd != -1) {
|
|
close(s);
|
|
warnx("Ignoring additional GDB connection.");
|
|
}
|
|
|
|
read_event = mevent_add(s, EVF_READ, gdb_readable, NULL);
|
|
if (read_event == NULL) {
|
|
if (arg != NULL)
|
|
err(1, "Failed to setup initial GDB connection");
|
|
pthread_mutex_unlock(&gdb_lock);
|
|
return;
|
|
}
|
|
write_event = mevent_add(s, EVF_WRITE, gdb_writable, NULL);
|
|
if (write_event == NULL) {
|
|
if (arg != NULL)
|
|
err(1, "Failed to setup initial GDB connection");
|
|
mevent_delete_close(read_event);
|
|
read_event = NULL;
|
|
}
|
|
|
|
cur_fd = s;
|
|
cur_vcpu = 0;
|
|
stopped_vcpu = -1;
|
|
|
|
/* Break on attach. */
|
|
first_stop = true;
|
|
report_next_stop = false;
|
|
gdb_suspend_vcpus();
|
|
pthread_mutex_unlock(&gdb_lock);
|
|
}
|
|
|
|
#ifndef WITHOUT_CAPSICUM
|
|
static void
|
|
limit_gdb_socket(int s)
|
|
{
|
|
cap_rights_t rights;
|
|
unsigned long ioctls[] = { FIONREAD };
|
|
|
|
cap_rights_init(&rights, CAP_ACCEPT, CAP_EVENT, CAP_READ, CAP_WRITE,
|
|
CAP_SETSOCKOPT, CAP_IOCTL);
|
|
if (caph_rights_limit(s, &rights) == -1)
|
|
errx(EX_OSERR, "Unable to apply rights for sandbox");
|
|
if (caph_ioctls_limit(s, ioctls, nitems(ioctls)) == -1)
|
|
errx(EX_OSERR, "Unable to apply rights for sandbox");
|
|
}
|
|
#endif
|
|
|
|
void
|
|
init_gdb(struct vmctx *_ctx)
|
|
{
|
|
int error, flags, optval, s;
|
|
struct addrinfo hints;
|
|
struct addrinfo *gdbaddr;
|
|
const char *saddr, *value;
|
|
char *sport;
|
|
bool wait;
|
|
|
|
value = get_config_value("gdb.port");
|
|
if (value == NULL)
|
|
return;
|
|
sport = strdup(value);
|
|
if (sport == NULL)
|
|
errx(4, "Failed to allocate memory");
|
|
|
|
wait = get_config_bool_default("gdb.wait", false);
|
|
|
|
saddr = get_config_value("gdb.address");
|
|
if (saddr == NULL) {
|
|
saddr = "localhost";
|
|
}
|
|
|
|
debug("==> starting on %s:%s, %swaiting\n",
|
|
saddr, sport, wait ? "" : "not ");
|
|
|
|
error = pthread_mutex_init(&gdb_lock, NULL);
|
|
if (error != 0)
|
|
errc(1, error, "gdb mutex init");
|
|
error = pthread_cond_init(&idle_vcpus, NULL);
|
|
if (error != 0)
|
|
errc(1, error, "gdb cv init");
|
|
|
|
memset(&hints, 0, sizeof(hints));
|
|
hints.ai_family = AF_UNSPEC;
|
|
hints.ai_socktype = SOCK_STREAM;
|
|
hints.ai_flags = AI_NUMERICSERV | AI_PASSIVE;
|
|
|
|
error = getaddrinfo(saddr, sport, &hints, &gdbaddr);
|
|
if (error != 0)
|
|
errx(1, "gdb address resolution: %s", gai_strerror(error));
|
|
|
|
ctx = _ctx;
|
|
s = socket(gdbaddr->ai_family, gdbaddr->ai_socktype, 0);
|
|
if (s < 0)
|
|
err(1, "gdb socket create");
|
|
|
|
optval = 1;
|
|
(void)setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval));
|
|
|
|
if (bind(s, gdbaddr->ai_addr, gdbaddr->ai_addrlen) < 0)
|
|
err(1, "gdb socket bind");
|
|
|
|
if (listen(s, 1) < 0)
|
|
err(1, "gdb socket listen");
|
|
|
|
stopped_vcpu = -1;
|
|
TAILQ_INIT(&breakpoints);
|
|
vcpus = calloc(guest_ncpus, sizeof(*vcpus));
|
|
vcpu_state = calloc(guest_ncpus, sizeof(*vcpu_state));
|
|
if (wait) {
|
|
/*
|
|
* Set vcpu 0 in vcpus_suspended. This will trigger the
|
|
* logic in gdb_cpu_add() to suspend the first vcpu before
|
|
* it starts execution. The vcpu will remain suspended
|
|
* until a debugger connects.
|
|
*/
|
|
CPU_SET(0, &vcpus_suspended);
|
|
stopped_vcpu = 0;
|
|
}
|
|
|
|
flags = fcntl(s, F_GETFL);
|
|
if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1)
|
|
err(1, "Failed to mark gdb socket non-blocking");
|
|
|
|
#ifndef WITHOUT_CAPSICUM
|
|
limit_gdb_socket(s);
|
|
#endif
|
|
mevent_add(s, EVF_READ, new_connection, NULL);
|
|
gdb_active = true;
|
|
freeaddrinfo(gdbaddr);
|
|
free(sport);
|
|
}
|