scripts: add gdb support script

Add a script that enhances gdb to be aware of QEMU data structures.

This patch adds a single gdb command, 'qemu mtree'.  The command is
similar to the monitor's 'info mtree', except that it prints MemoryRegion
addresses, and except for working from a core dump as well as a live instance.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 scripts/qemu-gdb.py |   89 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 89 insertions(+), 0 deletions(-)
 create mode 100644 scripts/qemu-gdb.py

Thanks, applied.

On Sun, Mar 18, 2012 at 14:48, Avi Kivity <avi@redhat.com> wrote:
> Add a script that enhances gdb to be aware of QEMU data structures.
>
> This patch adds a single gdb command, 'qemu mtree'.  The command is
> similar to the monitor's 'info mtree', except that it prints MemoryRegion
> addresses, and except for working from a core dump as well as a live instance.
>
> Signed-off-by: Avi Kivity <avi@redhat.com>
> ---
>  scripts/qemu-gdb.py |   89 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 89 insertions(+), 0 deletions(-)
>  create mode 100644 scripts/qemu-gdb.py
>
> diff --git a/scripts/qemu-gdb.py b/scripts/qemu-gdb.py
> new file mode 100644
> index 0000000..8a0f305
> --- /dev/null
> +++ b/scripts/qemu-gdb.py
> @@ -0,0 +1,89 @@
> +#!/usr/bin/python
> +
> +# GDB debugging support
> +#
> +# Copyright 2012 Red Hat, Inc. and/or its affiliates
> +#
> +# Authors:
> +#  Avi Kivity <avi@redhat.com>
> +#
> +# This work is licensed under the terms of the GNU GPL, version 2.  See
> +# the COPYING file in the top-level directory.
> +#
> +# Contributions after 2012-01-13 are licensed under the terms of the
> +# GNU GPL, version 2 or (at your option) any later version.
> +
> +
> +import gdb
> +
> +def isnull(ptr):
> +    return ptr == gdb.Value(0).cast(ptr.type)
> +
> +def int128(p):
> +    return long(p['lo']) + (long(p['hi']) << 64)
> +
> +class QemuCommand(gdb.Command):
> +    '''Prefix for QEMU debug support commands'''
> +    def __init__(self):
> +        gdb.Command.__init__(self, 'qemu', gdb.COMMAND_DATA,
> +                             gdb.COMPLETE_NONE, True)
> +
> +class MtreeCommand(gdb.Command):
> +    '''Display the memory tree hierarchy'''
> +    def __init__(self):
> +        gdb.Command.__init__(self, 'qemu mtree', gdb.COMMAND_DATA,
> +                             gdb.COMPLETE_NONE)
> +        self.queue = []
> +    def invoke(self, arg, from_tty):
> +        self.seen = set()
> +        self.queue_root('address_space_memory')
> +        self.queue_root('address_space_io')
> +        self.process_queue()
> +    def queue_root(self, varname):
> +        ptr = gdb.parse_and_eval(varname)['root']
> +        self.queue.append(ptr)
> +    def process_queue(self):
> +        while self.queue:
> +            ptr = self.queue.pop(0)
> +            if long(ptr) in self.seen:
> +                continue
> +            self.print_item(ptr)
> +    def print_item(self, ptr, offset = gdb.Value(0), level = 0):
> +        self.seen.add(long(ptr))
> +        addr = ptr['addr']
> +        addr += offset
> +        size = int128(ptr['size'])
> +        alias = ptr['alias']
> +        klass = ''
> +        if not isnull(alias):
> +            klass = ' (alias)'
> +        elif not isnull(ptr['ops']):
> +            klass = ' (I/O)'
> +        elif bool(ptr['ram']):
> +            klass = ' (RAM)'
> +        gdb.write('%s%016x-%016x %s%s (@ %s)\n'
> +                  % ('  ' * level,
> +                     long(addr),
> +                     long(addr + (size - 1)),
> +                     ptr['name'].string(),
> +                     klass,
> +                     ptr,
> +                     ),
> +                  gdb.STDOUT)
> +        if not isnull(alias):
> +            gdb.write('%s    alias: %s@%016x (@ %s)\n' %
> +                      ('  ' * level,
> +                       alias['name'].string(),
> +                       ptr['alias_offset'],
> +                       alias,
> +                       ),
> +                      gdb.STDOUT)
> +            self.queue.append(alias)
> +        subregion = ptr['subregions']['tqh_first']
> +        level += 1
> +        while not isnull(subregion):
> +            self.print_item(subregion, addr, level)
> +            subregion = subregion['subregions_link']['tqe_next']
> +
> +QemuCommand()
> +MtreeCommand()
> --
> 1.7.9
>
>