Add qemu 2.4.0

Change-Id: Ic99cbad4b61f8b127b7dc74d04576c0bcbaaf4f5
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>

1 files changed, 339 insertions, 0 deletions

diff --git a/qemu/scripts/dump-guest-memory.py b/qemu/scripts/dump-guest-memory.py
new file mode 100644
index 000000000..dc8e44acf
--- /dev/null
+++ b/qemu/scripts/dump-guest-memory.py
@@ -0,0 +1,339 @@
+# This python script adds a new gdb command, "dump-guest-memory". It
+# should be loaded with "source dump-guest-memory.py" at the (gdb)
+# prompt.
+#
+# Copyright (C) 2013, Red Hat, Inc.
+#
+# Authors:
+#   Laszlo Ersek <lersek@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or later. See
+# the COPYING file in the top-level directory.
+#
+# The leading docstring doesn't have idiomatic Python formatting. It is
+# printed by gdb's "help" command (the first line is printed in the
+# "help data" summary), and it should match how other help texts look in
+# gdb.
+
+import struct
+
+class DumpGuestMemory(gdb.Command):
+    """Extract guest vmcore from qemu process coredump.
+
+The sole argument is FILE, identifying the target file to write the
+guest vmcore to.
+
+This GDB command reimplements the dump-guest-memory QMP command in
+python, using the representation of guest memory as captured in the qemu
+coredump. The qemu process that has been dumped must have had the
+command line option "-machine dump-guest-core=on".
+
+For simplicity, the "paging", "begin" and "end" parameters of the QMP
+command are not supported -- no attempt is made to get the guest's
+internal paging structures (ie. paging=false is hard-wired), and guest
+memory is always fully dumped.
+
+Only x86_64 guests are supported.
+
+The CORE/NT_PRSTATUS and QEMU notes (that is, the VCPUs' statuses) are
+not written to the vmcore. Preparing these would require context that is
+only present in the KVM host kernel module when the guest is alive. A
+fake ELF note is written instead, only to keep the ELF parser of "crash"
+happy.
+
+Dependent on how busted the qemu process was at the time of the
+coredump, this command might produce unpredictable results. If qemu
+deliberately called abort(), or it was dumped in response to a signal at
+a halfway fortunate point, then its coredump should be in reasonable
+shape and this command should mostly work."""
+
+    TARGET_PAGE_SIZE = 0x1000
+    TARGET_PAGE_MASK = 0xFFFFFFFFFFFFF000
+
+    # Various ELF constants
+    EM_X86_64   = 62        # AMD x86-64 target machine
+    ELFDATA2LSB = 1         # little endian
+    ELFCLASS64  = 2
+    ELFMAG      = "\x7FELF"
+    EV_CURRENT  = 1
+    ET_CORE     = 4
+    PT_LOAD     = 1
+    PT_NOTE     = 4
+
+    # Special value for e_phnum. This indicates that the real number of
+    # program headers is too large to fit into e_phnum. Instead the real
+    # value is in the field sh_info of section 0.
+    PN_XNUM = 0xFFFF
+
+    # Format strings for packing and header size calculation.
+    ELF64_EHDR = ("4s" # e_ident/magic
+                  "B"  # e_ident/class
+                  "B"  # e_ident/data
+                  "B"  # e_ident/version
+                  "B"  # e_ident/osabi
+                  "8s" # e_ident/pad
+                  "H"  # e_type
+                  "H"  # e_machine
+                  "I"  # e_version
+                  "Q"  # e_entry
+                  "Q"  # e_phoff
+                  "Q"  # e_shoff
+                  "I"  # e_flags
+                  "H"  # e_ehsize
+                  "H"  # e_phentsize
+                  "H"  # e_phnum
+                  "H"  # e_shentsize
+                  "H"  # e_shnum
+                  "H"  # e_shstrndx
+                 )
+    ELF64_PHDR = ("I"  # p_type
+                  "I"  # p_flags
+                  "Q"  # p_offset
+                  "Q"  # p_vaddr
+                  "Q"  # p_paddr
+                  "Q"  # p_filesz
+                  "Q"  # p_memsz
+                  "Q"  # p_align
+                 )
+
+    def __init__(self):
+        super(DumpGuestMemory, self).__init__("dump-guest-memory",
+                                              gdb.COMMAND_DATA,
+                                              gdb.COMPLETE_FILENAME)
+        self.uintptr_t     = gdb.lookup_type("uintptr_t")
+        self.elf64_ehdr_le = struct.Struct("<%s" % self.ELF64_EHDR)
+        self.elf64_phdr_le = struct.Struct("<%s" % self.ELF64_PHDR)
+
+    def int128_get64(self, val):
+        assert (val["hi"] == 0)
+        return val["lo"]
+
+    def qlist_foreach(self, head, field_str):
+        var_p = head["lh_first"]
+        while (var_p != 0):
+            var = var_p.dereference()
+            yield var
+            var_p = var[field_str]["le_next"]
+
+    def qemu_get_ram_block(self, ram_addr):
+        ram_blocks = gdb.parse_and_eval("ram_list.blocks")
+        for block in self.qlist_foreach(ram_blocks, "next"):
+            if (ram_addr - block["offset"] < block["length"]):
+                return block
+        raise gdb.GdbError("Bad ram offset %x" % ram_addr)
+
+    def qemu_get_ram_ptr(self, ram_addr):
+        block = self.qemu_get_ram_block(ram_addr)
+        return block["host"] + (ram_addr - block["offset"])
+
+    def memory_region_get_ram_ptr(self, mr):
+        if (mr["alias"] != 0):
+            return (self.memory_region_get_ram_ptr(mr["alias"].dereference()) +
+                    mr["alias_offset"])
+        return self.qemu_get_ram_ptr(mr["ram_addr"] & self.TARGET_PAGE_MASK)
+
+    def guest_phys_blocks_init(self):
+        self.guest_phys_blocks = []
+
+    def guest_phys_blocks_append(self):
+        print "guest RAM blocks:"
+        print ("target_start     target_end       host_addr        message "
+               "count")
+        print ("---------------- ---------------- ---------------- ------- "
+               "-----")
+
+        current_map_p = gdb.parse_and_eval("address_space_memory.current_map")
+        current_map = current_map_p.dereference()
+        for cur in range(current_map["nr"]):
+            flat_range   = (current_map["ranges"] + cur).dereference()
+            mr           = flat_range["mr"].dereference()
+
+            # we only care about RAM
+            if (not mr["ram"]):
+                continue
+
+            section_size = self.int128_get64(flat_range["addr"]["size"])
+            target_start = self.int128_get64(flat_range["addr"]["start"])
+            target_end   = target_start + section_size
+            host_addr    = (self.memory_region_get_ram_ptr(mr) +
+                            flat_range["offset_in_region"])
+            predecessor = None
+
+            # find continuity in guest physical address space
+            if (len(self.guest_phys_blocks) > 0):
+                predecessor = self.guest_phys_blocks[-1]
+                predecessor_size = (predecessor["target_end"] -
+                                    predecessor["target_start"])
+
+                # the memory API guarantees monotonically increasing
+                # traversal
+                assert (predecessor["target_end"] <= target_start)
+
+                # we want continuity in both guest-physical and
+                # host-virtual memory
+                if (predecessor["target_end"] < target_start or
+                    predecessor["host_addr"] + predecessor_size != host_addr):
+                    predecessor = None
+
+            if (predecessor is None):
+                # isolated mapping, add it to the list
+                self.guest_phys_blocks.append({"target_start": target_start,
+                                               "target_end"  : target_end,
+                                               "host_addr"   : host_addr})
+                message = "added"
+            else:
+                # expand predecessor until @target_end; predecessor's
+                # start doesn't change
+                predecessor["target_end"] = target_end
+                message = "joined"
+
+            print ("%016x %016x %016x %-7s %5u" %
+                   (target_start, target_end, host_addr.cast(self.uintptr_t),
+                    message, len(self.guest_phys_blocks)))
+
+    def cpu_get_dump_info(self):
+        # We can't synchronize the registers with KVM post-mortem, and
+        # the bits in (first_x86_cpu->env.hflags) seem to be stale; they
+        # may not reflect long mode for example. Hence just assume the
+        # most common values. This also means that instruction pointer
+        # etc. will be bogus in the dump, but at least the RAM contents
+        # should be valid.
+        self.dump_info = {"d_machine": self.EM_X86_64,
+                          "d_endian" : self.ELFDATA2LSB,
+                          "d_class"  : self.ELFCLASS64}
+
+    def encode_elf64_ehdr_le(self):
+        return self.elf64_ehdr_le.pack(
+                                 self.ELFMAG,                 # e_ident/magic
+                                 self.dump_info["d_class"],   # e_ident/class
+                                 self.dump_info["d_endian"],  # e_ident/data
+                                 self.EV_CURRENT,             # e_ident/version
+                                 0,                           # e_ident/osabi
+                                 "",                          # e_ident/pad
+                                 self.ET_CORE,                # e_type
+                                 self.dump_info["d_machine"], # e_machine
+                                 self.EV_CURRENT,             # e_version
+                                 0,                           # e_entry
+                                 self.elf64_ehdr_le.size,     # e_phoff
+                                 0,                           # e_shoff
+                                 0,                           # e_flags
+                                 self.elf64_ehdr_le.size,     # e_ehsize
+                                 self.elf64_phdr_le.size,     # e_phentsize
+                                 self.phdr_num,               # e_phnum
+                                 0,                           # e_shentsize
+                                 0,                           # e_shnum
+                                 0                            # e_shstrndx
+                                )
+
+    def encode_elf64_note_le(self):
+        return self.elf64_phdr_le.pack(self.PT_NOTE,         # p_type
+                                       0,                    # p_flags
+                                       (self.memory_offset -
+                                        len(self.note)),     # p_offset
+                                       0,                    # p_vaddr
+                                       0,                    # p_paddr
+                                       len(self.note),       # p_filesz
+                                       len(self.note),       # p_memsz
+                                       0                     # p_align
+                                      )
+
+    def encode_elf64_load_le(self, offset, start_hwaddr, range_size):
+        return self.elf64_phdr_le.pack(self.PT_LOAD, # p_type
+                                       0,            # p_flags
+                                       offset,       # p_offset
+                                       0,            # p_vaddr
+                                       start_hwaddr, # p_paddr
+                                       range_size,   # p_filesz
+                                       range_size,   # p_memsz
+                                       0             # p_align
+                                      )
+
+    def note_init(self, name, desc, type):
+        # name must include a trailing NUL
+        namesz = (len(name) + 1 + 3) / 4 * 4
+        descsz = (len(desc)     + 3) / 4 * 4
+        fmt = ("<"   # little endian
+               "I"   # n_namesz
+               "I"   # n_descsz
+               "I"   # n_type
+               "%us" # name
+               "%us" # desc
+               % (namesz, descsz))
+        self.note = struct.pack(fmt,
+                                len(name) + 1, len(desc), type, name, desc)
+
+    def dump_init(self):
+        self.guest_phys_blocks_init()
+        self.guest_phys_blocks_append()
+        self.cpu_get_dump_info()
+        # we have no way to retrieve the VCPU status from KVM
+        # post-mortem
+        self.note_init("NONE", "EMPTY", 0)
+
+        # Account for PT_NOTE.
+        self.phdr_num = 1
+
+        # We should never reach PN_XNUM for paging=false dumps: there's
+        # just a handful of discontiguous ranges after merging.
+        self.phdr_num += len(self.guest_phys_blocks)
+        assert (self.phdr_num < self.PN_XNUM)
+
+        # Calculate the ELF file offset where the memory dump commences:
+        #
+        #   ELF header
+        #   PT_NOTE
+        #   PT_LOAD: 1
+        #   PT_LOAD: 2
+        #   ...
+        #   PT_LOAD: len(self.guest_phys_blocks)
+        #   ELF note
+        #   memory dump
+        self.memory_offset = (self.elf64_ehdr_le.size +
+                              self.elf64_phdr_le.size * self.phdr_num +
+                              len(self.note))
+
+    def dump_begin(self, vmcore):
+        vmcore.write(self.encode_elf64_ehdr_le())
+        vmcore.write(self.encode_elf64_note_le())
+        running = self.memory_offset
+        for block in self.guest_phys_blocks:
+            range_size = block["target_end"] - block["target_start"]
+            vmcore.write(self.encode_elf64_load_le(running,
+                                                   block["target_start"],
+                                                   range_size))
+            running += range_size
+        vmcore.write(self.note)
+
+    def dump_iterate(self, vmcore):
+        qemu_core = gdb.inferiors()[0]
+        for block in self.guest_phys_blocks:
+            cur  = block["host_addr"]
+            left = block["target_end"] - block["target_start"]
+            print ("dumping range at %016x for length %016x" %
+                   (cur.cast(self.uintptr_t), left))
+            while (left > 0):
+                chunk_size = min(self.TARGET_PAGE_SIZE, left)
+                chunk = qemu_core.read_memory(cur, chunk_size)
+                vmcore.write(chunk)
+                cur  += chunk_size
+                left -= chunk_size
+
+    def create_vmcore(self, filename):
+        vmcore = open(filename, "wb")
+        self.dump_begin(vmcore)
+        self.dump_iterate(vmcore)
+        vmcore.close()
+
+    def invoke(self, args, from_tty):
+        # Unwittingly pressing the Enter key after the command should
+        # not dump the same multi-gig coredump to the same file.
+        self.dont_repeat()
+
+        argv = gdb.string_to_argv(args)
+        if (len(argv) != 1):
+            raise gdb.GdbError("usage: dump-guest-memory FILE")
+
+        self.dump_init()
+        self.create_vmcore(argv[0])
+
+DumpGuestMemory()