Migration pull 2019-05-14

Small fixes/cleanups
One HMP/monitor fix

# gpg: Signature made Tue 14 May 2019 19:03:53 BST
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20190514b:
  monitor: Call mon_get_cpu() only once at hmp_gva2gpa()
  migration/ram.c: fix typos in comments
  migration: Fix use-after-free during process exit
  migration/savevm: wrap into qemu_loadvm_state_header()
  migration/savevm: load_header before load_setup
  migration/savevm: remove duplicate check of migration_is_blocked
  migration: update comments of migration bitmap
  migration/ram.c: start of migration_bitmap_sync_range is always 0
  qemu-option.hx: Update missed parameter for colo-compare
  migration/colo.h: Remove obsolete codes
  migration/colo.c: Remove redundant input parameter
  migration: savevm: fix error code with migration blockers
  vmstate: check subsection_found is enough
  migration: remove not used field xfer_limit
  migration: not necessary to check ops again
  migration: comment VMSTATE_UNUSED*() properly

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hmp_gva2gpa() calls mon_get_cpu() twice, which is unnecessary.
Not an actual bug, but this is reported as a defect by Coverity
Scan (CID 1401346).

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20190510185620.15757-1-ehabkost@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190510233729.15554-1-richardw.yang@linux.intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

It fixes heap-use-after-free which was found by clang's ASAN.

Control flow of this use-after-free:
main_thread:
    * Got SIGTERM and completes main loop
    * Calls migration_shutdown
      - migrate_fd_cancel (so, migration_thread begins to complete)
      - object_unref(OBJECT(current_migration));

migration_thread:
    * migration_iteration_finish -> schedule cleanup bh
    * object_unref(OBJECT(s)); (Now, current_migration is freed)
    * exits

main_thread:
    * Calls vm_shutdown -> drain bdrvs -> main loop
      -> cleanup_bh -> use after free

If you want to reproduce, these couple of sleeps will help:
vl.c:4613:
     migration_shutdown();
+    sleep(2);
migration.c:3269:
+    sleep(1);
     trace_migration_thread_after_loop();
     migration_iteration_finish(s);

Original output:
qemu-system-x86_64: terminating on signal 15 from pid 31980 (<unknown process>)
=================================================================
==31958==ERROR: AddressSanitizer: heap-use-after-free on address 0x61900001d210
  at pc 0x555558a535ca bp 0x7fffffffb190 sp 0x7fffffffb188
READ of size 8 at 0x61900001d210 thread T0 (qemu-vm-0)
    #0 0x555558a535c9 in migrate_fd_cleanup migration/migration.c:1502:23
    #1 0x5555594fde0a in aio_bh_call util/async.c:90:5
    #2 0x5555594fe522 in aio_bh_poll util/async.c:118:13
    #3 0x555559524783 in aio_poll util/aio-posix.c:725:17
    #4 0x555559504fb3 in aio_wait_bh_oneshot util/aio-wait.c:71:5
    #5 0x5555573bddf6 in virtio_blk_data_plane_stop
      hw/block/dataplane/virtio-blk.c:282:5
    #6 0x5555589d5c09 in virtio_bus_stop_ioeventfd hw/virtio/virtio-bus.c:246:9
    #7 0x5555589e9917 in virtio_pci_stop_ioeventfd hw/virtio/virtio-pci.c:287:5
    #8 0x5555589e22bf in virtio_pci_vmstate_change hw/virtio/virtio-pci.c:1072:9
    #9 0x555557628931 in virtio_vmstate_change hw/virtio/virtio.c:2257:9
    #10 0x555557c36713 in vm_state_notify vl.c:1605:9
    #11 0x55555716ef53 in do_vm_stop cpus.c:1074:9
    #12 0x55555716eeff in vm_shutdown cpus.c:1092:12
    #13 0x555557c4283e in main vl.c:4617:5
    #14 0x7fffdfdb482f in __libc_start_main
      (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #15 0x555556ecb118 in _start (x86_64-softmmu/qemu-system-x86_64+0x1977118)

0x61900001d210 is located 144 bytes inside of 952-byte region
  [0x61900001d180,0x61900001d538)
freed by thread T6 (live_migration) here:
    #0 0x555556f76782 in __interceptor_free
      /tmp/final/llvm.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:124:3
    #1 0x555558d5fa94 in object_finalize qom/object.c:618:9
    #2 0x555558d57651 in object_unref qom/object.c:1068:9
    #3 0x555558a55588 in migration_thread migration/migration.c:3272:5
    #4 0x5555595393f2 in qemu_thread_start util/qemu-thread-posix.c:502:9
    #5 0x7fffe057f6b9 in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x76b9)

previously allocated by thread T0 (qemu-vm-0) here:
    #0 0x555556f76b03 in __interceptor_malloc
      /tmp/final/llvm.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:146:3
    #1 0x7ffff6ee37b8 in g_malloc (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x4f7b8)
    #2 0x555558d58031 in object_new qom/object.c:640:12
    #3 0x555558a31f21 in migration_object_init migration/migration.c:139:25
    #4 0x555557c41398 in main vl.c:4320:5
    #5 0x7fffdfdb482f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)

Thread T6 (live_migration) created by T0 (qemu-vm-0) here:
    #0 0x555556f5f0dd in pthread_create
      /tmp/final/llvm.src/projects/compiler-rt/lib/asan/asan_interceptors.cc:210:3
    #1 0x555559538cf9 in qemu_thread_create util/qemu-thread-posix.c:539:11
    #2 0x555558a53304 in migrate_fd_connect migration/migration.c:3332:5
    #3 0x555558a72bd8 in migration_channel_connect migration/channel.c:92:5
    #4 0x555558a6ef87 in exec_start_outgoing_migration migration/exec.c:42:5
    #5 0x555558a4f3c2 in qmp_migrate migration/migration.c:1922:9
    #6 0x555558bb4f6a in qmp_marshal_migrate qapi/qapi-commands-migration.c:607:5
    #7 0x555559363738 in do_qmp_dispatch qapi/qmp-dispatch.c:131:5
    #8 0x555559362a15 in qmp_dispatch qapi/qmp-dispatch.c:174:11
    #9 0x5555571bac15 in monitor_qmp_dispatch monitor.c:4124:11
    #10 0x55555719a22d in monitor_qmp_bh_dispatcher monitor.c:4207:9
    #11 0x5555594fde0a in aio_bh_call util/async.c:90:5
    #12 0x5555594fe522 in aio_bh_poll util/async.c:118:13
    #13 0x5555595201e0 in aio_dispatch util/aio-posix.c:460:5
    #14 0x555559503553 in aio_ctx_dispatch util/async.c:261:5
    #15 0x7ffff6ede196 in g_main_context_dispatch
      (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x4a196)

SUMMARY: AddressSanitizer: heap-use-after-free migration/migration.c:1502:23
  in migrate_fd_cleanup
Shadow bytes around the buggy address:
  0x0c327fffb9f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c327fffba00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c327fffba10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c327fffba20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c327fffba30: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
=>0x0c327fffba40: fd fd[fd]fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fffba50: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fffba60: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fffba70: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fffba80: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fffba90: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable: 00
  Partially addressable: 01 02 03 04 05 06 07
  Heap left redzone: fa
  Freed heap region: fd
  Stack left redzone: f1
  Stack mid redzone: f2
  Stack right redzone: f3
  Stack after return: f5
  Stack use after scope: f8
  Global redzone: f9
  Global init order: f6
  Poisoned by user: f7
  Container overflow: fc
  Array cookie: ac
  Intra object redzone: bb
  ASan internal: fe
  Left alloca redzone: ca
  Right alloca redzone: cb
  Shadow gap: cc
==31958==ABORTING

Signed-off-by: Yury Kotov <yury-kotov@yandex-team.ru>
Message-Id: <20190408113343.2370-1-yury-kotov@yandex-team.ru>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  Fixed up comment formatting

On source side, we have qemu_savevm_state_header() to send related data,
while on the receiving side those steps are scattered in
qemu_loadvm_state().

This patch wrap those related steps into qemu_loadvm_state_header() to
make it friendly to read.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190424004700.12766-5-richardw.yang@linux.intel.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

In migration_thread() and qemu_savevm_state(), we savevm_state in
following sequence:

    qemu_savevm_state_header(f);
    qemu_savevm_state_setup(f);

Then it would be more proper to loadvm_state in the save sequence.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190424004700.12766-4-richardw.yang@linux.intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Current call flow of save_snapshot is:

  save_snapshot
    migration_is_blocked
      qemu_savevm_state
        migration_is_blocked

Since qemu_savevm_state is only called in save_snapshot, this means
migration_is_blocked has been already checked.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190424004700.12766-2-richardw.yang@linux.intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Since the ram bitmap and the unsent bitmap are split by RAMBlock
in commit 6b6712ef, it's better to update the comments about them.

Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Message-Id: <1555311089-18610-1-git-send-email-wang.yi59@zte.com.cn>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

We can eliminate to pass 0.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190430034412.12935-2-richardw.yang@linux.intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

We missed the iothread related args in this file.
This patch is used to fix this issue.

Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Message-Id: <20190426090730.2691-4-chen.zhang@intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Message-Id: <20190426090730.2691-3-chen.zhang@intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

The colo_do_failover no need the input parameter.

Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Message-Id: <20190426090730.2691-2-chen.zhang@intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

The only caller that checks the error code is looking for != 0,
so returning false is incorrect.

Fixes: 5aaac467 "migration: savevm: consult migration blockers"

Signed-off-by: Cole Robinson <crobinso@redhat.com>
Message-Id: <b991a4d0e6c4253bc08b2794c6084be55fc72e1d.1554851834.git.crobinso@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

subsection_found is true implies vmdesc is not NULL.

This patch remove the additional check on vmdesc and rename
subsection_found to vmdesc_has_subsections to make it more self-explain.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>

Message-Id: <20190403011016.12549-1-richardw.yang@linux.intel.com>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

MigrationState->xfer_limit is only set to 0 in migrate_init().

Remove this unnecessary field.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190326055726.10539-1-richardw.yang@linux.intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

During each iteration, se->ops is checked before each loop. So it is not
necessary to check it again and simplify the following check a little.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190327013130.26259-1-richardw.yang@linux.intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

It is error prone to use VMSTATE_UNUSED*() sometimes especially when
the size of the migration stream of the field is not the same as the
size of the structure (boolean is one example).  Comment it well so
people will be aware of this when people want to use it.

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20190329095713.14177-1-peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Improve code generation for vector duplication.
Add vector expansions for shifts by non-constant scalar.
Add vector expansions for shifts by vector.
Add integer and vector expansions for absolute value.
Several patches in preparation for Altivec.
Bug fix for tcg/aarch64 vs min/max.

# gpg: Signature made Tue 14 May 2019 00:58:02 BST
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [full]
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-tcg-20190513: (31 commits)
  tcg/aarch64: Do not advertise minmax for MO_64
  target/xtensa: Use tcg_gen_abs_i32
  target/tricore: Use tcg_gen_abs_tl
  target/s390x: Use tcg_gen_abs_i64
  target/ppc: Use tcg_gen_abs_tl
  target/ppc: Use tcg_gen_abs_i32
  target/cris: Use tcg_gen_abs_tl
  target/arm: Use tcg_gen_abs_i64 and tcg_gen_gvec_abs
  tcg/aarch64: Support vector absolute value
  tcg/i386: Support vector absolute value
  tcg: Add support for vector absolute value
  tcg: Add support for integer absolute value
  tcg/i386: Support vector scalar shift opcodes
  tcg: Add gvec expanders for vector shift by scalar
  tcg/aarch64: Support vector variable shift opcodes
  tcg/i386: Support vector variable shift opcodes
  tcg: Add gvec expanders for variable shift
  tcg: Add INDEX_op_dupm_vec
  tcg/aarch64: Implement tcg_out_dupm_vec
  tcg/i386: Implement tcg_out_dupm_vec
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

The min/max instructions are not available for 64-bit elements.

Fixes: 93f332a5
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20190423102145.14812-3-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20190423102145.14812-2-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Remove a function of the same name from target/arm/.
Use a branchless implementation of abs gleaned from gcc.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Allow expansion either via shift by scalar or by replicating
the scalar for shift by vector.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
v3: Use a private structure for do_gvec_shifts.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

The gvec expanders perform a modulo on the shift count.  If the target
requires alternate behaviour, then it cannot use the generic gvec
expanders anyway, and will have to have its own custom code.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Allow the backend to expand dup from memory directly, instead of
forcing the value into a temp first.  This is especially important
if integer/vector register moves do not exist.

Note that officially tcg_out_dupm_vec is allowed to fail.
If it did, we could fix this up relatively easily:

  VECE == 32/64:
    Load the value into a vector register, then dup.
    Both of these must work.

  VECE == 8/16:
    If the value happens to be at an offset such that an aligned
    load would place the desired value in the least significant
    end of the register, go ahead and load w/garbage in high bits.

    Load the value w/INDEX_op_ld{8,16}_i32.
    Attempt a move directly to vector reg, which may fail.
    Store the value into the backing store for OTS.
    Load the value into the vector reg w/TCG_TYPE_I32, which must work.
    Duplicate from the vector reg into itself, which must work.

All of which is well and good, except that all supported
hosts can support dupm for all vece, so all of the failure
paths would be dead code and untestable.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

The LD1R instruction does all the work.  Note that the only
useful addressing mode is a base register with no offset.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

At the same time, improve tcg_out_dupi_vec wrt broadcast
from the constant pool.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Currently stubbed out in all backends that support vectors.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

This case is similar to INDEX_op_mov_* in that we need to do
different things depending on the current location of the source.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
v3: Added some commentary to the tcg_reg_alloc_* functions.