Block layer patches

# gpg: Signature made Tue 18 Jul 2017 14:29:59 BST
# gpg:                using RSA key 0x7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream: (21 commits)
  qemu-img: Check for backing image if specified during create
  blockdev: move BDRV_O_NO_BACKING option forward
  block/vvfat: Fix compiler warning with gcc 7
  vvfat: initialize memory after allocating it
  vvfat: correctly parse non-ASCII short and long file names
  vvfat: add a constant for bootsector name
  vvfat: add constants for special values of name[0]
  qemu-iotests: Test unplug of -device without drive
  qemu-iotests: Test 'info block'
  scsi-disk: bdrv_attach_dev() for empty CD-ROM
  ide: bdrv_attach_dev() for empty CD-ROM
  block: List anonymous device BBs in query-block
  block/qapi: Use blk_all_next() for query-block
  block: Make blk_all_next() public
  block/qapi: Add qdev device name to query-block
  block: Make blk_get_attached_dev_id() public
  block/vpc.c: Handle write failures in get_image_offset()
  block/vmdk: Report failures in vmdk_read_cid()
  block: remove timer canceling in throttle_config()
  block: add clock_type field to ThrottleGroup
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Merge I/O 2017/07/18 v1

# gpg: Signature made Tue 18 Jul 2017 11:31:53 BST
# gpg:                using RSA key 0xBE86EBB415104FDF
# gpg: Good signature from "Daniel P. Berrange <dan@berrange.com>"
# gpg:                 aka "Daniel P. Berrange <berrange@redhat.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: DAF3 A6FD B26B 6291 2D0E  8E3F BE86 EBB4 1510 4FDF

* remotes/berrange/tags/pull-qio-2017-07-18-1:
  io: simplify qio_channel_attach_aio_context
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

s390: add z14 cpu model

- add a CPU model for the IBM z14 which was announced on July 17th 2017
- update linux headers to 4.13-rc0 to get a fix for an ioctl definition

# gpg: Signature made Tue 18 Jul 2017 09:56:24 BST
# gpg:                using RSA key 0x117BBC80B5A61C7C
# gpg: Good signature from "Christian Borntraeger (IBM) <borntraeger@de.ibm.com>"
# Primary key fingerprint: F922 9381 A334 08F9 DBAB  FBCA 117B BC80 B5A6 1C7C

* remotes/borntraeger/tags/s390x-20170718:
  s390x/cpumodel: z14 cpu models
  linux header sync against v4.13-rc1
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

# gpg: Signature made Tue 18 Jul 2017 05:15:03 BST
# gpg:                using RSA key 0xBDBE7B27C0DE3057
# gpg: Good signature from "Jeffrey Cody <jcody@redhat.com>"
# gpg:                 aka "Jeffrey Cody <jeff@codyprime.org>"
# gpg:                 aka "Jeffrey Cody <codyprime@gmail.com>"
# Primary key fingerprint: 9957 4B4D 3474 90E7 9D98  D624 BDBE 7B27 C0DE 3057

* remotes/cody/tags/block-pull-request:
  live-block-ops.txt: Rename, rewrite, and improve it
  bitmaps.md: Convert to rST; move it into 'interop' dir
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

nbd patches for 2017-07-17

- Eric Blake: nbd: Fix iotests failure due to changed client error message
- Eric Blake: [0/2] NBD fixes before softfreeze

# gpg: Signature made Mon 17 Jul 2017 23:12:20 BST
# gpg:                using RSA key 0xA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2017-07-17:
  nbd: Fix server reply to NBD_OPT_EXPORT_NAME of older clients
  nbd: Trace client command being sent
  nbd: Fix iotests failure due to changed client error message
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Queued s390x tcg patches, v2

# gpg: Signature made Mon 17 Jul 2017 22:22:23 BST
# gpg:                using RSA key 0xAD1270CC4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"
# Primary key fingerprint: 9CB1 8DDA F8E8 49AD 2AFC  16A4 AD12 70CC 4DD0 279B

* remotes/rth/tags/pull-s390-20170717:
  target/s390x: Fix risbg handling
  target/s390x: Allow to enable "idtes" feature for TCG
  target/s390x: Mark ETF3 and ETF3_ENH facilities as available
  target/s390x: Implement TRTR
  target/s390x: Implement SRSTU
  target/s390x: Tidy SRST
  target/s390x: Implement CONVERT UNICODE insns
  target/s390x: Implement CSST
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

VFIO fixes 2017-07-17

 - Init re-order to better support hot-add on SPAR (Alexey Kardashevskiy)

# gpg: Signature made Mon 17 Jul 2017 21:33:01 BST
# gpg:                using RSA key 0x239B9B6E3BB08B22
# gpg: Good signature from "Alex Williamson <alex.williamson@redhat.com>"
# gpg:                 aka "Alex Williamson <alex@shazbot.org>"
# gpg:                 aka "Alex Williamson <alwillia@redhat.com>"
# gpg:                 aka "Alex Williamson <alex.l.williamson@gmail.com>"
# Primary key fingerprint: 42F6 C04E 540B D1A9 9E7B  8A90 239B 9B6E 3BB0 8B22

* remotes/awilliam/tags/vfio-updates-20170717.0:
  vfio-pci, ppc64/spapr: Reorder group-to-container attaching
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

x86 and machine queue, 2017-07-17

# gpg: Signature made Mon 17 Jul 2017 19:46:14 BST
# gpg:                using RSA key 0x2807936F984DC5A6
# gpg: Good signature from "Eduardo Habkost <ehabkost@redhat.com>"
# Primary key fingerprint: 5A32 2FD5 ABC4 D3DB ACCF  D1AA 2807 936F 984D C5A6

* remotes/ehabkost/tags/x86-and-machine-pull-request:
  qmp: Include parent type on 'qom-list-types' output
  qmp: Include 'abstract' field on 'qom-list-types' output
  tests: Simplify abstract-interfaces check with a helper
  i386: add Skylake-Server cpu model
  i386: Update comment about XSAVES on Skylake-Client
  i386: expose "TCGTCGTCGTCG" in the 0x40000000 CPUID leaf
  fw_cfg: move QOM type defines and fw_cfg types into fw_cfg.h
  fw_cfg: move qdev_init_nofail() from fw_cfg_init1() to callers
  fw_cfg: switch fw_cfg_find() to locate the fw_cfg device by type rather than path
  qom: Fix ambiguous path detection when ambiguous=NULL
  Revert "machine: Convert abstract typename on compat_props to subclass names"
  test-qdev-global-props: Test global property ordering
  qdev: fix the order compat and global properties are applied
  tests: Test case for object_resolve_path*()
  device-crash-test: Fix regexp on whitelist
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Or, rather, force the open of a backing image if one was specified
for creation. Using a similar -unsafe option as rebase, allow qemu-img
to ignore the backing file validation if possible.

It may not always be possible, as in the existing case when a filesize
for the new image was not specified.

This is accomplished by shifting around the conditionals in
bdrv_img_create, such that a backing file is always opened unless we
provide BDRV_O_NO_BACKING. qemu-img is adjusted to pass this new flag
when -u is provided to create.

Sorry for the heinous looking diffstat, but it's mostly whitespace.

Inspired by: https://bugzilla.redhat.com/show_bug.cgi?id=1213786Signed-off-by: NJohn Snow <jsnow@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

For both external_snapshot_prepare and qmp_drive_mirror, we eventually
append the option BDRV_O_NO_BACKING. However, we generally do so after
we create the image.

To accommodate image creation wanting to verify that a backing file
exists or not, add this option prior to create to override checking
the existence of the backing file. This prevents QEMU from trying to
re-open a backing file that's already in use (thanks to qcow2 locking).
Signed-off-by: NJohn Snow <jsnow@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

gcc 7 complains that the sprintf() might write a null byte beyond the
end of the tail buffer.  That is wrong, but we can silence it by making
i unsigned (it can never be negative anyway, see the if condition right
before).  For some reason, this allows gcc to suddenly accurately
calculate the range of i so we can give the tail[] array the exact size
it needs to have (which is 8 bytes) without gcc complaining.

In addition, let us convert the sprintf() to snprintf(), because that is
always nicer, and add an assertion about the range of the return value
afterwards so we can see that "8 - len" will never be negative and thus
"entry->name + MIN(j, 8 - len)" will never be out of bounds.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This prevents some host to guest memory content leaks.

Fixes: https://bugs.launchpad.net/qemu/+bug/1599539Signed-off-by: NHervé Poussineau <hpoussin@reactos.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Write support works again when image contains non-ASCII names. It is either the
case when user created a non-ASCII filename, or when initial directory contained
a non-ASCII filename (since 0c36111f)
Signed-off-by: NHervé Poussineau <hpoussin@reactos.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Also add links to related compatibility problems.
Signed-off-by: NHervé Poussineau <hpoussin@reactos.org>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NHervé Poussineau <hpoussin@reactos.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This caused an assertion failure until recently because the BlockBackend
would be detached on unplug, but was in fact never attached in the first
place. Add a regression test.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

This test makes sure that all block devices show up on 'info block',
with all of the expected information, in different configurations.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

If no drive=... option is passed (for an empty drive), we don't only
lack the BlockBackend normally created by parse_drive(), but we also
need to manually call blk_attach_dev().

This fixes at least a segfault when unplugging such devices, the bug
that they didn't show up in query-block, and probably some more
problems.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

If no drive=... option is passed (for an empty drive), we don't only
lack the BlockBackend normally created by parse_drive(), but we also
need to manually call blk_attach_dev().

IDE does not support hot unplug, but if it did, qdev would take care to
call the matching blk_detach_dev() on unplug.

This fixes at least the bug that such devices didn't show up in
query-block, and probably some more problems.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

Instead of listing only monitor-owned BlockBackends in query-block, also
add those anonymous BlockBackends that are owned by a qdev device and as
such under the control of the user.

This allows using query-block to inspect BlockBackends for the modern
configuration syntax with -blockdev and -device.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

This patch replaces the blk_next() loop in query-block by a
blk_all_next() one so that we also get access to BlockBackends that
aren't owned by the monitor. For now, the next thing we do is check
whether each BB has a name, so there is no semantic difference.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

With -blockdev/-device, users can indirectly create anonymous
BlockBackends, while the state of such backends is still of interest. As
a preparation for making such BBs visible in query-block, make sure that
they can be identified even without a name by adding the ID/QOM path of
their qdev device to BlockInfo.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

Coverity (CID 1355236) points out that get_image_offset() doesn't check that
it actually succeeded in writing the updated block bitmap to the file.
Check the error return from bdrv_pwrite_sync() and propagate an error
response back up to the function which calls get_image_offset() for
a write so that it can return the error to its caller.

get_sector_offset() is only used for reads, but we move it to the
same API for consistency.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The function vmdk_read_cid() can fail if the read on the underlying
block device fails, or if there's a format error in the VMDK file.
However its API doesn't provide a mechanism to report these errors,
and in some cases we were returning a CID of 0 and in some cases a
CID of 0xffffffff, either of which might potentially be valid values.

Change the function to return 0 on success or a negative errno, and
return the CID via a uint32_t* argument. Update the callsites to
handle and propagate the error appropriately.

This fixes in passing a Coverity-spotted issue (CID 1350038) where
we weren't checking the return value from sscanf().
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

throttle_config() cancels the timers of the calling BlockBackend. This
doesn't make sense because other BlockBackends in the group remain
untouched. There's no need to cancel the timers in the one specific
BlockBackend so let's not do that. Throttled requests will run as
scheduled and future requests will follow the new configuration. This
also allows a throttle group's configuration to be changed even when it
has no members.
Signed-off-by: NManos Pitsidianakis <el13635@mail.ntua.gr>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Clock type in throttling is currently inferred by the ThrottleTimer's
clock type even though it is a per-ThrottleGroup property; it doesn't
make sense to have different clock types in the same group. Moving this
to a field in ThrottleGroup can simplify some of the throttle functions.
Signed-off-by: NManos Pitsidianakis <el13635@mail.ntua.gr>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

I can't see how overlay_bs could become NULL with the current code, but
other code in this function already checks it and we can make Coverity
happy with this check, so let's add it.

Cc: qemu-stable@nongnu.org
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

qemu-ga patch queue

* new command: qemu-get-osinfo
* build fix for OpenBSD
* better error-reporting for failure on keyfile dump
* remove redundant initialization of qa_state global
* include libpcre in w32 package
* w32 localization fixes for service installation/registration

v2:
* fix build issue with older GCCs introduced with guest_get_osinfo
* relocated some declarations in guest_get_osinfo

# gpg: Signature made Tue 18 Jul 2017 11:52:45 BST
# gpg:                using RSA key 0x3353C9CEF108B584
# gpg: Good signature from "Michael Roth <flukshun@gmail.com>"
# gpg:                 aka "Michael Roth <mdroth@utexas.edu>"
# gpg:                 aka "Michael Roth <mdroth@linux.vnet.ibm.com>"
# Primary key fingerprint: CEAC C9E1 5534 EBAB B82D  3FA0 3353 C9CE F108 B584

* remotes/mdroth/tags/qga-pull-2017-07-17-v2-tag:
  test-qga: add test for guest-get-osinfo
  test-qga: pass environemnt to qemu-ga
  qemu-ga: add guest-get-osinfo command
  qga: report error on keyfile dump error
  qga-win32: remove a redundancy code
  qemu-ga: check if utmpx.h is available on the system
  qemu-ga: add missing libpcre to MSI build
  qga-win: fix installation on localized windows
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

# gpg: Signature made Mon 17 Jul 2017 16:40:18 BST
# gpg:                using RSA key 0x9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/block-pull-request:
  block: fix shadowed variable in bdrv_co_pdiscard
  util/aio-win32: Only select on what we are actually waiting for
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Add test for guest-get-osinfo command.

Qemu-ga was modified to accept QGA_OS_RELEASE environment variable. If
the variable is defined it is interpreted as path to the os-release file
and it is parsed instead of the default paths.
Signed-off-by: NTomáš Golembiovský <tgolembi@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
* move declarations to beginning of functions
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

Modify fixture_setup() to pass environemnt variables to spawned qemu-ga
instance.
Signed-off-by: NTomáš Golembiovský <tgolembi@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

Add a new 'guest-get-osinfo' command for reporting basic information of
the guest operating system. This includes machine architecture,
version and release of the kernel and several fields from os-release
file if it is present (as defined in [1]).

[1] https://www.freedesktop.org/software/systemd/man/os-release.htmlSigned-off-by: NVinzenz Feenstra <vfeenstr@redhat.com>
Signed-off-by: NTomáš Golembiovský <tgolembi@redhat.com>
* moved declarations to beginning of functions
* dropped unecessary initialization of struct utsname
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

Queued target/mips patches

# gpg: Signature made Mon 17 Jul 2017 15:50:27 BST
# gpg:                using RSA key 0xBA9C78061DDD8C9B
# gpg: Good signature from "Aurelien Jarno <aurelien@aurel32.net>"
# gpg:                 aka "Aurelien Jarno <aurelien@jarno.fr>"
# gpg:                 aka "Aurelien Jarno <aurel32@debian.org>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 7746 2642 A9EF 94FD 0F77  196D BA9C 7806 1DDD 8C9B

* remotes/aurel/tags/pull-target-mips-20170717:
  target/mips: optimize WSBH, DSBH and DSHD
  mips: set CP0 Debug DExcCode for SDBBP instruction
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target-arm queue:
 * new model of the ARM MPS2/MPS2+ FPGA based development board
 * clean up DISAS_* exit conditions and fix various regressions
   since commits e75449a3 8a6b28c7 (in particular including
   ones which broke OP-TEE guests)
 * make Cortex-M3 and M4 correctly default to 8 PMSA regions

# gpg: Signature made Mon 17 Jul 2017 13:43:45 BST
# gpg:                using RSA key 0x3C2525ED14360CDE
# gpg: Good signature from "Peter Maydell <peter.maydell@linaro.org>"
# gpg:                 aka "Peter Maydell <pmaydell@gmail.com>"
# gpg:                 aka "Peter Maydell <pmaydell@chiark.greenend.org.uk>"
# Primary key fingerprint: E1A5 C593 CD41 9DE2 8E83  15CF 3C25 25ED 1436 0CDE

* remotes/pmaydell/tags/pull-target-arm-20170717:
  MAINTAINERS: Add entries for MPS2 board
  hw/arm/mps2: Add ethernet
  hw/arm/mps2: Add SCC
  hw/misc/mps2_scc: Implement MPS2 Serial Communication Controller
  hw/arm/mps2: Add timers
  hw/char/cmsdk-apb-timer: Implement CMSDK APB timer device
  hw/arm/mps2: Add UARTs
  hw/char/cmsdk-apb-uart.c: Implement CMSDK APB UART
  hw/arm/mps2: Implement skeleton mps2-an385 and mps2-an511 board models
  target/arm: use DISAS_EXIT for eret handling
  target/arm: use gen_goto_tb for ISB handling
  target/arm/translate: ensure gen_goto_tb sets exit flags
  target/arm/translate.h: expand comment on DISAS_EXIT
  target/arm/translate: make DISAS_UPDATE match declared semantics
  include/exec/exec-all: document common exit conditions
  target/arm: Make Cortex-M3 and M4 default to 8 PMSA regions
  qdev: support properties which don't set a default value
  qdev-properties.h: Explicitly set the default value for arraylen properties
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

This patch introduces the CPU model for z14, along with all base and
optional features.
Signed-off-by: NJason J. Herne <jjherne@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

# gpg: Signature made Mon 17 Jul 2017 13:17:17 BST
# gpg:                using RSA key 0xEF04965B398D6211
# gpg: Good signature from "Jason Wang (Jason Wang on RedHat) <jasowang@redhat.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 215D 46F4 8246 689E C77F  3562 EF04 965B 398D 6211

* remotes/jasowang/tags/net-pull-request:
  virtio-net: fix offload ctrl endian
  virtion-net: Prefer is_power_of_2()
  docs/colo-proxy.txt: Update colo-proxy usage of net driver with vnet_header
  net/filter-rewriter.c: Make filter-rewriter support vnet_hdr_len
  net/colo-compare.c: Add vnet packet's tcp/udp/icmp compare
  net/colo.c: Add vnet packet parse feature in colo-proxy
  net/colo-compare.c: Make colo-compare support vnet_hdr_len
  net/colo-compare.c: Introduce parameter for compare_chr_send()
  net/colo.c: Make vnet_hdr_len as packet property
  net/filter-mirror.c: Add new option to enable vnet support for filter-redirector
  net/filter-mirror.c: Make filter mirror support vnet support.
  net/filter-mirror.c: Introduce parameter for filter_send()
  net/net.c: Add vnet_hdr support in SocketReadState
  net: Add vnet_hdr_len arguments in NetClientState
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

This patch documents (including their QMP invocations) all the four
major kinds of live block operations:

  - `block-stream`
  - `block-commit`
  - `drive-mirror` (& `blockdev-mirror`)
  - `drive-backup` (& `blockdev-backup`)

Things considered while writing this document:

  - Use reStructuredText as markup language (with the goal of generating
    the HTML output using the Sphinx Documentation Generator).  It is
    gentler on the eye, and can be trivially converted to different
    formats.  (Another reason: upstream QEMU is considering to switch to
    Sphinx, which uses reStructuredText as its markup language.)

  - Raw QMP JSON output vs. 'qmp-shell'.  I debated with myself whether
    to only show raw QMP JSON output (as that is the canonical
    representation), or use 'qmp-shell', which takes key-value pairs.  I
    settled on the approach of: for the first occurrence of a command,
    use raw JSON; for subsequent occurrences, use 'qmp-shell', with an
    occasional exception.

  - Usage of `-blockdev` command-line.

  - Usage of 'node-name' vs. file path to refer to disks.  While we have
    `blockdev-{mirror, backup}` as 'node-name'-alternatives for
    `drive-{mirror, backup}`, the `block-commit` command still operates
    on file names for parameters 'base' and 'top'.  So I added a caveat
    at the beginning to that effect.

    Refer this related thread that I started (where I learnt
    `block-stream` was recently reworked to accept 'node-name' for 'top'
    and 'base' parameters):
    https://lists.nongnu.org/archive/html/qemu-devel/2017-05/msg06466.html
    "[RFC] Making 'block-stream', and 'block-commit' accept node-name"

All commands showed in this document were tested while documenting.

Thanks: Eric Blake for the section: "A note on points-in-time vs file
names".  This useful bit was originally articulated by Eric in his
KVMForum 2015 presentation, so I included that specific bit in this
document.
Signed-off-by: NKashyap Chamarthy <kchamart@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 20170717105205.32639-3-kchamart@redhat.com
Signed-off-by: NJeff Cody <jcody@redhat.com>