Let download_cloudinit() take an optional pubkey, which subclasses of
BootLinux can pass through setUp().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201102161859.156603-7-mreitz@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Whenever we encounter a directory with an st_dev or mount ID that
differs from that of its parent, we set the FUSE_ATTR_SUBMOUNT flag so
the guest can create a submount for it.

We only need to do so in lo_do_lookup().  The following functions return
a fuse_attr object:
- lo_create(), though fuse_reply_create(): Calls lo_do_lookup().
- lo_lookup(), though fuse_reply_entry(): Calls lo_do_lookup().
- lo_mknod_symlink(), through fuse_reply_entry(): Calls lo_do_lookup().
- lo_link(), through fuse_reply_entry(): Creating a link cannot create a
  submount, so there is no need to check for it.
- lo_getattr(), through fuse_reply_attr(): Announcing submounts when the
  node is first detected (at lookup) is sufficient.  We do not need to
  return the submount attribute later.
- lo_do_readdir(), through fuse_add_direntry_plus(): Calls
  lo_do_lookup().

Make announcing submounts optional, so submounts are only announced to
the guest with the announce_submounts option.  Some users may prefer the
current behavior, so that the guest learns nothing about the host mount
structure.

(announce_submounts is force-disabled when the guest does not present
the FUSE_SUBMOUNTS capability, or when there is no statx().)

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201102161859.156603-6-mreitz@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Using st_dev is not sufficient to uniquely identify a mount: You can
mount the same device twice, but those are still separate trees, and
e.g. by mounting something else inside one of them, they may differ.

Using statx(), we can get a mount ID that uniquely identifies a mount.
If that is available, add it to the lo_inode key.

Most of this patch is taken from Miklos's mail here:
https://marc.info/?l=fuse-devel&m=160062521827983


(virtiofsd-use-mount-id.patch attachment)

Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201102161859.156603-5-mreitz@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Check whether the glibc provides statx() and if so, define CONFIG_STATX.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201102161859.156603-4-mreitz@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

fuse_entry_param is converted to fuse_attr on the line (by
fill_entry()), so it should have a member that mirrors fuse_attr.flags.

fill_entry() should then copy this fuse_entry_param.attr_flags to
fuse_attr.flags.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201102161859.156603-3-mreitz@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

FUSE_SUBMOUNTS is a pure indicator by the kernel to signal that it
supports submounts.  It does not check its state in the init reply, so
there is nothing for fuse_lowlevel.c to do but to check its existence
and copy it into fuse_conn_info.capable.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201102161859.156603-2-mreitz@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

The commit 88fc1079 disabled remote
posix locks by default. But the --help message still says it is enabled
by default. So fix it to output no_posix_lock.

Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>
Message-Id: <20201027081558.29904-1-zhangjiachen.jaycee@bytedance.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Since commit 6f5fd837, vu_init() can fail if malloc() returns NULL.

This fixes the following Coverity warning:

  CID 1435958 (#1 of 1): Unchecked return value (CHECKED_RETURN)

Fixes: 6f5fd837 ("libvhost-user: support many virtqueues")
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20201102092339.2034297-1-philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

On ppc, and some other archs, it looks like syslog ends up using 'send'
rather than 'sendto'.

Reference: https://github.com/kata-containers/kata-containers/issues/1050



Reported-by:  <amulmek1@in.ibm.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20201102150750.34565-1-dgilbert@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

The new migrate_send_rp_req_pages_pending() call should greatly improve
destination responsiveness because it will resync faulted address after
postcopy recovery.  However it is also the 1st place to initiate the page
request from the main thread.

One thing is overlooked on that migrate_send_rp_message_req_pages() is not
designed to be thread-safe.  So if we wake the fault thread before syncing all
the faulted pages in the main thread, it means they can race.

Postpone the wake up operation after the sync of faulted addresses.

Fixes: 0c26781c ("migration: Sync requested pages after postcopy recovery")
Tested-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20201102153010.11979-3-peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

When postcopy recover happens, we need to reset last_rb after each return of
postcopy_pause_fault_thread() because that means we just got the postcopy
migration continued.

Unify this reset to the place right before we want to kick the fault thread
again, when we get the command MIG_CMD_POSTCOPY_RESUME from source.

This is actually more than that - because the main thread on destination will
now be able to call migrate_send_rp_req_pages_pending() too, so the fault
thread is not the only user of last_rb now.  Move the reset earlier will allow
the first call to migrate_send_rp_req_pages_pending() to use the reset value
even if called from the main thread.

(NOTE: this is not a real fix to 0c26781c mentioned below, however it is just
 a mark that when picking up 0c26781c we'd better have this one too; the real
 fix will come later)

Fixes: 0c26781c ("migration: Sync requested pages after postcopy recovery")
Tested-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20201102153010.11979-2-peterx@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

xen patch

- Rework Xen disk unplug to work with newer command line
  options.

# gpg: Signature made Mon 02 Nov 2020 14:42:37 GMT
# gpg:                using RSA key F80C006308E22CFD8A92E7980CF5572FD7FB55AF
# gpg:                issuer "anthony.perard@citrix.com"
# gpg: Good signature from "Anthony PERARD <anthony.perard@gmail.com>" [marginal]
# gpg:                 aka "Anthony PERARD <anthony.perard@citrix.com>" [marginal]
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 5379 2F71 024C 600F 778A  7161 D8D5 7199 DF83 42C8
#      Subkey fingerprint: F80C 0063 08E2 2CFD 8A92  E798 0CF5 572F D7FB 55AF

* remotes/aperard/tags/pull-xen-20201102:
  xen: rework pci_piix3_xen_ide_unplug

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

This is to allow IDE disks to be unplugged when adding to QEMU via:
    -drive file=/root/disk_file,if=none,id=ide-disk0,format=raw
    -device ide-hd,drive=ide-disk0,bus=ide.0,unit=0

as the current code only works for disk added with:
    -drive file=/root/disk_file,if=ide,index=0,media=disk,format=raw

Since the code already have the IDE controller as `dev`, we don't need
to use the legacy DriveInfo to find all the drive we want to unplug.
We can simply use `blk` from the controller, as it kind of was already
assume to be the same, by setting it to NULL.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>

Acked-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-Id: <20201027154058.495112-1-anthony.perard@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>

9pfs: only test case changes this time

* Fix occasional test failures with parallel tests.

* Fix coverity error in test code.

* Avoid error when auto removing test directory if it disappeared
  for some reason.

* Refactor: Rename functions to make top-level test functions fs_*()
  easily distinguishable from utility test functions do_*().

* Refactor: Drop unnecessary function arguments in utility test
  functions.

* More test cases using the 9pfs 'local' filesystem driver backend,
  namely for the following 9p requests: Tunlinkat, Tlcreate, Tsymlink
  and Tlink.

# gpg: Signature made Mon 02 Nov 2020 09:31:35 GMT
# gpg:                using RSA key 96D8D110CF7AF8084F88590134C2B58765A47395
# gpg:                issuer "qemu_oss@crudebyte.com"
# gpg: Good signature from "Christian Schoenebeck <qemu_oss@crudebyte.com>" [unknown]
# 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: ECAB 1A45 4014 1413 BA38  4926 30DB 47C3 A012 D5F4
#      Subkey fingerprint: 96D8 D110 CF7A F808 4F88  5901 34C2 B587 65A4 7395

* remotes/cschoenebeck/tags/pull-9p-20201102:
  tests/9pfs: add local Tunlinkat hard link test
  tests/9pfs: add local Tlink test
  tests/9pfs: add local Tunlinkat symlink test
  tests/9pfs: add local Tsymlink test
  tests/9pfs: add local Tunlinkat file test
  tests/9pfs: add local Tlcreate test
  tests/9pfs: add local Tunlinkat directory test
  tests/9pfs: simplify do_mkdir()
  tests/9pfs: Turn fs_mkdir() into a helper
  tests/9pfs: Turn fs_readdir_split() into a helper
  tests/9pfs: Factor out do_attach() helper
  tests/9pfs: Set alloc in fs_create_dir()
  tests/9pfs: Factor out do_version() helper
  tests/9pfs: Force removing of local 9pfs test directory
  tests/9pfs: fix coverity error in create_local_test_dir()
  tests/9pfs: fix test dir for parallel tests
  tests/9pfs: make create/remove test dir public

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

VFIO update 2020-11-01

 * Migration support (Kirti Wankhede)
 * s390 DMA limiting (Matthew Rosato)
 * zPCI hardware info (Matthew Rosato)
 * Lock guard (Amey Narkhede)
 * Print fixes (Zhengui li)
 * Warning/build fixes

# gpg: Signature made Sun 01 Nov 2020 20:38:10 GMT
# gpg:                using RSA key 239B9B6E3BB08B22
# gpg: Good signature from "Alex Williamson <alex.williamson@redhat.com>" [full]
# gpg:                 aka "Alex Williamson <alex@shazbot.org>" [full]
# gpg:                 aka "Alex Williamson <alwillia@redhat.com>" [full]
# gpg:                 aka "Alex Williamson <alex.l.williamson@gmail.com>" [full]
# Primary key fingerprint: 42F6 C04E 540B D1A9 9E7B  8A90 239B 9B6E 3BB0 8B22

* remotes/awilliam/tags/vfio-update-20201101.0: (32 commits)
  vfio: fix incorrect print type
  hw/vfio: Use lock guard macros
  s390x/pci: get zPCI function info from host
  vfio: Add routine for finding VFIO_DEVICE_GET_INFO capabilities
  s390x/pci: use a PCI Function structure
  s390x/pci: clean up s390 PCI groups
  s390x/pci: use a PCI Group structure
  s390x/pci: create a header dedicated to PCI CLP
  s390x/pci: Honor DMA limits set by vfio
  s390x/pci: Add routine to get the vfio dma available count
  vfio: Find DMA available capability
  vfio: Create shared routine for scanning info capabilities
  s390x/pci: Move header files to include/hw/s390x
  linux-headers: update against 5.10-rc1
  update-linux-headers: Add vfio_zdev.h
  qapi: Add VFIO devices migration stats in Migration stats
  vfio: Make vfio-pci device migration capable
  vfio: Add ioctl to get dirty pages bitmap during dma unmap
  vfio: Dirty page tracking when vIOMMU is enabled
  vfio: Add vfio_listener_log_sync to mark dirty pages
  ...

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

The type of input variable is unsigned int
while the printer type is int. So fix incorrect print type.

Signed-off-by: Zhengui li <lizhengui@huawei.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Use qemu LOCK_GUARD macros in hw/vfio.
Saves manual unlock calls

Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

We use the capability chains of the VFIO_DEVICE_GET_INFO ioctl to retrieve
the CLP information that the kernel exports.

To be compatible with previous kernel versions we fall back on previous
predefined values, same as the emulation values, when the ioctl is found
to not support capability chains. If individual CLP capabilities are not
found, we fall back on default values for only those capabilities missing
from the chain.

This patch is based on work previously done by Pierre Morel.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
[aw: non-Linux build fixes]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Now that VFIO_DEVICE_GET_INFO supports capability chains, add a helper
function to find specific capabilities in the chain.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

We use a ClpRspQueryPci structure to hold the information related to a
zPCI Function.

This allows us to be ready to support different zPCI functions and to
retrieve the zPCI function information from the host.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Add a step to remove all stashed PCI groups to avoid stale data between
machine resets.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

We use a S390PCIGroup structure to hold the information related to a
zPCI Function group.

This allows us to be ready to support multiple groups and to retrieve
the group information from the host.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

To have a clean separation between s390-pci-bus.h and s390-pci-inst.h
headers we export the PCI CLP instructions in a dedicated header.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

When an s390 guest is using lazy unmapping, it can result in a very
large number of oustanding DMA requests, far beyond the default
limit configured for vfio.  Let's track DMA usage similar to vfio
in the host, and trigger the guest to flush their DMA mappings
before vfio runs out.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
[aw: non-Linux build fixes]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Create new files for separating out vfio-specific work for s390
pci. Add the first such routine, which issues VFIO_IOMMU_GET_INFO
ioctl to collect the current dma available count.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
[aw: Fix non-Linux build with CONFIG_LINUX]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

The underlying host may be limiting the number of outstanding DMA
requests for type 1 IOMMU.  Add helper functions to check for the
DMA available capability and retrieve the current number of DMA
mappings allowed.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
[aw: vfio_get_info_dma_avail moved inside CONFIG_LINUX]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Rather than duplicating the same loop in multiple locations,
create a static function to do the work.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Seems a more appropriate location for them.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

commit 3650b228f83adda7e5ee532e2b90429c03f7b9ec

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
[aw: drop pvrdma_ring.h changes to avoid revert of d73415a3 ("qemu/atomic.h: rename atomic_ to qatomic_")]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

vfio_zdev.h is used by s390x zPCI support to pass device-specific
CLP information between host and userspace.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Added amount of bytes transferred to the VM at destination by all VFIO
devices

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

If the device is not a failover primary device, call
vfio_migration_probe() and vfio_migration_finalize() to enable
migration support for those devices that support it respectively to
tear it down again.
Removed migration blocker from VFIO PCI device specific structure and use
migration blocker from generic structure of  VFIO device.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

With vIOMMU, IO virtual address range can get unmapped while in pre-copy
phase of migration. In that case, unmap ioctl should return pages pinned
in that range and QEMU should find its correcponding guest physical
addresses and report those dirty.

Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
[aw: fix error_report types, fix cpu_physical_memory_set_dirty_lebitmap() cast]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

When vIOMMU is enabled, register MAP notifier from log_sync when all
devices in container are in stop and copy phase of migration. Call replay
and get dirty pages from notifier callback.

Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

vfio_listener_log_sync gets list of dirty pages from container using
VFIO_IOMMU_GET_DIRTY_BITMAP ioctl and mark those pages dirty when all
devices are stopped and saving state.
Return early for the RAM block section of mapped MMIO region.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
[aw: fix error_report types, fix cpu_physical_memory_set_dirty_lebitmap() cast]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Call VFIO_IOMMU_DIRTY_PAGES ioctl to start and stop dirty pages tracking
for VFIO devices.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Added helper functions to get IOMMU info capability chain.
Added function to get migration capability information from that
capability chain for IOMMU container.

Similar change was proposed earlier:
https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg03759.html



Disable migration for devices if IOMMU module doesn't support migration
capability.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Cc: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Cc: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

mr->ram_block is NULL when mr->is_iommu is true, then fr.dirty_log_mask
wasn't set correctly due to which memory listener's log_sync doesn't
get called.
This patch returns log_mask with DIRTY_MEMORY_MIGRATION set when
IOMMU is enabled.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Sequence  during _RESUMING device state:
While data for this device is available, repeat below steps:
a. read data_offset from where user application should write data.
b. write data of data_size to migration region from data_offset.
c. write data_size which indicates vendor driver that data is written in
   staging buffer.

For user, data is opaque. User should write data in the same order as
received.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Added .save_live_pending, .save_live_iterate and .save_live_complete_precopy
functions. These functions handles pre-copy and stop-and-copy phase.

In _SAVING|_RUNNING device state or pre-copy phase:
- read pending_bytes. If pending_bytes > 0, go through below steps.
- read data_offset - indicates kernel driver to write data to staging
  buffer.
- read data_size - amount of data in bytes written by vendor driver in
  migration region.
- read data_size bytes of data from data_offset in the migration region.
- Write data packet to file stream as below:
{VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data,
VFIO_MIG_FLAG_END_OF_STATE }

In _SAVING device state or stop-and-copy phase
a. read config space of device and save to migration file stream. This
   doesn't need to be from vendor driver. Any other special config state
   from driver can be saved as data in following iteration.
b. read pending_bytes. If pending_bytes > 0, go through below steps.
c. read data_offset - indicates kernel driver to write data to staging
   buffer.
d. read data_size - amount of data in bytes written by vendor driver in
   migration region.
e. read data_size bytes of data from data_offset in the migration region.
f. Write data packet as below:
   {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data}
g. iterate through steps b to f while (pending_bytes > 0)
h. Write {VFIO_MIG_FLAG_END_OF_STATE}

When data region is mapped, its user's responsibility to read data from
data_offset of data_size before moving to next steps.

Added fix suggested by Artem Polyakov to reset pending_bytes in
vfio_save_iterate().
Added fix suggested by Zhi Wang to add 0 as data size in migration stream and
add END_OF_STATE delimiter to indicate phase complete.

Suggested-by: Artem Polyakov <artemp@nvidia.com>
Suggested-by: Zhi Wang <zhi.wang.linux@gmail.com>
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>