qemu-iotests: fix -valgrind option for check

Commit 934659c switched the iotests to run qemu-io from a bash subshell,
in order to catch segfaults.  This method is incompatible with the
current valgrind_qemu_io() bash function.

Move the valgrind usage into the exec subshell in _qemu_io_wrapper(),
while making sure the original return value is passed back to the
caller.

Update test output for tests 039, 061, and 137 as it looks for the
specific subshell command when the process is terminated.

Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Message-id: 0066fd85d26ca641a1c25135ff2479b7985701cf.1446232490.git.jcody@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

qemu-iotests: fix cleanup of background processes

Commit 934659c switched the iotests to run qemu and qemu-nbd from a bash
subshell, in order to catch segfaults.  Unfortunately, this means the
process PID cannot be captured via '$!'. We stopped killing qemu and
qemu-nbd processes, leaving a lot of orphaned, running qemu processes
after executing iotests.

Since the process is using exec in the subshell, the PID is the
same as the subshell PID.

Track these PIDs for cleanup using pidfiles in the $TEST_DIR. Only
track the qemu PID, however, if requested - not all usage requires
killing the process.

Reported-by: John Snow <jsnow@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Message-id: 9e4f958b3895b7259b98d845bb46f000ba362869.1446232490.git.jcody@redhat.com
[mreitz@redhat.com: Replaced '! -z "..."' by '-n "..."']
Signed-off-by: Max Reitz <mreitz@redhat.com>

qemu-io: Correct error messages

Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qemu-io: Check for trailing chars

Make sure there's not trailing garbage, e.g.
"64k-whatever-i-want-here"

Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qemu-io: fix cvtnum lval types

cvtnum() returns int64_t: we should not be storing this
result inside of an int.

In a few cases, we need an extra sprinkling of error handling
where we expect to pass this number on towards a function that
expects something smaller than int64_t.

Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: test 'blockdev-snapshot' using a file BDS as the overlay

This test checks that it is not possible to create a snapshot if the
requested overlay node is a BDS which does not support backing images.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: Remove inner quotation marks in iotest 085

This patch removes the inner quotation marks in all cases like this:

   cmd=" ... "${variable}" ... "

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: Disallow snapshots if the overlay doesn't support backing files

This addresses scenarios like this one:

  { 'execute': 'blockdev-add', 'arguments':
    { 'options': { 'driver': 'qcow2',
                   'node-name': 'new0',
                   'file': { 'driver': 'file',
                             'filename': 'new.qcow2',
                             'node-name': 'file0' } } } }

  { 'execute': 'blockdev-snapshot', 'arguments':
    { 'node': 'virtio0',
      'overlay': 'file0' } }

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

throttle: Use bs->throttle_state instead of bs->io_limits_enabled

There are two ways to check for I/O limits in a BlockDriverState:

- bs->throttle_state: if this pointer is not NULL, it means that this
  BDS is member of a throttling group, its ThrottleTimers structure
  has been initialized and its I/O limits are ready to be applied.

- bs->io_limits_enabled: if true it means that the throttle_state
  pointer is valid _and_ the limits are currently enabled.

The latter is used in several places to check whether a BDS has I/O
limits configured, but what it really checks is whether requests
are being throttled or not. For example, io_limits_enabled can be
temporarily set to false in cases like bdrv_read_unthrottled() without
otherwise touching the throtting configuration of that BDS.

This patch replaces bs->io_limits_enabled with bs->throttle_state in
all cases where what we really want to check is the existence of I/O
limits, not whether they are currently enabled or not.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

throttle: Check for pending requests in throttle_group_unregister_bs()

throttle_group_unregister_bs() removes a BlockDriverState from its
throttling group and destroys the timers. This means that there must
be no pending throttled requests at that point (because it would be
impossible to complete them), so the caller has to drain them first.

At the moment throttle_group_unregister_bs() is only called from
bdrv_io_limits_disable(), which already takes care of draining the
requests, so there's nothing to worry about, but this patch makes
this invariant explicit in the documentation and adds the relevant
assertions.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qemu-img: add check for zero-length job len

The mirror job doesn't update its total length until
it has already started running, so we should translate
a zero-length job-len as meaning 0%.

Otherwise, we may get divide-by-zero faults.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qcow2: avoid misaligned 64bit bswap

If we create a buffer directly on the stack by using 12 bytes, there's
no guarantee the 64bit value we want to swap will be aligned, which
could cause errors with undefined behavior.

Spotted with clang -fsanitize=undefined and observed in iotests 15, 26,
44, 115 and 121.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qemu-iotests: Test the reopening of overlay_bs in 'block-commit'

The 'block-commit' command needs the overlay image of 'top' to
be opened in read-write mode in order to update the backing file
string. If 'top' is not the active layer or its backing file then its
overlay needs to be reopened during the block job.

This is a test case for that scenario.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

commit: reopen overlay_bs before base

'block-commit' needs write access to two different nodes of the chain:

- 'base', because that's where the data is written to.
- the overlay of 'top', because it needs to update the backing file
  string to point to 'base' after the operation.

Both images have to be opened in read-write mode, and commit_start()
takes care of reopening them if necessary.

With the current implementation, however, when overlay_bs is reopened
in read-write mode it has the side effect of making 'base' read-only
again, eventually making 'block-commit' fail.

This needs to be fixed in bdrv_reopen(), but until we get to that it
can be worked around simply by swapping the order of base and
overlay_bs in the reopen queue.

In order to reproduce this bug, overlay_bs needs to be initially in
read-only mode. That is: the 'top' parameter of 'block-commit' cannot
be the active layer nor its immediate backing chain.

Cc: qemu-stable@nongnu.org
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: add tests for the 'blockdev-snapshot' command

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: add a 'blockdev-snapshot' QMP command

One of the limitations of the 'blockdev-snapshot-sync' command is that
it does not allow passing BlockdevOptions to the newly created
snapshots, so they are always opened using the default values.

Extending the command to allow passing options is not a practical
solution because there is overlap between those options and some of
the existing parameters of the command.

This patch introduces a new 'blockdev-snapshot' command with a simpler
interface: it just takes two references to existing block devices that
will be used as the source and target for the snapshot.

Since the main difference between the two commands is that one of them
creates and opens the target image, while the other uses an already
opened one, the bulk of the implementation is shared.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: support passing 'backing': '' to 'blockdev-add'

Passing an empty string allows opening an image but not its backing
file. This was already described in the API documentation, only the
implementation was missing.

This is useful for creating snapshots using images opened with
blockdev-add, since they are not supposed to have a backing image
before the operation.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: rename BlockdevSnapshot to BlockdevSnapshotSync

We will introduce the 'blockdev-snapshot' command that will require
its own struct for the parameters, so we need to rename this one in
order to avoid name clashes.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: check for existing device IDs in external_snapshot_prepare()

The 'snapshot-node-name' parameter of blockdev-snapshot-sync allows
setting the node name of the image that is going to be created.

Before creating the image, external_snapshot_prepare() checks that the
name is not already being used. The check is however incomplete since
it only considers existing node names, but node names must not clash
with device IDs either because they share the same namespace.

If the user attempts to create a snapshot using the name of an
existing device for the 'snapshot-node-name' parameter the operation
will eventually fail, but only after the new image has been created.

This patch replaces bdrv_find_node() with bdrv_lookup_bs() to extend
the check to existing device IDs, and thus detect possible name
clashes before the new image is created.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

iotests: Add test for change-related QMP commands

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

hmp: Add read-only-mode option to change command

Expose the new read-only-mode option of 'blockdev-change-medium' for the
'change' HMP command.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev: read-only-mode for blockdev-change-medium

Add an option to qmp_blockdev_change_medium() which allows changing the
read-only status of the block device whose medium is changed.

Some drives do not have a inherently fixed read-only status; for
instance, floppy disks can be set read-only or writable independently of
the drive. Some users may find it useful to be able to therefore change
the read-only status of a block device when changing the medium.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

hmp: Use blockdev-change-medium for change command

Use separate code paths for the two overloaded functions of the 'change'
HMP command, and invoke the 'blockdev-change-medium' QMP command if used
on a block device (by calling qmp_blockdev_change_medium()).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qmp: Introduce blockdev-change-medium

Introduce a new QMP command 'blockdev-change-medium' which is intended
to replace the 'change' command for block devices. The existing function
qmp_change_blockdev() is accordingly renamed to
qmp_blockdev_change_medium().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: Inquire tray state before tray-moved events

blk_dev_change_media_cb() is called for all potential tray movements;
however, it is possible to request closing the tray but nothing actually
happening (on a floppy disk drive without a medium).

Thus, the actual tray status should be inquired before sending a
tray-moved event (and an event should be sent whenever the status
changed).

Checking @load is now superfluous; it was necessary because it was
possible to change a medium without having explicitly opened the tray
and closed it again (or it might have been possible, at least). This is
no longer possible, though.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev: Implement change with basic operations

Implement 'change' on block devices by calling blockdev-open-tray,
blockdev-remove-medium, blockdev-insert-medium (a variation of that
which does not need a node-name) and blockdev-close-tray.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev: Implement eject with basic operations

Implement 'eject' by calling blockdev-open-tray and
blockdev-remove-medium.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev: Add blockdev-insert-medium

And a helper function for that, which directly takes a pointer to the
BDS to be inserted instead of its node-name (which will be used for
implementing 'change' using blockdev-insert-medium).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev: Add blockdev-remove-medium

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev: Add blockdev-close-tray

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev: Add blockdev-open-tray

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: Add functions for inheriting a BBRS

In order to open a BDS which inherits a BB's root state,
blk_get_open_flags_from_root_state() is used to inquire the flags to be
passed to bdrv_open(), and blk_apply_root_state() is used to apply the
remaining state after the BDS has been opened.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: Make bdrv_states public

When inserting a BDS tree into a BB, we will need to add the root BDS to
this list. Since we will want to do that in the blockdev-insert-medium
implementation in blockdev.c, we will need access to it there.

This patch is not exactly elegant, but bdrv_states will be removed in
the future anyway because we no longer need it since we have BBs.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: Add blk_remove_bs()

This function removes the BlockDriverState associated with the given
BlockBackend from that BB and sets the BDS pointer in the BB to NULL.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block: Don't call blk_bs() twice in bdrv_lookup_bs()

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Merge remote-tracking branch 'remotes/dgibson/tags/ppc-next-20151111' into staging

ppc patch queue - 2015-11-11

Highlights:
  - Updated SLOF version for "pseries machine
  - Bugfix / cleanup for KVM hash page table allocation

# gpg: Signature made Wed 11 Nov 2015 02:30:51 GMT using RSA key ID 20D9B392
# gpg: Good signature from "David Gibson <david@gibson.dropbear.id.au>"
# gpg:                 aka "David Gibson (Red Hat) <dgibson@redhat.com>"
# gpg:                 aka "David Gibson (ozlabs.org) <dgibson@ozlabs.org>"
# 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: 75F4 6586 AE61 A66C C44E  87DC 6C38 CACA 20D9 B392

* remotes/dgibson/tags/ppc-next-20151111:
  spapr: Handle failure of KVM_PPC_ALLOCATE_HTAB ioctl
  ppc: Let kvmppc_reset_htab() return 0 for !CONFIG_KVM
  pseries: Update SLOF firmware image to qemu-slof-20151103
  ppc: Add/Re-introduce MMU model definitions needed by PR KVM

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

spapr: Handle failure of KVM_PPC_ALLOCATE_HTAB ioctl

KVM_PPC_ALLOCATE_HTAB ioctl can return -ENOMEM for KVM guests and QEMU
never handled this correctly. But this didn't cause any problems till
now as KVM_PPC_ALLOCATE_HTAB ioctl returned with smaller than requested
HTAB when enough contiguous memory wasn't available in the host.
After the proposed kernel change: https://patchwork.ozlabs.org/patch/530501/,
KVM_PPC_ALLOCATE_HTAB ioctl will not fallback to lower sized HTAB
allocation and will fail if requested HTAB size can't be met.

Check for such failures in QEMU and abort appropriately. This will
prevent guest kernel from hanging/freezing during early boot by doing
graceful exit when host is unable to allocate requested HTAB.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

ppc: Let kvmppc_reset_htab() return 0 for !CONFIG_KVM

The !CONFIG_KVM implementation of kvmppc_reset_htab() returns -1
by default. Change this to return 0 so that we fall back to user space
HTAB allocation for emulated guests.

This fixes the make check failures for ppc64 emulated target.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

pseries: Update SLOF firmware image to qemu-slof-20151103

The changes are:
1. supports recent binutils;
2. 64bit BARs behind PCI bridges supported;
3. Many fixes for USB keyboard support - keys, XHCI;
4. virtio-vga support.

This image was built with:
gcc version 4.8.3 20140911 (Red Hat 4.8.3-7) (GCC)
GNU ld version 2.23.2

The full changelog is:
  > version: update to 20151103
  > documentation: Add a clause about signing off
  > qemu/js2x/client: Support binutils >= 2.25.1
  > Fix special keys on USB
  > Fix function keys on USB
  > pci-scan: program 64-bit mem bar range in pci-bridge bar
  > Allow to build SLOF on Little Endian host
  > usb-xhci: add keyboard support
  > usb-xhci: ready the link trb early
  > usb-xhci: scan usb high speed ports
  > usb-xhci: bulk improve event handling loop
  > usb-xhci: return on allocation failure
  > usb-xhci: add delay in shutdown path
  > usb-xhci: event trbs does not need link trb
  > usb-hid: refactor usb key reading
  > takeover: Fix header includes
  > board-js2x: Add missing file dma-function.fs
  > vga: Add support for virtio-vga
  > qemu-vga: Use MMIO BAR instead of legacy IO ports
  > slof: Change call_c() function to a proper assembler function

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

ppc: Add/Re-introduce MMU model definitions needed by PR KVM

Commit aa4bb5875231 (ppc: Add mmu_model defines for arch 2.03 and 2.07)
removed the mmu_model definition POWERPC_MMU_2_06a which is needed by
PR KVM. Reintroduce it and also add POWERPC_MMU_2_07a.

This fixes QEMU crash (qemu: fatal: Unknown MMU model) during booting
of PR KVM guest.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Merge remote-tracking branch 'remotes/awilliam/tags/vfio-update-20151110.0' into staging

VFIO updates 2015-11-10

 - Make Windows happy with vfio-pci devices exposed on conventional
   PCI buses on q35 by hiding PCIe capability (Alex Williamson)
 - Convert to g_new() where appropriate (Markus Armbruster)

# gpg: Signature made Tue 10 Nov 2015 19:46:41 GMT using RSA key ID 3BB08B22
# 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>"

* remotes/awilliam/tags/vfio-update-20151110.0:
  vfio: Use g_new() & friends where that makes obvious sense
  vfio/pci: Hide device PCIe capability on non-express buses for PCIe VMs

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

vfio: Use g_new() & friends where that makes obvious sense

g_new(T, n) is neater than g_malloc(sizeof(T) * n).  It's also safer,
for two reasons.  One, it catches multiplication overflowing size_t.
Two, it returns T * rather than void *, which lets the compiler catch
more type errors.

This commit only touches allocations with size arguments of the form
sizeof(T).  Same Coccinelle semantic patch as in commit b45c03f.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

vfio/pci: Hide device PCIe capability on non-express buses for PCIe VMs

When we have a PCIe VM, such as Q35, guests start to care more about
valid configurations of devices relative to the VM view of the PCI
topology.  Windows will error with a Code 10 for an assigned device if
a PCIe capability is found for a device on a conventional bus.  We
also have the possibility of IOMMUs, like VT-d, where the where the
guest may be acutely aware of valid express capabilities on physical
hardware.

Some devices, like tg3 are adversely affected by this due to driver
dependencies on the PCIe capability.  The only solution for such
devices is to attach them to an express capable bus in the VM.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Merge remote-tracking branch 'remotes/juanquintela/tags/migration/20151110' into staging

migration/next for 20151110

# gpg: Signature made Tue 10 Nov 2015 14:23:26 GMT using RSA key ID 5872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>"
# gpg:                 aka "Juan Quintela <quintela@trasno.org>"

* remotes/juanquintela/tags/migration/20151110: (57 commits)
  migration: qemu_savevm_state_cleanup becomes mandatory operation
  Inhibit ballooning during postcopy
  Disable mlock around incoming postcopy
  End of migration for postcopy
  Postcopy: Mark nohugepage before discard
  postcopy: Wire up loadvm_postcopy_handle_ commands
  Start up a postcopy/listener thread ready for incoming page data
  Postcopy; Handle userfault requests
  Round up RAMBlock sizes to host page sizes
  Host page!=target page: Cleanup bitmaps
  Don't iterate on precopy-only devices during postcopy
  Don't sync dirty bitmaps in postcopy
  postcopy: Check order of received target pages
  Postcopy: Use helpers to map pages during migration
  postcopy_ram.c: place_page and helpers
  Page request: Consume pages off the post-copy queue
  Page request: Process incoming page request
  Page request: Add MIG_RP_MSG_REQ_PAGES reverse command
  Postcopy: End of iteration
  Postcopy: Postcopy startup in migration thread
  ...

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

migration: qemu_savevm_state_cleanup becomes mandatory operation

since commit
    commit 94f5a43704129ca4995aa3385303c5ae225bde42
    Author: Liang Li <liang.z.li@intel.com>
    Date:   Mon Nov 2 15:37:00 2015 +0800

    migration: defer migration_end & blk_mig_cleanup

when actual .cleanup callbacks calling was removed from complete operations.

The patch fixes regression introduced by the commit above results in
100% reliable assert for virtio-scsi VM with iothreads enabled during
'virsh create-snapshot' operation:
    assert(i != mr->ioeventfd_nb);
    memory_region_del_eventfd
    virtio_pci_set_host_notifier_internal
    virtio_pci_set_host_notifier
    virtio_scsi_dataplane_start
    virtio_scsi_handle_cmd
    virtio_queue_notify_vq
    virtio_queue_host_notifier_read
    aio_dispatch

Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Liang Li <liang.z.li@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Juan Quintela <quintela@redhat.com>
CC: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Inhibit ballooning during postcopy

Postcopy detects accesses to pages that haven't been transferred yet
using userfaultfd, and it causes exceptions on pages that are 'not
present'.
Ballooning also causes pages to be marked as 'not present' when the
guest inflates the balloon.
Potentially a balloon could be inflated to discard pages that are
currently inflight during postcopy and that may be arriving at about
the same time.

To avoid this confusion, disable ballooning during postcopy.

When disabled we drop balloon requests from the guest.  Since ballooning
is generally initiated by the host, the management system should avoid
initiating any balloon instructions to the guest during migration,
although it's not possible to know how long it would take a guest to
process a request made prior to the start of migration.
Guest initiated ballooning will not know if it's really freed a page
of host memory or not.

Queueing the requests until after migration would be nice, but is
non-trivial, since the set of inflate/deflate requests have to
be compared with the state of the page to know what the final
outcome is allowed to be.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Disable mlock around incoming postcopy

Userfault doesn't work with mlock; mlock is designed to nail down pages
so they don't move, userfault is designed to tell you when they're not
there.

munlock the pages we userfault protect before postcopy.
mlock everything again at the end if mlock is enabled.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

End of migration for postcopy

Tweak the end of migration cleanup; we don't want to close stuff down
at the end of the main stream, since the postcopy is still sending pages
on the other thread.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Postcopy: Mark nohugepage before discard

Prior to servicing userfault requests we must ensure we've not got
huge pages in the area that might include non-transferred memory,
since a hugepage could incorrectly mark the whole huge page as present.

We mark the area as non-huge page (nhp) just before we perform
discards; the discard code now tells us to discard any areas
that haven't been sent (as well as any that are redirtied);
any already formed transparent-huge-pages get fragmented
by this discard process if they cotnain any discards.

Transparent huge pages that have been entirely transferred
and don't contain any discards are not broken by this mechanism;
they stay as huge pages.

By starting postcopy after a full precopy pass, many of the pages
then stay as huge pages; this is important for maintaining performance
after the end of the migration.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

postcopy: Wire up loadvm_postcopy_handle_ commands

Wire up more of the handlers for the commands on the destination side,
in particular loadvm_postcopy_handle_run now has enough to start the
guest running.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Start up a postcopy/listener thread ready for incoming page data

The loading of a device state (during postcopy) may access guest
memory that's still on the source machine and thus might need
a page fill; split off a separate thread that handles the incoming
page data so that the original incoming migration code can finish
off the device data.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Postcopy; Handle userfault requests

userfaultfd is a Linux syscall that gives an fd that receives a stream
of notifications of accesses to pages registered with it and allows
the program to acknowledge those stalls and tell the accessing
thread to carry on.

We convert the requests from the kernel into messages back to the
source asking for the pages.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Round up RAMBlock sizes to host page sizes

RAMBlocks that are not a multiple of host pages in length
cause problems for postcopy (I've seen an ACPI table on aarch64
be 5k in length - i.e. 5x target-page), so round RAMBlock sizes
up to a host-page.

This potentially breaks migration compatibility due to changes
in RAMBlock sizes; however:
   1) x86 and s390 I think always have host=target page size
   2) When I've tried on Power the block sizes already seem aligned.
   3) I don't think there's anything else that maintains per-version
      machine-types for compatibility.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Host page!=target page: Cleanup bitmaps

Prior to the start of postcopy, ensure that everything that will
be transferred later is a whole host-page in size.

This is accomplished by discarding partially transferred host pages
and marking any that are partially dirty as fully dirty.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Don't iterate on precopy-only devices during postcopy

During the postcopy phase we must not call the iterate method on
precopy-only devices, since they may have done some cleanup during
the _complete call at the end of the precopy phase.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Don't sync dirty bitmaps in postcopy

Once we're in postcopy the source processors are stopped and memory
shouldn't change any more, so there's no need to look at the dirty
map.

There are two notes to this:
  1) If we do resync and a page had changed then the page would get
     sent again, which the destination wouldn't allow (since it might
     have also modified the page)
  2) Before disabling this I'd seen very rare cases where a page had been
     marked dirtied although the memory contents are apparently identical

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

postcopy: Check order of received target pages

Ensure that target pages received within a host page are in order.
This shouldn't trigger, but in the cases where the sender goes
wrong and sends stuff out of order it produces a corruption that's
really nasty to debug.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Postcopy: Use helpers to map pages during migration

In postcopy, the destination guest is running at the same time
as it's receiving pages; as we receive new pages we must put
them into the guests address space atomically to avoid a running
CPU accessing a partially written page.

Use the helpers in postcopy-ram.c to map these pages.

qemu_get_buffer_in_place is used to avoid a copy out of qemu_file
in the case that postcopy is going to do a copy anyway.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

postcopy_ram.c: place_page and helpers

postcopy_place_page (etc) provide a way for postcopy to place a page
into guests memory atomically (using the copy ioctl on the ufd).

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Page request: Consume pages off the post-copy queue

When transmitting RAM pages, consume pages that have been queued by
MIG_RPCOMM_REQPAGE commands and send them ahead of normal page scanning.

Note:
  a) After a queued page the linear walk carries on from after the
unqueued page; there is a reasonable chance that the destination
was about to ask for other closeby pages anyway.

  b) We have to be careful of any assumptions that the page walking
code makes, in particular it does some short cuts on its first linear
walk that break as soon as we do a queued page.

  c) We have to be careful to not break up host-page size chunks, since
this makes it harder to place the pages on the destination.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Page request: Process incoming page request

On receiving MIG_RPCOMM_REQ_PAGES look up the address and
queue the page.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Page request: Add MIG_RP_MSG_REQ_PAGES reverse command

Add MIG_RP_MSG_REQ_PAGES command on Return path for the postcopy
destination to request a page from the source.

Two versions exist:
   MIG_RP_MSG_REQ_PAGES_ID that includes a RAMBlock name and start/len
   MIG_RP_MSG_REQ_PAGES that just has start/len for use with the same
                        RAMBlock as a previous MIG_RP_MSG_REQ_PAGES_ID

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Postcopy: End of iteration

The end of migration in postcopy is a bit different since some of
the things normally done at the end of migration have already been
done on the transition to postcopy.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Postcopy: Postcopy startup in migration thread

Rework the migration thread to setup and start postcopy.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

postcopy: ram_enable_notify to switch on userfault

Mark the area of RAM as 'userfault'
Start up a fault-thread to handle any userfaults we might receive
from it (to be filled in later)

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

postcopy: Incoming initialisation

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

migration_completion: Take current state

Soon we'll be in either ACTIVE or POSTCOPY_ACTIVE when we
complete migration, and we need to know which we expect to be
in to change state safely.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Postcopy: Maintain unsentmap

Maintain an 'unsentmap' of pages that have yet to be sent.
This is used in the following patches to discard some set of
the pages already sent as we enter postcopy mode.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Add qemu_savevm_state_complete_postcopy

Add qemu_savevm_state_complete_postcopy to complement
qemu_savevm_state_complete_precopy together with a new
save_live_complete_postcopy method on devices.

The save_live_complete_precopy method is called on
all devices during a precopy migration, and all non-postcopy
devices during a postcopy migration at the transition.

The save_live_complete_postcopy method is called at
the end of postcopy for all postcopiable devices.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Avoid sending vmdescription during postcopy

VMDescription is normally sent at the end, after all
of the devices; however that's not the end for postcopy,
so just don't send it when in postcopy.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

MIGRATION_STATUS_POSTCOPY_ACTIVE: Add new migration state

'MIGRATION_STATUS_POSTCOPY_ACTIVE' is entered after migrate_start_postcopy

'migration_in_postcopy' is provided for other sections to know if
they're in postcopy.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

migration_completion: Take current state

Soon we'll be in either ACTIVE or POSTCOPY_ACTIVE when we
complete migration, and we need to know which we expect to be
in to change state safely.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

migrate_start_postcopy: Command to trigger transition to postcopy

Once postcopy is enabled (with migrate_set_capability), the migration
will still start on precopy mode.  To cause a transition into postcopy
the:

  migrate_start_postcopy

command must be issued.  Postcopy will start sometime after this
(when it's next checked in the migration loop).

Issuing the command before migration has started will error,
and issuing after it has finished is ignored.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

postcopy: OS support test

Provide a check to see if the OS we're running on has all the bits
needed for postcopy.

Creates postcopy-ram.c which will get most of the other helpers we need.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Modify save_live_pending for postcopy

Modify save_live_pending to return separate postcopiable and
non-postcopiable counts.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

MIG_CMD_PACKAGED: Send a packaged chunk of migration stream

MIG_CMD_PACKAGED is a migration command that wraps a chunk of migration
stream inside a package whose length can be determined purely by reading
its header.  The destination guarantees that the whole MIG_CMD_PACKAGED
is read off the stream prior to parsing the contents.

This is used by postcopy to load device state (from the package)
while leaving the main stream free to receive memory pages.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Add wrappers and handlers for sending/receiving the postcopy-ram migration messages.

The state of the postcopy process is managed via a series of messages;
   * Add wrappers and handlers for sending/receiving these messages
   * Add state variable that track the current state of postcopy

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Add migration-capability boolean for postcopy-ram.

The 'postcopy ram' capability allows postcopy migration of RAM;
note that the migration starts off in precopy mode until
postcopy mode is triggered (see the migrate_start_postcopy
patch later in the series).

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Rework loadvm path for subloops

Postcopy needs to have two migration streams loading concurrently;
one from memory (with the device state) and the other from the fd
with the memory transactions.

Split the core of qemu_loadvm_state out so we can use it for both.

Allow the inner loadvm loop to quit and cause the parent loops to
exit as well.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Return path: Source handling of return path

Open a return path, and handle messages that are received upon it.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

migration_is_setup_or_active

Add 'migration_is_setup_or_active' utility function to check state.
(It gets postcopy added to it's list later on in the series)

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Return path: Send responses from destination to source

Add migrate_send_rp_message to send a message from destination to source along the return path.
  (It uses a mutex to let it be called from multiple threads)
Add migrate_send_rp_shut to send a 'shut' message to indicate
  the destination is finished with the RP.
Add migrate_send_rp_ack to send a 'PONG' message in response to a PING
  Use it in the MSG_RP_PING handler

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Return path: Control commands

Add two src->dest commands:
   * OPEN_RETURN_PATH - To request that the destination open the return path
   * PING - Request an acknowledge from the destination

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Migration commands

Create QEMU_VM_COMMAND section type for sending commands from
source to destination.  These commands are not intended to convey
guest state but to control the migration process.

For use in postcopy.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Return path: socket_writev_buffer: Block even on non-blocking fd's

The destination sets the fd to non-blocking on incoming migrations;
this also affects the return path from the destination, and thus we
need to make sure we can safely write to the return path.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Merge remote-tracking branch 'remotes/pmaydell/tags/pull-target-arm-20151110' into staging

target-arm queue:
 * fix bugs in gdb singlestep handling and breakpoints
 * minor code cleanup in arm_gic
 * clean up error messages in hw/arm/virt
 * fix highbank kernel booting by adding a board-setup blob

# gpg: Signature made Tue 10 Nov 2015 13:43:52 GMT using RSA key ID 14360CDE
# 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>"

* remotes/pmaydell/tags/pull-target-arm-20151110:
  target-arm: Clean up DISAS_UPDATE usage in AArch32 translation code
  hw/arm/virt: error_report cleanups
  arm: highbank: Implement PSCI and dummy monitor
  arm: highbank: Defeature CPU override
  arm: boot: Add secure_board_setup flag
  hw/intc/arm_gic: Remove the definition of NUM_CPU
  target-arm: Fix gdb singlestep handling in arm_debug_excp_handler()

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

Return path: Open a return path on QEMUFile for sockets

Postcopy needs a method to send messages from the destination back to
the source, this is the 'return path'.

Wire it up for 'socket' QEMUFile's.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Add Linux userfaultfd.h header

Postcopy uses the userfaultfd.h feature in the Linux kernel; include
the header.

(In early versions of the patch series we had this, and then we dropped
this by only including it if the kernel headers defined the syscall
number; however 1842bdfd added the syscall definition to our
headers, which means we can't tell if the kernel has it or not)

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Rename save_live_complete to save_live_complete_precopy

In postcopy we're going to need to perform the complete phase
for postcopiable devices at a different point, start out by
renaming all of the 'complete's to make the difference obvious.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

migrate_init: Call from savevm

Suspend to file is very much like a migrate, and it makes life
easier if we have the Migration state available, so initialise it
in the savevm.c code for suspending.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewd-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

ram_load: Factor out host_from_stream_offset call and check

The main RAM load loop has a call to host_from_stream_offset for
each page type that actually loads data with the same test;
factor it out before the switch.

The host = NULL is to silence a bogus gcc warning of
an unitialised in the RAM_SAVE_COMPRESS_PAGE case, it
doesn't seem to realise that host is always initialised by the if at
the top in the cases the switch takes.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

ram_debug_dump_bitmap: Dump a migration bitmap as text

Useful for debugging the migration bitmap and other bitmaps
of the same format (including the sentmap in postcopy).

The bitmap is printed to stderr.
Lines that are all the expected value are excluded so the output
can be quite compact for many bitmaps.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Add QEMU_MADV_NOHUGEPAGE

Add QEMU_MADV_NOHUGEPAGE as an OS-independent version of
MADV_NOHUGEPAGE.

We include sys/mman.h before making the test to ensure
that we pick up the system defines.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Add wrapper for setting blocking status on a QEMUFile

Add a wrapper to change the blocking status on a QEMUFile
rather than having to use qemu_set_block(qemu_get_fd(f));
it seems best to avoid exposing the fd since not all QEMUFile's
really have one.  With this wrapper we could move the implementation
down to be different on different transports.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Add qemu_get_buffer_in_place to avoid copies some of the time

qemu_get_buffer always copies the data it reads to a users buffer,
however in many cases the file buffer inside qemu_file could be given
back to the caller, avoiding the copy.  This isn't always possible
depending on the size and alignment of the data.

Thus 'qemu_get_buffer_in_place' either copies the data to a supplied
buffer or updates a pointer to the internal buffer if convenient.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Rename mis->file to from_src_file

'file' becomes confusing when you have flows in each direction;
rename to make it clear.
This leaves just the main forward direction ms->file, which is used
in a lot of places and is probably not worth renaming given the churn.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

qemu_ram_block_by_name

Add a function to find a RAMBlock by name; use it in two
of the places that already open code that loop; we've
got another use later in postcopy.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

qemu_ram_block_from_host

Postcopy sends RAMBlock names and offsets over the wire (since it can't
rely on the order of ramaddr being the same), and it starts out with
HVA fault addresses from the kernel.

qemu_ram_block_from_host translates a HVA into a RAMBlock, an offset
in the RAMBlock and the global ram_addr_t value.

Rewrite qemu_ram_addr_from_host to use qemu_ram_block_from_host.

Provide qemu_ram_get_idstr since its the actual name text sent on the
wire.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Move page_size_init earlier

The HOST_PAGE_ALIGN macros don't work until the page size variables
have been set up; later in postcopy I use those macros in the RAM
code, and it can be triggered using -object.

Fix this by initialising page_size_init() earlier - it's currently
initialised inside the accelerators, move it up into vl.c.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Move configuration section writing

The vmstate_configuration is currently written
in 'qemu_savevm_state_begin', move it to
'qemu_savevm_state_header' since it's got a hard
requirement that it must be the 1st thing after
the header.
(In postcopy some 'command' sections get sent
early before the saving of the main sections
and hence before qemu_savevm_state_begin).

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>