* src/qemu_driver.c: Support arbitrary callbacks for "secondary
  prompts".  Reimplement qemudMonitorCommandExtra using such a
  callback.

The if ((nlptr...)) implicitly assumes commptr != NULL (and that "buf"
starts with "cmd").  Make the assumption explicit, it will be broken in
a future patch.

* src/qemu_driver.c: Don't assume buffered monitor output echoes the
  command.

Per prior discussion -- this was, indeed, trivial.

I'm a little disappointed to be breaking the ordering characteristics of
the enum (as it had been ordered by increasing time requirements and
decreasing output size), but breaking any save files with the old
constants in the headers would of course be worse.

>From 2a9cdcfc88de091a8d34aa3fc3b1208d7681790e Mon Sep 17 00:00:00 2001
From: Charles Duffy <Charles_Duffy@dell.com>
Date: Fri, 28 Aug 2009 11:49:54 -0500
Subject: [PATCH] support lzop save compression for qemu

One of the larger disincentives towards use of compression for migrated-out save
files is performance impact. This patch adds support for lzop; CPU time for
compression is about 5x faster than gzip (the next most performant algorithm)
and decompression is about 3x faster.
Signed-off-by: NCharles Duffy <Charles_Duffy@dell.com>
Signed-off-by: NChris Lalancette <clalance@redhat.com>

qemudExtractMonitorPath() was doing a VIR_ALLOC_N followed by a
strncpy.  However, this isn't necessary; we can do the same thing
using strndup, which is much safer.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

Fix up a small memory leak pointed out by DanB; I was forgetting
to release memory allocated to driver->saveImageFormat.
Also add the "save_image_format" and "security" entries to
the augeas lens.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

As we start/shutdown guests, or hotplug/hot-unplug devices, we can add
or delete devices as appropriate from a list of active devices.

Then, in pciReset(), we can use this to determine whether its safe to
reset a device as a side effect of resetting another device.

* src/qemu_conf.h: add activePciHostdevs to qemud_driver

* src/qemu_driver.c: maintain the activePciHostdevs list, and pass it
  to pciResetDevice()

* src/pci.[ch]: pass the activeDevs list to pciResetDevice() and use
  it to determine whether a Secondary Bus Reset is safe

The qemuPrepareHostDevices() and qemuDomainReAttachHostDevices()
functions are clutter with a bunch of calls to pciGetDevice() and
pciFreeDevice() obscuring the basic logic.

Add a pciDeviceList type and add a qemuGetPciHostDeviceList() function
to build a list from a domain definition. Use this in prepare/re-attach
fto simplify things and eliminate the multiple pciGetDevice calls.

This is especially useful because in the next patch we need to iterate
the hostdevs list a third time and we also need a list type for keeping
track of active devices.

* src/pci.[ch]: add pciDeviceList type and also a per-device 'managed'
  property

* src/libvirt_private.syms: export the new functions

* src/qemu_driver.c: add qemuGetPciHostDeviceList() and re-write
  qemuPrepareHostDevices() and qemuDomainReAttachHostDevices() to use it

Newer versions of QEMU accept 'pci_add auto', but older versions require
'pci_add pci_addr=auto'

* src/qemu_driver.c: use pci_addr= in qemudDomainAttachHostPciDevice()
  for older versions of QEMU

* src/qemu_driver.c: Add missing break statement in
  qemudDomainDetachHostDevice()

When we hot-unplug a PCI host device from a guest, we should reset it.

Both managed and unmanaged devices should be reset, but only managed
devices should be re-attached.

* src/qemu_driver.c: reset devices in qemudDomainDetachHostPciDevice()

Right now we're only resetting managed devices before hotplug, but we
should reset them irrespective of whether they are managed.

* src/qemu_driver.c: reset all PCI hostdevs before hotplug

It turns out that the previous attempt at this doesn't work well
in the case of hotplug. We need qemuCheckPciHostDevice() to
disallow the reset affecting devices already attach to the guest,
but we still need to avoid double locking the virDomainObjPtr.

This is all getting messy, I've a better idea.

This reverts commit 63188082 and
c106c8a1.

* src/qemu_driver.c, src/pci.[ch], src/xen_unified.c,
  src/libvirt_private.syms: revert a bunch of stuff.

The current code makes a poor effort at updating the device arrays after
hot-unplug. Fix that and combine the two code paths into one.

* src/qemu_driver.c: fix list updating in qemudDomainDetachNetDevice(),
  qemudDomainDetachPciDiskDevice() and qemudDomainDetachHostPciDevice()

Implement a compressed save image format for qemu.  While ideally
we would have the choice between compressed/non-compressed
available to the libvirt API, unfortunately there is no "flags"
parameter to the virDomainSave() API.  Therefore, implement this
as a qemu.conf option.  gzip, bzip2, and lzma are implemented, and
it should be very easy to implement additional compression
methods.

One open question is if/how we should detect the compression
binaries.  One way to do it is to do compile-time setting of the
paths (via configure.in), but that doesn't seem like a great thing
to do.  My preferred solution is not to detect at all;
when we go to run the commands that need them, if they
aren't available, or aren't available in one of the standard paths,
then we'll fail.  That's also the solution implemented in this patch.

In the future, we'll have a more robust (managed) save/restore API,
at which time we can expose this functionality properly in the API.

V2: get rid of redundant dd command and just use >> to append data.
V3: Add back the missing pieces for the enum and bumping the save version.
V4: Make the compressed field in the save_header an int.
    Implement LZMA compression.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

If a PCI device reset causes other devices to be reset, allow it so long
as those other devices are note assigned to another active domain.

Note, we need to take the driver lock qemudNodeDeviceReset() because the
check function will iterate over the domain list.

* src/qemu_conf.c: add qemuCheckPciHostDevice() to iterate over active
  domains checking whether the affected device is assigned

* src/pci.[ch]: add pciDeviceEquals() helper

When using a Secondary Bus Reset, all devices on the bus are reset.

Extend the pciResetDevice() API so that a 'check' callback can be
supplied which will verify that it is safe to reset the other devices
on the bus.

The virDomainObjPtr parameter is needed so that when the check function
iterates over the domain list, it can avoid double locking.

* src/pci.[ch]: add a 'check' callback to pciResetDevice(), re-work
  pciIterDevices() to pass the check function to the iter functions,
  use the check function in the bus iterator, return the first unsafe
  device from pciBusCheckOtherDevices() and include its details in
  the bus reset error message.

* src/qemu_driver.c, src/xen_uninified.c: just pass NULL as the
  check function for now

Currently, if we are unable to reset a PCI device we return a fairly
generic 'No PCI reset capability available' error message.

Fix that by returning an error from the individual reset messages and
using that error to construct the higher level error mesage.

* src/pci.c: set errors in pciTryPowerManagementReset() and
  pciTrySecondaryBusReset() on failure; use those error messages
  in pciResetDevice(), or explain that no reset support is available

When the guest shuts down, we should attempt to restore all PCI host
devices to a sane state.

In the case of managed hostdevs, we should reset and re-attach the
devices. In the case of unmanaged hostdevs, we should just reset them.

Note, KVM will already reset assigned devices when the guest shuts
down using whatever means it can, so we are only doing it to cover the
cases the kernel can't handle.

* src/qemu_driver.c: add qemuDomainReAttachHostDevices() and call
  it from qemudShutdownVMDaemon()

Attaching a host PCI device to a qemu guest is done with a
straightforward 'pci_add auto host host=XX:XX.X' command.

Like with NIC and disk hotplug, we need to retain the guest PCI address
assigned by qemu so that we can use it for hot-unplug.

Identifying a device for detach is done using the host PCI address.

Managed mode is handled by detaching/resetting the device before
attaching it to the guest and re-attaching it after detaching it from
the guest.

* src/qemu_driver.c: add qemudDomainAttachHostPciDevice() and
  qemudDomainDetachHostPciDevice()

* src/domain_conf.h: add somewhere to store the guest PCI address

* src/domain_conf.c: handle formatting and parsing the guest PCI
  address

Re-factor the hostdev hotplug code so that we can easily add PCI
hostdev hotplug to qemudDomainAttachHostDevice().

* src/qemu_driver.c: rename qemudDomainAttachHostDevice() to
  qemudDomainAttachHostUsbDevice(); make qemudDomainAttachHostDevice()
  handle all hostdev types

* src/libvirt_private.syms: export a couple of hostdev related
  ToString() functions

As of qemu 0.10.6, qemu now honors the -S flag on incoming migration.
That means that when the migration completes, we have to issue a
'cont' command to get the VM running again.  We do it unconditionally
since it won't hurt on older qemu.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

When doing a restore, we were forgetting to update the state file
for the VM.  That means that if you do a save/restore, then shut
down libvirtd, then start it back up, you'll see the state of the
guest as "paused", even though it is really running.  We were
just forgetting a "virDomainSaveStatus" call in the restor path.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

If we're running qemu unprivileged, we need to chown any supplied kernel
or initrd before spawning it.

* src/qemu_driver.c: rename qemuDomainSetDiskOwnership() to
  qemuDomainSetFileOwnership(), pass it a path string instead of a disk
  definition and use it for chowning the kernel/initrd in
  qemuDomainSetAllDeviceOwnership()

Signed-off-by: NChris Lalancette <clalance@redhat.com>

Signed-off-by: NChris Lalancette <clalance@redhat.com>

Signed-off-by: NChris Lalancette <clalance@redhat.com>

Signed-off-by: NChris Lalancette <clalance@redhat.com>

Fix up qemudDomainMigratePrepare2 to use virGetHostname instead of
gethostname.  Besides the fact that virGetHostname is far more clever,
there was a latent bug in the handling that could cause a buffer overflow
on a very long hostname.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

* src/qemu_driver.c: Check that monitor device is not NULL
  before runing a command to protect against bugs in caller

* src/qemu_driver.c: Add check that QEMU is active before attemting
  to shutdown. Fix error code for check in destroy method

* src/util.c: Don't drop capabilities until after the PID file has
  been written. Kill off child if writing the PID file fails
* src/qemu_driver.c: Remove bogus trailing '/' in state dir

* src/qemu_driver.c: fix qemudOpenMonitorUnix() to retry on ENOENT
  instead of EACCES which is the error one receive when the socket
  error hasn't shown up yet

* src/qemu_driver.c: implement missing features in qemudDomainGetVcpus
  for 'cpu' and 'cpuTime' fields

In order to hotplug a network/bridge backed NIC, we need to first create
the tap file descriptor, add the tap interface to the bridge and then
pass the file descriptor to the qemu process using the 'getfd' monitor
command.

Once the tapfd has been accepted, we create the network backend using
host_net_add, supplying the name assigned to the tapfd. If this fails,
we need to close the tapfd in qemu using the 'closefd' monitor command.

If the version of qemu does not support the getfd/closefd monitor
commands we detect "unknown command" in the getfd reply and fail the
attach operation.

* src/qemu_driver.c: add support for tapfd based hotplug in
  qemudDomainAttachNetDevice()

Add qemudMonitorCommandWithFd() which allows a file descriptor to be
sent to qemu over a unix monitor socket using SCM_RIGHTS. See the
unix(7) and cmsg(3) man pages.

* src/qemu_conf.c: add a scm_fd param to qemudMonitorCommandExtra(),
  add qemudMonitorCommandWithFd(), implement SCM_RIGHTS support in
  qemudMonitorSendUnix()

Switch from using write() to using sendmsg() on QEMU's monitor socket
so that we can add support for SCM_RIGHTS.

* src/qemu_driver.c: add sendmsg() based qemudMonitorSendUnix() and use
  it when the monitor fd is a unix socket

Add a little helper function to write the monitor command followed by
carriage return in a single write.

This doesn't make any real difference, but allows us to more easily
switch to using sendmsg() when using the monitor over a unix socket.

* src/qemu_conf.c: split qemudMonitorSend() out

In subsequent patches we're going to have a file descriptor to close
too, so centralize the error handling cleanups to make things easier.

* src/qemu_conf.c: in qemudDomainAttachNetDevice() consolidate the
  error handling cleanups together

With hotplug, we're going to want to pass a tapfd name rather than an
actual file descriptor, so prepare the way by passing a string tapfd to
qemuBuildHostNetStr().

* src/qemu_conf.h: qemuBuildHostNetStr() takes a string tapfd now

* src/qemu_conf.c: pass qemuBuildHostNetStr() a string rather than an
  actual file descriptor

* src/qemu_driver.c: update qemudDomainAttachNetDevice() for change

By probing for qemu machine types, we increased the time of a
GetCapabilities call from 100us to a whopping 60ms.

This patch takes the approach of only probing for machine types
when the mtime of the emulator binary changed since the last time
the capabilities were generated.

* src/capabilities.h: cache the emulator binary mtime

* src/qemu_conf.c: add qemudGetOldMachines() to copy the machine
  types from the old caps struct if the mtime for the binary hasn't
  changed

* src/qemu_conf.h, src/qemu_driver.c: pass the old caps pointer to
  qemudCapsInit()