This controller is implicit on q35 machinetypes. It provides 31 PCIe
(*not* PCI) slots as controller 0.

Currently there are no devices that can connect to pcie-root, and no
implicit pci controller on a q35 machine, so q35 is still
unusable. For a usable q35 system, we need to add a
"dmi-to-pci-bridge" pci controller, which can connect to pcie-root,
and provides standard pci slots that can be used to connect other
devices.

Previous refactoring of the guest PCI address reservation/allocation
code allowed for slot types other than basic PCI (e.g. PCI express,
non-hotpluggable slots, etc) but would not auto-allocate a slot for a
device that required any type other than a basic hot-pluggable
PCI slot.

This patch refactors the code to be aware of different slot types
during auto-allocation of addresses as well - as long as there is an
empty slot of the required type, it will be found and used.

The piece that *wasn't* added is that we don't auto-create a new PCI
bus when needed for anything except basic PCI devices. This is because
there are multiple different types of controllers that can provide,
for example, a PCI express slot (in addition to the pcie-root
controller, these can also be found on a "root-port" or on a
"downstream-switch-port"). Since we currently don't support any PCIe
devices (except pending support for dmi-to-pci-bridge), we can defer
any decision on what to do about this.

* The functions qemuDomainPCIAddressReserveAddr and
qemuDomainPCIAddressReserveSlot were very similar (and should have
been more similar) and were about to get more code added to them which
would create even more duplicated code, so this patch gives
qemuDomainPCIAddressReserveAddr a "reserveEntireSlot" arg, then
replaces the body of qemuDomainPCIAddressReserveSlot with a call to
qemuDomainPCIAddressReserveAddr.

You will notice that addrs->lastaddr was previously set in
qemuDomainPCIAddressReserveAddr (but *not* set in
qemuDomainPCIAddressReserveSlot). For consistency and cleanliness of
code, that bit was removed and put into the one caller of
qemuDomainPCIAddressReserveAddr (there is a similar place where the
caller of qemuDomainPCIAddressReserveSlot sets lastaddr). This does
guarantee identical functionality to pre-patch code, but in practice
isn't really critical, because lastaddr is just keeping track of where
to start when looking for a free slot - if it isn't updated, we will
just start looking on a slot that's already occupied, then skip up to
one that isn't.

* qemuCollectPCIAddress was essentially doing the same thing as
qemuDomainPCIAddressReserveAddr, but with some extra special case
checking at the beginning. The duplicate code has been replaced with
a call to qemuDomainPCIAddressReserveAddr. This required adding a
"fromConfig" boolean, which is only used to change the log error
code from VIR_ERR_INTERNAL_ERROR (when the address was
auto-generated by libvirt) to VIR_ERR_XML_ERROR (when the address is
coming from the config); without this differentiation, it would be
difficult to tell if an error was caused by something wrong in
libvirt's auto-allocate code or just bad config.

* the bit of code in qemuDomainPCIAddressValidate that checks the
connect type flags is going to be used in a couple more places where
we don't need to also check the slot limits (because we're generating
the slot number ourselves), so that has been pulled out into a
separate qemuDomainPCIAddressFlagsCompatible function.

* qemuDomainPCIAddressSetNextAddr

The name of this function was confusing because 1) other functions in
the file that end in "Addr" are only operating on a single function of
one PCI slot, not the entire slot, while functions that do something
with the entire slot end in "Slot", and 2) it didn't contain a verb
describing what it is doing (the "Set" refers to the set that contains
all PCI buses in the system, used to keep track of which slots in
which buses are already reserved for use).

It is now renamed to qemuDomainPCIAddressReserveNextSlot, which more
clearly describes what it is doing. Arguably, it could have been
changed to qemuDomainPCIAddressSetReserveNextSlot, but 1) the word
"set" is confusing in this context because it could be intended as a
verb or as a noun, and 2) most other functions that operate on a
single slot or address within this set are also named
qemuDomainPCIAddress... rather than qemuDomainPCIAddressSet... Only
the Create, Free, and Grow functions for an address set (which modify the
entire set, not just one element) use "Set" in their name.

* qemuPCIAddressAsString, qemuPCIAddressValidate

All the other functions in this set are named
qemuDomainPCIAddressxxxxx, so I renamed these to be consistent.

Since PCI bridges, PCIe bridges, PCIe switches, and PCIe root ports
all share the same namespace, they are all defined as controllers of
type='pci' in libvirt (but with a differing model attribute). Each of
these controllers has a certain connection type upstream, allows
certain connection types downstream, and each can either allow a
single downstream connection at slot 0, or connections from slot 1 -
31.

Right now, we only support the pci-root and pci-bridge devices, both
of which only allow PCI devices to connect, and both which have usable
slots 1 - 31. In preparation for adding other types of controllers
that have different capabilities, this patch 1) adds info to the
qemuDomainPCIAddressBus object to indicate the capabilities, 2) sets
those capabilities appropriately for pci-root and pci-bridge devices,
and 3) validates that the controller being connected to is the proper
type when allocating slots or validating that a user-selected slot is
appropriate for a device..

Having this infrastructure in place will make it much easier to add
support for the other PCI controller types.

While it would be possible to do all the necessary checking by just
storing the controller model in the qemyuDomainPCIAddressBus, it
greatly simplifies all the validation code to also keep a "flags",
"minSlot" and "maxSlot" for each - that way we can just check those
attributes rather than requiring a nearly identical switch statement
everywhere we need to validate compatibility.

You may notice many places where the flags are seemingly hard-coded to

  QEMU_PCI_CONNECT_HOTPLUGGABLE | QEMU_PCI_CONNECT_TYPE_PCI

This is currently the correct value for all PCI devices, and in the
future will be the default, with small bits of code added to change to
the flags for the few devices which are the exceptions to this rule.

Finally, there are a few places with "FIXME" comments. Note that these
aren't indicating places that are broken according to the currently
supported devices, they are places that will need fixing when support
for new PCI controller models is added.

To assure that there was no regression in the auto-allocation of PCI
addresses or auto-creation of integrated pci-root, ide, and usb
controllers, a new test case (pci-bridge-many-disks) has been added to
both the qemuxml2argv and qemuxml2xml tests. This new test defines a
domain with several dozen virtio disks but no pci-root or
pci-bridges. The .args file of the new test case was created using
libvirt sources from before this patch, and the test still passes
after this patch has been applied.

Although these two enums are named ..._LAST, they really had the value
of ..._SIZE. This patch changes their values so that, e.g.,
QEMU_PCI_ADDRESS_SLOT_LAST really is the slot number of the last slot
on a PCI bus.

The implicit IDE, USB, and video controllers provided by the PIIX3
chipset in the pc-* machinetypes are not present on other
machinetypes, so we shouldn't be doing the special checking for
them. This patch places those validation checks into a separate
function that is only called for machine types that have a PIIX3 chip
(which happens to be the i440fx-based pc-* machine types).

One qemuxml2argv test data file had to be changed - the
pseries-usb-multi test had included a piix3-usb-uhci device, which was
being placed at a specific address, and also had slot 2 auto reserved
for a video device, but the pseries virtual machine doesn't actually
have a PIIX3 chip, so even if there was a piix3-usb-uhci driver for
it, the device wouldn't need to reside at slot 1 function 2. I just
changed the .argv file to have the generic slot info for the two
devices that results when the special PIIX3 code isn't executed.

qemuDomainPCIAddressBus was an array of QEMU_PCI_ADDRESS_SLOT_LAST
uint8_t's, which worked fine as long as every PCI bus was
identical. In the future, some PCI busses will allow connecting PCI
devices, and some will allow PCIe devices; also some will only allow
connection of a single device, while others will allow connecting 31
devices.

In order to keep track of that information for each bus, we need to
turn qemuDomainPCIAddressBus into a struct, for now with just one
member:

   uint8_t slots[QEMU_PCI_ADDRESS_SLOT_LAST];

Additional members will come in later patches.

The item in qemuDomainPCIAddresSet that contains the array of
qemuDomainPCIAddressBus is now called "buses" to be more consistent
with the already existing "nbuses" (and with the new "slots" array).

Split out into its own separate routine

Make the secret fetching code common for qemuBuildRBDString() and
qemuBuildDriveURIString() using the virDomainDiskDef.

The difference with already supported pool types (dir, fs, block)
is: there are two modes for iscsi pool (or network pools in future),
one can specify it either to use the volume target path (the path
showed up on host) with mode='host', or to use the remote URI qemu
supports (e.g. file=iscsi://example.org:6000/iqn.1992-01.com.example/1)
with mode='direct'.

For 'host' mode, it copies the volume target path into disk->src. For
'direct' mode, the corresponding info in the *one* pool source host def
is copied to disk->hosts[0].

Introduce a new helper to check if the disk source is of block type

The alias for hostdevs of type SCSI can be too long for QEMU if
larger LUNs are encountered. Here's a real life example:

    <hostdev mode='subsystem' type='scsi' managed='no'>
      <source>
        <adapter name='scsi_host0'/>
        <address bus='0' target='19' unit='1088634913'/>
      </source>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </hostdev>

this results in a too long drive id, resulting in QEMU yelling

Property 'scsi-generic.drive' can't find value 'drive-hostdev-scsi_host0-0-19-1088634913'

This commit changes the alias back to the default hostdev$(index)
scheme.
Signed-off-by: NViktor Mihajlovski <mihajlov@linux.vnet.ibm.com>

When user does not specify any model for scsi controller, or worse, no
controller at all, but libvirt automatically adds scsi controller with
no model, we are not searching for virtio-scsi and thus this can fail
for example on qemu which doesn't support lsi logic adapter.

This means that when qemu on x86 doesn't support lsi53c895a and the
user adds the following to an XML without any scsi controller:

<disk ...>
  ...
  <target dev='sda'>
</disk>

libvirt fails like this:
 # virsh define asdf.xml
 error: Failed to define domain from asdf.xml
 error: internal error Unable to determine model for scsi controller

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=974943

When virAsprintf was changed from a function to a macro
reporting OOM error in dc6f2dad, it was documented as returning
0 on success. This is incorrect, it returns the number of bytes
written as asprintf does.

Some of the functions were converted to use virAsprintf's return
value directly, changing the return value on success from 0 to >= 0.

For most of these, this is not a problem, but the change in
virPCIDriverDir breaks PCI passthrough.

The return value check in virhashtest pre-dates virAsprintf OOM
conversion.

vmwareMakePath seems to be unused.

Merge the virCommandPreserveFD / virCommandTransferFD methods
into a single virCommandPasFD method, and use a new
VIR_COMMAND_PASS_FD_CLOSE_PARENT to indicate their difference
in behaviour
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Since previous patches has prepared everything for us, we may now
implement live hotplug of a character device.

It's caller's responsibility to free return value of
qemuBuildChrDeviceStr().

Error out on negative index values.

https://bugzilla.redhat.com/show_bug.cgi?id=981261

The function being introduced is responsible for creating command
line argument for '-device' for given character device. Based on
the chardev type, it calls appropriate qemuBuild.*ChrDeviceStr(),
e.g.  qemuBuildSerialChrDeviceStr() for serial chardev and so on.

The chardev alias assignment is going to be needed in a separate
places, so it should be moved into a separate function rather
than copying code randomly around.

Convert the type of loop iterators named 'i', 'j', k',
'ii', 'jj', 'kk', to be 'size_t' instead of 'int' or
'unsigned int', also santizing 'ii', 'jj', 'kk' to use
the normal 'i', 'j', 'k' naming
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

If a domain is configured to have all its memory locked, we need to set
RLIMIT_MEMLOCK so that QEMU is actually allowed to lock the memory.

XML:
<features>
  <hyperv>
    <vapic state='on'/>
    <spinlocks state='on' retries='4096'/>
  </hyperv>
</features>

results in the following QEMU command line:
qemu -cpu <cpu_model>,hv_vapic,hv_spinlocks=0x1000

https://bugzilla.redhat.com/show_bug.cgi?id=784836

Add new CPU features for HyperV:
vapic for virtual APIC support
spinlocks for setting spinlock support

<features>
  <hyperv>
    <vapic state='on'/>
    <spinlocks state='on' retries='4096'/>
  </hyperv>
</features>

https://bugzilla.redhat.com/show_bug.cgi?id=784836

https://bugzilla.redhat.com/show_bug.cgi?id=964177

Though both libvirt and QEMU's document say RTC_CHANGE returns
the offset from the host UTC, qemu actually returns the offset
from the specified date instead when specific date is provided
(-rtc base=$date).

It's not safe for qemu to fix it in code, it worked like that
for 3 years, changing it now may break other QEMU use cases.
What qemu tries to do is to fix the document:

http://lists.gnu.org/archive/html/qemu-devel/2013-05/msg04782.html

And in libvirt side, instead of replying on the value from qemu,
this converts the offset returned from qemu to the offset from
host UTC, by:

  /*
   * a: the offset from qemu RTC_CHANGE event
   * b: The specified date (-rtc base=$date)
   * c: the host date when libvirt gets the RTC_CHANGE event
   * offset: What libvirt will report
   */

  offset = a + (b - c);

The specified date (-rtc base=$date) is recorded in clock's def as
an internal only member (may be useful to exposed outside?).

Internal only XML tag "basetime" is introduced to not lose the
guest's basetime after libvirt restarting/reloading:

<clock offset='variable' adjustment='304' basis='utc' basetime='1370423588'/>

Use virStringSplit. Change the 'error' label to 'cleanup' to prevent
memory leaks on error.

Found with 'git grep "= 1"'.

Currently, if there's an error opening /dev/vhost-net (e.g. because
it doesn't exist) but it's not required we proceed with vhostfd array
filled with -1 and vhostfdSize unchanged. Later, when constructing
the qemu command line only non-negative items within vhostfd array
are taken into account. This means, vhostfdSize may be greater than
the actual count of non-negative items in vhostfd array. This results
in improper command line arguments being generated, e.g.:

-netdev tap,fd=21,id=hostnet0,vhost=on,vhostfd=(null)

With previous patch, we accept negative value as length of string to
duplicate. So there is no need to pass strlen(src) in case we want to do
duplicate the whole string.

In order to learn libvirt multiqueue several things must be done:

1) The '/dev/net/tun' device needs to be opened multiple times with
IFF_MULTI_QUEUE flag passed to ioctl(fd, TUNSETIFF, &ifr);

2) Similarly, '/dev/vhost-net' must be opened as many times as in 1)
in order to keep 1:1 ratio recommended by qemu and kernel folks.

3) The command line construction code needs to switch from 'fd=X' to
'fds=X:Y:...:Z' and from 'vhostfd=X' to 'vhostfds=X:Y:...:Z'.

4) The monitor handling code needs to learn to pass multiple FDs.

Currently, we have one huge function to construct qemu command line.
This is very ineffective esp. if there's a fault somewhere.