Open /dev/vhost-scsi, and record the resulting file descriptor, so that
the guest has access to the host device outside of the libvirt daemon.
Pass this information, along with data parsed from the XML file, to build
a device string for the qemu command line.  That device string will be
for either a vhost-scsi-ccw device in the case of an s390 machine, or
vhost-scsi-pci for any others.
Signed-off-by: NEric Farman <farman@linux.vnet.ibm.com>

For machinetypes with a pci-root bus (all legacy PCI), libvirt will
make a "fake" reservation for one extra slot prior to assigning
addresses to unaddressed PCI endpoint devices in the domain. This will
trigger auto-adding of a pci-bridge for the final device to be
assigned an address *if that device would have otherwise instead been
the last device on the last available pci-bridge*; thus it assures
that there will always be at least one slot left open in the domain's
bus topology for expansion (which is important both for hotplug (since
a new pci-bridge can't be added while the guest is running) as well as
for offline additions to the config (since adding a new device might
otherwise in some cases require re-addressing existing devices, which
we want to avoid)).

It's important to note that for the above case (legacy PCI), we must
check for the special case of all slots on all buses being occupied
*prior to assigning any addresses*, and avoid attempting to reserve
the extra address in that case, because there is no free address in
the existing topology, so no place to auto-add a pci-bridge for
expansion (i.e. it would always fail anyway). Since that condition can
only be reached by manual intervention, this is acceptable.

For machinetypes with pcie-root (Q35, aarch64 virt), libvirt's
methodology for automatically expanding the bus topology is different
- pcie-root-ports are plugged into slots (soon to be functions) of
pcie-root as needed, and the new endpoint devices are assigned to the
single slot in each pcie-root-port. This is done so that the devices
are, by default, hotpluggable (the slots of pcie-root don't support
hotplug, but the single slot of the pcie-root-port does). Since
pcie-root-ports can only be plugged into pcie-root, and we don't
auto-assign endpoint devices to the pcie-root slots, this means
topology expansion doesn't compete with endpoint devices for slots, so
we don't need to worry about checking for all "useful" slots being
free *prior* to assigning addresses to new endpoint devices - as a
matter of fact, if we attempt to reserve the open slots before the
used slots, it can lead to errors.

Instead this patch just reserves one slot for a "future potential"
PCIe device after doing the assignment for actual devices, but only
if the only PCI controller defined prior to starting address
assignment was pcie-root, and only if we auto-added at least one PCI
controller during address assignment. This assures two things:

1) that reserving the open slots will only be done when the domain is
   initially defined, never at any time after, and

2) that if the user understands enough about PCI controllers that they
   are adding them manually, that we don't mess up their plan by
   adding extras - if they know enough to add one pcie-root-port, or
   to manually assign addresses such that no pcie-root-ports are
   needed, they know enough to add extra pcie-root-ports if they want
   them (this could be called the "libguestfs clause", since
   libguestfs needs to be able to create domains with as few
   devices/controllers as possible).

This is set to reserve a single free port for now, but could be
increased in the future if public sentiment goes in that direction
(it's easy to increase later, but essentially impossible to decrease)

Real Q35 hardware has an ICH9 chip that includes several integrated
devices at particular addresses (see the file docs/q35-chipset.cfg in
the qemu source). libvirt already attempts to put the first two sets
of ich9 USB2 controllers it finds at 00:1D.* and 00:1A.* to match the
real hardware. This patch does the same for the ich9 "HD audio"
device.

The main inspiration for this patch is that currently the *only*
device in a reasonable "workstation" type virtual machine config that
requires a legacy PCI slot is the audio device, Without this patch,
the standard Q35 machine created by virt-manager will have a
dmi-to-pci-bridge and a pci-bridge just for the sound device; with the
patch (and if you change the sound device model from the default
"ich6" to "ich9"), the machine definition constructed by virt-manager
has absolutely no legacy PCI controllers - any legacy PCI devices
(e.g. video and sound) are on pcie-root as integrated devices.

Previously libvirt would only add pci-bridge devices automatically
when an address was requested for a device that required a legacy PCI
slot and none was available. This patch expands that support to
dmi-to-pci-bridge (which is needed in order to add a pci-bridge on a
machine with a pcie-root), and pcie-root-port (which is needed to add
a hotpluggable PCIe device). It does *not* automatically add
pcie-switch-upstream-ports or pcie-switch-downstream-ports (and
currently there are no plans for that).

Given the existing code to auto-add pci-bridge devices, automatically
adding pcie-root-ports is fairly straightforward. The
dmi-to-pci-bridge support is a bit tricky though, for a few reasons:

1) Although the only reason to add a dmi-to-pci-bridge is so that
   there is a reasonable place to plug in a pci-bridge controller,
   most of the time it's not the presence of a pci-bridge *in the
   config* that triggers the requirement to add a dmi-to-pci-bridge.
   Rather, it is the presence of a legacy-PCI device in the config,
   which triggers auto-add of a pci-bridge, which triggers auto-add of
   a dmi-to-pci-bridge (this is handled in
   virDomainPCIAddressSetGrow() - if there's a request to add a
   pci-bridge we'll check if there is a suitable bus to plug it into;
   if not, we first add a dmi-to-pci-bridge).

2) Once there is already a single dmi-to-pci-bridge on the system,
   there won't be a need for any more, even if it's full, as long as
   there is a pci-bridge with an open slot - you can also plug
   pci-bridges into existing pci-bridges. So we have to make sure we
   don't add a dmi-to-pci-bridge unless there aren't any
   dmi-to-pci-bridges *or* any pci-bridges.

3) Although it is strongly discouraged, it is legal for a pci-bridge
   to be directly plugged into pcie-root, and we don't want to
   auto-add a dmi-to-pci-bridge if there is already a pci-bridge
   that's been forced directly into pcie-root.

Although libvirt will now automatically create a dmi-to-pci-bridge
when it's needed, the code still remains for now that forces a
dmi-to-pci-bridge on all domains with pcie-root (in
qemuDomainDefAddDefaultDevices()). That will be removed in a future
patch.

For now, the pcie-root-ports are added one to a slot, which is a bit
wasteful and means it will fail after 31 total PCIe devices (30 if
there are also some PCI devices), but helps keep the changeset down
for this patch. A future patch will have 8 pcie-root-ports sharing the
functions on a single slot.

Andrea had the right idea when he disabled the "reserve an extra
unused slot" bit for aarch64/virt. For *any* PCI Express-based
machine, it is pointless since 1) an extra legacy-PCI slot can't be
used for hotplug, since hotplug into legacy PCI slots doesn't work on
PCI Express machinetypes, and 2) even for "coldplug" expansion,
everybody will want to expand using Express controllers, not legacy
PCI.

This patch eliminates the extra slot reserve unless the system has a
pci-root (i.e. legacy PCI)

The nec-usb-xhci device (which is a USB3 controller) has always
presented itself as a PCI device when plugged into a legacy PCI slot,
and a PCIe device when plugged into a PCIe slot, but libvirt has
always auto-assigned it to a legacy PCI slot.

This patch changes that behavior to auto-assign to a PCIe slot on
systems that have pcie-root (e.g. Q35 and aarch64/virt).

Since we don't yet auto-create pcie-*-port controllers on demand, this
means a config with an nec-xhci USB controller that has no PCI address
assigned will also need to have an otherwise-unused pcie-*-port
controller specified:

   <controller type='pci' model='pcie-root-port'/>
   <controller type='usb' model='nec-xhci'/>

(this assumes there is an otherwise-unused slot on pcie-root to accept
the pcie-root-port)

The e1000e is an emulated network device based on the Intel 82574,
present in qemu 2.7.0 and later. Among other differences from the
e1000, it presents itself as a PCIe device rather than legacy PCI. In
order to get it assigned to a PCIe controller, this patch updates the
flags setting for network devices when the model name is "e1000e".

(Note that for some reason libvirt has never validated the network
device model names other than to check that there are no dangerous
characters in them. That should probably change, but is the subject of
another patch.)

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1343094

libvirt previously assigned nearly all devices to a "hotpluggable"
legacy PCI slot even on machines with a PCIe root bus (and even though
most such machines don't even support hotplug on legacy PCI slots!)
Forcing all devices onto legacy PCI slots means that the domain will
need a dmi-to-pci-bridge (to convert from PCIe to legacy PCI) and a
pci-bridge (to provide hotpluggable legacy PCI slots which, again,
usually aren't hotpluggable anyway).

To help reduce the need for these legacy controllers, this patch tries
to assign virtio-1.0-capable devices to PCIe slots whenever possible,
by setting appropriate connectFlags in
virDomainCalculateDevicePCIConnectFlags(). Happily, when that function
was written (just a few commits ago) it was created with a
"virtioFlags" argument, set by both of its callers, which is the
proper connectFlags to set for any virtio-*-pci device - depending on
the arch/machinetype of the domain, and whether or not the qemu binary
supports virtio-1.0, that flag will have either been set to PCI or
PCIe. This patch merely enables the functionality by setting the flags
for the device to whatever is in virtioFlags if the device is a
virtio-*-pci device.

NB: the first virtio video device will be placed directly on bus 0
slot 1 rather than on a pcie-root-port due to the override for primary
video devices in qemuDomainValidateDevicePCISlotsQ35(). Whether or not
to change that is a topic of discussion, but this patch doesn't change
that particular behavior.

NB2: since the slot must be hotpluggable, and pcie-root (the PCIe root
complex) does *not* support hotplug, this means that suitable
controllers must also be in the config (i.e. either pcie-root-port, or
pcie-downstream-port). For now, libvirt doesn't add those
automatically, so if you put virtio devices in a config for a qemu
that has PCIe-capable virtio devices, you'll need to add extra
pcie-root-ports yourself. That requirement will be eliminated in a
future patch, but for now, it's simple to do this:

   <controller type='pci' model='pcie-root-port'/>
   <controller type='pci' model='pcie-root-port'/>
   <controller type='pci' model='pcie-root-port'/>
   ...

Partially Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1330024

This patch cleans up the connect flags for certain types/models of
devices that aren't PCI to return 0. In the future that may be used as
an indicator to the caller about whether or not a device needs a PCI
address. For now it's just ignored, except for in
virDomainPCIAddressEnsureAddr() - called during device hotplug - (and
in some cases actually needs to be re-set to PCI|HOTPLUGGABLE just in
case someone (in some old config) has manually set a PCI address for a
device that isn't PCI.

Before now, all the qemu hotplug functions assumed that all devices to
be hotplugged were legacy PCI endpoint devices
(VIR_PCI_CONNECT_TYPE_PCI_DEVICE). This worked out "okay", because all
devices *are* legacy PCI endpoint devices on x86/440fx machinetypes,
and hotplug didn't work properly on machinetypes using PCIe anyway
(hotplugging onto a legacy PCI slot doesn't work, and until commit
b87703cf any attempt to manually specify a PCIe address for a
hotplugged device would be erroneously rejected).

This patch makes all qemu hotplug operations honor the pciConnectFlags
set by the single all-knowing function
qemuDomainDeviceCalculatePCIConnectFlags(). This is done in 3 steps,
but in a single commit since we would have to touch the other points
at each step anyway:

1) add a flags argument to the hypervisor-agnostic
virDomainPCIAddressEnsureAddr() (previously it hardcoded
..._PCI_DEVICE)

2) add a new qemu-specific function qemuDomainEnsurePCIAddress() which
gets the correct pciConnectFlags for the device from
qemuDomainDeviceConnectFlags(), then calls
virDomainPCIAddressEnsureAddr().

3) in qemu_hotplug.c replace all calls to
virDomainPCIAddressEnsureAddr() with calls to
qemuDomainEnsurePCIAddress()

So in effect, we're putting a "shim" on top of all calls to
virDomainPCIAddressEnsureAddr() that sets the right pciConnectFlags.

Set pciConnectFlags in each device's DeviceInfo and then use those
flags later when validating existing addresses in
qemuDomainCollectPCIAddress() and when assigning new addresses with
qemuDomainPCIAddressReserveNextAddr() (rather than scattering the
logic about which devices need which type of slot all over the place).

Note that the exact flags set by
qemuDomainDeviceCalculatePCIConnectFlags() are different from the
flags previously set manually in qemuDomainCollectPCIAddress(), but
this doesn't matter because all validation of addresses in that case
ignores the setting of the HOTPLUGGABLE flag, and treats PCIE_DEVICE
and PCI_DEVICE the same (this lax checking was done on purpose,
because there are some things that we want to allow the user to
specify manually, e.g. assigning a PCIe device to a PCI slot, that we
*don't* ever want libvirt to do automatically. The flag settings that
we *really* want to match are 1) the old flag settings in
qemuDomainAssignDevicePCISlots() (which is HOTPLUGGABLE | PCI_DEVICE
for everything except PCI controllers) and 2) the new flag settings
done by qemuDomainDeviceCalculatePCIConnectFlags() (which are
currently exactly that - HOTPLUGGABLE | PCI_DEVICE for everything
except PCI controllers).

The lowest level function of this trio
(qemuDomainDeviceCalculatePCIConnectFlags()) aims to be the single
authority for the virDomainPCIConnectFlags to use for any given device
using a particular arch/machinetype/qemu-binary.

qemuDomainFillDevicePCIConnectFlags() sets info->pciConnectFlags in a
single device (unless it has no virDomainDeviceInfo, in which case
it's a NOP).

qemuDomainFillAllPCIConnectFlags() sets info->pciConnectFlags in all
devices that have a virDomainDeviceInfo

The latter two functions aren't called anywhere yet. This commit is
just making them available. Later patches will replace all the current
hodge-podge of flag settings with calls to this single authority.

As with other devices assign the slot number right away when adding the
device. This will make the slot numbers static as we do with other
addressing elements and it will ultimately simplify allocation of the
alias in a static way which does not break with qemu.

When starting a new domain, we allocate the USB addresses and keep
an address cache in the domain object's private data.

However this data is lost on libvirtd restart.

Also generate the address cache if all the addresses have been
specified, so that devices hotplugged after libvirtd restart
also get theirs assigned.

https://bugzilla.redhat.com/show_bug.cgi?id=1387666

Commit 19a148b7 dropped the cache from QEMU's private domain object.
Assume the callers do not have the cache by default and use
a longer name for the internal ones that do.

This makes the shorter 'virDomainVirtioSerialAddrAutoAssign'
name availabe for a function that will not require the cache.

An upcoming commit will remove the "flag" argument from all the calls
to reserve the next available address|slot, but I don't want to change
the arguments in the hypervisor-agnostic
virDomainPCIAddressReserveNext*() functions, so this patch places a
simple qemu-specific wrapper around those functions - the new
functions don't take a flags arg, but grab it from the device's
info->pciConnectFlags.

instead of calling virDomainPCIAddressGetNextSlot() (which I want to
turn into a local static in domain_addr.c).

This error should only ever be seen by a developer anyway, but the
existing message made even less sense that this new version.

This is already set by virDomainPCIAddressSetAlloc().

More occurences of repeatedly dereferencing the same pointer stored in
an array are replaced with the definition of a temporary pointer that
is then used directly. No functional change.

There's no functional change here. This pointer was just used so many
times that the extra long lines became annoying.

All definition validation that doesn't depend on qemu capabilities
and was allowed previously as valid definition should be placed into
qemuDomainDefValidate.

The check whether video type is supported or not was based on an enum
that translates type into model.  Use switch to ensure that if new
video type is added, it will be properly handled.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

The 'multi' element in PCI address struct used as 'virTristateSwitch',
and its default value is 'VIR_TRISTATE_SWITCH_ABSENT'. Current PCI
process use 'false' to initialization 'multi', which is ambiguously
for assignment or comparison. This patch use '{0}' to initialize
the whole PCI address struct, which fix the 'multi' initialization
and makes code more simplify and explicitly.
Signed-off-by: NXian Han Yu <xhyubj@linux.vnet.ibm.com>

Dropping the caching of ccw address set.
The cached set is not required anymore, because the set is now being
recalculated from the domain definition on demand, so the cache
can be deleted.

The address sets (pci, ccw, virtio serial) are currently cached
in qemu private data, but all the information required to recreate
these sets is in the domain definition. Therefore I am removing
the redundant data and adding a way to recalculate these sets.

Add a function that calculates the ccw address set
from the domain definition.

Dropping the caching of virtio serial address set.
The cached set is not required anymore, because the set is now being
recalculated from the domain definition on demand, so the cache
can be deleted.

Credit goes to Cole Robinson.

The address sets (pci, ccw, virtio serial) are currently cached
in qemu private data, but all the information required to recreate
these sets is in the domain definition. Therefore I am removing
the redundant data and adding a way to recalculate these sets.

Add a function that calculates the virtio serial address set
from the domain definition.

Credit goes to Cole Robinson.

When parsing a command line with USB devices that have
no address specified, QEMU automatically adds a USB hub
if the device would fill up all the available USB ports.

To help most of the users, add one hub if there are more
USB devices than available ports. For wilder configurations,
expect the user to provide us with more hubs and/or controllers.

USB disks, redirected devices, host devices and serial devices
are supported.

Automatically assign addresses to USB devices.

Just like reserving, this is only done for newly defined domains.

https://bugzilla.redhat.com/show_bug.cgi?id=1215968

Check if they fit on the USB controllers the domain has,
and error out if two devices try to use the same address.

This new function checks for both the architecture and the
machine type, so we can use it instead of writing the same
checks over and over again.

Pass 'true' if we are not dealing with a migration.

There has been some progress lately in enabling virtio-pci on
aarch64 guests; however, guest OS support is still spotty at best,
so most guests are going to be using virtio-mmio instead.

Currently, mach-virt guests are closely modeled after q35 guests,
and that includes always adding a dmi-to-pci-bridge that's just
impossible to get rid of. While that's acceptable (if suboptimal)
for q35, where you will always need some kind of PCI device anyway,
mach-virt guests should be allowed to avoid it.

Commit ff212622 changed the error message to be more
detailed about the failure at hand; however, while the new
error message claims that "bus must be <= index", the error
message is displayed if "idx <= addr->bus", ie. when bus
is larger than or *equal to* index.

Change the error message to report the correct constraint,
and format it in a way that mirrors the check exactly to
make it clearer to people reading the code. The new error
message reads "index must be larger than bus".

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1339900

IS_USB2_CONTROLLER() is useful in more places aside from just when
assigning PCI addresses in QEMU, and is checking for enum values that
are all defined in conf/domain_conf.h anyway, so define it there
instead.

Based on some digital archaeology performed by jtomko, it's been determined
that the persistentAddrs variable is no longer necessary...

The variable was added by:
commit 141dea6b
CommitDate: 2010-02-12 17:25:52 +0000
    Add persistence of PCI addresses to QEMU

Where it was set to 0 on domain startup if qemu did not support the
QEMUD_CMD_FLAG_DEVICE capability, to clear the addresses at shutdown,
because QEMU might make up different ones next time.

As of commit f5dd58a6
CommitDate: 2012-07-11 11:19:05 +0200
    qemu: Extended qemuDomainAssignAddresses to be callable from
    everywhere.

this was broken, when the persistentAddrs = 0 assignment was moved
inside qemuDomainAssignPCIAddresses and while it pretends to check
for !QEMU_CAPS_DEVICE, its parent qemuDomainAssignAddresses is only
called if QEMU_CAPS_DEVICE is present.

Since commit id '20a0fa8e' removed the QEMU_CAPS_DEVICE, Coverity notes
that it's no longer possible to have 'addrs' be NULL when checking for
a live domain since qemuDomainPCIAddressSetCreate would have jumped to
cleanup if addrs was NULL.

Rather than only assigning a PCI address when no address is given at
all, also do it when the config says that the address type is 'pci',
but it gives no address (virDeviceInfoPCIAddressWanted()).

There are also several places after parsing but prior to address
assignment where code previously expected that any info with address
type='pci' would have a *valid* PCI address, which isn't always the
case - now we check not only for type='pci', but also for a valid
address (virDeviceInfoPCIAddressPresent()).

The test case added in this patch was directly copied from Cole's patch titled:

    qemu: Wire up address type=pci auto_allocate