This controller provides a single PCIe port on a new root. It is
similar to pci-expander-bus, intended to provide a bus that can be
associated with a guest-identifiable NUMA node, but is for
machinetypes with PCIe rather than PCI (e.g. q35-based machinetypes).
Aside from PCIe vs. PCI, the other main difference is that a
pci-expander-bus has a companion pci-bridge that is automatically
attached along with it, but pcie-expander-bus has only a single port,
and that port will only connect to a pcie-root-port, or to a
pcie-switch-upstream-port. In order for the bus to be of any use in
the guest, it must have either a pcie-root-port or a
pcie-switch-upstream-port attached (and one or more
pcie-switch-downstream-ports attached to the
pcie-switch-upstream-port).
This is backed by the qemu device "pxb".
The pxb device always includes a pci-bridge that is at the bus number
of the pxb + 1.
busNr and <node> from the <target> subelement are used to set the
bus_nr and numa_node options for pxb.
During post-parse we validate that the domain's machinetype is
440fx-based (since the pxb device only works on 440fx-based machines),
and <node> also gets a sanity check to assure that the NUMA node
specified for the pxb (if any - it's optional) actually exists on the
guest.
This is a standard PCI root bus (not a bridge) that can be added to a
440fx-based domain. Although it uses a PCI slot, this is *not* how it
is connected into the PCI bus hierarchy, but is only used for
control. Each pci-expander-bus provides 32 slots (0-31) that can
accept hotplug of standard PCI devices.
The usefulness of pci-expander-bus relative to a pci-bridge is that
the NUMA node of the bus can be specified with the <node> subelement
of <target>. This gives guest-side visibility to the NUMA node of
attached devices (presuming that management apps only assign a device
to a bus that has a NUMA node number matching the node number of the
device on the host).
Each pci-expander-bus also has a "busNr" attribute. The expander-bus
itself will take the busNr specified, and all buses that are connected
to this bus (including the pci-bridge that is automatically added to
any expander bus of model "pxb" (see the next commit)) will use
busNr+1, busNr+2, etc, and the pci-root (or the expander-bus with next
lower busNr) will use bus numbers lower than busNr.
There are two places in qemu_domain_address.c where we have a switch
statement to convert PCI controller models
(VIR_DOMAIN_CONTROLLER_MODEL_PCI*) into the connection type flag that
is matched when looking for an upstream connection for that model of
controller (VIR_PCI_CONNECT_TYPE_*). This patch makes a utility
function in conf/domain_addr.c to do that, so that when a new PCI
controller is added, we only need to add the new model-->connect-type
in a single place.
The flags used to determine which devices could be plugged into which
controllers were quite confusing, as they tried to create classes of
connections, then put particular devices into possibly multiple
classes, while sometimes setting multiple flags for the controllers
themselves. The attempt to have a single flag indicate, e.g. that a
root-port or a switch-downstream-port could connect was not only
confusing, it was leading to a situation where it would be impossible
to specify exactly the right combinations for a new controller.
The solution is for the VIR_PCI_CONNECT_TYPE_* flags to have a 1:1
correspondence with each type of PCI controller, plus a flag for a PCI
endpoint device and another for a PCIe endpoint device (the only
exception to this is that pci-bridge and pcie-expander-bus controllers
have their upstream connection classified as
VIR_PCI_CONNECT_TYPE_PCI_DEVICE since they can be plugged into
*exactly* the same ports as any endpoint device). Each device then
has a single flag for connect type (plus the HOTPLUG flag if that
device can e hotplugged), and each controller sets the CONNECT bits
for all controllers that can be plugged into it, as well as for either
type of endpoint device that can be plugged in (and the HOTPLUG flag
if it can accept hotplugged devices).
With this change, it is *slightly* easier to understand the matching
of connections (as long as you remember that the flag for a
device/upstream-facing connection of a controller is the same as that
device's type, while the flags for a controller's downstream
connections is the OR of all device types that can be plugged into
that controller). More importantly, it will be possible to correctly
specify what can be plugged into a pcie-switch-expander-bus, when
support for it is added.
Add new function to manage adding the controller -device options to the
command line removing that task from the mainline qemuBuildCommandLine.
Also adjust to using const virDomainDef instead of virDomainDefPtr.
This causes collateral damage in order to modify called APIs to use
the const virDomainDef instead as well.
Signed-off-by: John Ferlan <jferlan@redhat.com>
This does nothing more than adding the new device and capability.
The device is present since QEMU 2.6.0.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Create new modules qemu_domain_address.c and qemu_domain_address.h to
contain all the new functions and header data. Additionally move any
supporting static functions.
Make qemuDomainSupportsPCI non static.
Also, move and rename the following:
qemuSetSCSIControllerModel to qemuDomainSetSCSIControllerModel
qemuCollectPCIAddress to qemuDomainCollectPCIAddress
qemuValidateDevicePCISlotsPIIX3 to qemuDomainValidateDevicePCISlotsPIIX3
qemuAssignDevicePCISlots to qemuDomainAssignDevicePCISlots
Signed-off-by: John Ferlan <jferlan@redhat.com>
