Assigning PCIe Buses

You can use the Oracle VM Server for SPARC software to assign an entire PCIe bus (also known as a root complex) to a domain. An entire PCIe bus consists of the PCIe bus itself, and all of its PCI switches and devices. PCIe buses that are present on a server are identified with names such as pci@400 (pci_0). An I/O domain that is configured with an entire PCIe bus is also known as a root domain.

The following diagram shows a system that has two PCIe buses (pci_0 and pci_1). Each bus is assigned to a different domain. Thus, the system is configured with two I/O domains.

Figure 6-1 Assigning a PCIe Bus to an I/O Domain

image:Diagram shows how to assign a PCIe bus to an I/O domain.

The maximum number of I/O domains that you can create with PCIe buses depends on the number of PCIe buses that are available on the server. For example, if you are using a Sun SPARC Enterprise T5440 server, you can have up to four I/O domains.

Note - Some Sun UltraSPARC servers have only one PCIe bus. In such cases, you can create an I/O domain by assigning a PCIe endpoint (or direct I/O-assignable) device to a domain. See Assigning PCIe Endpoint Devices. If the system has a Network Interface Unit (NIU), you can also assign an NIU to a domain to create an I/O domain.

When you assign a PCIe bus to an I/O domain, all devices on that bus are owned by that I/O domain. You are not permitted to assign any of the PCIe endpoint devices on that bus to other domains. Only the PCIe endpoint devices on the PCIe buses that are assigned to the primary domain can be assigned to other domains.

When a server is initially configured in a Logical Domains environment or is using the factory-default configuration, the primary domain has access to all the physical device resources. This means that the primary domain is the only I/O domain configured on the system and that it owns all the PCIe buses.

How to Create an I/O Domain by Assigning a PCIe Bus

This example procedure shows how to create a new I/O domain from an initial configuration where several buses are owned by the primary domain. By default the primary domain owns all buses present on the system. This example is for a Sun SPARC Enterprise T5440 server. This procedure can also be used on other servers. The instructions for different servers might vary slightly from these, but you can obtain the basic principles from this example.

First, you must retain the bus that has the primary domain's boot disk. Then, remove another bus from the primary domain and assign it to another domain.

Caution - All internal disks on the supported servers might be connected to a single PCIe bus. If a domain is booted from an internal disk, do not remove that bus from the domain. Also, ensure that you are not removing a bus with devices (such as network ports) that are used by a domain. If you remove the wrong bus, a domain might not be able to access the required devices and could become unusable. To remove a bus that has devices that are used by a domain, reconfigure that domain to use devices from other buses. For example, you might have to reconfigure the domain to use a different on-board network port or a PCIe card from a different PCIe slot.

In this example, the primary domain only uses a ZFS pool (rpool (c0t1d0s0)) and network interface (nxge0). If the primary domain uses more devices, repeat Steps 2-4 for each device to ensure that none are located on the bus that will be removed.

Verify that the primary domain owns more than one PCIe bus.

primary# ldm list-io
NAME                                      TYPE   DOMAIN   STATUS
----                                      ----   ------   ------
pci_0                                     BUS    primary  
pci_1                                     BUS    primary  
pci_2                                     BUS    primary  
pci_3                                     BUS    primary  
MB/PCIE0                                  PCIE   -        EMP
MB/PCIE1                                  PCIE   primary  OCC
MB/HBA                                    PCIE   primary  OCC
MB/PCIE4                                  PCIE   -        EMP
MB/PCIE5                                  PCIE   -        EMP
MB/XAUI1                                  PCIE   primary  OCC
MB/PCIE2                                  PCIE   primary  OCC
MB/PCIE3                                  PCIE   primary  OCC
MB/PCIE6                                  PCIE   primary  OCC
MB/PCIE7                                  PCIE   -        EMP

Determine the device path of the boot disk, which needs to be retained.

For UFS file systems, run the df / command to determine the device path of the boot disk.
```
primary# df /
/                  (/dev/dsk/c0t1d0s0 ): 1309384 blocks   457028 files
```

For ZFS file systems, first run the df / command to determine the pool name, and then run the zpool status command to determine the device path of the boot disk.

primary# df /
/                  (rpool/ROOT/s10s_u8wos_08a):245176332 blocks 245176332 files
primary# zpool status rpool
 zpool status rpool
  pool: rpool
 state: ONLINE
 scrub: none requested
config:

        NAME        STATE     READ WRITE CKSUM
        rpool       ONLINE       0     0     0
          c0t1d0s0  ONLINE       0     0     0

Determine the physical device to which the block device is linked.
The following example uses block device c1t0d0s0:
```
primary# ls -l /dev/dsk/c0t1d0s0
lrwxrwxrwx   1 root     root          49 Oct  1 10:39 /dev/dsk/c0t1d0s0 ->
../../devices/pci@400/pci@0/pci@1/scsi@0/sd@1,0:a
```
In this example, the physical device for the primary domain's boot disk is connected to bus pci@400, which corresponds to the earlier listing of pci_0. This means that you cannot assign pci_0 (pci@400) to another domain.

Determine the network interface that is used by the system.

Oracle Solaris 10. Run the following command:

primary# dladm show-dev
vsw0            link: up        speed: 1000  Mbps       duplex: full
nxge0           link: up        speed: 1000  Mbps       duplex: full
nxge1           link: unknown   speed: 0     Mbps       duplex: unknown
nxge2           link: unknown   speed: 0     Mbps       duplex: unknown
nxge3           link: unknown   speed: 0     Mbps       duplex: unknown

Oracle Solaris 11. Run the following command:

primary# dladm show-phys
LINK              MEDIA                STATE      SPEED  DUPLEX    DEVICE
net0              Ethernet             unknown    0      unknown   vnet0
net1              Ethernet             up         1000   full      vsw0
net2              Ethernet             up         1000   full      nxge0

Interfaces that are in the unknown state are not configured, so they are not used. In this example, the nxge0 interface is used.

Determine the physical device to which the network interface is linked.
The following command uses the nxge0 network interface:
```
primary# ls -l /dev/nxge0
lrwxrwxrwx   1 root     root          46 Oct  1 10:39 /dev/nxge0 ->
../devices/pci@500/pci@0/pci@c/network@0:nxge0
```
In this example, the physical device for the network interface used by the primary domain is under bus pci@500, which corresponds to the earlier listing of pci_1. So, the other two buses, pci_2 (pci@600) and pci_3 (pci@700), can safely be assigned to other domains because they are not used by the primary domain.
If the network interface used by the primary domain was on a bus that you want to assign to another domain, the primary domain would need to be reconfigured to use a different network interface.
Remove the buses that do not contain the boot disk or the network interface from the primary domain.
In this example, bus pci_2 and bus pci_3 are being removed from the primary domain. You might see a message from the ldm command that the primary domain is entering delayed reconfiguration mode.
```
primary# ldm remove-io pci_2 primary
primary# ldm remove-io pci_3 primary
```
Save this configuration to the service processor.
In this example, the configuration is io-domain.
```
primary# ldm add-config io-domain
```
This configuration, io-domain, is also set as the next configuration to be used after the reboot.

Note - Currently, no more than eight configurations can be saved in the SP of UltraSPARC T2 and UltraSPARC T2 Plus systems, not including the factory-default configuration. On SPARC T3 and SPARC T4 systems, 10 Mbytes of space is available for storing configurations. The total number of saved configurations depends on the size of each configuration that is stored in the SP.
Reboot the primary domain so that the change takes effect.
```
primary# shutdown -i6 -g0 -y
```
Stop the domain to which you want to add the PCIe bus.
The following example stops the ldg1 domain:
```
primary# ldm stop ldg1
```
Add the available bus to the domain that needs direct access.
The available bus is pci_2 and the domain is ldg1.
```
primary# ldm add-io pci_2 ldg1
```
Restart the domain so that the change takes affect.
The following commands restart the ldg1 domain:
```
primary# ldm start ldg1
```

Confirm that the correct bus is still assigned to the primary domain and the correct bus is assigned to domain ldg1.

primary# ldm list-io
NAME                                      TYPE   DOMAIN   STATUS
----                                      ----   ------   ------
pci_0                                     BUS    primary  
pci_1                                     BUS    primary  
pci_2                                     BUS    ldg1
pci_3                                     BUS    
MB/PCIE0                                  PCIE   -        EMP
MB/PCIE1                                  PCIE   primary  OCC
MB/HBA                                    PCIE   primary  OCC
MB/PCIE4                                  PCIE   -        EMP
MB/PCIE5                                  PCIE   -        EMP
MB/XAUI1                                  PCIE   primary  OCC
MB/PCIE2                                  PCIE   -        UNK
MB/PCIE3                                  PCIE   -        UNK
MB/PCIE6                                  PCIE   -        UNK
MB/PCIE7                                  PCIE   -        UNK

This output confirms that the PCIe buses pci_0 and pci_1 and the devices below them are assigned to domain primary, and that pci_2 and its devices are assigned to ldg1.

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