Re: MSI-X not enabled for ixgbe device-passthrough

[Chris Wright <chrisw@sous-sol.org>]

* Hannes Reinecke (hare@suse.de) wrote:
> Chris Wright wrote:
> > * Hannes Reinecke (hare@suse.de) wrote:
> >> Hi all,
> >>
> >> I'm trying to setup a system with device-passthrough for
> >> an ixgbe NIC.
> >> The device itself seems to work, but it isn't using MSI-X.
> >> So some more advanced features like DCB offloading etc
> >> won't work.
> > 
> > Please send the relevant dmesg from the guest when it initializes the
> > device.  BTW, more typical case for that NIC is to assign the VF to the
> > guest, not the whole PF.
> > 
> Yes, I know. But my kernel I'm testing with doesn't have one for ixgbe.

Ah, you mean it's an older (heh, ok, older actually means not brand new
upstream) kernel, w/out the recent sr-iov additions, fair enough.

> So I tested that one. And KVM really should enable MSI-X here,
> VFs notwithstanding.

Yeah, although it's not just KVM involved, it's very much driven by
the guest too.  The guest will see (or at least should see) the MSI-X
capability, and decide based on the number of queues whether to enable
MSI-X (completely driver dependent here).

Did you have a chance to boot the guest again, and send the lspci -vvv from
the guest POV?  You should see two PCI capabilities (MSI and 0x40 and
MSI-X at 0x50).

Actually, I have one of these devices, let me give it a quick test...
working fine here.  Here's some relevant information:

Host:

$ sudo lspci -v -s 04:00.0
04:00.0 Ethernet controller: Intel Corporation 82599EB 10-Gigabit Network Connection (rev 01)
	Subsystem: Intel Corporation Ethernet Server Adapter X520-2
	Flags: bus master, fast devsel, latency 0, IRQ 16
	Memory at f8080000 (64-bit, prefetchable) [size=512K]
	I/O ports at d020 [size=32]
	Memory at f8104000 (64-bit, prefetchable) [size=16K]
	Capabilities: [40] Power Management version 3
	Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
	Capabilities: [70] MSI-X: Enable+ Count=64 Masked-
	Capabilities: [a0] Express Endpoint, MSI 00
	Capabilities: [100] Advanced Error Reporting
	Capabilities: [140] Device Serial Number 00-1b-21-ff-ff-3f-a1-b0
	Capabilities: [150] Alternative Routing-ID Interpretation (ARI)
	Capabilities: [160] Single Root I/O Virtualization (SR-IOV)

$ grep kvm /proc/interrupts 
  95:        289          0          0          0          0          0          0          0          0          0          0          0          0          0          0          0   PCI-MSI-edge      kvm_assigned_msix_device
  96:         32          0          0          0        292          0          0          0          0          0          0          0          0          0          0          0   PCI-MSI-edge      kvm_assigned_msix_device
  97:          2          0          0          0          0          0          0          0          0          0          0          0          0          0          0          0   PCI-MSI-edge      kvm_assigned_msix_device

Guest side:
$ sudo lspci -vvv -s 00:04.0
00:04.0 Ethernet controller: Intel Corporation 82599EB 10-Gigabit Network Connection (rev 01)
	Subsystem: Intel Corporation Ethernet Server Adapter X520-2
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0, Cache Line Size: 64 bytes
	Interrupt: pin A routed to IRQ 11
	Region 0: Memory at f2080000 (32-bit, non-prefetchable)
	Region 2: I/O ports at c200
	Region 4: Memory at f2100000 (32-bit, non-prefetchable)
	Capabilities: [40] MSI: Enable- Count=1/1 Maskable- 64bit-
		Address: 00000000  Data: 0000
	Capabilities: [50] MSI-X: Enable+ Count=64 Masked-
		Vector table: BAR=4 offset=00000000
		PBA: BAR=4 offset=00002000

$ grep eth1 /proc/interrupts
177:        387       PCI-MSI-X  eth1-rx-0
185:        421       PCI-MSI-X  eth1-tx-0
193:          2       PCI-MSI-X  eth1:lsc

$ dmesg | grep -e 00:04.0 -e ixgbe
ixgbe: Intel(R) 10 Gigabit PCI Express Network Driver - version 2.0.8-k2
ixgbe: Copyright (c) 1999-2009 Intel Corporation.
ACPI: PCI Interrupt 0000:00:04.0[A] -> Link [LNKD] -> GSI 10 (level, high) -> IRQ 10
PCI: Setting latency timer of device 0000:00:04.0 to 64
ixgbe: 0000:00:04.0: ixgbe_init_interrupt_scheme: Multiqueue Disabled: Rx Queue count = 1, Tx Queue count = 1
ixgbe 0000:00:04.0: (PCI Express:2.5Gb/s:Width x8) 00:1b:21:3f:a1:b0
ixgbe 0000:00:04.0: MAC: 2, PHY: 11, SFP+: 5, PBA No: e66562-003
ixgbe 0000:00:04.0: Intel(R) 10 Gigabit Network Connection
ixgbe: eth1 NIC Link is Up 10 Gbps, Flow Control: None