Subject: Re: [PATCH V7 00/17] Enable SRIOV on POWER8

From: Wei Yang <[email-masked]>
Date: Wed, 20 Aug 2014 10:34:04 +0800

On Tue, Aug 19, 2014 at 03:19:42PM -0600, Bjorn Helgaas wrote:
>On Thu, Jul 24, 2014 at 02:22:10PM +0800, Wei Yang wrote:
>> This patch set enables the SRIOV on POWER8.
>> 
>> The gerneral idea is put each VF into one individual PE and allocate required
>> resources like DMA/MSI.
>> 
>> One thing special for VF PE is we use M64BT to cover the IOV BAR. M64BT is one
>> hardware on POWER platform to map MMIO address to PE. By using M64BT, we could
>> map one individual VF to a VF PE, which introduce more flexiblity to users.
>> 
>> To achieve this effect, we need to do some hack on pci devices's resources.
>> 1. Expand the IOV BAR properly.
>>    Done by pnv_pci_ioda_fixup_iov_resources().
>> 2. Shift the IOV BAR properly.
>>    Done by pnv_pci_vf_resource_shift().
>> 3. IOV BAR alignment is the total size instead of an individual size on
>>    powernv platform.
>>    Done by pnv_pcibios_sriov_resource_alignment().
>> 4. Take the IOV BAR alignment into consideration in the sizing and assigning.
>>    This is achieved by commit: "PCI: Take additional IOV BAR alignment in
>>    sizing and assigning"
>> 
>> Test Environment:
>>        The SRIOV device tested is Emulex Lancer and Mellanox ConnectX-3 on
>>        POWER8.
>> 
>> Examples on pass through a VF to guest through vfio:
>> 	1. install necessary modules
>> 	   modprobe vfio
>> 	   modprobe vfio-pci
>> 	2. retrieve the iommu_group the device belongs to
>> 	   readlink /sys/bus/pci/devices/0000:06:0d.0/iommu_group
>> 	   ../../../../kernel/iommu_groups/26
>> 	   This means it belongs to group 26
>> 	3. see how many devices under this iommu_group
>> 	   ls /sys/kernel/iommu_groups/26/devices/
>> 	4. unbind the original driver and bind to vfio-pci driver
>> 	   echo 0000:06:0d.0 > /sys/bus/pci/devices/0000:06:0d.0/driver/unbind
>> 	   echo  1102 0002 > /sys/bus/pci/drivers/vfio-pci/new_id
>> 	   Note: this should be done for each device in the same iommu_group
>> 	5. Start qemu and pass device through vfio
>> 	   /home/ywywyang/git/qemu-impreza/ppc64-softmmu/qemu-system-ppc64 \
>> 		   -M pseries -m 2048 -enable-kvm -nographic \
>> 		   -drive file=/home/ywywyang/kvm/fc19.img \
>> 		   -monitor telnet:localhost:5435,server,nowait -boot cd \
>> 		   -device "spapr-pci-vfio-host-bridge,id=CXGB3,iommu=26,index=6"
>> 
>> Verify this is the exact VF response:
>> 	1. ping from a machine in the same subnet(the broadcast domain)
>> 	2. run arp -n on this machine
>> 	   9.115.251.20             ether   00:00:c9:df:ed:bf   C eth0
>> 	3. ifconfig in the guest
>> 	   # ifconfig eth1
>> 	   eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
>> 	        inet 9.115.251.20  netmask 255.255.255.0  broadcast 9.115.251.255
>> 		inet6 fe80::200:c9ff:fedf:edbf  prefixlen 64  scopeid 0x20<link>
>> 	        ether 00:00:c9:df:ed:bf  txqueuelen 1000 (Ethernet)
>> 	        RX packets 175  bytes 13278 (12.9 KiB)
>> 	        RX errors 0  dropped 0  overruns 0  frame 0
>> 		TX packets 58  bytes 9276 (9.0 KiB)
>> 	        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
>> 	4. They have the same MAC address
>> 
>> 	Note: make sure you shutdown other network interfaces in guest.
>> 
>> ---
>> v6 -> v7:
>>    1. add IORESOURCE_ARCH flag for IOV BAR on powernv platform.
>>    2. when IOV BAR has IORESOURCE_ARCH flag, the size is retrieved from
>>       hardware directly. If not, calculate as usual.
>>    3. reorder the patch set, group them by subsystem:
>>       PCI, powerpc, powernv
>>    4. rebase it on 3.16-rc6
>
>This doesn't apply for me on v3.16-rc6:
>
>  02:48:57 ~/linux$ stg rebase v3.16-rc6
>  Checking for changes in the working directory ... done
>  Rebasing to "v3.16-rc6" ... done
>  No patches applied
>  02:49:14 ~/linux$ stg import -M --sign m/wy
>  Checking for changes in the working directory ... done
>  Importing patch "pci-iov-export-interface-for" ... done
>  Importing patch "pci-iov-get-vf-bar-size-from" ... done
>  Importing patch "pci-add-weak" ... done
>  Importing patch "pci-take-additional-iov-bar" ... done
>  Importing patch "powerpc-pci-don-t-unset-pci" ... done
>  Importing patch "powerpc-pci-define" ... done
>  Importing patch "powrepc-pci-refactor-pci_dn" ... done
>  Importing patch "powerpc-powernv-use-pci_dn-in" ... error: patch failed:
>  arch/powerpc/platforms/powernv/pci.c:376
>  error: arch/powerpc/platforms/powernv/pci.c: patch does not apply
>  stg import: Diff does not apply cleanly
>
>What am I missing?
>
>I assume you intend these all to go through my tree just to keep them all
>together.  The ideal rebase target for me would be v3.17-rc1.

Ok, I will rebase it on v3.17-rc1 upstream. While I guess the conflict is due
to some patches from Gavin, which is not merged at that moment. I will make
sure it applies to v3.17-rc1.

>
>Given the arch/powerpc parts, I'll want an ack from Ben.  I just chatted
>with him about these, so I assume that's not a problem, but we should make
>it explicit.
>
>Bjorn

-- 
Richard Yang
Help you, Help me