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Bug 1326546

Summary: [Q35] No slot/function available for xio3130-downstream when boot up with multiple downstreams
Product: Red Hat Enterprise Linux 7 Reporter: jingzhao <jinzhao>
Component: qemu-kvm-rhevAssignee: Marcel Apfelbaum <marcel>
Status: CLOSED NOTABUG QA Contact: Virtualization Bugs <virt-bugs>
Severity: high Docs Contact:
Priority: high    
Version: 7.3CC: chayang, jinzhao, juzhang, knoel, virt-maint, xfu
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2016-05-11 02:19:30 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description jingzhao 2016-04-13 03:09:16 UTC
Description of problem:
No slot/function available for xio3130-downstream when boot up with 1 upstream with multiple downstreams

Version-Release number of selected component (if applicable):
kernel-3.10.0-373.el7.x86_64
qemu-kvm-rhev-2.5.0-4.el7.x86_64
seabios-1.9.1-2.el7.x86_64

How reproducible:
3/3

Steps to Reproduce:
1. Boot guest with multiple downstreams:
1 upsteam attached multiple downstream

sh mulit-downstream.sh 33

[root@localhost home]# cat multi-downstream.sh 
#!/bin/sh

MACHINE=q35
SMP=4,cores=2,threads=2,sockets=1
MEM=2G
GUEST_IMG=/home/rhel.img
IMG_FORMAT=qcow2

CLI="/usr/libexec/qemu-kvm -enable-kvm -M $MACHINE -smp $SMP -m $MEM -name vm1 -drive file=$GUEST_IMG,if=none,id=guest-img,format=$IMG_FORMAT,werror=stop,rerror=stop -device ide-hd,drive=guest-img,bus=ide.0,unit=0,id=os-disk,bootindex=0 -spice port=5931,disable-ticketing -vga qxl -monitor stdio -serial unix:/tmp/console,server,nowait -qmp tcp:0:6666,server,nowait -chardev file,path=/home/seabios.log,id=seabios -device isa-debugcon,chardev=seabios,iobase=0x402 -boot menu=on,reboot-timeout=8,strict=on -device ioh3420,bus=pcie.0,id=root.0,slot=1 -device x3130-upstream,bus=root.0,id=upstream"
while [ ${i:=0} -lt ${1:-0} ]
do
    dstreamId=$((i))
    chassisId=$((dstreamId+1))
    blkDiskId=$((dstreamId))


    qemu-img create -f qcow2 /home/disk/disk$blkDiskId  100M
    CLI="$CLI -device xio3130-downstream,bus=upstream,id=downstream$dstreamId,chassis=$chassisId"
    CLI="$CLI -drive file=/home/disk/disk$blkDiskId,if=none,id=disk$blkDiskId,format=qcow2 "
    CLI="$CLI -device virtio-blk-pci,scsi=off,drive=disk$blkDiskId,id=virtio-blk$blkDiskId,bus=downstream$dstreamId,disable-modern=off,disable-legacy=on"
    i=$((i+1))
done

$CLI



Actual results:
No slot/function available for xio3130-downstream

Expected results:
guest can boot up with multiple downstreams (256 downstreams)

Additional info:

Comment 2 Marcel Apfelbaum 2016-05-10 16:25:57 UTC
Hi,

I didn't run the script, but it seems you are trying to attach 33 downstream ports to an upstream port? If so, this is not a valid configuration because an upstream port supports maximum 32 downstream ports.

You can uses nested switches if you need more than 32 ports, on port 31 add an upstream port and you have now another 32 ports.

Thanks,
Marcel

Comment 3 jingzhao 2016-05-11 02:19:30 UTC
(In reply to Marcel Apfelbaum from comment #2)
> Hi,
> 
> I didn't run the script, but it seems you are trying to attach 33 downstream
> ports to an upstream port? If so, this is not a valid configuration because
> an upstream port supports maximum 32 downstream ports.
> 
> You can uses nested switches if you need more than 32 ports, on port 31 add
> an upstream port and you have now another 32 ports.
> 
> Thanks,
> Marcel

Hi Marcel

  Sorry for the mistake, yes, an upstream support maximum 32 downstream ports, I will close this bug and tried it with nested switches.

Thanks
Jing