Il 18/08/2014 11:12, Gonglei (Arei) ha scritto: > Hi, > >> Subject: Re: [Question] Why doesn't PCIe hotplug work for Q35 machine? >> >> On Sun, 2014-08-17 at 13:00 +0200, Michael S. Tsirkin wrote: >>> On Fri, Aug 15, 2014 at 07:33:29AM +0000, Gonglei (Arei) wrote: >>>> Hi, >>>> >>>> I noticed that the qemu-2.1 release change log says >>>> " PCIe: Basic hot-plug/hot-unplug support for Q35 machine." >>>> And then I made a testing for the hotplugging function of Q35. >>>> But I'm failed, and I got the dmesg log in guest os as below: >>>> >>>> [ 159.035250] Pciehp 0000:05:00.0:pcie24: Button pressed on Slot (0 - 4) >>>> [ 159.035274] Pciehp 0000:05:00.0:pcie24: Card present on Slot (0 - 4) >>>> [ 159.036517] Pciehp 0000:05:00.0:pcie24: PCI slot #0 - 4 - powering on due >> to button press. >>>> [ 159.188049] Pciehp 0000:05:00.0:pcie24: Failed to check link status >>>> [ 159.201968] Pciehp 0000:05:00.0:pcie24: Card not present on Slot (0 - 4) >>>> [ 159.202529] Pciehp 0000:05:00.0:pcie24: Already disabled on Slot (0 - 4) >>>> >>>> Steps of testing: >>>> >>>> #1. QEMU version: >>>> >>>> The lateset master tree source. >>>> >>>> #2. Command line: >>>> >>>> ./qemu-system-x86_64 -enable-kvm -m 2048 -machine q35 -device >> ide-drive,bus=ide.2,drive=MacHDD \ >>>> -drive id=MacHDD,if=none,file=/mnt/sdb/gonglei/image/redhat_q35.img >> -monitor stdio -vnc :10 -readconfig ../docs/q35-chipset.cfg >>>> QEMU 2.0.93 monitor - type 'help' for more information >>>> (qemu) device_add >> virtio-net-pci,id=nic2,bus=pcie-switch-downstream-port-1-1,addr=1.0 >>> >>> I don't think you can use any slot except slot 0 for pci express. > > OK. Does the PCIe specification say that? > I appreciate very much that you explain more.
The closest I could find is in "7.3. Configuration Transaction Rules"/"7.3.1. Device Number": With non-ARI Devices, PCI Express components are restricted to implementing a single Device Number on their primary interface (Upstream Port) [...] Downstream Ports that do not have ARI Forwarding enabled must associate only Device 0 with the device attached to the Logical Bus representing the Link from the Port. Configuration Requests targeting the Bus Number associated with a Link specifying Device Number 0 are delivered to the device attached to the Link; Configuration Requests specifying all other Device Numbers (1-31) must be terminated by the Switch Downstream Port or the Root Port with an Unsupported Request Completion Status (equivalent to Master Abort in PCI). Paolo >> Indeed, only slot 0 can be used, try the same without specifying the addr >> property. >> > > OK, got it. Thank you so much. > >>>> (qemu) info network >>>> hub 0 >>>> \ user.0: index=0,type=user,net=10.0.2.0,restrict=off >>>> \ e1000.0: index=0,type=nic,model=e1000,macaddr=52:54:00:12:34:56 >>>> >>>> #3. Guest OS: >>>> >>>> Both rhel-server-7.0-x86_64 and SLES-11-SP3-DVD-x86_64-GM. >>>> >>>> #4. Content of ../docs/q35-chipset.cfg: >>>> >>>> [snip] >>>> >>>> ## >>>> # Example PCIe switch with two downstream ports >>>> # >>>> [device "pcie-switch-upstream-port-1"] >>>> driver = "x3130-upstream" >>>> bus = "ich9-pcie-port-4" >>>> addr = "00.0" >>>> >>>> [device "pcie-switch-downstream-port-1-1"] >>>> driver = "xio3130-downstream" >>>> multifunction = "on" >>>> bus = "pcie-switch-upstream-port-1" >>>> addr = "00.0" >>>> port = "1" >>>> chassis = "5" >>>> >>>> [device "pcie-switch-downstream-port-1-2"] >>>> driver = "xio3130-downstream" >>>> multifunction = "on" >>>> bus = "pcie-switch-upstream-port-1" >>>> addr = "00.1" >>>> port = "1" >>>> chassis = "6" >>>> >>>> [device "ich9-ehci-1"] >>>> driver = "ich9-usb-ehci1" >>>> multifunction = "on" >>>> bus = "pcie.0" >>>> addr = "1d.7" >>>> >>>> [snip] >>>> >>>> BTW, except testing hotplug of downstream ports, I also test the root port >>>> with "device_add virtio-net-pci,id=nic2,bus=ich9-pcie-port-1,addr=1.0", but >>>> I got the same result. >>> >>> Same thing. >> Agreed, and also make sure that ich9-pcie-port-1 is a root port's bus and not >> an upstream port's bus. >> > Yes, it is. > >> Thanks, >> Marcel >> >>> >>>> Am I wrong in some places? Or a QEMU bug? Thanks for any help. >>>> >>>> Best regards, >>>> -Gonglei >>>> >>> >>> We might want to add a check for this, to produce a >>> better error message. >>> >> > Work in progress. Thanks! > > I also find other questions. Will post in a patch series. > > Best regards, > -Gonglei >
