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 (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. Am I wrong in some places? Or a QEMU bug? Thanks for any help. Best regards, -Gonglei