Hi, Somewhere between 5.1.0 and 5.2.0-rc1 there's a migration breakage on the nec-usb-xhci device:
[dgilbert@dgilbert-t580 try]$ ./x86_64-softmmu/qemu-system-x86_64 -M pc-q35-5.1 -device nec-usb-xhci -nographic -incoming tcp::4444 qemu-system-x86_64: get_pci_config_device: Bad config data: i=0x72 read: 88 device: 80 cmask: ff wmask: 71 w1cmask:0 qemu-system-x86_64: Failed to load PCIDevice:config qemu-system-x86_64: Failed to load xhci:parent_obj qemu-system-x86_64: error while loading state for instance 0x0 of device '0000:00:03.0/xhci' qemu-system-x86_64: load of migration failed: Invalid argument lspci is showing the MSI count ifferent, but I'm not sure if that's the only problem or not: 5.1.0 showing: [root@localhost ~]# lspci -v -s 00:03.0 -v 00:03.0 USB controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 03) (prog-if 30 [XHCI]) Subsystem: Red Hat, Inc. QEMU Virtual Machine 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 23 Region 0: Memory at febd4000 (64-bit, non-prefetchable) [size=16K] Capabilities: [90] MSI-X: Enable+ Count=16 Masked- Vector table: BAR=0 offset=00003000 PBA: BAR=0 offset=00003800 Capabilities: [a0] Express (v2) Root Complex Integrated Endpoint, MSI 00 DevCap: MaxPayload 128 bytes, PhantFunc 0 ExtTag- RBE+ DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq- RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop- MaxPayload 128 bytes, MaxReadReq 128 bytes DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr- TransPend- DevCap2: Completion Timeout: Not Supported, TimeoutDis-, LTR-, OBFF Not Supported AtomicOpsCap: 32bit- 64bit- 128bitCAS- DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled AtomicOpsCtl: ReqEn- Capabilities: [70] MSI: Enable- Count=1/16 Maskable- 64bit+ Address: 0000000000000000 Data: 0000 Kernel driver in use: xhci_hcd 5.2.0rc1 showing [root@localhost ~]# lspci -v -s 00:03.0 -v 00:03.0 USB controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 03) (prog-if 30 [XHCI]) Subsystem: Red Hat, Inc. QEMU Virtual Machine 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 23 Region 0: Memory at febd4000 (64-bit, non-prefetchable) [size=16K] Capabilities: [90] MSI-X: Enable+ Count=1 Masked- Vector table: BAR=0 offset=00003000 PBA: BAR=0 offset=00003800 Capabilities: [a0] Express (v2) Root Complex Integrated Endpoint, MSI 00 DevCap: MaxPayload 128 bytes, PhantFunc 0 ExtTag- RBE+ DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq- RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop- MaxPayload 128 bytes, MaxReadReq 128 bytes DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr- TransPend- DevCap2: Completion Timeout: Not Supported, TimeoutDis-, LTR-, OBFF Not Supported AtomicOpsCap: 32bit- 64bit- 128bitCAS- DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled AtomicOpsCtl: ReqEn- Capabilities: [70] MSI: Enable- Count=1/1 Maskable- 64bit+ Address: 0000000000000000 Data: 0000 Kernel driver in use: xhci_hcd I see there's quite a few differences in the output of info qtree for the device. Dave -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK