Re: [PATCH 1/2] vfio: Make vfio-pci available on 64-bit host platforms only

["Cédric Le Goater" <clg@redhat.com>]

>>> I see PPC is defined in target/ppc/Kconfig so I think these mark the target not the host. Vfio-pci works with qemu-system-ppc 
>>
>> Ah ! I am surprised. Which host and QEMU machine please ?
> 
> I've seen people do this on x86_64 host with pegasos2, amigaone and mac99 running 32 bit guests (AmigaOS and MacOS). Some people running older 32 bit Windows versions on pc machine might also use this.


I tried with :

     qemu-system-ppc -m 1G -smp 1 -M mac99,via=pmu -cpu g4  ....

There are some errors/warnings:

     qemu-system-ppc: -device vfio-pci,host=0000:0c:00.0: warning: MSI-X is not supported by interrupt controller
     Cannot manage 'ethernet controller' PCI device type 'network':
     >>
     >>  8086 10c9 (2 0 0)
     >> set_property: NULL phandle
     
     >> =============================================================
     >> OpenBIOS 1.1 [Sep 24 2024 19:56]
     ...

but it does work :

     root@debian-powerpc:~# uname -a
     Linux debian-powerpc 6.1.0-7-powerpc #1 Debian 6.1.20-1 (2023-03-19) ppc GNU/Linux
     root@debian-powerpc:~# lspci -s  00:10.0 -vv
     00:10.0 Ethernet controller: Intel Corporation 82576 Gigabit Network Connection (rev 01)
     	Subsystem: Beijing Sinead Technology Co., Ltd. 82576 Gigabit Network Connection
     	Device tree node: /sys/firmware/devicetree/base/pci@f2000000/pci8086,10c9@10
     	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 27
     	Region 0: Memory at 82080000 (32-bit, non-prefetchable) [size=128K]
     	Region 1: Memory at 82400000 (32-bit, non-prefetchable) [size=4M]
     	Region 2: I/O ports at 1080 [size=32]
     	Region 3: Memory at 82800000 (32-bit, non-prefetchable) [size=16K]
     	Expansion ROM at 82c00000 [disabled] [size=4M]
     	Capabilities: [40] Power Management version 3
     		Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
     		Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=1 PME-
     	Capabilities: [a0] Express (v2) Endpoint, MSI 00
     		DevCap:	MaxPayload 512 bytes, PhantFunc 0, Latency L0s <512ns, L1 <64us
     			ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0W
     		DevCtl:	CorrErr- NonFatalErr- FatalErr+ UnsupReq-
     			RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ FLReset-
     			MaxPayload 256 bytes, MaxReadReq 512 bytes
     		DevSta:	CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr+ TransPend-
     		LnkCap:	Port #0, Speed 2.5GT/s, Width x4, ASPM L0s L1, Exit Latency L0s <4us, L1 <64us
     			ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp-
     		LnkCtl:	ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
     			ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
     		LnkSta:	Speed 2.5GT/s, Width x1 (downgraded)
     			TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
     		DevCap2: Completion Timeout: Range ABCD, TimeoutDis+ NROPrPrP- LTR-
     			 10BitTagComp- 10BitTagReq- OBFF Not Supported, ExtFmt- EETLPPrefix-
     			 EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit-
     			 FRS- TPHComp- ExtTPHComp-
     			 AtomicOpsCap: 32bit- 64bit- 128bitCAS-
     		DevCtl2: Completion Timeout: 16ms to 55ms, TimeoutDis- LTR- 10BitTagReq- OBFF Disabled,
     			 AtomicOpsCtl: ReqEn-
     		LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete- EqualizationPhase1-
     			 EqualizationPhase2- EqualizationPhase3- LinkEqualizationRequest-
     			 Retimer- 2Retimers- CrosslinkRes: unsupported
     	Kernel driver in use: igb
     	Kernel modules: igb
     root@debian-powerpc:~# ip link show dev enp0s16
     2: enp0s16: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
         link/ether 80:61:5f:0a:2f:c4 brd ff:ff:ff:ff:ff:ff


The number of VFIO combinations drives me nuts. It's worse than PPC.

Thanks,

C.