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From: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Leon Romanovsky <leon@kernel.org>, Jason Gunthorpe <jgg@ziepe.ca>
Subject: Re: Write to srvio_numvfs triggers kernel panic
Date: Sun, 8 May 2022 11:07:40 +0000	[thread overview]
Message-ID: <87ee14l1tx.fsf@epam.com> (raw)
In-Reply-To: <20220507154145.GA568412@bhelgaas>


Hello Bjorn,

Bjorn Helgaas <helgaas@kernel.org> writes:

> On Sat, May 07, 2022 at 10:22:32AM +0000, Volodymyr Babchuk wrote:
>> Bjorn Helgaas <helgaas@kernel.org> writes:
>> > On Wed, May 04, 2022 at 07:56:01PM +0000, Volodymyr Babchuk wrote:
>> >> 
>> >> I have encountered issue when PCI code tries to use both fields in
>> >> 
>> >>         union {
>> >> 		struct pci_sriov	*sriov;		/* PF: SR-IOV info */
>> >> 		struct pci_dev		*physfn;	/* VF: related PF */
>> >> 	};
>> >> 
>> >> (which are part of struct pci_dev) at the same time.
>> >> 
>> >> Symptoms are following:
>> >> 
>> >> # echo 1 > /sys/bus/pci/devices/0000:01:00.0/sriov_numvfs
>> >> 
>> >> pci 0000:01:00.2: reg 0x20c: [mem 0x30018000-0x3001ffff 64bit]
>> >> pci 0000:01:00.2: VF(n) BAR0 space: [mem 0x30018000-0x30117fff 64bit] (contains BAR0 for 32 VFs)
>> >>  Unable to handle kernel paging request at virtual address 0001000200000010
>
>> >> Debugging showed the following:
>> >> 
>> >> pci_iov_add_virtfn() allocates new struct pci_dev:
>> >> 
>> >> 	virtfn = pci_alloc_dev(bus);
>> >> and sets physfn:
>> >> 	virtfn->is_virtfn = 1;
>> >> 	virtfn->physfn = pci_dev_get(dev);
>> >> 
>> >> then we will get into sriov_init() via the following call path:
>> >> 
>> >> pci_device_add(virtfn, virtfn->bus);
>> >>   pci_init_capabilities(dev);
>> >>     pci_iov_init(dev);
>> >>       sriov_init(dev, pos);
>> >
>> > We called pci_device_add() with the VF.  pci_iov_init() only calls
>> > sriov_init() if it finds an SR-IOV capability on the device:
>> >
>> >   pci_iov_init(struct pci_dev *dev)
>> >     pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
>> >     if (pos)
>> >       return sriov_init(dev, pos);
>> >
>> > So this means the VF must have an SR-IOV capability, which sounds a
>> > little dubious.  From PCIe r6.0:
>> 
>> [...]
>> 
>> Yes, I dived into debugging and came to the same conclusions. I'm still
>> investigating this, but looks like my PCIe controller (DesignWare-based)
>> incorrectly reads configuration space for VF. Looks like instead of
>> providing access VF config space, it reads PF's one.
>> 
>> > Can you supply the output of "sudo lspci -vv" for your system?
>> 
>> Sure:
>> 
>> root@spider:~# lspci -vv
>> 00:00.0 PCI bridge: Renesas Technology Corp. Device 0031 (prog-if 00 [Normal decode])
>>         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
>>         Interrupt: pin A routed to IRQ 189
>>         Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
>>         I/O behind bridge: [disabled]
>>         Memory behind bridge: 30000000-301fffff [size=2M]
>>         Prefetchable memory behind bridge: [disabled]
>>         Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR-
>>         BridgeCtl: Parity- SERR+ NoISA- VGA- VGA16- MAbort- >Reset- FastB2B-
>>                 PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
>>         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=0 PME-
>>         Capabilities: [50] MSI: Enable+ Count=128/128 Maskable+ 64bit+
>>                 Address: 0000000004030040  Data: 0000
>>                 Masking: fffffffe  Pending: 00000000
>>         Capabilities: [70] Express (v2) Root Port (Slot-), MSI 00
>>                 DevCap: MaxPayload 256 bytes, PhantFunc 0
>>                         ExtTag+ RBE+
>>                 DevCtl: CorrErr+ NonFatalErr+ FatalErr+ UnsupReq+
>>                         RlxdOrd+ ExtTag+ PhantFunc- AuxPwr- NoSnoop+
>>                         MaxPayload 128 bytes, MaxReadReq 512 bytes
>>                 DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr+ TransPend-
>>                 LnkCap: Port #0, Speed 5GT/s, Width x2, ASPM L0s L1, Exit Latency L0s <4us, L1 <64us
>>                         ClockPM- Surprise- LLActRep+ BwNot- ASPMOptComp+
>>                 LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk-
>>                         ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
>>                 LnkSta: Speed 5GT/s (ok), Width x2 (ok)
>>                         TrErr- Train- SlotClk- DLActive+ BWMgmt- ABWMgmt-
>>                 RootCap: CRSVisible-
>>                 RootCtl: ErrCorrectable- ErrNon-Fatal- ErrFatal- PMEIntEna+ CRSVisible-
>>                 RootSta: PME ReqID 0000, PMEStatus- PMEPending-
>>                 DevCap2: Completion Timeout: Not Supported, TimeoutDis+, NROPrPrP+, LTR+
>>                          10BitTagComp+, 10BitTagReq-, OBFF Not Supported, ExtFmt-, EETLPPrefix-
>>                          EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit-
>>                          FRS-, LN System CLS Not Supported, TPHComp-, ExtTPHComp-, ARIFwd-
>>                          AtomicOpsCap: Routing- 32bit- 64bit- 128bitCAS-
>>                 DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR+, OBFF Disabled ARIFwd-
>>                          AtomicOpsCtl: ReqEn- EgressBlck-
>>                 LnkCtl2: Target Link Speed: 5GT/s, EnterCompliance- SpeedDis-
>>                          Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
>>                          Compliance De-emphasis: -6dB
>>                 LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, EqualizationPhase1-
>>                          EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
>>         Capabilities: [100 v2] Advanced Error Reporting
>>                 UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
>>                 UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
>>                 UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
>>                 CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr-
>>                 CEMsk:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
>>                 AERCap: First Error Pointer: 00, ECRCGenCap- ECRCGenEn- ECRCChkCap- ECRCChkEn-
>>                         MultHdrRecCap+ MultHdrRecEn- TLPPfxPres- HdrLogCap-
>>                 HeaderLog: 00000000 00000000 00000000 00000000
>>                 RootCmd: CERptEn- NFERptEn- FERptEn-
>>                 RootSta: CERcvd- MultCERcvd- UERcvd- MultUERcvd-
>>                          FirstFatal- NonFatalMsg- FatalMsg- IntMsg 0
>>                 ErrorSrc: ERR_COR: 0000 ERR_FATAL/NONFATAL: 0000
>>         Capabilities: [148 v1] Device Serial Number 00-00-00-00-00-00-00-00
>>         Capabilities: [158 v1] Secondary PCI Express
>>                 LnkCtl3: LnkEquIntrruptEn-, PerformEqu-
>>                 LaneErrStat: 0
>>         Capabilities: [178 v1] Physical Layer 16.0 GT/s <?>
>>         Capabilities: [19c v1] Lane Margining at the Receiver <?>
>>         Capabilities: [1bc v1] L1 PM Substates
>>                 L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+ L1_PM_Substates+
>>                           PortCommonModeRestoreTime=10us PortTPowerOnTime=14us
>>                 L1SubCtl1: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+
>>                            T_CommonMode=0us LTR1.2_Threshold=0ns
>>                 L1SubCtl2: T_PwrOn=10us
>>         Capabilities: [1cc v1] Vendor Specific Information: ID=0002 Rev=4 Len=100 <?>
>>         Capabilities: [2cc v1] Vendor Specific Information: ID=0001 Rev=1 Len=038 <?>
>>         Capabilities: [304 v1] Data Link Feature <?>
>>         Capabilities: [310 v1] Precision Time Measurement
>>                 PTMCap: Requester:+ Responder:+ Root:+
>>                 PTMClockGranularity: 16ns
>>                 PTMControl: Enabled:- RootSelected:-
>>                 PTMEffectiveGranularity: Unknown
>>         Capabilities: [31c v1] Vendor Specific Information: ID=0004 Rev=1 Len=054 <?>
>>         Kernel driver in use: pcieport
>>         Kernel modules: pci_endpoint_test
>> 
>> 01:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd Device a824 (prog-if 02 [NVM Express])
>>         Subsystem: Samsung Electronics Co Ltd Device a809
>>         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
>>         Interrupt: pin A routed to IRQ 0
>>         NUMA node: 0
>>         Region 0: Memory at 30010000 (64-bit, non-prefetchable) [size=32K]
>>         Expansion ROM at 30000000 [virtual] [disabled] [size=64K]
>>         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=0 PME-
>>         Capabilities: [70] Express (v2) Endpoint, MSI 00                                                                                                                               [8/5710]
>>                 DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited
>>                         ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0.000W
>>                 DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
>>                         RlxdOrd+ ExtTag+ PhantFunc- AuxPwr- NoSnoop+ FLReset-
>>                         MaxPayload 128 bytes, MaxReadReq 512 bytes
>>                 DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr- TransPend-
>>                 LnkCap: Port #0, Speed 16GT/s, Width x4, ASPM not supported
>>                         ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+
>>                 LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk-
>>                         ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
>>                 LnkSta: Speed 5GT/s (downgraded), Width x2 (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: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled
>>                          AtomicOpsCtl: ReqEn-
>>                 LnkCtl2: Target Link Speed: 16GT/s, EnterCompliance- SpeedDis-
>>                          Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
>>                          Compliance De-emphasis: -6dB
>>                 LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, EqualizationPhase1-
>>                          EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
>>         Capabilities: [b0] MSI-X: Enable+ Count=64 Masked-
>>                 Vector table: BAR=0 offset=00004000
>>                 PBA: BAR=0 offset=00003000
>>         Capabilities: [100 v2] Advanced Error Reporting
>>                 UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
>>                 UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
>>                 UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
>>                 CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr-
>>                 CEMsk:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
>>                 AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
>>                         MultHdrRecCap+ MultHdrRecEn- TLPPfxPres- HdrLogCap-
>>                 HeaderLog: 00000000 00000000 00000000 00000000
>>         Capabilities: [148 v1] Device Serial Number d3-42-50-11-99-38-25-00
>>         Capabilities: [168 v1] Alternative Routing-ID Interpretation (ARI)
>>                 ARICap: MFVC- ACS-, Next Function: 0
>>                 ARICtl: MFVC- ACS-, Function Group: 0
>>         Capabilities: [178 v1] Secondary PCI Express
>>                 LnkCtl3: LnkEquIntrruptEn-, PerformEqu-
>>                 LaneErrStat: 0
>>         Capabilities: [198 v1] Physical Layer 16.0 GT/s <?>
>>         Capabilities: [1c0 v1] Lane Margining at the Receiver <?>
>>         Capabilities: [1e8 v1] Single Root I/O Virtualization (SR-IOV)
>>                 IOVCap: Migration-, Interrupt Message Number: 000
>>                 IOVCtl: Enable- Migration- Interrupt- MSE- ARIHierarchy-
>>                 IOVSta: Migration-
>>                 Initial VFs: 32, Total VFs: 32, Number of VFs: 0, Function Dependency Link: 00
>>                 VF offset: 2, stride: 1, Device ID: a824
>>                 Supported Page Size: 00000553, System Page Size: 00000001
>>                 Region 0: Memory at 0000000030018000 (64-bit, non-prefetchable)
>>                 VF Migration: offset: 00000000, BIR: 0
>>         Capabilities: [3a4 v1] Data Link Feature <?>
>>         Kernel driver in use: nvme
>>         Kernel modules: nvme
>
> I guess this is before enabling SR-IOV on 01:00.0, so it doesn't show
> the VFs themselves.

Yes. Because kernel crashed without your suggested patch.

>> > It could be that the device has an SR-IOV capability when it
>> > shouldn't.  But even if it does, Linux could tolerate that better
>> > than it does today.
>> 
>> Agree there. I can create simple patch that checks for is_virtfn
>> in sriov_init(). But what to do if it is set?
>
> Maybe something like this?  It makes no sense to me that a VF would
> have an SR-IOV capability, but ...
>
> If the below avoids the problem, maybe collect another "lspci -vv"
> output including the VF(s).
>

I had another crash in nvme_pci_enable(), for which I made quick
workaround. And now yeah, it looks like I have some issues with
my root complex HW:

[skipping bridge info]

01:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd Device a824 (prog-if 02 [NVM Express])
        Subsystem: Samsung Electronics Co Ltd Device a809
        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
        Interrupt: pin A routed to IRQ 0
        NUMA node: 0
        Region 0: Memory at 30010000 (64-bit, non-prefetchable) [size=32K]
        Expansion ROM at 30000000 [virtual] [disabled] [size=64K]
        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=0 PME-
                Capabilities: [70] Express (v2) Endpoint, MSI 00
                DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited
                        ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0.000W
                DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
                        RlxdOrd+ ExtTag+ PhantFunc- AuxPwr- NoSnoop+ FLReset-
                        MaxPayload 128 bytes, MaxReadReq 512 bytes
                DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr- TransPend-
                LnkCap: Port #0, Speed 16GT/s, Width x4, ASPM not supported
                        ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+
                LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk-
                        ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
                LnkSta: Speed 5GT/s (downgraded), Width x2 (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: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled
                         AtomicOpsCtl: ReqEn-
                LnkCtl2: Target Link Speed: 16GT/s, EnterCompliance- SpeedDis-
                         Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
                         Compliance De-emphasis: -6dB
                LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, EqualizationPhase1-
                         EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
        Capabilities: [b0] MSI-X: Enable- Count=64 Masked-
                Vector table: BAR=0 offset=00004000
                PBA: BAR=0 offset=00003000
        Capabilities: [100 v2] Advanced Error Reporting
                UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
                UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
                UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
                CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr-
                CEMsk:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
                AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
                        MultHdrRecCap+ MultHdrRecEn- TLPPfxPres- HdrLogCap-
                HeaderLog: 00000000 00000000 00000000 00000000
        Capabilities: [148 v1] Device Serial Number d3-42-50-11-99-38-25-00
        Capabilities: [168 v1] Alternative Routing-ID Interpretation (ARI)
                ARICap: MFVC- ACS-, Next Function: 0
                ARICtl: MFVC- ACS-, Function Group: 0
        Capabilities: [178 v1] Secondary PCI Express
                LnkCtl3: LnkEquIntrruptEn-, PerformEqu-
                LaneErrStat: 0
        Capabilities: [198 v1] Physical Layer 16.0 GT/s <?>
        Capabilities: [1c0 v1] Lane Margining at the Receiver <?>
        Capabilities: [1e8 v1] Single Root I/O Virtualization (SR-IOV)
                IOVCap: Migration-, Interrupt Message Number: 000
                IOVCtl: Enable+ Migration- Interrupt- MSE+ ARIHierarchy-
                IOVSta: Migration-
                Initial VFs: 32, Total VFs: 32, Number of VFs: 1, Function Dependency Link: 00
                VF offset: 2, stride: 1, Device ID: a824
                Supported Page Size: 00000553, System Page Size: 00000001
                Region 0: Memory at 0000000030018000 (64-bit, non-prefetchable)
                VF Migration: offset: 00000000, BIR: 0
        Capabilities: [3a4 v1] Data Link Feature <?>
        Kernel driver in use: nvme
        Kernel modules: nvme

01:00.2 Non-Volatile memory controller: Samsung Electronics Co Ltd Device a824 (prog-if 02 [NVM Express])
        Subsystem: Samsung Electronics Co Ltd Device a809
        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
        Interrupt: pin A routed to IRQ 0
        NUMA node: 0
        Region 0: Memory at 30018000 (64-bit, non-prefetchable) [size=32K]
        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=0 PME-
        Capabilities: [70] Express (v2) Endpoint, MSI 00
                DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited
                        ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0.000W
                DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
                        RlxdOrd+ ExtTag+ PhantFunc- AuxPwr- NoSnoop+ FLReset-
                        MaxPayload 128 bytes, MaxReadReq 512 bytes
                DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr- TransPend-
                LnkCap: Port #0, Speed 16GT/s, Width x4, ASPM not supported
                        ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+
                LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk-
                        ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
                LnkSta: Speed 5GT/s (downgraded), Width x2 (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: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled
                         AtomicOpsCtl: ReqEn-
                LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, EqualizationPhase1-
                         EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
        Capabilities: [b0] MSI-X: Enable- Count=64 Masked-
                Vector table: BAR=0 offset=00004000
                PBA: BAR=0 offset=00003000
        Capabilities: [100 v2] Advanced Error Reporting
                UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
                UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
                UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
                CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr-
                CEMsk:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
                AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn-
                        MultHdrRecCap+ MultHdrRecEn- TLPPfxPres- HdrLogCap-
                HeaderLog: 00000000 00000000 00000000 00000000
        Capabilities: [148 v1] Device Serial Number d3-42-50-11-99-38-25-00
        Capabilities: [168 v1] Alternative Routing-ID Interpretation (ARI)
                ARICap: MFVC- ACS-, Next Function: 0
                ARICtl: MFVC- ACS-, Function Group: 0
        Capabilities: [178 v1] Secondary PCI Express
                LnkCtl3: LnkEquIntrruptEn-, PerformEqu-
                LaneErrStat: 0
        Capabilities: [198 v1] Physical Layer 16.0 GT/s <?>
        Capabilities: [1c0 v1] Lane Margining at the Receiver <?>
        Capabilities: [1e8 v1] Single Root I/O Virtualization (SR-IOV)
                IOVCap: Migration-, Interrupt Message Number: 000
                IOVCtl: Enable+ Migration- Interrupt- MSE+ ARIHierarchy-
                IOVSta: Migration-
                Initial VFs: 32, Total VFs: 32, Number of VFs: 1, Function Dependency Link: 00
                VF offset: 2, stride: 1, Device ID: a824
                Supported Page Size: 00000553, System Page Size: 00000001
                Region 0: Memory at 0000000030018000 (64-bit, non-prefetchable)
                VF Migration: offset: 00000000, BIR: 0
        Capabilities: [3a4 v1] Data Link Feature <?>
        Kernel modules: nvme

As you can see, output for func 0 and func 2 is identical, so yeah,
looks like my system reads config space for func 0 in both cases.

Now at least I know where to look. Thank you for your help.

> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index 952217572113..9c5184384a45 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -901,6 +901,10 @@ int pci_iov_init(struct pci_dev *dev)
>  	if (!pci_is_pcie(dev))
>  		return -ENODEV;
>  
> +	/* Some devices include SR-IOV cap on VFs as well as PFs */
> +	if (dev->is_virtfn)
> +		return -ENODEV;
> +
>  	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
>  	if (pos)
>  		return sriov_init(dev, pos);

Thanks, this patch helped. You can have my

Tested-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>

if you are going to include it in the kernel.

On other hand, I'm wondering if it is correct to have both is_virtfn and
is_physfn in the first place, as there can 4 combinations and only two
(or three?) of them are valid. Maybe it is worth to replace them with
enum?

-- 
Volodymyr Babchuk at EPAM

  reply	other threads:[~2022-05-08 20:19 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-04 19:56 Write to srvio_numvfs triggers kernel panic Volodymyr Babchuk
2022-05-06 20:17 ` Bjorn Helgaas
2022-05-07  1:34   ` Jason Gunthorpe
2022-05-07 10:25     ` Volodymyr Babchuk
2022-05-08 11:19       ` Leon Romanovsky
2022-05-09 18:22         ` Keith Busch
2022-05-07 10:22   ` Volodymyr Babchuk
2022-05-07 15:41     ` Bjorn Helgaas
2022-05-08 11:07       ` Volodymyr Babchuk [this message]
2022-05-09 16:49         ` Bjorn Helgaas
2022-05-09 16:58           ` Alex Williamson
2022-05-10  6:39             ` Christoph Hellwig
2022-05-10 17:37               ` Bjorn Helgaas
2022-05-12  7:18                 ` Volodymyr Babchuk

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