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Mon, 21 Sep 2026 09:26:23 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (smtpav04.fra02v.mail.ibm.com [10.20.54.103]) by smtprelay03.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 68L9QJIb47710508 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 21 Sep 2026 09:26:19 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E93A72004B; Mon, 21 Sep 2026 09:26:18 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BF61D20043; Mon, 21 Sep 2026 09:26:17 +0000 (GMT) Received: from [9.123.2.177] (unknown [9.123.2.177]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 21 Sep 2026 09:26:17 +0000 (GMT) Message-ID: <4243a207-32d4-40ee-b41a-4bc862492e46@linux.ibm.com> Date: Mon, 21 Sep 2026 14:56:16 +0530 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG] PCIe passthrough of MCS9990 fails To: Timothy Pearson , linuxppc-dev Cc: Ritesh Harjani , Harsh Prateek Bora , Shivaprasad G Bhat , Gautam Menghani References: <133526175.85096.1789756371777.JavaMail.zimbra@raptorengineeringinc.com> <1582840094.85102.1789757342292.JavaMail.zimbra@raptorengineeringinc.com> Content-Language: en-US From: Narayana Murty N In-Reply-To: <1582840094.85102.1789757342292.JavaMail.zimbra@raptorengineeringinc.com> Content-Type: text/plain; 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On 19/09/26 12:19 AM, Timothy Pearson wrote: > I've also seen the following failure in the guest when passing through more than one PCIe function: > > [ 0.710454] pci 0000:01:00.1: EHCI: unrecognized capability 00 > [ 0.710546] EEH: Recovering PHB#0-PE#10001 > [ 0.710598] EEH: PE location: N/A, PHB location: N/A > [ 0.710669] EEH: Frozen PHB#0-PE#10001 detected > [ 0.710745] EEH: Call Trace: > [ 0.710832] EEH: [000000007d519995] __eeh_send_failure_event+0x7c/0x160 > [ 0.710944] EEH: [00000000419515d5] eeh_dev_check_failure+0x2e0/0x6d0 > [ 0.711011] EEH: [000000008950df7e] quirk_usb_early_handoff+0xca4/0xfd0 > [ 0.711076] EEH: [000000002528ae55] pci_fixup_device+0x140/0x2d0 > [ 0.711137] EEH: [000000002e85a626] pci_apply_final_quirks+0xb4/0x1b8 > [ 0.711199] EEH: [00000000e0915ba4] do_one_initcall+0x80/0x3b0 > [ 0.711255] EEH: [0000000014cb0304] kernel_init_freeable+0x340/0x3e4 > [ 0.711311] EEH: [00000000b18e64ad] kernel_init+0x30/0x1a0 > [ 0.711357] EEH: [0000000047d4e5e3] ret_from_kernel_user_thread+0x14/0x1c > [ 0.711413] EEH: This PCI device has failed 1 times in the last hour and will be permanently disabled after 5 failures. > [ 0.711493] EEH: Notify device drivers to shutdown > [ 0.711538] EEH: Beginning: 'error_detected(IO frozen)' > [ 0.711584] PCI 0000:01:00.1#10001: EEH: no driver > [ 0.711589] PCI 0000:01:00.3#10001: EEH: no driver > [ 0.711644] PCI 0000:01:00.5#10001: EEH: no driver > [ 0.711689] PCI 0000:01:00.7#10001: EEH: no driver > [ 0.711737] EEH: Finished:'error_detected(IO frozen)' with aggregate recovery state:'none' > [ 0.711860] EEH: Collect temporary log > [ 0.712602] EEH: of node=0000:01:00.1 > [ 0.712654] EEH: PCI device/vendor: 99909710 > [ 0.712720] EEH: PCI cmd/status register: 00100146 > [ 0.712761] EEH: PCI-E capabilities and status follow: > [ 0.712876] EEH: PCI-E 00: 00010010 00008fc1 0000283f 01078011 > [ 0.712989] EEH: PCI-E 10: 00110008 00000000 000003c0 00000000 > [ 0.713044] EEH: PCI-E 20: 00000000 > [ 0.713082] EEH: of node=0000:01:00.3 > [ 0.713129] EEH: PCI device/vendor: 99909710 > [ 0.713187] EEH: PCI cmd/status register: 00100146 > [ 0.713232] EEH: PCI-E capabilities and status follow: > [ 0.713345] EEH: PCI-E 00: 00010010 00008fc1 0000283f 01078011 > [ 0.713460] EEH: PCI-E 10: 00110008 00000000 000003c0 00000000 > [ 0.713513] EEH: PCI-E 20: 00000000 > [ 0.713547] EEH: of node=0000:01:00.5 > [ 0.713595] EEH: PCI device/vendor: 99909710 > [ 0.713655] EEH: PCI cmd/status register: 00100146 > [ 0.713700] EEH: PCI-E capabilities and status follow: > [ 0.713812] EEH: PCI-E 00: 00010010 00008fc1 0000283f 01078011 > [ 0.713938] EEH: PCI-E 10: 00110008 00000000 000003c0 00000000 > [ 0.714007] EEH: PCI-E 20: 00000000 > [ 0.714052] EEH: of node=0000:01:00.7 > [ 0.714108] EEH: PCI device/vendor: 99909710 > [ 0.714182] EEH: PCI cmd/status register: 00100146 > [ 0.714239] EEH: PCI-E capabilities and status follow: > [ 0.714371] EEH: PCI-E 00: 00010010 00008fc1 0000283f 01078011 > [ 0.714501] EEH: PCI-E 10: 00110008 00000000 000003c0 00000000 > [ 0.714571] EEH: PCI-E 20: 00000000 > [ 0.714623] EEH: Reset with hotplug activity > [ 0.714942] pci 0000:01:00.1: quirk_usb_early_handoff+0x0/0xfd0 took 12340 usecs > [ 0.716273] PCI: CLS 0 bytes, default 128 > [ 0.716424] Trying to unpack rootfs image as initramfs... > [ 0.725599] Initialise system trusted keyrings > [ 0.725679] Key type blacklist registered > [ 0.725797] workingset: timestamp_bits=38 max_order=19 bucket_order=0 > [ 0.725891] zbud: loaded > > Passing through one single EHCI function seems to at least allow the guest to boot, but only *once* after each power cycle. > > All functions are in the same IOMMU group: > > [ 617.749136] pci 0031:01:00.0: BAR 0 [mem size 0x00001000]: can't claim; no address assigned > [ 617.749797] pci 0031:01:00.1: BAR 0 [mem size 0x00001000]: can't claim; no address assigned > [ 617.750412] pci 0031:01:00.2: BAR 0 [mem size 0x00001000]: can't claim; no address assigned > [ 617.751035] pci 0031:01:00.3: BAR 0 [mem size 0x00001000]: can't claim; no address assigned > [ 617.751668] pci 0031:01:00.4: BAR 0 [mem size 0x00001000]: can't claim; no address assigned > [ 617.752270] pci 0031:01:00.5: BAR 0 [mem size 0x00001000]: can't claim; no address assigned > [ 617.752871] pci 0031:01:00.6: BAR 0 [mem size 0x00001000]: can't claim; no address assigned > [ 617.753467] pci 0031:01:00.7: BAR 0 [mem size 0x00001000]: can't claim; no address assigned > [ 617.754039] pci 0031:00:00.0: disabling bridge window [io 0x0000-0xffffffffffffffff] to [bus 01] (unused) > [ 617.754642] pci 0031:00:00.0: disabling bridge window [mem 0x00000000-0xffffffffffffffff 64bit pref] to [bus 01] (unused) > [ 617.755257] pci 0031:01:00.0: BAR 0 [mem 0x620c080000000-0x620c080000fff]: assigned > [ 617.755813] pci 0031:01:00.1: BAR 0 [mem 0x620c080010000-0x620c080010fff]: assigned > [ 617.756195] pci 0031:01:00.2: BAR 0 [mem 0x620c080020000-0x620c080020fff]: assigned > [ 617.756559] pci 0031:01:00.3: BAR 0 [mem 0x620c080030000-0x620c080030fff]: assigned > [ 617.756923] pci 0031:01:00.4: BAR 0 [mem 0x620c080040000-0x620c080040fff]: assigned > [ 617.757281] pci 0031:01:00.5: BAR 0 [mem 0x620c080050000-0x620c080050fff]: assigned > [ 617.757635] pci 0031:01:00.6: BAR 0 [mem 0x620c080060000-0x620c080060fff]: assigned > [ 617.757980] pci 0031:01:00.7: BAR 0 [mem 0x620c080070000-0x620c080070fff]: assigned > [ 617.758332] pci 0031:00:00.0: PCI bridge to [bus 01] > [ 617.758662] pci 0031:00:00.0: bridge window [mem 0x620c080000000-0x620c0ffefffff] > [ 617.759016] pci_bus 0031:01: Configuring PE for bus > [ 617.759357] pci 0031:01 : [PE# fd] Secondary bus 0x0000000000000001 associated with PE#fd > [ 617.759875] pci 0031:01:00.0: Configured PE#fd > [ 617.760213] pci 0031:01 : [PE# fd] Setting up 32-bit TCE table at 0..80000000 > [ 617.762565] pci 0031:01 : [PE# fd] Setting up window#0 0..7ffffffffff pg=10000 > [ 617.763014] pci 0031:01 : [PE# fd] Enabling 64-bit DMA bypass > [ 617.763631] pci 0031:01:00.0: Adding to iommu group 10 > [ 617.764218] pci 0031:01:00.0: enabling device (0140 -> 0142) > [ 617.764735] pci 0031:01:00.1: Added to existing PE#fd > [ 617.765064] pci 0031:01:00.1: Adding to iommu group 10 > [ 617.765483] pci 0031:01:00.1: enabling device (0140 -> 0142) > [ 617.766003] pci 0031:01:00.2: Added to existing PE#fd > [ 617.766331] pci 0031:01:00.2: Adding to iommu group 10 > [ 617.766764] pci 0031:01:00.2: enabling device (0140 -> 0142) > [ 617.767179] pci 0031:01:00.3: Added to existing PE#fd > [ 617.767517] pci 0031:01:00.3: Adding to iommu group 10 > [ 617.767932] pci 0031:01:00.3: enabling device (0140 -> 0142) > [ 617.768339] pci 0031:01:00.4: Added to existing PE#fd > [ 617.768655] pci 0031:01:00.4: Adding to iommu group 10 > [ 617.769068] pci 0031:01:00.4: enabling device (0140 -> 0142) > [ 617.769468] pci 0031:01:00.5: Added to existing PE#fd > [ 617.769768] pci 0031:01:00.5: Adding to iommu group 10 > [ 617.770176] pci 0031:01:00.5: enabling device (0140 -> 0142) > [ 617.770623] pci 0031:01:00.6: Added to existing PE#fd > [ 617.770921] pci 0031:01:00.6: Adding to iommu group 10 > [ 617.771321] pci 0031:01:00.6: enabling device (0140 -> 0142) > [ 617.771729] pci 0031:01:00.7: Added to existing PE#fd > [ 617.772014] pci 0031:01:00.7: Adding to iommu group 10 > [ 617.772451] pci 0031:01:00.7: enabling device (0140 -> 0142) > > > ----- Original Message ----- >> From: "Timothy Pearson" >> To: "linuxppc-dev" >> Cc: "Ritesh Harjani" >> Sent: Friday, September 18, 2026 1:32:51 PM >> Subject: [BUG] PCIe passthrough of MCS9990 fails > >> When passing through all eight PCIe functions of a MCS9990 PCIe USB >> multifunction 1.0/2.0 controller on a PowerNV POWER9 host using qemu, the guest >> fails to launch: >> >> qemu-system-ppc64: -device vfio-pci,host=0031:01:00.1,bus=bridge-1,addr=00.1: >> vfio 0031:01:00.1: Failed to set up TRIGGER eventfd signaling for interrupt >> INTX-0: VFIO_DEVICE_SET_IRQS failure: Device or resource busy >> >> If I instead pass through only one function, or only pass through odd functions >> (the EHCI controller set), I get the following errors in the guest: >> >> [ 0.886625] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002, >> bcdDevice= 6.18 >> [ 0.886710] usb usb1: New USB device strings: Mfr=3, Product=2, >> SerialNumber=1 >> [ 0.886791] usb usb1: Product: EHCI Host Controller >> [ 0.886845] usb usb1: Manufacturer: Linux 6.18.38 ehci_hcd >> [ 0.886902] usb usb1: SerialNumber: 0000:01:00.0 >> [ 1.142469] usb 1-1: new high-speed USB device number 2 using ehci-pci >> [ 6.530490] usb 1-1: device descriptor read/64, error -110 >> [ 22.147501] usb 1-1: device descriptor read/64, error -110 >> [ 22.371536] usb 1-1: new high-speed USB device number 3 using ehci-pci >> [ 27.526896] usb 1-1: device descriptor read/64, error -110 >> [ 43.141934] usb 1-1: device descriptor read/64, error -110 >> [ 43.245985] usb usb1-port1: attempt power cycle >> [ 43.638173] usb 1-1: new high-speed USB device number 4 using ehci-pci >> [ 54.491254] usb 1-1: device not accepting address 4, error -110 >> [ 54.611274] usb 1-1: new high-speed USB device number 5 using ehci-pci >> >> If I reboot the guest, SLOF fails as follows: >> >> Scanning USB >> EHCI: Initializing >> usb-ehci: reset failed >> usb-ehci: control transfer timed out_ >> usb-ehci: unable to setup device on port 0 >> >> Note that this card works perfectly on the host kernel. From what I can tell so far, this looks like it may be related to the passthrough device falling back to legacy INTx on a shared IRQ. My current suspicion is that the multifunction device may not provide usable per-function INTx masking, so VFIO cannot safely mask one function while the IRQ is shared by the other functions. That could explain the interrupt behaviour we are seeing, but I would like to confirm the actual interrupt mode before drawing any conclusion. Could you please share the following from the failing setup? lspci -vvv for all functions of the multifunction device on the host lspci -vvv for the passed-through device inside the guest /proc/interrupts on the host before and after starting the guest any VFIO/IRQ related messages from host dmesg the relevant QEMU command line In particular, I would like to confirm whether the device is actually running with legacy INTx, whether the functions share the same host IRQ, and whether MSI/MSI-X is being enabled successfully in the guest. Thanks, Narayana >