[Kernel 7.0.14] Qualcomm WCN785x Wi-Fi 7 (ath12k) PCI Passthrough fails: QMI DMA allocation failed (Works on bare-metal)

yanlong · August 6, 2026, 11:25am

Hello everyone,

I am trying to get my onboard Wi-Fi 7 card working under Qubes, but the ath12k driver is failing to initialize the wireless interfaces when passed through to sys-net.

I have already verified that this is not a hardware defect. The card works flawlessly on this exact machine when booting bare-metal Windows, Fedora, and Ubuntu. The issue seems strictly isolated to Xen PCI passthrough, DMA memory allocation, and possibly MSI vector translation.

Hardware & Environment:

Motherboard: ASUS ProArt X870E-Creator
Network Controller: Qualcomm Technologies, Inc WCN785x Wi-Fi 7(802.11be) 320MHz 2x2 [FastConnect 7800]
PCI ID: 17cb:1107 (rev 01)
Kernel: 7.0.14-1.qubes.fc41.x86_64 (Running in both dom0 and sys-net)
sys-net virt_mode: hvm

Troubleshooting Steps Already Taken:
Following the PCI troubleshooting guide for large DMA buffers, I applied the following configurations to sys-net, but the core still fails to start:

Increased sys-net initial memory to 800MB (qvm-prefs sys-net memory 800)
Expanded the software IO translation buffer (qvm-prefs sys-net kernelopts "nopat swiotlb=16384")

Symptoms / Logs:
The PCI device successfully attaches to sys-net (bound to pciback in dom0), but no wlan interface is created.

[    3.564916] ath12k_wifi7_pci 0000:00:06.0: BAR 0 [mem 0xf2400000-0xf25fffff 64bit]: assigned
[    3.566690] ath12k_wifi7_pci 0000:00:06.0: Wi-Fi 7 Hardware name: wcn7850 hw2.0
[    3.567752] ath12k_wifi7_pci 0000:00:06.0: MSI vectors: 1
[    4.295404] ath12k_wifi7_pci 0000:00:06.0: qmi dma allocation failed (7274496 B type 1), will try later with small size
[    4.303056] ath12k_wifi7_pci 0000:00:06.0: chip_id 0x2 chip_family 0x4 board_id 0xff soc_id 0x40170200
[    4.303083] ath12k_wifi7_pci 0000:00:06.0: fw_version 0x1103006c fw_build_timestamp 2026-03-06 09:10 fw_build_id QC_IMAGE_VERSION_STRING=WLAN.HMT.1.1.c7-00108-QCAHMTSWPI_V1.0_V2.0_SILICONZ_UPSTREAM-3
[    4.422397] ath12k_wifi7_pci 0000:00:06.0: leaving PCI ASPM disabled to avoid MHI M2 problems
[    5.476869] ath12k_wifi7_pci 0000:00:06.0: failed to receive control response completion, polling..
[    6.501374] ath12k_wifi7_pci 0000:00:06.0: Service connect timeout
[    6.501412] ath12k_wifi7_pci 0000:00:06.0: failed to connect to HTT: -110
[    6.501566] ath12k_wifi7_pci 0000:00:06.0: failed to start core: -110

I know there was a highly successful community patch for the previous generation ath11k chips that bypassed Xen MSI translation issues by manually passing host_msi_vector_addr and host_msi_vector_data to the kernel.

Looking at my logs (specifically the HTT -110 timeout), it looks like the ath12k driver is suffering from the exact same MSI translation bug under Xen.

Is anyone currently working on porting the host_msi_vector_addr patch to the ath12k driver, or is there an alternative kernel parameter recommended to force Xen to map these interrupts correctly?

Any guidance is greatly appreciated!

ChrisA · August 6, 2026, 10:16pm

Hi yanlong

I agree, that it looks depressingly like the issue from the ath11k, where Qubes / Xen doesn’t work.

I believe we’ll need the technical insight from someone like @marmarek to tell if it is the same issue .. and he would probably know, if something is happening in the Xen development.

marmarek · August 6, 2026, 10:38pm

Looking at the message, I’d say too little memory in sys-net. But since you tried increasing it already, that’s probably something else. It is possible it’s the same MSI issue, but from the above messages it isn’t obvious to me.

yanlong · August 7, 2026, 8:17am

is there any way i can be of more help? for now, i will just use my PC with ethernet (a bit of a hassle since i have to manually set up IPV4 every reboot) but I’d love to help any way i can so that the problem is solved in coming versions.