Re: [6.1.y] Regression from b1e6e80a1b42 ("xen/swiotlb: add alignment check for dma buffers") when booting with Xen and mpt3sas_cm0 _scsih_probe failures

[Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>]

Hi Salvatore,

On 08/02/25 21:26, Salvatore Bonaccorso wrote:
> Hi Juergen, hi all,
> 
> Radoslav Bodó reported in Debian an issue after updating our kernel
> from 6.1.112 to 6.1.115. His report in full is at:
> 
> https://bugs.debian.org/1088159
> 

Note:
We have seen this on 5.4.y kernel: More details here:
https://lore.kernel.org/all/9dd91f6e-1c66-4961-994e-dbda87d69dad@oracle.com/


Thanks,
Harshit


> He reports that after switching to 6.1.115 (and present in any of the
> later 6.1.y series) booting under xen, the mptsas devices are not
> anymore accessible, the boot shows:
> 
> mpt3sas version 43.100.00.00 loaded
> mpt3sas_cm0: 63 BIT PCI BUS DMA ADDRESSING SUPPORTED, total mem (8086116 kB)
> mpt3sas_cm0: CurrentHostPageSize is 0: Setting default host page size to 4k
> mpt3sas_cm0: MSI-X vectors supported: 96
> mpt3sas_cm0:  0 40 40
> mpt3sas_cm0: High IOPs queues : disabled
> mpt3sas0-msix0: PCI-MSI-X enabled: IRQ 447
> mpt3sas0-msix1: PCI-MSI-X enabled: IRQ 448
> mpt3sas0-msix2: PCI-MSI-X enabled: IRQ 449
> mpt3sas0-msix3: PCI-MSI-X enabled: IRQ 450
> mpt3sas0-msix4: PCI-MSI-X enabled: IRQ 451
> mpt3sas0-msix5: PCI-MSI-X enabled: IRQ 452
> mpt3sas0-msix6: PCI-MSI-X enabled: IRQ 453
> mpt3sas0-msix7: PCI-MSI-X enabled: IRQ 454
> mpt3sas0-msix8: PCI-MSI-X enabled: IRQ 455
> mpt3sas0-msix9: PCI-MSI-X enabled: IRQ 456
> mpt3sas0-msix10: PCI-MSI-X enabled: IRQ 457
> mpt3sas0-msix11: PCI-MSI-X enabled: IRQ 458
> mpt3sas0-msix12: PCI-MSI-X enabled: IRQ 459
> mpt3sas0-msix13: PCI-MSI-X enabled: IRQ 460
> mpt3sas0-msix14: PCI-MSI-X enabled: IRQ 461
> mpt3sas0-msix15: PCI-MSI-X enabled: IRQ 462
> mpt3sas0-msix16: PCI-MSI-X enabled: IRQ 463
> mpt3sas0-msix17: PCI-MSI-X enabled: IRQ 464
> mpt3sas0-msix18: PCI-MSI-X enabled: IRQ 465
> mpt3sas0-msix19: PCI-MSI-X enabled: IRQ 466
> mpt3sas0-msix20: PCI-MSI-X enabled: IRQ 467
> mpt3sas0-msix21: PCI-MSI-X enabled: IRQ 468
> mpt3sas0-msix22: PCI-MSI-X enabled: IRQ 469
> mpt3sas0-msix23: PCI-MSI-X enabled: IRQ 470
> mpt3sas0-msix24: PCI-MSI-X enabled: IRQ 471
> mpt3sas0-msix25: PCI-MSI-X enabled: IRQ 472
> mpt3sas0-msix26: PCI-MSI-X enabled: IRQ 473
> mpt3sas0-msix27: PCI-MSI-X enabled: IRQ 474
> mpt3sas0-msix28: PCI-MSI-X enabled: IRQ 475
> mpt3sas0-msix29: PCI-MSI-X enabled: IRQ 476
> mpt3sas0-msix30: PCI-MSI-X enabled: IRQ 477
> mpt3sas0-msix31: PCI-MSI-X enabled: IRQ 478
> mpt3sas0-msix32: PCI-MSI-X enabled: IRQ 479
> mpt3sas0-msix33: PCI-MSI-X enabled: IRQ 480
> mpt3sas0-msix34: PCI-MSI-X enabled: IRQ 481
> mpt3sas0-msix35: PCI-MSI-X enabled: IRQ 482
> mpt3sas0-msix36: PCI-MSI-X enabled: IRQ 483
> mpt3sas0-msix37: PCI-MSI-X enabled: IRQ 484
> mpt3sas0-msix38: PCI-MSI-X enabled: IRQ 485
> mpt3sas0-msix39: PCI-MSI-X enabled: IRQ 486
> mpt3sas_cm0: iomem(0x00000000ac400000), mapped(0x00000000d9f45f61), size(65536)
> mpt3sas_cm0: ioport(0x0000000000006000), size(256)
> mpt3sas_cm0: CurrentHostPageSize is 0: Setting default host page size to 4k
> mpt3sas_cm0: scatter gather: sge_in_main_msg(1), sge_per_chain(7), sge_per_io(128), chains_per_io(19)
> mpt3sas_cm0: failure at drivers/scsi/mpt3sas/mpt3sas_scsih.c:12348/_scsih_probe()!
> 
> We were able to bissect the changes (see https://bugs.debian.org/1088159#64) down to
> 
> b1e6e80a1b42 ("xen/swiotlb: add alignment check for dma buffers")
> 
> #regzbot introduced: b1e6e80a1b42
> #regzbot link: https://bugs.debian.org/1088159
> 
> reverting the commit resolves the issue.
> 
> Does that ring some bells?
> 
> In fact we have two more bugs reported with similar symptoms but not
> yet confirmed they are the same, but I'm referencing them here as well
> in case we are able to cross-match to root cause:
> 
> https://bugs.debian.org/1093371 (megaraid_sas didn't work anymore with
> Xen)
> 
> and
> 
> https://bugs.debian.org/1087807 (Unable to boot: i40e swiotlb buffer
> is full)
> 
> (but again the these are yet not confirmed to have the same root
> cause).
> 
> Thanks in advance,
> 
> Regards,
> Salvatore
>