On Sun, 10 Jul 2016 13:17:41 -0500 David <david...@gmail.com> wrote: > I have run into a strange problem, while setting up my Fedora 24 box for > KVM, i noticed that my raid array stopped showing as an available drive. > After a lot of troubleshooting and reinstalling linux to this PC 2 more > times, i have narrowed it down to one setting in my GRUB config. > intel_iommu=on > > Just taking that one setting out and rebuilding my grub2-efi.cfg will make > the array readable again. When IOMMU is on, the system can see that there > is a raid card and array, but it lists the partition table as unknown. It > also will not successfully create a new GPT partition table on the array. > With IOMMU off, it can read the partition table and partition fine, read > and write data, and everything works fine. > > My raid is 4 1TB disks in Raid 10e, GPT partition formatted NTFS. > > $ lspci -v -s 03:0e.0 > 03:0e.0 RAID bus controller: Adaptec AAC-RAID > Subsystem: Adaptec 3805 > Flags: bus master, stepping, 66MHz, medium devsel, latency 32, IRQ 57 > Memory at fa600000 (64-bit, non-prefetchable) [size=2M] > Expansion ROM at fa800000 [disabled] [size=256K] > Capabilities: <access denied> > Kernel driver in use: aacraid > Kernel modules: aacraid
No DMAR faults in dmesg? There's a fair chance this is one of those devices that does DMA with the wrong requester ID and therefore enabling the IOMMU prevents it from working. We have a mechanism in the kernel to handle such DMA aliasing if you can verify the issue. Thanks, Alex _______________________________________________ vfio-users mailing list vfio-users@redhat.com https://www.redhat.com/mailman/listinfo/vfio-users