intel_iommu=on causes boot to hang

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flotsam
Posts: 14
Joined: 2014/08/27 21:41:40

intel_iommu=on causes boot to hang

Post by flotsam » 2018/08/31 01:04:37

I am running 3.10.0-862.11.6.el7.x86_64 on a Dell T330. VT-d is enabled in the BIOS (Virtualization technology enabled). I added intel_iommu=on to the GRUB_CMDLINE_LINUX setting and then rebuild the menu with grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg. Now the boot hangs. I see the following on the screen:

[ 1.831718] 18042: No controller found
[ OK ] Started Show Plymouth Boot Screen.
[ OK ] Reached target Paths.
[ OK ] Reached target Basic System.
[ 2.461189] megraid_sas 0000:01:00.0: Init cmd return status SUCCESS for SCSI host 0
[ 2.478655] DMAR: DRHD: handling fault status reg 3
[ 2.478706] DMAR: [DMA Read] Request device [01:00.0] faoult addr 7efae000 [fault reason 06] PRE Read access is not s...
[ 2.695329] logitech-djreceiver 0003:046D:C52B.003: logi_dj_raw_event: invalid device index:0

Then the system simply hangs. If I remove intel_iommu=on then all goes back to normal.

Any suggestions?

hunter86_bg
Posts: 2019
Joined: 2015/02/17 15:14:33
Location: Bulgaria
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Re: intel_iommu=on causes boot to hang

Post by hunter86_bg » 2018/08/31 04:06:06

In my bios there is a special option for IOMMU and is disabled by default.
Could you check the BIOS again?

flotsam
Posts: 14
Joined: 2014/08/27 21:41:40

Re: intel_iommu=on causes boot to hang

Post by flotsam » 2018/08/31 14:11:41

It turns out that my raid card doesn't support IOMMU. To clarify the interaction: The first time I try to boot with intel_iommu=on, I get the error reported. Subsequent boots fail before I ever get to the boot menu because of an error with the raid card. It appears that going into the BIOS setup clears whatever is left over from the attempt to enable IOMMU and subsequent boots work properly without complaints from the raid card. There is more information at this link https://www.dell.com/community/PowerEdg ... -p/4632026.

flotsam
Posts: 14
Joined: 2014/08/27 21:41:40

Re: intel_iommu=on causes boot to hang

Post by flotsam » 2018/08/31 14:13:29

hunter86_bg wrote:
2018/08/31 04:06:06
In my bios there is a special option for IOMMU and is disabled by default.
Could you check the BIOS again?
Thanks. Yes, I have checked repeatedly. "Virtualization technology" is enabled in the BIOS.

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