Hi,

On 10/16/18 3:56 PM, Sedat Dilek wrote:
On Tue, Oct 16, 2018 at 8:37 AM Lu Baolu <baolu...@linux.intel.com> wrote:

Hi Sedat,

Sorry for late reply.

Do you still have this issue with newer rc's (like 4.19-rc8)?

I checked the dmesg log you attached there, it seems that the vt-d was
not on actually.


Hi Lu,

Thanks for asking.

I am running a Clang-7 compiled Linux 4.19-rc6 and VirtualBox is
reporting "IOMMU found".

root@iniza:~# dmesg | grep -i iommu
[    0.000000] Command line: initrd=\initrd.img-4.19.0-rc6-1-amd64-cbl
root=UUID=4c2aa544-6e86-44d2-9329-572623867b3d ro intel_iommu=on
[    0.145385] Kernel command line:
initrd=\initrd.img-4.19.0-rc6-1-amd64-cbl
root=UUID=4c2aa544-6e86-44d2-9329-572623867b3d ro intel_iommu=on
[    0.145411] DMAR: IOMMU enabled
[    0.243068] DMAR-IR: IOAPIC id 2 under DRHD base  0xfed91000 IOMMU 1
[    0.893466] iommu: Adding device 0000:00:00.0 to group 0
[    0.893475] iommu: Adding device 0000:00:02.0 to group 1
[    0.893490] iommu: Adding device 0000:00:14.0 to group 2
[    0.893498] iommu: Adding device 0000:00:14.2 to group 2
[    0.893508] iommu: Adding device 0000:00:15.0 to group 3
[    0.893519] iommu: Adding device 0000:00:16.0 to group 4
[    0.893545] iommu: Adding device 0000:00:1c.0 to group 5
[    0.893564] iommu: Adding device 0000:00:1c.6 to group 6
[    0.893580] iommu: Adding device 0000:00:1d.0 to group 7
[    0.893598] iommu: Adding device 0000:00:1d.2 to group 8
[    0.893624] iommu: Adding device 0000:00:1f.0 to group 9
[    0.893632] iommu: Adding device 0000:00:1f.2 to group 9
[    0.893640] iommu: Adding device 0000:00:1f.3 to group 9
[    0.893648] iommu: Adding device 0000:00:1f.4 to group 9
[    0.893656] iommu: Adding device 0000:00:1f.6 to group 9
[    0.893676] iommu: Adding device 0000:04:00.0 to group 10
[    0.893693] iommu: Adding device 0000:3e:00.0 to group 11
[    1.116440] AMD IOMMUv2 driver by Joerg Roedel <jroe...@suse.de>
[    1.116463] AMD IOMMUv2 functionality not available on this system
[   42.117773] vboxpci: IOMMU found

How can I be sure Intel-IOMMU is working correctly beyond checking dmesg logs?

Perhaps you need to check whether you've configured your VirtualBox to
simulate an Intel-IOMMU device.

Best regards,
Lu Baolu


[1] recommends to check...

root@iniza:~# find /sys | grep dmar

Shall I re-check with Linux v4.19-rc8?

Thanks in advance.

Regards,
- Sedat -

[1] 
https://stackoverflow.com/questions/44286683/check-for-iommu-support-on-linux
[2] https://www.kernel.org/doc/Documentation/Intel-IOMMU.txt

Best regards,
Lu Baolu

On 9/5/18 8:04 PM, Sedat Dilek wrote:
Hi Joerg,

"intel_ioomu=on" was working fine here on my ThinkPad T470 with
debian/testing AMD64 with Linux v4.17.y and v4.18.y.

With testing Linux v4.19-rc1 and v4.19-rc2 my machine is not booting -
black screen.
These kernels are built with LLVM/Clang v7.0.0rc2 (v4.18.y too).

Furthermore, I switched from GRUB to systemd-boot v239.

[ /boot/efi/loader/entries/debian.conf ]

title Debian GNU/Linux buster/sid [ debian kernel ]
linux /vmlinuz-4.17.0-3-amd64
initrd /initrd.img-4.17.0-3-amd64
options root=UUID=4c2aa544-6e86-44d2-9329-572623867b3d ro intel_iommu=on

[ /boot/efi/loader/entries/debian-llvmlinux.conf ]

title Debian GNU/Linux buster/sid [ llvmlinux kernel (EXPERIMENTAL) ]
linux /vmlinuz-4.19.0-rc2-3-iniza-llvmlinux
initrd /initrd.img-4.19.0-rc2-3-iniza-llvmlinux
options root=UUID=4c2aa544-6e86-44d2-9329-572623867b3d ro

Any hints or hints to debug this?
Any other kernel boot cheats [1] I can try?

My kernel-config and dmesg output is attached.

Thanks in advance.

Regards,
- Sedat -


Documentation/intel_txt.txt
Documentation/admin-guide/kernel-parameters.txt
Documentation/Intel-IOMMU.txt

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/admin-guide/kernel-parameters.txt#n1645
[2] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/Intel-IOMMU.txt
[3] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/intel_txt.txt


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