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drecx

Member

From: The Wired

Registered: 2016-04-23

Posts: 1

vt-d is not properly enable, not yielding iommu_group

I'm in the process of setting up VGA passthrough on my former Windows gaming PC.  Browsing reddit I found this guide [http://bufferoverflow.io/?p=1], which states that if vt-d is properly enable, I should be able to find /sys/bus/pci/devices/(mydevicesbus)/iommu_group/devices. I'm not able to find this.

I've enabled vt-d in the UEFI menu and have update my syslinux.cfg to APPEND intel_iommu=1. To further diagnose the issue I ran

dmesg | grep -e DMAR -e IOMMU
[    0.000000] ACPI: DMAR 0x00000000BD341ED8 0000B8 (v01 INTEL  BDW      00000001 INTL 00000001)
[    0.027422] DMAR: Host address width 39
[    0.027424] DMAR: DRHD base: 0x000000fed90000 flags: 0x0
[    0.027431] DMAR: dmar0: reg_base_addr fed90000 ver 1:0 cap c0000020660462 ecap f0101a
[    0.027432] DMAR: DRHD base: 0x000000fed91000 flags: 0x1
[    0.027434] DMAR: dmar1: reg_base_addr fed91000 ver 1:0 cap d2008c20660462 ecap f010da
[    0.027435] DMAR: RMRR base: 0x000000bdea5000 end: 0x000000bdeb3fff
[    0.027436] DMAR: RMRR base: 0x000000bf000000 end: 0x000000cf1fffff
[    0.027437] DMAR-IR: IOAPIC id 8 under DRHD base  0xfed91000 IOMMU 1
[    0.027438] DMAR-IR: HPET id 0 under DRHD base 0xfed91000
[    0.027439] DMAR-IR: x2apic is disabled because BIOS sets x2apic opt out bit.
[    0.027439] DMAR-IR: Use 'intremap=no_x2apic_optout' to override the BIOS setting.
[    0.027659] DMAR-IR: Enabled IRQ remapping in xapic mode

After adding intremap=no_x2apic_optout to my syslinux.cfg I rung dmesg again and get:

dmesg | grep -e DMAR -e IOMMU                                                                                                    ]
[    0.000000] ACPI: DMAR 0x00000000BD341ED8 0000B8 (v01 INTEL  BDW      00000001 INTL 00000001)
[    0.026626] DMAR: Host address width 39
[    0.026628] DMAR: DRHD base: 0x000000fed90000 flags: 0x0
[    0.026634] DMAR: dmar0: reg_base_addr fed90000 ver 1:0 cap c0000020660462 ecap f0101a
[    0.026635] DMAR: DRHD base: 0x000000fed91000 flags: 0x1
[    0.026637] DMAR: dmar1: reg_base_addr fed91000 ver 1:0 cap d2008c20660462 ecap f010da
[    0.026638] DMAR: RMRR base: 0x000000bdea5000 end: 0x000000bdeb3fff
[    0.026639] DMAR: RMRR base: 0x000000bf000000 end: 0x000000cf1fffff
[    0.026640] DMAR-IR: IOAPIC id 8 under DRHD base  0xfed91000 IOMMU 1
[    0.026641] DMAR-IR: HPET id 0 under DRHD base 0xfed91000
[    0.026642] DMAR-IR: Queued invalidation will be enabled to support x2apic and Intr-remapping.
[    0.026859] DMAR-IR: Enabled IRQ remapping in x2apic mode

Here is my lspci output:

lspci -nnk | grep NVIDIA                                                                                                         ]
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GM206 [GeForce GTX 960] [10de:1401] (rev a1)
01:00.1 Audio device [0403]: NVIDIA Corporation Device [10de:0fba] (rev a1)

What can I do to further properly enable vt-d so that iommu_group is recognized?