[AMD][Family 17h][Zen] IOMMU Enablement State

[cyring]

CoreFreq version [1.79.5]

Git branch availability [master]

• MATISSE and APU of models 20h can now be queried for their IOMMU state

• The same option found in BIOS at:

• Contribution: If you want to get yours, please post your lspci -nn output regarding the IOMMU device

[olejon]

Yes. Don't know where you found that option, since you searched in UEFI. But on my Motherboard it's called SR-IOV and it's the only Setting under some Section in Advanced. A drop-down.

Default = Disabled and no Auto option...

00:00.2 IOMMU [0806]: Advanced Micro Devices, Inc. [AMD] Device [1022:1481]

[cyring]

Thanks for your test but if the device shows up in lspci then it has to be enabled or auto in BIOS. Meanwhile I will check my BIOS if SR-IOV and IOMMU are or not separated options ?

[olejon]

It's enabled. Only other option is disabled (no Auto). I've been through ALL Settings 100 times and NOWHERE have I've seen IOMMU... As I understand it it's the same as VT-d on Intel (a website said so).

I can try searching...

I read this: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.0/html/hardware_considerations_for_implementing_sr-iov/index

[olejon]

Found it!

• It's under
  • Advanced > AMD CBS
• Not that it changed anything. Seems like Auto was enough to enable it, with SR-IOV = Enabled
• Pretty darn sure Technologies before said I/O MMU AMD-V = [OFF]

# lspci -nn
00:00.2 IOMMU [0806]: Advanced Micro Devices, Inc. [AMD] Device [1022:1481]

[cyring]

Thanks for your efforts.

So do you mean you get a match between the BIOS state and the CoreFreq state ?

IOMMU disabled in both ? IOMMU enabled in both ?

[olejon]

• First has SR-IOV = Enabled only and was then IOMMU = Auto before I found it (seems enough to enable SR-IOV only)
• Second has Both = Enabled (not that it does anything it seems)

Default is SR-IOV = Disabled and IOMMU = Auto. Which seems to disable AMD-V.

[cyring]

IOMMU state confirmed with Ryzen 2700X https://github.com/cyring/CoreFreq/issues/54#issuecomment-652788534

[olejon]

You got it right? Just SR-IOV = Enabled and let IOMMU = Auto and it enables it, according to lspci -nn and CoreFreq > Technologies. I guess you can reproduce that. You have ASUS too.