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Questions tagged [iommu]

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What happens if the block driver returns I/O error when handling addr fault for swap

If a block device was attached as a swap space, there can now be virtual addresses which require operation from the block driver to be read/written. When such address is accessed, a page fault is ...
melonfsck's user avatar
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1 answer
3k views

How can enable iommu in AMD CPU during boot?

Motherboard info: sudo dmidecode -t baseboard | grep -B 1 Product Manufacturer: Colorful Technology And Development Co.,LTD Product Name: BATTLE-AX B450M-HD CPU info: sudo dmidecode -t ...
showkey's user avatar
  • 395
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1 answer
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What is the IOMMU configuration used for the Intel machines?

In kernel boot options (https://www.kernel.org/doc/Documentation/x86/x86_64/boot-options.txt) I noticed the following option: iommu=[<size>][,noagp][,off][,force][,noforce] [,memaper[=<...
sammy17's user avatar
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3 votes
1 answer
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How to disable/enable bounce-buffers in IOMMU?

I am trying to figure out how to disable bounce buffers used in IOMMU when the hardware IOMMU is used. To give more context, when IOMMU_DEFAULT_DMA_STRICT is set in the kernel it enables strict IOTLB ...
sammy17's user avatar
  • 95
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1 answer
255 views

Move SSD into the same IOMMU group as the second GPU

I have a working Qemu configuration with GPU-pass-through. Now I would like to pass also a SSD to the quest. I have read that the pass-through-devices should be in the same group. The following script:...
ceving's user avatar
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1 vote
0 answers
70 views

Difference between modprobe and pci files to remove add devices

I am trying to see how these two set of commands differ if I just have one nvme device. Block device ls -l /sys/block/nvme0n1 lrwxrwxrwx 1 root root 0 Apr 28 11:59 /sys/block/nvme0n1 -> ../devices/...
pointnotfoe's user avatar
4 votes
1 answer
2k views

How does mmio get routed to io devices?

I am trying to understand how IO devices are mapped into the 'regular' memory address space on modern x86 machines running Linux. Some details which I am trying to make sense of are: cat /proc/iomem ...
shafe's user avatar
  • 201
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1 answer
376 views

Gnome hangs with VFIO gpu passthrough

On my computer, I have 2 discrete GPUs. I've been using VFIO to pass the second GPU to a Windows VM to work with some programs. Now I want to pass my more powerful first GPU to the Windows VM in order ...
Emre Talha's user avatar
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0 answers
1k views

how to check if iommu is enabled?

I have a centos 7.2 linux installed. I want to check if IOMMU is enabled in the system or not. How can i figure it out? Is there any /proc or /sys entry i can check to make sure is it enabled or not?
saurin's user avatar
  • 39
3 votes
1 answer
1k views

Can a Linux Swap Partition Be Too Big?

Can a Linux swap partition be too big? I'm pretty certain the answer is, "no" but I haven't found any resources on-point, so thought I'd ask. In contrast, the main Windows swap file, ...
ebsf's user avatar
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Is it possible to force specific ram size in linux kernel (with unrecognized sticks)?

First of all I'm asking for an old PowerMac G5 Quad which ultimately is able to boot with 2x1GB DDR2 2x4GB DDR2 2x4GB DDR2 2x4GB DDR2 Problem is it utilizes only the first 2 gigs. The other 3 pairs ...
FISOCPP's user avatar
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1 answer
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Virtualization frameworks and containers effectiveness on hardware without iommu capability?

Is it worth installing VirtualBox with a Linux based distributed OS like Kali or Qubes if your hardware does not support iommu? Is there any benefit in regards to security if isolation is limited?
Noob needing help's user avatar
0 votes
1 answer
605 views

How to isolate (reserve) GPUs with identical hardware IDs via IOMMU / dracut / kernel parameters (in VoidLinux)

I'm trying to set up pci/gpu passthrough on void. Specifically, using the vfio-pci driver to "reserve" one of the GPUs. I have been following the procedure outlined in this void-docs PR (and ...
vn-ck's user avatar
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1 answer
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ACPI and AMD GPU errors while attempting to install Ubuntu or Mint

I have been trying to dual boot windows and Linux. I am facing similar problems for both Ubuntu and Mint. The attached image shows the errors that i am getting
Raheel Hammad's user avatar
5 votes
0 answers
402 views

How can I prevent USB drivers (EHCI) from loading on specific USB controller (PCIe card)?

I'm using Debian 10.8 with Linux Kernel 4.19.0-14. I'm trying to use IOMMU to passthrough an entire USB controller (PCI Express card), but I'm having problems. The kernel is loading the ohci_pci and ...
SofaKng's user avatar
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1 vote
2 answers
2k views

Too few IOMMU groups - split?

I bought AMD RyZEN 5 2400G, Gigabyte B450M D3SH and 16GB RAM. Some elder GPU AMD Radeon HD 6XXX I took for passing through. But I was unpleasantly surprised with the IOMMU grouping. I put the GPU in ...
schweik's user avatar
  • 1,310
2 votes
0 answers
969 views

How to fix AMD-Vi: Unable to read/write to IOMMU perf counter. at boot Void Linux

I am using an amd laptop. CPU: AMD Ryzen 5 3500U with Radeon Vega Mobile Gfx (8) @ 2.100GHz GPU: AMD ATI 03:00.0 Picasso While starting void I get this message on top AMD-Vi: Unable to read/write ...
Alok's user avatar
  • 21
3 votes
0 answers
3k views

What is the appropiate iommu kernel parameter for Ryzen5 1600 and multiple RX580 GPU?

Reserving all the PCIe slot for RX580 prevents my PC to boot, due to such errors AMD-VI IOTLB_INV_TIMEOUT, AER: Corrected error received or kernel panic. Adding the linux parameters with iommu=soft ...
ywiyogo's user avatar
  • 160
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0 answers
2k views

Debian boot error: AMD-Vi: Unable to write to IOMMU perf counter

I'm booting a stable live Debian USB (with persistence) on a Windows 10 laptop with an AMD Ryzen 5 2500U processor. I should add that I've tried both the official and non-free Debian versions. The ...
NoExpert's user avatar
  • 489
3 votes
0 answers
613 views

Linux, at what point a device can write to the main memory through DMA?

I am trying to figure out how and when Linux gives the permission to perform direct memory access (DMA) to the peripheral devices on PCIe. I have read how DMA is initiated in the kernel's "DMA ...
xealits's user avatar
  • 2,163
2 votes
0 answers
1k views

Problem with IOMMU passthrough of i915 after Debian update

Yesterday, after six stable months I upgraded my Debian 10 box to Debian 4.19.98-1+deb10u1 (2020-04-27). I am running a KVM hypervisor and Windows 10 Pro as a VM on that box. The Win VM uses the i915 ...
sdittmar's user avatar
  • 121
3 votes
1 answer
7k views

VT-d support enabled but IOMMU groups are missing

On a Supermicro A2SDi-8C+-HLN4F Atom C3758 system I see that VT-d support is enabled in the BIOS but I can't find any IOMMU groups under Linux (Fedora 31): $ ls /sys/kernel/iommu_groups $ The kernel ...
maxschlepzig's user avatar
  • 57.9k
4 votes
3 answers
10k views

What are the implication of using iommu=force in the boot kernel options?

I have to follow a hardening procedure for a linux os, in this procedure it tels us that the kernel option must have iommu=force. What does it do ? What could be the difference without specifying ...
iXô's user avatar
  • 205
1 vote
0 answers
620 views

Intel CPU stepping - naming convention

I'm having trouble enabling IOMMU on Centos 8 (4.18.0-147.8.1.el8_1.x86_64) and I'm starting to think that my CPU doesn't support VT-d. On the Intel ARK page for my CPU it says "yes" for VT-x and VT-...
rmercier's user avatar
2 votes
0 answers
177 views

Can't access RAM from PCIe device

I use Intel Xeon with centos8 , kernel 4.18. There is also an FPGA connected to CPU through PCIe. The FPGA try to access RAM (through DMA) using physical address in RAM, but it fails in access. ...
ransh's user avatar
  • 1,437
0 votes
1 answer
752 views

Arch Linux stuck at "Loading version 240" after modifying configs

I'm trying to get GPU passthrough to work on a VM. I've been following this video https://www.youtube.com/watch?v=6FI31QDtyy4. The differences between what I did and what he did in the video was ...
Cubxity's user avatar
1 vote
2 answers
886 views

Passthrough Sonnet USB-C card to Windows guest via KVM and vfio

I am trying to passthrough a USB card to a guest, but I can't seem to make the VFIO driver stick, instead it seems that the host loads and takes over the card. I have a GPU successfully passed through,...
Stonecraft's user avatar
1 vote
0 answers
326 views

Share aarch64 page tables created by Linux with SMMU [closed]

I am currently working on creating a shared virtual address space in Linux arm64 on a Xilinx Zynq Ultrascale+ board. In the future it should be possible to share pointers/addresses between the Cortex ...
Mauli's user avatar
  • 19
1 vote
1 answer
1k views

How do I translate between qemu-system arguments and virt-install arguments so I can unify partially working commands?

I am in the process of setting up VFIO with KVM. I have the VFIO itself working, in that the VFIO'd GPU displays the UEFI shell screen when I start the VM. I am also able to create a working Windows ...
Stonecraft's user avatar
16 votes
1 answer
27k views

What are the implication of iommu=soft?

I've got new laptop at work (Lenovo A485) and there are few issues with it. It prints AMD-Vi: IOAPIC[32] not in IVRS table and kernel panic after that. So far I've figured few ways to get the system ...
graywolf's user avatar
  • 941
0 votes
1 answer
154 views

Ubuntu server 17.04 PCI-DMA out of IOMMU space. Status DRDY

I'm trying to install ubuntu server 17.04 on a system running 4 disks in a RAID 10 array. I'm getting a lot of errors, see attached. Can somebody please tell me what is going on. Are these errors ...
Chris Pavey's user avatar
3 votes
0 answers
427 views

Is possible to re-add a removed iommu device?

I use pci passthrough. Unfortunately my card is sharing the same irq of an usb controller. I use this procedure: Find the sharing irq, in my case return 21 lspci -s 00:05:00 -vvv Find the irq ...
elbarna's user avatar
  • 12.8k
3 votes
1 answer
2k views

Why does PCI passthrough not give my device to the guest OS?

I want to try PCI passthrough. I have passed an old capture video card to a Windows XP guest. IOMMU is enabled; vfio_pci is loaded I run this command: virsh nodedev-detach pci_0000_05_05_0 lspci ...
elbarna's user avatar
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