[fedora-virt] No iommu_group links in /sys/bus/pci/devices/

[Alex Williamson]

On Tue, 2013-06-25 at 18:46 +0200, Mario Ceresa wrote:
> Dear all,
> following Cole's suggestions I installed the fedora-virt-preview repo and
> tried again with VGA
> passthrough from [1]
> 
> For this setup i use a nvidia card as the primary one and a radeon hd 7850
> as the passthrough device.
> 
> However, there are no iommu_group links neither under
> /sys/bus/pci/devices/0000:05:00.0/ (which is my radeon card) nor under any
> of the other devices.
> 
> AFAIG it should be the vfio module which creates these links so I guess
> it's not working for me.
> 
> The driver loads correctly: there are no errors in dmesg and lsmod shows:
> vfio_pci               32063  0
> vfio                   19210  1 vfio_pci
> 
> I added iommu=pt iommu=1 to grub

iommu=1 is not a valid option.  The user in archlinux thread is using an
AMD system, which enables the iommu by default.  On an Intel system, use
intel_iommu=on

> My system currently includes:
> 
> * libvrit 1.0.6
> * qemu 1.5.0
> * kernel 3.9.6
> 
> Maybe the kernel is outdated?
> 
> I know the functionality is experimental so it's just to know if I'm doing
> some obvious mistakes.
> 
> Thanks for your help,
> 
> Best regards,
> 
> Mario
> 
> [1] https://bbs.archlinux.org/viewtopic.php?id=162768
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