[vfio-users] USB card prevents qemu finding its harddrive

[leesteken at pm.me]

Hi,

Adding a device might shift the other (virtual) devices including the disk controller, or the disk controller might conflict with the default address that is used when you use -device to add it, which might remove (or not add) the disk controller.

Try adding ,addr=0x?? to the -device parameter where you select an unused address for the ??.
You might have to select a (virtual) bus as well as part of the -device parameter.


hope this helps, Arjen

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Sunday, December 22, 2019 1:14 PM, Ede Wolf <listac at nebelschwaden.de> wrote:

> So I've bought this rather expensive USB 3.0 controller, making sure it
> was compatible to everything on this planet and having a native pcie v2
> interface and now I am having the problem, as soon as it gets passed
> through, qemu cannot find it's boot disk any more.
>
> "Boot failed. Could not read the boot disk". The boot menu only shows
> legacy option rom or pxe.
>
> I have no remote idea, where the relation between those two could be. It
> is not, that the start up of the VM itself is failing, because of a
> misconfiguration, it's just, that after powering on of the guest, it
> cannot find any harddrives any more and tries to pxe boot instead.
>
> As soon as I remove:
> -device vfio-pci,host=0a:00.0,x-vga=off
>
> from the configuration, the guest starts just normal - with another card
> still passed through. So it is not a general passthrough problem. And
> I've had passed through two cards before.
>
> Needless to say, the guest image lives on a regular sata harddrive and
> is not attached to that card in any way.
> In addition, it is the only device in its vfio group, making it an even
> more simple config:
>
> journalctl -k | grep -i iommu | grep 25
>
> ========================================
>
> Dez 22 11:50:17 kernel: pci 0000:0a:00.0: Adding to iommu group 25
>
> lspci -s "0a:00.0" -n -v
>
> =========================
>
> 0a:00.0 0c03: 1106:3483 (rev 01) (prog-if 30 [XHCI])
> Subsystem: 1106:3483
> Flags: fast devsel, IRQ 16, NUMA node 0
> Memory at bf700000 (64-bit, non-prefetchable) [size=4K]
> Capabilities: [80] Power Management version 3
> Capabilities: [90] MSI: Enable- Count=1/4 Maskable- 64bit+
> Capabilities: [c4] Express Endpoint, MSI 00
> Capabilities: [100] Advanced Error Reporting
> Kernel driver in use: vfio-pci
> Kernel modules: xhci_pci
>
> How is it possible that this card affects the boot drive of qemu? Where
> is the connection between "-drive file=/home/VM/guest.img" and "-device
> vfio-pci"? And how to eventually debug this?
>
> Since this behaviour is related to vfio-pci, I am hoping, this is still
> the correct list, even though this seems to affect qemu as whole. In a
> quite obscure, magical way, one might add.
>
> Thanks very much for any help
>
> Ede
>
> P.S.: Preparation, even though the config should not be the issue:
>
> The Delock 5x USB Card (VIA)
>
> =============================
>
> ExecStart=-/usr/bin/sh -c 'echo "0000:0a:00.0" >
> /sys/bus/pci/devices/0000:0a:00.0/driver/unbind'
> ExecStart=/usr/bin/sh -c 'echo 1106 3483 >
> /sys/bus/pci/drivers/vfio-pci/new_id'
> ExecStart=/usr/bin/sh -c 'chgrp kvm /dev/vfio/25'
> ExecStart=/usr/bin/sh -c 'chmod 0660 /dev/vfio/25'
>
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