lsusb doesn't work in AppVMs

[joanna]

On both 3.0.4. and 3.2.7 I get the following:

[root@rflab user]# lsusb
unable to initialize libusb: -99

No matter whether there is, or there is no, USB controller assigned to the AppVM...

Interestingly a net or proxy VMs do not exhibit such behaviour...?!

[joanna]

Ok, this seems to be caused by the lack of ehci_hcd kernel module. When this module is unloaded in the usbvm, it displays the same error.

Now, the interesting part is, that in a normal AppVM (to which I assigned to USB controllers, exactly the same ones as I also assigned to my UsbVM) I get the following (always!):

[   30.560041] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[   30.560409] ehci_hcd 0000:00:00.0: device not available (can't reserve [mem 0xf162a000-0xf162a3ff])
[   30.560565] ehci_hcd 0000:00:01.0: device not available (can't reserve [mem 0xf1629000-0xf16293ff])

However, the very same USB controllers, always work fine when I assign them to the UsbVM! (Of course, I made sure to wait for one VM to shutdown correctly, and only then started another one).

What is the difference?

[joanna]

Yes, I disabled memory balancing for the AppVM (it gets 800MB).

[joanna]

Ok, solved it! The problem was that the AppVM had maxmem > mem -- and for PV domains with devices assined we need to ensure that maxmem = mem!

[marmarek]

Hmm... USB devices (especially lsusb) works for me in AppVM with:

• memory: 400 MB
• maxmem: 2GB
• as in default: enabled dynamic memory management (aka 'meminfo-writer')
• 2 usb controllers assigned (1.1 and 2.0)
• current memory: 530 MB