USB passtrough stopped working after changing VM RAM allocation above 65024MB

[zxhaxdr]

I've been using the vm normally without any issue until yesterday when I increase the RAM for the VM to 65024 (and above). When using larger RAM allocation the usb controller stopped working and my Ubuntu vm thrown errors like

"device descriptor read *** error - 110", and "xhci host not responding **" etc.

When this happened, I reduced the ram but the vm always freeze at BIOS screen and I have to reboot host machine to make the vm work again. Tried Windows vm but same problem.

Tried to search for any answer but no luck.

Could someone help please? Thanks.

Edited February 10, 2020 by zxhaxdr

[zxhaxdr]

Here's my specs

 

Model: Custom

M/B: MSI X370 GAMING PLUS (MS-7A33) Version 3.0

BIOS: American Megatrends Inc. Version 5.JQ. Dated: 11/29/2019

CPU: AMD Ryzen 7 3700X 8-Core @ 4200 MHz

HVM: Enabled

IOMMU: Enabled

Cache: 512 KiB, 4096 KiB, 32768 KiB

Memory: 128 GiB DDR4 (max. installable capacity 128 GiB)

Network: eth0: 1000 Mbps, full duplex, mtu 1500

Kernel: Linux 4.19.98-Unraid x86_64

OpenSSL: 1.1.1d

[testdasi]

1 hour ago, zxhaxdr said:

M/B: MSI X370 GAMING PLUS (MS-7A33) Version 3.0

Memory: 128 GiB DDR4 (max. installable capacity 128 GiB)

Your motherboard only supports up to 64GB RAM.

I think only X570 chipset supports 128GB RAM.

 

If you run your RAM at 2133MHz or 1866 MHz, you may get away with 128GB on X370 it but it's unlikely.

[zxhaxdr]

39 minutes ago, testdasi said:

Your motherboard only supports up to 64GB RAM.

I think only X570 chipset supports 128GB RAM.

 

If you run your RAM at 2133MHz or 1866 MHz, you may get away with 128GB on X370 it but it's unlikely.

Hi thanks. The mobo says the maximum is 64Gb but with 4 x 32G rank 2 ram sticks it's actually working. I think there's are cases people try x370 with 128G ram and it even works on first gen Ryzen 1800. I mean the host machine is completely fine and I also could run multiple VM instances that sum up to 128G ram, all fine. However when I assign around 64G to a single VM, the USB controller stopped working. The RAM is running at 3200MHz now which is the stock speed of Corsair Vengeance LPX and it's very stable, but I can try 2133 later see if it changes anything.

Also I will try what happens if I exclude that particular USB controller (just for testing purposes but I need that USB controller passed trough anyway). Thank you very much.

[zxhaxdr]

I just tried to passthrough another USB controller and it works flawlessly with 102400MB ram. The differences between these two controllers are:

1. the working one is an on-board controller USB controller: ASMedia Technology Inc. ASM2142 USB 3.1 Host Controller.

2. the bad one is a pcie add-on USB controller: VIA Technologies, Inc. VL805 USB 3.0 Host Controller (rev 01).

They belong to the same IOMMU group before broken apart by the multi-function override.