Onboard SATA Controller passthrough?

[gogito]

I've been running Proxmox for close to a year now and it's been rock solid. I currently have an OMV VM with 2 HDD passthrough. Just recently I found out that I can passthrough the entire SATA controller and I want to do that. Hope you guys can help me with some questions related to it.

My current OMV VM hardware:


1. In the PCI passthrough, I see my ONBOARD Sata controller and various other devices (looks like all of them). Are they all treated as PCI devices? I thought only stuff like NVMe SSD and PCIe cards are PCI devices.



2. Also does that mean that I just need to choose to passthrough my SATA controller to my VM and that's done? No need for any command or anything?

3. I see that my SATA controller is in the same group as SMBus controller. Is this gonna be an issue if I want to passthrough?

4. As mentioned. I currently already pass through the 2 HDD on the controller directly to the VM, would there be any issue if I shutdown the VM, passthrough the controller and restart the VM? Will OMV have any issue?

Thanks in advance!

 

[leesteken]

Just recently I found out that I can passthrough the entire SATA controller and I want to do that.

There are several threads about on-board SATA controller PCIe passthrough and most are about having trouble because the controlers don't reset properly (and become useless to the VM) and/or there are other devices in the same IOMMU group.

1. In the PCI passthrough, I see my ONBOARD Sata controller and various other devices (looks like all of them). Are they all treated as PCI devices? I thought only stuff like NVMe SSD and PCIe cards are PCI devices.

On-board devices are nowadays often PCIe or even internal USB devices. SATA controllers are no exception and it will be trial and error (and it might not work with passthrough) like every other PCI(e) device.

View attachment 42274

2. Also does that mean that I just need to choose to passthrough my SATA controller to my VM and that's done? No need for any command or anything?

It depends whether the SATA controller resets properly or not. You'll find out by trying. Make sure there are not drives connected to it that are in use by Proxmox. Proxmox might crash or hang or fill its disks with error logs when starting the VM, so be prepared to hard power cycle the system.

3. I see that my SATA controller is in the same group as SMBus controller. Is this gonna be an issue if I want to passthrough?

Maybe. There is another device in the same IOMMU group 11 and you can share devices in the same group with other VMs and/or the Proxmox host. The Proxmox host will lose the SMBus Controller device (even when you only pass the SATA controller). This might be a problem or you might not even notice it and be fine. Do you have another SATA controller in your system?

4. As mentioned. I currently already pass through the 2 HDD on the controller directly to the VM, would there be any issue if I shutdown the VM, passthrough the controller and restart the VM? Will OMV have any issue?

I don't know OMV enough to say. The operating system inside the VM will need to have support for your SATA controller.
The drives will look different to the operating system inside the VM, as they are no longer connected to the virtual drive controller as QEMU HARDDISKs.

 

[Michael.Uray]

Is there actually a benefit if you pass the whole controller through to the VM compared to just the disk?
Do I have to expect then a better performance or maybe a better SMART support?

Right now i have passed through the disk to TrueNAS scale, but it looks SMART is not working for it:

 

[vanity2761]

For truenas to work as transparently as possible, it is generally recommended to install it on baremetal and passthrough a quality HBA connected to pcie which connects your SAS/SATA drives.

However, you can still passthrough your onboard pcie SATA controller without investing in a dedicated HBA. If you do so successfully, the exact error you are facing shouldn't exist and truenas will have a perfect native and non-virtualized control of the HDD.