On Wed, Nov 13, 2024 at 11:48 AM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Wed, Nov 13, 2024 at 11:27:47AM +0530, Jason fab wrote: > > Hello, > > > > I would like to know if the linux kernel usb subsystem supports > > Virtualization based Trusted IO Management (USB VTIO)? > > What exactly is that, I can't seem to search for it and have not heard > of it before. Do you have a link to it somewhere? Is there a USB.org > specification published for it? I came across the below xHCI document and am wondering if the Linux kernel already supports it. Here is the link to the document: https://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/extensible-host-controler-interface-usb-xhci.pdf Section 4.5 USB Virtualization Based Trusted IO Management (USB VTIO): The USB Virtualization based Trusted IO Management capability provided by the xHC is optional functionality that enables a multi SW/HW function ownership and access model for the various XHCI defined memory structures and messages. As an example we can view a PCI based xHC implementation as using the PCI defined function as the method to comply with the USB VTIO requirements. The PCI Bus/Device/Function (BDF) for a given PCI function is determined during the standard PCI enumeration of devices. PCI controllers captures its BDF when it receives a downstream Type-0 Config Write (CfgWr0) cycle targeting its Configuration header. This latched value is used as a "Requester ID" or “DMA Identification” for all transactions initiated by the controller. The PCI BDF which is determined by the standard PCI discovery/enumeration process will be referred to as the Primary DMA-ID. > > thanks, > > greg k-h
