On Mon, Feb 25, 2019 at 2:14 PM James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > > Being able to get away without any LPC support code at all seems like > > a win, as does not having any ACPI or DeviceTree parsing code. > > Injecting the hardware information via the kernel command line isn't > > impossible, but it's not an attractive solution. > > Heh, but isn't that exactly what crosvm did for usb: > > https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/add5a4c3751778e5380f00b2ee6cebcb6bda48fc My understanding is that the crosvm USB code is intended to allow arbitrary USB hardware to be passed through to the guest - doing this via virtio sounds complicated (you'd need a virtio driver that covered every USB class, and how would you manage that for devices that are handled in userland at the moment), whereas the virtio TPM support is intended to pass through a software TPM rather than grant access to the host TPM. > Effectively it bypasses the hypervisor altogether and simply makes a > direct connection to the host devices. The TPM could actually work in > exactly the same way, except you'd have to use the socsim IP connection > (which all TSSs support) rather than a file descriptor. I don't really follow - how would in-kernel TPM features work then?
