Qubes 4 install not seeing VT-d/VT-x

[Gaijin]

While attempting to upgrade from R3.2 to R4.0.1 I get the error:
Missing features: IOMMU/VT-d/AMD-Vi, Interrupt Remapping

I have an ASRock H67DE motherboard with an Intel i7-2600 CPU which
according to the specs supports both VT-d and VT-x, and I have both
specifically enabled in the BIOS. However, the Qubes 4 installer
apparently can't see them. (I wonder if this is because I can only boot
the installation USB in Legacy mode and not AHCI mode)

I'm wondering if it would be OK to proceed with the install despite this
warning. Is there a way to check whether these BIOS settings are visible
to Qubes, or is this warning a clear indicator that they're not? (I
still have R3.2 working)

[awokd]

Gaijin wrote on 3/23/19 3:32 AM:

In R3.2's dom0 run qubes-hcl-report. Look for the 5 lines at the bottom.
You can proceed with the install, but if you don't really have support
it will fail when trying to set up sys-net after the initial
post-install reboot.

[Gaijin]

I guess you mean the first five items instead of the last.
I posted my HCL here:
https://groups.google.com/forum/#!topic/qubes-users/URIPsM1VURU
Looks like I do not have IOMMU or remapping available to Qubes.

I wouldn't get far without sys-net.

According to Intel my CPU does support VT-d and VT-x, might there be
some way to try to force Qubes? I've been using this machine since R1,
and would love to keep using it if possible.

[awokd]

Gaijin:

Those lines are on the bottom of the screen when you run it. :)
In addition to your CPU, your motherboard and BIOS/EFI also have to
support IOMMU for it to work. Without it, you can install 4.0 and
manually set up your sys-* VMs in PV mode, but this bypasses some of the
security improvements. Probably time for a hardware upgrade, unfortunately.