Comment 3 for bug 1896528

As to the original reason for this bug, on UC20 with the current pc-kernel, I had to add not just the mptspi kernel module but also it's dependencies, obviously. For brevity they were:

scsi/scsi_transport_spi.ko
message/fusion/mptbase.ko
message/fusion/mptscsih.ko
message/fusion/mptspi.ko

After adding all of these modules to the initramfs and then adding mptspi to modules-load.d/ubuntu-core-initramfs.conf also in the initramfs, then I was able to boot a UC20 VM using VMWare Fusion Player that was using all the default SCSI drive settings on my old Intel Macbook.

So it stands to reason if we want the generic amd64 pc-kernel to boot on as many VM software's out there as possible we should add these kernel modules to the initramfs or the kernel itself. It appears that these modules add a total of 281K (uncompressed) to the initramfs, so IMHO they are intrusive to add.