Disabled MSI-X for NVMe passthrough on ESXi must be reverted because VMware fixed the bug on their end
Back in 2017 there was a VMware bug with NVMe passthrough that prevented the NVMe driver to load correctly. It was caused by MSI-X interactions between VMware and the driver.
A fix was provided in illumos-gate: https://www.illumos.org/issues/7723 It was a simple work around, to avoid using MSI-X altogether.
Meanwhile, VMware fixed the issue: https://kb.vmware.com/s/article/2150585
The side effect of the VMware fix is that the current NVMe driver in illumos-gate is not working any more on any of the updated VMware versions.
We reverted the MSI-X fix and confirmed on our OmniOSce build that after the revert the NVMe dirver loads correctly and the drives can be seen. We did not do any further testing, yet.