I am working on a custom PCI device model, plugged into VirtualBox via PDM. It's mostly working, lspci for example shows it's present. But I am having a problem with Message Signaled Interrupts (MSI).
The following quote from Ch.3 of the VirtualBox User Manual implies that the ICP9 chipset must be used for MSI support, and I have seen supporting evidence in web searches and VBox source code (OSE 5.0.16 tarball).
Can someone confirm or refute with certainty that the PIIX3 chipset does not support MSI and ICH9 is required for device models using MSI?...VirtualBox 4.0 introduced an emulation of the more modern ICH9 chipset, which supports PCI express,
three PCI buses, PCI-to-PCI bridges and Message Signaled Interrupts (MSI)...
How worried should I be about this excerpt from the same paragraph? A quick test of ICH9 VM did not go well. I've actually tried with Fedora 23, Fedora 18 and Ubuntu 14 guests (all 64-bit) without success, but not yet dug into it because this quote worries me.
Note that the ICH9 support is experimental and not recommended for guest operating systems which do not require it.