On Fri, Sep 04, 2020 at 11:13:25AM -0600, Jon Derrick wrote: > Some platforms have an AHCI controller behind VMD. These platforms are > working correctly except for a case when the AHCI MSI is programmed with > VMD IRQ vector 0 (0xfee00000). When programmed with any other interrupt > (0xfeeNN000), the MSI is routed correctly and is handled by VMD. Placing > the AHCI MSI(s) in the fast-interrupt allow list solves the issue. The only reason we have the fast vs. slow is because of the non-posted transactions from slow driver's interrupt handlers tanking performance of the nvme devices sharing the same vector. The microsemi switchtec was one of the first such devices identified that led to the current split in the VMD domain. AHCI's driver also has non-posted transactions in their interrupt handling, so you probably don't want those devices sharing vectors with your fast nvme devices.
