Corrected CC: list. DON'T send email to linux-scsi-owner without good reason because that's DaveM and he's been known to be wrathful when poked incorrectly ... On Mon, 2010-06-21 at 15:56 -0600, Moore, Eric wrote: > Where does a SCSI lower layer driver obtain the MSIX Vector Index on a > per IO basis? This is the index into the MSIX Vector Table. It doesn't; that's a pci/msix issue, so you use the regular pci msix APIs. If you look at how the other HBAs do it, they store the table in a host structure and pass a pointer to the particular table entry into the request_irq() routine. > Our controller is going to have a separate reply queue for each MSIX Vector. > > At driver load time, I will pass an array of msix_entry when calling > pci_enable_msix. Each entry represents a different reply queue. Then > I will call request_irq() for each vector/entry. I will have a single > ISR callback with each vector/entry having a different data pointer > for bus_id. Each data area will contain a unique reply queue, msix > vector index, among other info. > > From shost->queuecommand, I will need to setup the proper MSI Vector > Index for each IO. That way when the interrupt is called, it will > have the proper data pointer passed in bus_id, which contains the > matching reply queue. According to my co-worker working windows > drivers, I suppose to get the MSI Vector Index from the OS on a per IO > basis. He said he is obtaining the MSI Vector Index from > StorPortGetStartIoPerfParams. The index is returned inside > PerfParms.MessageNumber. If I parse this correctly, you're asking how to route the I/O in the HBA? That's a hba decision based on queueing parameters (and possibly incoming CPU number or VM originator) because which queue the msix interrupt comes back on is a HBA programming specific thing, the routing is done in the issue. > I'm not sure if the MSIX vector table is aligned with CPU IDs, meaning > does smp_processor_id() aligns with the entries in the MSIX vector > table? Meaning does CPU ID 0 is the 1st entry in the MSIX vector > table, CPU ID 2 is the 2nd entry in the table, CPU ID 3 is the 3rd > entry, and so on. Or is there another API in Linux to get the MSIX > Vector Index per IO basis? So I think what you're saying is that you plan to have one MSI-X vector per CPU (which is possbile)? If so, you just bind the vector affinity of the interrupt to the CPU you want. If it's something more complex than this, I'd suggest asking the PCI list ... I cc'd them in case they have any insight. James -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
