Alexey Kardashevskiy <a...@ozlabs.ru> writes: > On 08/01/2013 04:02 AM, Anthony Liguori wrote: >> Alexey Kardashevskiy <a...@ozlabs.ru> writes: >> >>> On the sPAPR platform a guest allocates MSI/MSIX vectors via RTAS >>> hypercalls which return global IRQ numbers to a guest so it only >>> operates with those and never touches MSIMessage. >>> >>> Therefore MSIMessage handling is completely hidden in QEMU. >>> >>> Previously every sPAPR PCI host bridge implemented its own MSI window >>> to catch msi_notify()/msix_notify() calls from QEMU devices (virtio-pci >>> or vfio) and route them to the guest via qemu_pulse_irq(). >>> MSIMessage used to be encoded as: >>> .addr - address within the PHB MSI window; >>> .data - the device index on PHB plus vector number. >>> The MSI MR write function translated this MSIMessage to a global IRQ >>> number and called qemu_pulse_irq(). >>> >>> However the total number of IRQs is not really big (at the moment it is >>> 1024 IRQs starting from 4096) and even 16bit data field of MSIMessage >>> seems to be enough to store an IRQ number there. >>> >>> This simplifies MSI handling in sPAPR PHB. Specifically, this does: >>> 1. remove a MSI window from a PHB; >>> 2. add a single memory region for all MSIs to sPAPREnvironment >>> and spapr_pci_msi_init() to initialize it; >>> 3. encode MSIMessage as: >>> * .addr - a fixed address of SPAPR_PCI_MSI_WINDOW==0x40000000000ULL; >>> * .data as an IRQ number. >>> 4. change IRQ allocator to align first IRQ number in a block for MSI. >>> MSI uses lower bits to specify the vector number so the first IRQ has to >>> be aligned. MSIX does not need any special allocator though. >>> >>> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> >> >> Reviewed-by: Anthony Liguori <aligu...@us.ibm.com> >> >> Does this actually fix any bug or is this just refactoring? If it's the >> later, it'll have to wait until after the 1.7 window opens up. > > > This is refactoring which should make IRQFD enablement on spapr > easier.
Okay, I'll apply it after hard freeze then. Regards, Anthony Liguori > > > > -- > Alexey
