On Sun, Aug 03, 2014 at 08:57:39AM +0000, Eli Cohen wrote: >>> >>>What is the problem with masking the interrupts with the PCI command >>>register? I'm asking because I want to understand in which devices we >>>have the problem, and if it could be fixed by firmware guys. >>>What are the implications of having the quirk? >>> > >>The way to mask the interrupt through PCI command register isn't taking effect on IBM power platform. So we have to have the >quirk so that the interrupt could be masked from interrupt controller side with function disable_irq_nosync(). >> >>If the interrupt can't be masked properly, we detect interrupt storm reported from host/guest when passing through those devices >via VFIO without suprise. > >Hi Gavin, >Does it have any effect on performance. Also, can you tell in which cases interrupts need to be masked? > Eli, more code needed to be run for masking the LSI from interrupt controller side than from PCI command register. I was passing through Mellanox devices from host to guest with VFIO, and I designated to use LSI in the guest side. More details could be found in drivers/vfio/pci/vfio_pci_intrs.c::vfio_intx_handler() Thanks, Gavin -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
