On Thu, Oct 21, 2010 at 03:10:19PM +0800, Sheng Yang wrote: > On Thursday 21 October 2010 03:02:24 Marcelo Tosatti wrote: > > On Wed, Oct 20, 2010 at 04:26:24PM +0800, Sheng Yang wrote: > > > Here is v2. > > > > > > Changelog: > > > > > > v1->v2 > > > > > > The major change from v1 is I've added the in-kernel MSI-X mask emulation > > > support, as well as adding shortcuts for reading MSI-X table. > > > > > > I've taken Michael's advice to use mask/unmask directly, but unsure about > > > exporting irq_to_desc() for module... > > > > > > Also add flush_work() according to Marcelo's comments. > > > > > > Sheng Yang (8): > > > PCI: MSI: Move MSI-X entry definition to pci_regs.h > > > irq: Export irq_to_desc() to modules > > > KVM: x86: Enable ENABLE_CAP capability for x86 > > > KVM: Move struct kvm_io_device to kvm_host.h > > > KVM: Add kvm_get_irq_routing_entry() func > > > KVM: assigned dev: Preparation for mask support in userspace > > > KVM: assigned dev: Introduce io_device for MSI-X MMIO accessing > > > KVM: Emulation MSI-X mask bits for assigned devices > > > > Why does the current scheme, without msix per-vector mask support, is > > functional at all? Luck? > > Well, I believe we are lucky... We just ignored the operation in the past. > > I had raised this issue when Michael begin to work on MSI-X support in QEmu long > ago, but then I was busy on some other things. Until now when Eddie want to add > MSI-X in-kernel acceleration, we back to it... > > And about the "flush_work()" you commented, I still think even for the native > device, it's possible that the short time after OS write to the mask bit, the > interrupt may be delivered, if the device already send the message out on the > bus(I just guess, haven't observed)... The spec didn't say that the finish of > writing mask bit behavior would also get all message on the bus delivered. So I > think leave the work a little late would also be fine. Yes ... but e.g. bus read afterwards would have to flush the write up the bus... > -- > regards > Yang, Sheng -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
