On Tue, Nov 20, 2012 at 11:04 AM, Alex Lyakas <alex@xxxxxxxxxxxxxxxxx> wrote: > Hello list, I was advised to post this question by Jesse Barnes; I also > posted to KVM list. When you post a question to more than one list, you should always send a *single* message with all the lists being copied. That way everybody can tell what progress is being made, and we can avoid duplicating effort. I see via a Google search that you've gotten responses on the KVM list, e.g., http://www.spinics.net/lists/kvm/msg82997.html, so I assume you don't need any more help from linux-pci. If that's not the case, please add linux-pci to the CC: list of the thread where you're working on this. > I am running Ubuntu-Precise 3.2.0-29-generic #46, with stock KVM ("QEMU > emulator version 1.0 (qemu-kvm-1.0)") on a Dell R510 server. I have one > dual-port Intel's NIC 82599, of which I spawn 32 VFs from each port. I spawn > virtual machines with KVM, each VM has 4 VFs attached (two from each PF). > > Once in a while, in particular when I spawn multiple VMs in parallel, I hit > an issue that one of the VFs does not have an IRQ assigned to it. I am > checking this in /proc/interrupts, looking for entries like > "kvm:0000:03:14.6". In some cases, an entry is missing for a particular VF. > As a result, the VF within the VM is non-functional. > > I debugged this issue further, by adding prints to kvm.ko code. I see that > the failure happens in kvm_vm_ioctl_assigned_device/KVM_ASSIGN_DEV_IRQ path, > which calls assigned_device_enable_host_msix() function, which calls > pci_enable_msix(), which fails with EINVAL or with ENOMEM. This path is > called twice for each VF. > > I see that first pci_enable_msix() returns -12/-22, and when > kvm_vm_ioctl_set_msix_nr() is called again, it sees that adev->entries_nr != > 0 and fails the call with EINVAL. I can repro it only when spawning like 8 > or 10 VMs in parallel, but it doesn't happen every time. So it seems like > this is not a resource shortage problem, but some race somewhere. > > I tested this with several version of ixgbe drivers, including the in-tree > version that comes with Precise. It reproduces with all the versions. > > Can anybody pls advise on how to debug this issue further? > > Thanks, > Alex. > -- > 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 -- 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
