> Subject: Re: pci-stub error and MSI-X for KVM guest > > * Fischer, Anna (anna.fischer@xxxxxx) wrote: > > I am running Fedora Core 12 with a 2.6.31 kernel. I use the Intel > > 82576 SR-IOV network card and want to assign its Virtual Functions > (VFs) > > to separate KVM guests. My guests also run Fedora Core 12 with a > 2.6.31 > > kernel. I use the latest igb driver in the host OS and load it with 2 > > VFs activated. Then I assign those to my KVM guests. I use virt- > manager > > to do this which then takes care of configuring pci-stub. > > By 2.6.31 are you referring to the stock Fedora 12 kernel package? Yes. > > This works fine in principle and I can see the PCI device in the > > guest under lspci. However, the 82576 VF driver requires the OS > > to support MSI-X. My Fedora installation is configured with MSI-X, > > e.g. CONFIG_PCI_MSI is 'y'. When I load the driver it tells me it > cannot > > initialize MSI-X for the device, and under /proc/interrupts I can see > > that MSI-X does not seem to work. Is this a KVM/QEMU limitation? It > works > > for me when running the VF driver under a non-virtualized Linux system. > > No, this should work fine. QEMU/KVM supports MSI-X to guest as well as > VFs. Actually, I just got this to work. However, it only works if I call qemu-kvm from the command line, while it doesn't work when I start the guest via the virt-manager. So this seems to be an issue with Fedora's virt-manager rather than with KVM/QEMU. If I call qemu-kvm from the command line then I get the pci-stub messages saying 'irq xx for MSI/MSI-x' when the guest boots up and the VF device works just fine inside the guest. When I start the guest using virt-manager then I don't see any of these irq allocation messages from pci-stub. Any idea what the problem could be here? > > Also, when I do an lspci on the KVM guest, that is fine, but when I > > do an lspci -v then the guest crashes down. In the host OS under dmesg > > I can see this: > > > > pci-stub 0000:03:10.0: restoring config space at offset 0x1 (was > 0x100000, writing 0x100004) > > > > Is this a known issue? My qemu-kvm version is 2:0.11.0. > > No, I've not seen the crash before. What do you mean "the guest crashes > down"? So this also only happens when starting the guest using virt-manager. It works fine when starting qemu-kvm from the command line. This is weird as I call it with the same parameters as I can see virt-manager uses under 'ps -ef | grep qemu'. The guest crashes down means that the QEMU process is terminated. I don't see anything in the logs. It just disappears. > This looks like a Fedora specific version (rpm version). Can you verify > this is from Fedora packages vs. upstream source? If it's Fedora, > would be useful to open a bug there. Yes, I am using KVM/QEMU which ships with the Fedora Core 12 distribution. Thanks for your help, Anna -- 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
