On 2012-07-01 17:06, Michael Tokarev wrote: > When running current git version of qemu-kvm with -M pc-1.0 Just to clarify: you are talking about stable-1.1 git, not master. > and with vhost-net enabled, it crashes with SIGSEGV right when > linux guest loads a virtio-net module. > > I haven't tried to debug this deeply. The first result is: > > (gdb) ru -M pc-1.0 -nodefconfig -nodefaults -rtc base=utc -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -netdev tap,ifname=tap-kvm,script=no,id=hostnet0,vhost=on -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:b4:05:b5,bus=pci.0,addr=0x3 -vga cirrus > Starting program: /build/kvm/debian/build/x86_64-softmmu/qemu-system-x86_64 -M pc-1.0 -nodefconfig -nodefaults -rtc base=utc -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -netdev tap,ifname=tap-kvm,script=no,id=hostnet0,vhost=on -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:b4:05:b5,bus=pci.0,addr=0x3 -vga cirrus > ... > Program received signal SIGSEGV, Segmentation fault. > [Switching to Thread 0xf65f4b70 (LWP 11245)] > 0x5668b01a in virtio_pci_mask_vq (vector=vector@entry=1, vq=0x57064448, > masked=masked@entry=0, > dev=<error reading variable: Unhandled dwarf expression opcode 0xfa>) > at /build/kvm/debian/hw/virtio-pci.c:546 > 546 int r = kvm_set_irqfd(dev->msix_irq_entries[vector].gsi, > > Now, my gdb can't read `dev' variable. One level up the stack > this variable is shown correctly: > > #1 0x5668b15d in virtio_pci_mask_notifier (dev=0x57062748, vector=1, masked=0) > at /build/kvm/debian/hw/virtio-pci.c:576 > 576 r = virtio_pci_mask_vq(dev, vector, virtio_get_queue(vdev, n), masked); > (gdb) p dev->msix_irq_entries[vector].gsi > Cannot access memory at address 0x10 > (gdb) p dev > $1 = (PCIDevice *) 0x57062748 > (gdb) p dev->msix_irq_entries > $4 = (KVMMsiMessage *) 0x0 > > So it looks like msix isn't initialized for -M pc-1.0 ? Yes, because the machine option defaults are missing here. Will send a patch. Also vhost is buggy as it depends on in-kernel irqchip but doesn't check for it. Needs to be fixed as well. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux -- 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
