On Wed, 2016-08-17 at 18:13 +0200, Andrew Jones wrote: > On Wed, Aug 17, 2016 at 08:08:11PM +0800, Kevin Zhao wrote: > > > > Hi all, > > Now I'm investigating net device hot plug and disk hotplug for > > AArch64. For virtio , the default address is virtio-mmio. After Libvirt > > 1.3.5, user can explicitly specify the address-type to pci and so libvirt > > will pass the virtio-pci parameters to the Qemu. > > Both my host and guest OS is Debian8, and Qemu version is 2.6.0. > > Libvirt version is 1.3.5. > > For net-device, I change the address-type to pci, and libvirt pass the > > command below: > > -device > > virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:0d:25:25,bus=pci.2,addr=0x1 > > > > After booting, the eth0 device disappear(eth0 occur when the address > > is virtio-mmio), > > but I can find another net-device enp2s1, also it can't work for dhcp: > > Running lspci: 02:01.0 Ethernet controller: Red Hat, Inc Virtio network > > device > > I'm not sure whether it worked. > > > > For disk device,* when I change the address-type to pci, the whole > > qemu command is :* > > https://paste.fedoraproject.org/409553/, but the VM can not boot > > successfully. Does Qemu not support device disk of virtio-pci in AArch64 > > just as it in X86_64? > > Thanks~Since I am not very familiar with Qemu, really looking forward > > to your response. > > > > Best Regards, > > Kevin Zhao > > libvirt 1.3.5 is a bit old. Later versions no longer unconditionally add > the i82801b11 bridge, which was necessary to use PCI devices with the PCIe > host bridge mach-virt has. IMO, libvirt and qemu still have a long way to > go in order to configure a base/standard mach-virt PCIe machine.
Debian 8, the guest OS Kevin is trying to boot, is even older, and in particular it doesn't have any virtio-pci support. By the way, the same issue was raised on the libvirt list as well https://www.redhat.com/archives/libvir-list/2016-August/msg00854.html and there's some more information there. > 1) If we want to support both PCIe devices and PCI, then things are messy. > Currently we propose dropping PCI support. mach-virt pretty much > exclusively uses virtio, which can be set to PCIe mode (virtio-1.0) > 2) root complex ports, switches (upstream/downstream ports) are currently > based on Intel parts. Marcel is thinking about creating generic models. Huge +1 from me! Way to go, Marcel! :) > 3) libvirt needs to learn how to plug everything together, in proper PCIe > fashion, leaving holes for hotplug. Work on this front is ongoing on the libvirt front as we speak. > 4) Probably more... I forget all the different issues we discovered when > we started playing with this a few months ago. > > The good news is that x86 folk want all the same things for the q35 model. > mach-virt enthusiasts like us get to ride along pretty much for free. > > So, using virtio-pci with mach-virt and libvirt isn't possible right now, > not without manual changes to the XML. It might be nice to document how to > manually convert a guest, so developers who want to use virtio-pci don't > have to abandon libvirt. I'd have to look into that, or ask one of our > libvirt friends to help. Certainly the instructions would be for latest > libvirt though. Things are very much in flux, though, so I'm not entirely sure putting out any sort of official document would be a good idea right now. We'll definitely help eg. through the mailing lists and similar channels, but committing any configuration to a more static media seems premature. > Finally, FWIW, with a guest kernel of 4.6.4-301.fc24.aarch64. The > following qemu command line works for me. > (notice the use of PCIe), and my network interface gets labeled enp0s1. > > $QEMU -machine virt-2.6,accel=kvm -cpu host \ > -m 1024 -smp 1 -nographic \ > -bios /usr/share/AAVMF/AAVMF_CODE.fd \ > -device ioh3420,bus=pcie.0,id=pcie.1,port=1,chassis=1 \ > -device ioh3420,bus=pcie.0,id=pcie.2,port=2,chassis=2 \ > -device >virtio-scsi-pci,disable-modern=off,disable-legacy=on,bus=pcie.1,addr=00.0,id=scsi0 > \ > -drive >file=/home/drjones/.local/libvirt/images/fedora.qcow2,format=qcow2,if=none,id=drive-scsi0-0-0-0 > \ > -device >scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 > \ > -netdev user,id=hostnet0 \ > -device >virtio-net-pci,disable-modern=off,disable-legacy=on,bus=pcie.2,addr=00.0,netdev=hostnet0,id=net0 > > I prefer always using virtio-scsi for the disk, but a similar command > line can be used for a virtio-blk-pci disk. Does the same command line work if you don't specify any of the disable-* options? I'm asking because I tried running a Fedora 24 guest through libvirt, which doesn't support those options yet, and I get virtio_blk virtio2: virtio: device uses modern interface but does not have VIRTIO_F_VERSION_1 virtio_blk: probe of virtio2 failed with error -22 Isn't the default for 2.6 disable-modern=off, disable-legacy=off? Or was that 2.7? I tried both anyway ;) -- Andrea Bolognani / Red Hat / Virtualization
