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Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network d
From: |
Alex Williamson |
Subject: |
Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices |
Date: |
Tue, 21 May 2019 08:18:20 -0600 |
On Tue, 21 May 2019 09:21:57 +0200
Jens Freimann <address@hidden> wrote:
> On Mon, May 20, 2019 at 04:56:57PM -0600, Alex Williamson wrote:
> >On Fri, 17 May 2019 14:58:16 +0200
> >Jens Freimann <address@hidden> wrote:
> >> Command line example:
> >>
> >> qemu-system-x86_64 -enable-kvm -m 3072 -smp 3 \
> >> -machine q35,kernel-irqchip=split -cpu host \
> >> -k fr \
> >> -serial stdio \
> >> -net none \
> >> -qmp unix:/tmp/qmp.socket,server,nowait \
> >> -monitor telnet:127.0.0.1:5555,server,nowait \
> >> -device
> >> pcie-root-port,id=root0,multifunction=on,chassis=0,addr=0xa \
> >> -device pcie-root-port,id=root1,bus=pcie.0,chassis=1 \
> >> -device pcie-root-port,id=root2,bus=pcie.0,chassis=2 \
> >> -netdev
> >> tap,script=/root/bin/bridge.sh,downscript=no,id=hostnet1,vhost=on \
> >> -device
> >> virtio-net-pci,netdev=hostnet1,id=net1,mac=52:54:00:6f:55:cc,bus=root2,failover=on
> >> \
> >> /root/rhel-guest-image-8.0-1781.x86_64.qcow2
> >>
> >> Then the primary device can be hotplugged via
> >> (qemu) device_add
> >> vfio-pci,host=5e:00.2,id=hostdev0,bus=root1,standby=net1
> >
> >Is this standby= option only valid for Network/Ethernet class code
> >devices? If so, perhaps vfio-pci code should reject the option on any
> >non-ethernet devices. The option is also non-intuitive for users, only
> >through examples like above can we see it relates to the id of the
> >secondary device. Could we instead name it something like
> >"standby_net_failover_pair_id="?
>
> It is only for ethernet (VFs), I will add code to reject non-ethernet VF
> devices.
> I agree the name is not descriptive and the one you suggest seems good to
> me.
> >
> >Also, this feature requires matching MAC addresses per the description,
> >where is that done? Is it the user's responsibility to set the MAC on
> >the host device prior to the device_add? If so, is this actually not
> >only specific to ethernet devices, but ethernet VFs?
>
> Yes, it's the users responsibility and the MACs are then matched by
> the net_failover driver in the guest. It makes sense for ethernet VFs only,
> I'll add a check for that.
FWIW, I'd probably stop at Ethernet class devices, vfio doesn't really
expose whether a device is a VF, so we'd likely need to resort to
getting that info through sysfs. It also seems like there might be
some limited-use cases of copying the MAC from a PF to the virtio nic
or use of utilities on the host for modifiying a PF MAC, perhaps via
eeprom. So while we expect the typical use case to be a VF, it's
probably ugly and unnecessarily restrictive to enforce it. Thanks,
Alex
- Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices, (continued)
- Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices, Alex Williamson, 2019/05/20
- Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices, Jens Freimann, 2019/05/21
- Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices, Michael S. Tsirkin, 2019/05/28
- Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices, Jens Freimann, 2019/05/29
- Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices, Michael S. Tsirkin, 2019/05/30
- Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices, Jens Freimann, 2019/05/31
- Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices,
Alex Williamson <=
Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices, Daniel P . Berrangé, 2019/05/21
Re: [Qemu-devel] [PATCH 0/4] add failover feature for assigned network devices, Michael S. Tsirkin, 2019/05/21