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Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as e
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest |
Date: |
Wed, 25 Sep 2013 13:06:32 +0300 |
On Wed, Sep 25, 2013 at 09:55:02AM +0000, Zhanghaoyu (A) wrote:
> >> >> Hi, all
> >> >>
> >> >> Do live migration if emulated NIC's MAC has been changed, RARP with
> >> >> wrong MAC address will broadcast via qemu_announce_self in destination,
> >> >> so, long time network disconnection probably happen.
> >> >
> >> >Good catch.
> >> >
> >> >> I want to do below works to resolve this problem, 1. change
> >> >> NICConf's MAC as soon as emulated NIC's MAC changed in guest
> >> >
> >> >This will make it impossible to revert it correctly on reset, won't it?
> >> >
> >> You are right.
> >> virsh reboot <domain>, or virsh reset <domain>, or reboot VM from guest,
> >> will revert emulated NIC's MAC to original one maintained in NICConf.
> >> During the reboot/reset flow in qemu, emulated NIC's reset handler
> >> will sync the MAC address in NICConf to the MAC address in emulated NIC
> >> structure, e.g., virtio_net_reset sync the MAC address in NICConf to
> >> VirtIONet'mac.
> >>
> >> BTW, in native scenario, reboot will revert the changed MAC to original
> >> one, too.
> >>
> >> >> 2. sync NIC's (more precisely, queue) MAC to corresponding NICConf
> >> >> in NIC's migration load handler
> >> >>
> >> >> Any better ideas?
> >> >>
> >> >> Thanks,
> >> >> Zhang Haoyu
> >> >
> >> >I think announce needs to poke at the current MAC instead of the default
> >> >one in NICConf.
> >> >We can make it respect link down state while we are at it.
> >> >
> >> NICConf structures are incorporated in different emulated NIC's
> >> structure, e.g., VirtIONet, E1000State_st, RTL8139State, etc., since so
> >> many kinds of emulated NICs, they are described by different structures,
> >> how to find all NICs' current MAC?
> >>
> >> Maybe we can introduce a pointer member 'current_mac' to NICConf
> >> structure, which points to the current MAC, then we can find all current
> >> MACs from NICConf.current_mac.
> >
> >I wouldn't make it a pointer, just a buffer with the mac, copy it there.
> >Maybe call it "softmac" that's what it is really.
> >
> >> Can we broadcast the RARP with current MAC in NIC's migration load handler
> >> respectively?
> >>
> >> Thanks,
> >> Zhang Haoyu
> >
> >It's not so simple, you need to retry several times.
> >
> Could you make a statement for 'retry several times' ?
> Is it the process of retrying several times to sending RARP in
> qemu_announce_self_once?
yes
> 'broadcast the RARP with current MAC in NIC's migration load handler
> respectively' is distributing the job of what qemu_announce_self does to
> every NIC's migration load handler,
> e.g., in virtio NIC's migration load handler virtio_net_load, we can create a
> timer to retry several times to send ARAP with current MAC for this NIC, just
> as same as qemu_announce_self does.
I don't see a lot of value in this yet.
> >> >Happily recent linux guests aren't affected since they do announcements
> >> >from guest.
> >> >
> >> >--
> >> >MST
- [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Zhanghaoyu (A), 2013/09/22
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Michael S. Tsirkin, 2013/09/22
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Zhanghaoyu (A), 2013/09/25
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Michael S. Tsirkin, 2013/09/25
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Zhanghaoyu (A), 2013/09/25
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Zhanghaoyu (A), 2013/09/25
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Michael S. Tsirkin, 2013/09/25
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Markus Armbruster, 2013/09/25
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Michael S. Tsirkin, 2013/09/25
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Zhanghaoyu (A), 2013/09/25
- Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Markus Armbruster, 2013/09/26
Re: [Qemu-devel] [RFC] sync NIC's MAC maintained in NICConf as soon as emualted NIC's MAC changed in guest, Jason Wang, 2013/09/25