RE: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-26 Thread Christian Benvenuti (benve) 
 -Original Message-
 From: Roopa Prabhu (roprabhu)
 Sent: Thursday, September 15, 2011 6:47 AM
 To: Michael S. Tsirkin
 Cc: Sridhar Samudrala; net...@vger.kernel.org;
 dragos.tatu...@gmail.com; a...@arndb.de; David Wang (dwang2);
Christian
 Benvenuti (benve); ka...@trash.net; da...@davemloft.net;
 eric.duma...@gmail.com; mc...@broadcom.com; kvm@vger.kernel.org
 Subject: Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address
 filtering support for passthru mode
 
 
 
 The netlink patch is still in the works. I will post the patches after
 I
 clean it up a bit and also accommodate or find answers to most
 questions
 discussed for non-passthru case. Thought I will post the netlink
 interface
 here to see if anyone has any early comments. I have a
 rtnl_link_ops-set_rx_filter defined.
 
 [IFLA_RX_FILTER] = {
 [IFLA_ADDRESS_FILTER] = {
 [IFLA_ADDRESS_FILTER_FLAGS]
 [IFLA_ADDRESS_LIST] = {
 [IFLA_ADDRESS_LIST_ENTRY]
 }
 }
 [IFLA_VLAN_FILTER] = {
 [IFLA_VLAN_LIST] = {
 [IFLA_VLAN]
 }
 }
 }
 
 Some open questions:
 - The VLAN filter above shows a VLAN list. It could also be a
 bitmap or
 the interface could provide both a bitmap and VLAN list for more
 flexibility
 . Like the below
 
 [IFLA_RX_FILTER] = {
 [IFLA_ADDRESS_FILTER] = {
 [IFLA_ADDRESS_FILTER_FLAGS]
 [IFLA_ADDRESS_LIST] = {
 [IFLA_ADDRESS_LIST_ENTRY]
 }
 }
 [IFLA_VLAN_FILTER] = {
 [IFLA_VLAN_BITMAP]
 [IFLA_VLAN_LIST] = {
 [IFLA_VLAN]
 }
 }
 }

The simplest interface probably is to stick to a bitmap (knowing that in
the worst
case it will take 256 bytes, but we can compress it ...), because
sending
a vlan list may end up requiring much more than that (on interfaces
configured as trunks).
This regardless of whether the most common use case is that of a server
configured
with just few vlans or that of a switch configured with few trunks.

Another option would be a list of ranges, but that one would not work
well
in those cases where trunks are configured, for example, to carry big
numbers
of odd or even vlan IDs or other groups of vlans IDs that cannot be
grouped
into ranges. Probably an acceptable compromise, if we care about the
size
of this attribute, would be:
- to use a list of IDs for less than 256 vlans (or a list of ranges)
- to use a bitmap for more than 256 vlan.

I would recommend the two attributes (IFLA_VLAN_BITMAP and
IFLA_VLAN_LIST)
to be mutually exclusive to reduce the complexity of the merging and
error/misconfig detection code.

 - Do you see any advantage in keeping Unicast and multicast
address
 list
 separate ? Something like the below :
 [IFLA_RX_FILTER] = {
 [IFLA_ADDRESS_FILTER_FLAGS]
 [IFLA_UC_ADDRESS_FILTER] = {
 [IFLA_ADDRESS_LIST] = {
 [IFLA_ADDRESS_LIST_ENTRY]
 }
 }
 [IFLA_MC_ADDRESS_FILTER] = {
 [IFLA_ADDRESS_LIST] = {
 [IFLA_ADDRESS_LIST_ENTRY]
 }
 }
 [IFLA_VLAN_FILTER] = {
 [IFLA_VLAN_LIST] = {
 [IFLA_VLAN]
 }
 }
 }

I personally like the idea of grouping UC and MC addresses into two
distinct
attributes/groups.
The receiver (the kernel) would have to check them anyway (I suppose),
but
I like the idea of having the kernel being able to detect the case
where, for
example, the user configures a MC address thinking he is actually
configuring
a UC address.

Most probably the iproute2 commands used to configure/add/del UC and MC
address
will be assigned two different keywords.
BTW, once this code will be in, it will be possible for ip link show
to show
all UC/MC MAC addresses; right now ip link only shows dev-dev_addr.
This output is useful for debugging.

The output from ip maddr only shows the MC list and anyway I think the
best
place for the list of MAC addresses is ip link show.

Would ip link show also show the list of vlans?
Probably, best would be to add new flags (to ask for the extended
output) or
simply add the extra output (uc/mc/vlan lists) under the already
existent -s flag ?

 - Is there any need to keep address and vlan filters separate. And
 have
 two rtnl_link_ops, set_rx_address_filter, set_rx_vlan_filter ?. I
don't
 see
 one .
 
 [IFLA_RX_ADDRESS_FILTER] = {
 [IFLA_ADDRESS_FILTER_FLAGS]
 [IFLA_ADDRESS_LIST] = {
 [IFLA_ADDRESS_LIST_ENTRY]
 }
 }
 [IFLA_RX_VLAN_FILTER] = {
 [IFLA_VLAN_LIST] = {
 [IFLA_VLAN]
 }
 }

I think both approaches are good.
Anyway, given that you can have/configure nested vlans, having
IFLA_RX_VLAN_FILTER
inside IFLA_RX_FILTER would be syntactically correct too.

/Chris

 
 Thanks,
 Roopa
 
 
 
 On 9/12/11 10:02 AM, Roopa Prabhu ropra...@cisco.com wrote:
 
 
 
 
  On 9/11/11 12:03 PM, Michael S. Tsirkin m...@redhat.com wrote:
 
  On Sun, Sep 11

Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-15 Thread Roopa Prabhu 


The netlink patch is still in the works. I will post the patches after I
clean it up a bit and also accommodate or find answers to most questions
discussed for non-passthru case. Thought I will post the netlink interface
here to see if anyone has any early comments. I have a
rtnl_link_ops-set_rx_filter defined.

[IFLA_RX_FILTER] = {
[IFLA_ADDRESS_FILTER] = {
[IFLA_ADDRESS_FILTER_FLAGS]
[IFLA_ADDRESS_LIST] = {
[IFLA_ADDRESS_LIST_ENTRY]
}
}
[IFLA_VLAN_FILTER] = {
[IFLA_VLAN_LIST] = {
[IFLA_VLAN]
}
}
}

Some open questions:
- The VLAN filter above shows a VLAN list. It could also be a bitmap or
the interface could provide both a bitmap and VLAN list for more flexibility
. Like the below  

[IFLA_RX_FILTER] = {
[IFLA_ADDRESS_FILTER] = {
[IFLA_ADDRESS_FILTER_FLAGS]
[IFLA_ADDRESS_LIST] = {
[IFLA_ADDRESS_LIST_ENTRY]
}
}
[IFLA_VLAN_FILTER] = {
[IFLA_VLAN_BITMAP]
[IFLA_VLAN_LIST] = {
[IFLA_VLAN]
}
}
}

- Do you see any advantage in keeping Unicast and multicast address list
separate ? Something like the below :
[IFLA_RX_FILTER] = {
[IFLA_ADDRESS_FILTER_FLAGS]
[IFLA_UC_ADDRESS_FILTER] = {
[IFLA_ADDRESS_LIST] = {
[IFLA_ADDRESS_LIST_ENTRY]
}
}
[IFLA_MC_ADDRESS_FILTER] = {
[IFLA_ADDRESS_LIST] = {
[IFLA_ADDRESS_LIST_ENTRY]
}
}
[IFLA_VLAN_FILTER] = {
[IFLA_VLAN_LIST] = {
[IFLA_VLAN]
}
}
} 

- Is there any need to keep address and vlan filters separate. And have
two rtnl_link_ops, set_rx_address_filter, set_rx_vlan_filter ?. I don't see
one .

[IFLA_RX_ADDRESS_FILTER] = {
[IFLA_ADDRESS_FILTER_FLAGS]
[IFLA_ADDRESS_LIST] = {
[IFLA_ADDRESS_LIST_ENTRY]
}
}
[IFLA_RX_VLAN_FILTER] = {
[IFLA_VLAN_LIST] = {
[IFLA_VLAN]
}
} 


Thanks,
Roopa



On 9/12/11 10:02 AM, Roopa Prabhu ropra...@cisco.com wrote:

 
 
 
 On 9/11/11 12:03 PM, Michael S. Tsirkin m...@redhat.com wrote:
 
 On Sun, Sep 11, 2011 at 06:18:01AM -0700, Roopa Prabhu wrote:
 
 
 
 On 9/11/11 2:44 AM, Michael S. Tsirkin m...@redhat.com wrote:
 
 
 Yes, but what I mean is, if the size of the single filter table
 is limited, we need to decide how many addresses is
 each guest allowed. If we let one guest ask for
 as many as it wants, it can lock others out.
 
 Yes true. In these cases ie when the number of unicast addresses being
 registered is more than it can handle, The VF driver will put the VF  in
 promiscuous mode (Or at least its supposed to do. I think all drivers do
 that).
 
 
 Thanks,
 Roopa
 
 Right, so that works at least but likely performs worse
 than a hardware filter. So we better allocate it in
 some fair way, as a minimum. Maybe a way for
 the admin to control that allocation is useful.
 
 Yes I think we will have to do something like that. There is a maximum that hw
 can support. Might need to consider that too. But there is no interface to get
 that today. I think the virtualization case gets a little trickier. Virtio-net
 allows upto 64 unicast addresses. But the lowerdev may allow only upto say 10
 unicast addresses (I think intel supports 10 unicast addresses on the VF). Am
 not sure if there is a good way to notify the guest of blocked addresses.
 Maybe putting the lower dev in promiscuous mode could be a policy decision too
 in this case. 
 
 One other thing, I had indicated that I will look up details on opening my
 patch for non-passthru to enable hw filtering (without adding filtering
 support in macvlan right away. Ie phase1). Turns out in current code in
 macvlan_handle_frame, for non-passthru case, it does not fwd unicast pkts
 destined to macs other than the ones in macvlan hash. So a filter or hash
 lookup there for additional unicast addresses needs to be definitely added for
 non-passthru.
 
 Thanks,
 Roopa
 
 
  

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-12 Thread Roopa Prabhu 



On 9/11/11 11:52 AM, Michael S. Tsirkin m...@redhat.com wrote:

 On Sun, Sep 11, 2011 at 06:18:02AM -0700, Roopa Prabhu wrote:
 
 
 
 On 9/11/11 2:38 AM, Michael S. Tsirkin m...@redhat.com wrote:
 
 On Fri, Sep 09, 2011 at 09:33:33AM -0700, Roopa Prabhu wrote:

 
 It's probably more interesting for a card without SRIOV support.
 
 If its an SRIOV card I am assuming people likely using PASSTHRU mode.
 Non-SRIOV cards will use any of the non-PASSTHRU mode.
 
 
 we will have to add filter lookup in macvlan
 to filter pkts for each guest.
 
 Any chance to enable hardware filters for that?
 
 NAFAIK. Am not sure how you would do it too. Its still a single device from
 where the host receives traffic from.
 
 Thanks,
 Roopa
 
 VMDQ cards might let you program mac addresses for individula rings.
 
I tried to lookup more information on this. I dint find any concrete
information. I am not sure if individual rings show up as separate netdev.
Any more info on how a VMDQ nic is used with macvlan ?.

I came across this 
http://www.linux-kvm.org/wiki/images/6/6a/KvmForum2008$kdf2008_7.pdf

Thanks,
Roopa
 
 

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-12 Thread Roopa Prabhu 



On 9/11/11 12:03 PM, Michael S. Tsirkin m...@redhat.com wrote:

 On Sun, Sep 11, 2011 at 06:18:01AM -0700, Roopa Prabhu wrote:
 
 
 
 On 9/11/11 2:44 AM, Michael S. Tsirkin m...@redhat.com wrote:
 
 
 Yes, but what I mean is, if the size of the single filter table
 is limited, we need to decide how many addresses is
 each guest allowed. If we let one guest ask for
 as many as it wants, it can lock others out.
 
 Yes true. In these cases ie when the number of unicast addresses being
 registered is more than it can handle, The VF driver will put the VF  in
 promiscuous mode (Or at least its supposed to do. I think all drivers do
 that).
 
 
 Thanks,
 Roopa
 
 Right, so that works at least but likely performs worse
 than a hardware filter. So we better allocate it in
 some fair way, as a minimum. Maybe a way for
 the admin to control that allocation is useful.

Yes I think we will have to do something like that. There is a maximum that
hw can support. Might need to consider that too. But there is no interface
to get that today. I think the virtualization case gets a little trickier.
Virtio-net allows upto 64 unicast addresses. But the lowerdev may allow only
upto say 10 unicast addresses (I think intel supports 10 unicast addresses
on the VF). Am not sure if there is a good way to notify the guest of
blocked addresses. Maybe putting the lower dev in promiscuous mode could be
a policy decision too in this case.

One other thing, I had indicated that I will look up details on opening my
patch for non-passthru to enable hw filtering (without adding filtering
support in macvlan right away. Ie phase1). Turns out in current code in
macvlan_handle_frame, for non-passthru case, it does not fwd unicast pkts
destined to macs other than the ones in macvlan hash. So a filter or hash
lookup there for additional unicast addresses needs to be definitely added
for non-passthru.

Thanks,
Roopa


 

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-12 Thread Roopa Prabhu 



On 9/11/11 9:30 PM, Sridhar Samudrala s...@us.ibm.com wrote:

 On 9/11/2011 6:18 AM, Roopa Prabhu wrote:
 
 
 On 9/11/11 2:44 AM, Michael S. Tsirkinm...@redhat.com  wrote:
 
 AFAIK, though it might maintain a single filter table space in hw, hw does
 know which filter belongs to which VF. And the OS driver does not need to
 do
 anything special. The VF driver exposes a VF netdev. And any uc/mc
 addresses
 registered with a VF netdev are registered with the hw by the driver. And
 hw
 will filter and send only pkts that the VF has expressed interest in.
 
 No special filter partitioning in hw is required.
 
 Thanks,
 Roopa
 Yes, but what I mean is, if the size of the single filter table
 is limited, we need to decide how many addresses is
 each guest allowed. If we let one guest ask for
 as many as it wants, it can lock others out.
 Yes true. In these cases ie when the number of unicast addresses being
 registered is more than it can handle, The VF driver will put the VF  in
 promiscuous mode (Or at least its supposed to do. I think all drivers do
 that).
 
 What does putting VF in promiscuous mode mean?  How can the NIC decide
 which set
 of mac addresses are passed to the VF? Does it mean VF sees all the
 packets received
 by the NIC including packets destined for other VFs/PF?
 
Yes I think so. After your question I looked at 2 other  VF drivers and
looks like they return error if num unicast addresses exceeds the number
supported by hw and don't put the VF in promiscuous mode. But one could put
the VF in promiscuous mode by changing IFF_FLAGS I think.

The original in-kernel passthru mode code puts the VF in promiscuous mode by
default. Am assuming that works well with other sriov cards you got a chance
to try out with.

Thanks,
Roopa

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-11 Thread Michael S. Tsirkin 
On Fri, Sep 09, 2011 at 09:33:33AM -0700, Roopa Prabhu wrote:
 
 
 
 On 9/8/11 10:55 PM, Michael S. Tsirkin m...@redhat.com wrote:
 
  On Thu, Sep 08, 2011 at 07:53:11PM -0700, Roopa Prabhu wrote:
  Phase 1: Goal: Enable hardware filtering for all macvlan modes
  - In macvlan passthru mode the single guest virtio-nic connected will
receive traffic that he requested for
  - In macvlan non-passthru mode all guest virtio-nics sharing the
physical nic will see all other guest traffic
but the filtering at guest virtio-nic
  
  I don't think guests currently filter anything.
  
  I was referring to Qemu-kvm virtio-net in
  virtion_net_receive-receive_filter. I think It only passes pkts that the
  guest OS is interested. It uses the filter table that I am passing to
  macvtap in this patch.
  
  This happens after userspace thread gets woken up and data
  is copied there. So relying on filtering at that level is
  going to be very inefficient on a system with
  multiple active guests. Further, and for that reason, vhost-net
  doesn't do filtering at all, relying on the backends
  to pass it correct packets.
 
 Ok thanks for the info. So in which case, phase 1 is best for PASSTHRU mode
 and for non-PASSTHRU when there is a single guest connected to a VF.
 For non-PASSTHRU multi guest sharing the same VF, Phase 1 is definitely
 better than putting the VF in promiscuous mode.
 But to address the concern you mention above, in phase 2 when we have more
 than one guest sharing the VF,

It's probably more interesting for a card without SRIOV support.

 we will have to add filter lookup in macvlan
 to filter pkts for each guest.

Any chance to enable hardware filters for that?

 This will need some performance tests too.
 
 Will start investigating the netlink interface comments for phase 1 first.
 
 Thanks!
 -Roopa
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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-11 Thread Michael S. Tsirkin 
On Thu, Sep 08, 2011 at 08:00:53PM -0700, Roopa Prabhu wrote:
 
 
 
 On 9/8/11 12:33 PM, Michael S. Tsirkin m...@redhat.com wrote:
 
  On Thu, Sep 08, 2011 at 12:23:56PM -0700, Roopa Prabhu wrote:
  
  I think the main usecase for passthru mode is to assign a SR-IOV VF to
  a single guest.
  
  Yes and for the passthru usecase this patch should be enough to enable
  filtering in hw (eventually like I indicated before I need to fix vlan
  filtering too).
  
  So with filtering in hw, and in sriov VF case, VFs
  actually share a filtering table. How will that
  be partitioned?
 
 AFAIK, though it might maintain a single filter table space in hw, hw does
 know which filter belongs to which VF. And the OS driver does not need to do
 anything special. The VF driver exposes a VF netdev. And any uc/mc addresses
 registered with a VF netdev are registered with the hw by the driver. And hw
 will filter and send only pkts that the VF has expressed interest in.
 
 No special filter partitioning in hw is required.
 
 Thanks,
 Roopa

Yes, but what I mean is, if the size of the single filter table
is limited, we need to decide how many addresses is
each guest allowed. If we let one guest ask for
as many as it wants, it can lock others out.

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-11 Thread Roopa Prabhu 



On 9/11/11 2:44 AM, Michael S. Tsirkin m...@redhat.com wrote:

 
 AFAIK, though it might maintain a single filter table space in hw, hw does
 know which filter belongs to which VF. And the OS driver does not need to do
 anything special. The VF driver exposes a VF netdev. And any uc/mc addresses
 registered with a VF netdev are registered with the hw by the driver. And hw
 will filter and send only pkts that the VF has expressed interest in.
 
 No special filter partitioning in hw is required.
 
 Thanks,
 Roopa
 
 Yes, but what I mean is, if the size of the single filter table
 is limited, we need to decide how many addresses is
 each guest allowed. If we let one guest ask for
 as many as it wants, it can lock others out.

Yes true. In these cases ie when the number of unicast addresses being
registered is more than it can handle, The VF driver will put the VF  in
promiscuous mode (Or at least its supposed to do. I think all drivers do
that).


Thanks,
Roopa


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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-11 Thread Roopa Prabhu 



On 9/11/11 2:38 AM, Michael S. Tsirkin m...@redhat.com wrote:

 On Fri, Sep 09, 2011 at 09:33:33AM -0700, Roopa Prabhu wrote:
 
 
 
 On 9/8/11 10:55 PM, Michael S. Tsirkin m...@redhat.com wrote:
 
 On Thu, Sep 08, 2011 at 07:53:11PM -0700, Roopa Prabhu wrote:
 Phase 1: Goal: Enable hardware filtering for all macvlan modes
 - In macvlan passthru mode the single guest virtio-nic connected will
   receive traffic that he requested for
 - In macvlan non-passthru mode all guest virtio-nics sharing the
   physical nic will see all other guest traffic
   but the filtering at guest virtio-nic
 
 I don't think guests currently filter anything.
 
 I was referring to Qemu-kvm virtio-net in
 virtion_net_receive-receive_filter. I think It only passes pkts that the
 guest OS is interested. It uses the filter table that I am passing to
 macvtap in this patch.
 
 This happens after userspace thread gets woken up and data
 is copied there. So relying on filtering at that level is
 going to be very inefficient on a system with
 multiple active guests. Further, and for that reason, vhost-net
 doesn't do filtering at all, relying on the backends
 to pass it correct packets.
 
 Ok thanks for the info. So in which case, phase 1 is best for PASSTHRU mode
 and for non-PASSTHRU when there is a single guest connected to a VF.
 For non-PASSTHRU multi guest sharing the same VF, Phase 1 is definitely
 better than putting the VF in promiscuous mode.
 But to address the concern you mention above, in phase 2 when we have more
 than one guest sharing the VF,
 
 It's probably more interesting for a card without SRIOV support.
 
If its an SRIOV card I am assuming people likely using PASSTHRU mode.
Non-SRIOV cards will use any of the non-PASSTHRU mode.


 we will have to add filter lookup in macvlan
 to filter pkts for each guest.
 
 Any chance to enable hardware filters for that?
 
NAFAIK. Am not sure how you would do it too. Its still a single device from
where the host receives traffic from.

Thanks,
Roopa
 

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-11 Thread Michael S. Tsirkin 
On Sun, Sep 11, 2011 at 06:18:02AM -0700, Roopa Prabhu wrote:
 
 
 
 On 9/11/11 2:38 AM, Michael S. Tsirkin m...@redhat.com wrote:
 
  On Fri, Sep 09, 2011 at 09:33:33AM -0700, Roopa Prabhu wrote:
  
  
  
  On 9/8/11 10:55 PM, Michael S. Tsirkin m...@redhat.com wrote:
  
  On Thu, Sep 08, 2011 at 07:53:11PM -0700, Roopa Prabhu wrote:
  Phase 1: Goal: Enable hardware filtering for all macvlan modes
  - In macvlan passthru mode the single guest virtio-nic connected 
  will
receive traffic that he requested for
  - In macvlan non-passthru mode all guest virtio-nics sharing the
physical nic will see all other guest traffic
but the filtering at guest virtio-nic
  
  I don't think guests currently filter anything.
  
  I was referring to Qemu-kvm virtio-net in
  virtion_net_receive-receive_filter. I think It only passes pkts that the
  guest OS is interested. It uses the filter table that I am passing to
  macvtap in this patch.
  
  This happens after userspace thread gets woken up and data
  is copied there. So relying on filtering at that level is
  going to be very inefficient on a system with
  multiple active guests. Further, and for that reason, vhost-net
  doesn't do filtering at all, relying on the backends
  to pass it correct packets.
  
  Ok thanks for the info. So in which case, phase 1 is best for PASSTHRU mode
  and for non-PASSTHRU when there is a single guest connected to a VF.
  For non-PASSTHRU multi guest sharing the same VF, Phase 1 is definitely
  better than putting the VF in promiscuous mode.
  But to address the concern you mention above, in phase 2 when we have more
  than one guest sharing the VF,
  
  It's probably more interesting for a card without SRIOV support.
  
 If its an SRIOV card I am assuming people likely using PASSTHRU mode.
 Non-SRIOV cards will use any of the non-PASSTHRU mode.
 
 
  we will have to add filter lookup in macvlan
  to filter pkts for each guest.
  
  Any chance to enable hardware filters for that?
  
 NAFAIK. Am not sure how you would do it too. Its still a single device from
 where the host receives traffic from.
 
 Thanks,
 Roopa

VMDQ cards might let you program mac addresses for individula rings.


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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-11 Thread Michael S. Tsirkin 
On Sun, Sep 11, 2011 at 06:18:01AM -0700, Roopa Prabhu wrote:
 
 
 
 On 9/11/11 2:44 AM, Michael S. Tsirkin m...@redhat.com wrote:
 
  
  AFAIK, though it might maintain a single filter table space in hw, hw does
  know which filter belongs to which VF. And the OS driver does not need to 
  do
  anything special. The VF driver exposes a VF netdev. And any uc/mc 
  addresses
  registered with a VF netdev are registered with the hw by the driver. And 
  hw
  will filter and send only pkts that the VF has expressed interest in.
  
  No special filter partitioning in hw is required.
  
  Thanks,
  Roopa
  
  Yes, but what I mean is, if the size of the single filter table
  is limited, we need to decide how many addresses is
  each guest allowed. If we let one guest ask for
  as many as it wants, it can lock others out.
 
 Yes true. In these cases ie when the number of unicast addresses being
 registered is more than it can handle, The VF driver will put the VF  in
 promiscuous mode (Or at least its supposed to do. I think all drivers do
 that).
 
 
 Thanks,
 Roopa

Right, so that works at least but likely performs worse
than a hardware filter. So we better allocate it in
some fair way, as a minimum. Maybe a way for
the admin to control that allocation is useful.

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-11 Thread Sridhar Samudrala 

On 9/11/2011 6:18 AM, Roopa Prabhu wrote:



On 9/11/11 2:44 AM, Michael S. Tsirkinm...@redhat.com  wrote:


AFAIK, though it might maintain a single filter table space in hw, hw does
know which filter belongs to which VF. And the OS driver does not need to do
anything special. The VF driver exposes a VF netdev. And any uc/mc addresses
registered with a VF netdev are registered with the hw by the driver. And hw
will filter and send only pkts that the VF has expressed interest in.

No special filter partitioning in hw is required.

Thanks,
Roopa

Yes, but what I mean is, if the size of the single filter table
is limited, we need to decide how many addresses is
each guest allowed. If we let one guest ask for
as many as it wants, it can lock others out.

Yes true. In these cases ie when the number of unicast addresses being
registered is more than it can handle, The VF driver will put the VF  in
promiscuous mode (Or at least its supposed to do. I think all drivers do
that).

What does putting VF in promiscuous mode mean?  How can the NIC decide 
which set
of mac addresses are passed to the VF? Does it mean VF sees all the 
packets received

by the NIC including packets destined for other VFs/PF?

Thanks
Sridhar

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-09 Thread Roopa Prabhu 



On 9/8/11 9:25 PM, Sridhar Samudrala s...@us.ibm.com wrote:

 On 9/8/2011 8:00 PM, Roopa Prabhu wrote:
 
 
 On 9/8/11 12:33 PM, Michael S. Tsirkinm...@redhat.com  wrote:
 
 On Thu, Sep 08, 2011 at 12:23:56PM -0700, Roopa Prabhu wrote:
 I think the main usecase for passthru mode is to assign a SR-IOV VF to
 a single guest.
 
 Yes and for the passthru usecase this patch should be enough to enable
 filtering in hw (eventually like I indicated before I need to fix vlan
 filtering too).
 So with filtering in hw, and in sriov VF case, VFs
 actually share a filtering table. How will that
 be partitioned?
 AFAIK, though it might maintain a single filter table space in hw, hw does
 know which filter belongs to which VF. And the OS driver does not need to do
 anything special. The VF driver exposes a VF netdev. And any uc/mc addresses
 registered with a VF netdev are registered with the hw by the driver. And hw
 will filter and send only pkts that the VF has expressed interest in.
 Does your NIC  driver support adding multiple mac addresses to a VF?
 I have tried a few other SR-IOV NICs sometime back and they didn't
 support this feature.

Yes our nic does. I thought Intel's also does (see ixgbevf_set_rx_mode).
Though I have not really tried using it on an Intel card. I think most cards
should at the least support multicast filters.

If the lower dev does not support unicast filtering, dev_uc_add(lowerdev,..)
puts the lower dev in promiscous mode. Though..i think I can chcek this
before hand in macvlan_open and put the lowerdev in promiscuous mode if it
does not support filtering.

 
 Currently, we don't have an interface to add multiple mac addresses to a
 netdev other than an
 indirect way of creating a macvlan /if on top of it.

Yes I think so. I have been using only macvlan to test.

Thanks,
Roopa

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-09 Thread Roopa Prabhu 



On 9/8/11 10:55 PM, Michael S. Tsirkin m...@redhat.com wrote:

 On Thu, Sep 08, 2011 at 07:53:11PM -0700, Roopa Prabhu wrote:
 Phase 1: Goal: Enable hardware filtering for all macvlan modes
 - In macvlan passthru mode the single guest virtio-nic connected will
   receive traffic that he requested for
 - In macvlan non-passthru mode all guest virtio-nics sharing the
   physical nic will see all other guest traffic
   but the filtering at guest virtio-nic
 
 I don't think guests currently filter anything.
 
 I was referring to Qemu-kvm virtio-net in
 virtion_net_receive-receive_filter. I think It only passes pkts that the
 guest OS is interested. It uses the filter table that I am passing to
 macvtap in this patch.
 
 This happens after userspace thread gets woken up and data
 is copied there. So relying on filtering at that level is
 going to be very inefficient on a system with
 multiple active guests. Further, and for that reason, vhost-net
 doesn't do filtering at all, relying on the backends
 to pass it correct packets.

Ok thanks for the info. So in which case, phase 1 is best for PASSTHRU mode
and for non-PASSTHRU when there is a single guest connected to a VF.
For non-PASSTHRU multi guest sharing the same VF, Phase 1 is definitely
better than putting the VF in promiscuous mode.
But to address the concern you mention above, in phase 2 when we have more
than one guest sharing the VF, we will have to add filter lookup in macvlan
to filter pkts for each guest. This will need some performance tests too.

Will start investigating the netlink interface comments for phase 1 first.

Thanks!
-Roopa

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-08 Thread Michael S. Tsirkin 
On Wed, Sep 07, 2011 at 10:20:28PM -0700, Roopa Prabhu wrote:
 On 9/7/11 5:34 AM, Michael S. Tsirkin m...@redhat.com wrote:
 
  On Tue, Sep 06, 2011 at 03:35:40PM -0700, Roopa Prabhu wrote:
  This patch is an attempt at providing address filtering support for macvtap
  devices in PASSTHRU mode. Its still a work in progress.
  Briefly tested for basic functionality. Wanted to get some feedback on the
  direction before proceeding.
  
  
  Good work, thanks.
  
 
 Thanks.
 
  I have hopefully CC'ed all concerned people.
  
  kvm crowd might also be interested.
  Try using ./scripts/get_maintainer.pl as well.
  
 Thanks for the tip. Expanded CC list a bit more.
 
  PASSTHRU mode today sets the lowerdev in promiscous mode. In PASSTHRU mode
  there is a 1-1 mapping between macvtap device and physical nic or VF. And 
  all
  filtering is done in lowerdev hw. The lowerdev does not need to be in
  promiscous mode as long as the guest filters are passed down to the 
  lowerdev.
  This patch tries to remove the need for putting the lowerdev in promiscous
  mode. 
  I have also referred to the thread below where TUNSETTXFILTER was mentioned
  in 
  this context: 
   http://patchwork.ozlabs.org/patch/69297/
  
  This patch basically passes the addresses got by TUNSETTXFILTER to macvlan
  lowerdev.
  
  I have looked at previous work and discussions on this for qemu-kvm
  by Michael Tsirkin, Alex Williamson and Dragos Tatulea
  http://patchwork.ozlabs.org/patch/78595/
  http://patchwork.ozlabs.org/patch/47160/
  https://patchwork.kernel.org/patch/474481/
  
  Redhat bugzilla by Michael Tsirkin:
  https://bugzilla.redhat.com/show_bug.cgi?id=655013
  
  I used Michael's qemu-kvm patch for testing the changes with KVM
  
  I would like to cover both MAC and vlan filtering in this work.
  
  Open Questions/Issues:
  - There is a need for vlan filtering to complete the patch. It will require
a new tap ioctl cmd for vlans.
Some ideas on this are:
  
a) TUNSETVLANFILTER: This will entail we send the whole vlan bitmap 
  filter
  (similar to tun_filter for addresses). Passing the vlan id's to lower
  device will mean going thru the whole list of vlans every time.
  
OR
  
b) TUNSETVLAN with vlan id and flag to set/unset
  
Does option 'b' sound ok ?
  
  - In this implementation we make the macvlan address list same as the 
  address
list that came in the filter with TUNSETTXFILTER. This will not cover 
  cases
where the macvlan device needs to have other addresses that are not
necessarily in the filter. Is this a problem ?
  
  What cases do you have in mind?
  
 This patch targets only macvlan PASSTHRU mode and for PASSTHRU mode I don't
 see a problem with uc/mc address list being the same in all the stacked
 netdevs in the path. I called that out above to make sure I was not missing
 any case in PASSTHRU mode where this might be invalid. Otherwise I don't see
 a problem in the simple PASSTHRU use case this patch supports.
 
  - The patch currently only supports passing of IFF_PROMISC and 
  IFF_MULTICAST
  filter flags to lowerdev
  
  This patch series implements the following
  01/3 - macvlan: Add support for unicast filtering in macvlan
  02/3 - macvlan: Add function to set addr filter on lower device in passthru
  mode
  03/3 - macvtap: Add support for TUNSETTXFILTER
  
  Please comment. Thanks.
  
  Signed-off-by: Roopa Prabhu ropra...@cisco.com
  Signed-off-by: Christian Benvenuti be...@cisco.com
  Signed-off-by: David Wang dwa...@cisco.com
  
  The security isn't lower than with promisc, so I don't see
  a problem with this as such.
  
  There are more features we'll want down the road though,
  so let's see whether the interface will be able to
  satisfy them in a backwards compatible way before we
  set it in stone. Here's what I came up with:
  
  How will the filtering table be partitioned within guests?
 
 Since this patch supports macvlan PASSTHRU mode only, in which the lower
 device has 1-1 mapping to the guest nic, it does not require any
 partitioning of filtering table within guests. Unless I missed understanding
 something. 
 If the lower device were being shared by multiple guest network interfaces
 (non PASSTHRU mode), only then we will need to maintain separate filter
 tables for each guest network interface in macvlan and forward the pkt to
 respective guest interface after a filter lookup. This could affect
 performance too I think.

Not with hardware filtering support. Which is where we'd need to
partition the host nic mac table between guests.

 I chose to support PASSTHRU Mode only at first because its simpler and all
 code additions are in control path only.

I agree. It would be a bit silly to have a dedicated interface
for passthough and a completely separate one for
non passthrough.

  
  A way to limit what the guest can do would also be useful.
  How can this be done? selinux?
 
 I vaguely remember a thread on the same context.. had a suggestion to

Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-08 Thread Roopa Prabhu 



On 9/8/11 10:42 AM, Sridhar Samudrala s...@us.ibm.com wrote:

 On Thu, 2011-09-08 at 09:19 -0700, Roopa Prabhu wrote:
 
 
 On 9/8/11 4:08 AM, Michael S. Tsirkin m...@redhat.com wrote:
 
 On Wed, Sep 07, 2011 at 10:20:28PM -0700, Roopa Prabhu wrote:
 On 9/7/11 5:34 AM, Michael S. Tsirkin m...@redhat.com wrote:
 
 On Tue, Sep 06, 2011 at 03:35:40PM -0700, Roopa Prabhu wrote:
 This patch is an attempt at providing address filtering support for
 macvtap
 devices in PASSTHRU mode. Its still a work in progress.
 Briefly tested for basic functionality. Wanted to get some feedback on
 the
 direction before proceeding.
 
 
 Good work, thanks.
 
 
 Thanks.
 
 I have hopefully CC'ed all concerned people.
 
 kvm crowd might also be interested.
 Try using ./scripts/get_maintainer.pl as well.
 
 Thanks for the tip. Expanded CC list a bit more.
 
 PASSTHRU mode today sets the lowerdev in promiscous mode. In PASSTHRU
 mode
 there is a 1-1 mapping between macvtap device and physical nic or VF. And
 all
 filtering is done in lowerdev hw. The lowerdev does not need to be in
 promiscous mode as long as the guest filters are passed down to the
 lowerdev.
 This patch tries to remove the need for putting the lowerdev in
 promiscous
 mode. 
 I have also referred to the thread below where TUNSETTXFILTER was
 mentioned
 in 
 this context:
  http://patchwork.ozlabs.org/patch/69297/
 
 This patch basically passes the addresses got by TUNSETTXFILTER to
 macvlan
 lowerdev.
 
 I have looked at previous work and discussions on this for qemu-kvm
 by Michael Tsirkin, Alex Williamson and Dragos Tatulea
 http://patchwork.ozlabs.org/patch/78595/
 http://patchwork.ozlabs.org/patch/47160/
 https://patchwork.kernel.org/patch/474481/
 
 Redhat bugzilla by Michael Tsirkin:
 https://bugzilla.redhat.com/show_bug.cgi?id=655013
 
 I used Michael's qemu-kvm patch for testing the changes with KVM
 
 I would like to cover both MAC and vlan filtering in this work.
 
 Open Questions/Issues:
 - There is a need for vlan filtering to complete the patch. It will
 require
   a new tap ioctl cmd for vlans.
   Some ideas on this are:
 
   a) TUNSETVLANFILTER: This will entail we send the whole vlan bitmap
 filter
 (similar to tun_filter for addresses). Passing the vlan id's to lower
 device will mean going thru the whole list of vlans every time.
 
   OR
 
   b) TUNSETVLAN with vlan id and flag to set/unset
 
   Does option 'b' sound ok ?
 
 - In this implementation we make the macvlan address list same as the
 address
   list that came in the filter with TUNSETTXFILTER. This will not cover
 cases
   where the macvlan device needs to have other addresses that are not
   necessarily in the filter. Is this a problem ?
 
 What cases do you have in mind?
 
 This patch targets only macvlan PASSTHRU mode and for PASSTHRU mode I don't
 see a problem with uc/mc address list being the same in all the stacked
 netdevs in the path. I called that out above to make sure I was not missing
 any case in PASSTHRU mode where this might be invalid. Otherwise I don't
 see
 a problem in the simple PASSTHRU use case this patch supports.
 
 - The patch currently only supports passing of IFF_PROMISC and
 IFF_MULTICAST
 filter flags to lowerdev
 
 This patch series implements the following
 01/3 - macvlan: Add support for unicast filtering in macvlan
 02/3 - macvlan: Add function to set addr filter on lower device in
 passthru
 mode
 03/3 - macvtap: Add support for TUNSETTXFILTER
 
 Please comment. Thanks.
 
 Signed-off-by: Roopa Prabhu ropra...@cisco.com
 Signed-off-by: Christian Benvenuti be...@cisco.com
 Signed-off-by: David Wang dwa...@cisco.com
 
 The security isn't lower than with promisc, so I don't see
 a problem with this as such.
 
 There are more features we'll want down the road though,
 so let's see whether the interface will be able to
 satisfy them in a backwards compatible way before we
 set it in stone. Here's what I came up with:
 
 How will the filtering table be partitioned within guests?
 
 Since this patch supports macvlan PASSTHRU mode only, in which the lower
 device has 1-1 mapping to the guest nic, it does not require any
 partitioning of filtering table within guests. Unless I missed
 understanding
 something. 
 If the lower device were being shared by multiple guest network interfaces
 (non PASSTHRU mode), only then we will need to maintain separate filter
 tables for each guest network interface in macvlan and forward the pkt to
 respective guest interface after a filter lookup. This could affect
 performance too I think.
 
 Not with hardware filtering support. Which is where we'd need to
 partition the host nic mac table between guests.
 
 I need to understand this more. In non passthru case when a VF or physical
 nic is shared between guests, the nic does not really know about the guests,
 so I was thinking we do the same thing as we do for the passthru case (ie
 send all the address filters from macvlan to the physical nic). So at the
 hardware,

Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-08 Thread Michael S. Tsirkin 
On Thu, Sep 08, 2011 at 09:19:32AM -0700, Roopa Prabhu wrote:
  There are more features we'll want down the road though,
  so let's see whether the interface will be able to
  satisfy them in a backwards compatible way before we
  set it in stone. Here's what I came up with:
  
  How will the filtering table be partitioned within guests?
  
  Since this patch supports macvlan PASSTHRU mode only, in which the lower
  device has 1-1 mapping to the guest nic, it does not require any
  partitioning of filtering table within guests. Unless I missed 
  understanding
  something. 
  If the lower device were being shared by multiple guest network interfaces
  (non PASSTHRU mode), only then we will need to maintain separate filter
  tables for each guest network interface in macvlan and forward the pkt to
  respective guest interface after a filter lookup. This could affect
  performance too I think.
  
  Not with hardware filtering support. Which is where we'd need to
  partition the host nic mac table between guests.
  
 I need to understand this more. In non passthru case when a VF or physical
 nic is shared between guests,

For example, consider a VF given to each guest. Hardware supports a fixed
total number of filters, which can be partitioned between VFs.

 the nic does not really know about the guests,
 so I was thinking we do the same thing as we do for the passthru case (ie
 send all the address filters from macvlan to the physical nic). So at the
 hardware, filtering is done for all guests sharing the nic. But if we want
 each virtio-net nic or guest to get exactly what it asked for
 macvlan/macvtap needs to maintain a copy of each guest filter and do a
 lookup and send only the requested traffic to the guest. Here is the
 performance hit that I was seeing. Please see my next comment for further
 details. 

It won't be any slower than attaching a non-passthrough macvlan
to a device, will it?

 
  I chose to support PASSTHRU Mode only at first because its simpler and all
  code additions are in control path only.
  
  I agree. It would be a bit silly to have a dedicated interface
  for passthough and a completely separate one for
  non passthrough.
 
 Agree. The reason I did not focus on non-passthru case in the initial
 version was because I was thinking things to do in the non-passthru case
 will be just add-ons to the passthru case. But true Better to flush out the
 non-pasthru case details.
 
 After dwelling on this a bit more how about the below:
 
 Phase 1: Goal: Enable hardware filtering for all macvlan modes
 - In macvlan passthru mode the single guest virtio-nic connected will
   receive traffic that he requested for
 - In macvlan non-passthru mode all guest virtio-nics sharing the
   physical nic will see all other guest traffic
   but the filtering at guest virtio-nic

I don't think guests currently filter anything.

   will make sure each guest
   eventually sees traffic he asked for. This is still better than
   putting the physical nic in promiscuous mode.
 
 (This is mainly what my patch does...but will need to remove the passthru
 check and see if there are any thing else needed for non-passthru case)

I'm fine with sticking with passthrough, make non passthrough
a separate phase.

 
 Phase 2: Goal: Enable filtering at macvlan so that each guest virtio-nic
 receives only what he requested for.
 - In this case, in addition to pushing the filters down to the physical
   nic we will have to maintain the same filter in macvlan and do a filter
   lookup before forwarding the traffic to a virtio-nic.
 
 But I am thinking phase 2 might be redundant given virtio-nic already does
 filtering for the guest.

It does? Do you mean the filter that qemu does in userspace?

 In which case we might not need phase 2 at all. I
 might have been over complicating things.
 
 Please comment. And please correct if I missed something.
  
  
  
  A way to limit what the guest can do would also be useful.
  How can this be done? selinux?
  
  I vaguely remember a thread on the same context.. had a suggestion to
  maintain pre-approved address lists and allow guest filter registration of
  only those addresses for security. This seemed reasonable. Plus the ability
  to support additional address registration from guest could be made
  configurable (One of your ideas again from prior work).
  
  I am not an selinux expert, but I am thinking we can use it to only allow 
  or
  disallow access or operations to the macvtap device. (?). I will check more
  on this.
  
  We'd have to have a way to revoke that as well.
  
 Yes true.
 
 
  
  Any thoughts on spoofing filtering?
  
  I can only think of checking addresses against an allowed address list.
  Don't know of any other ways. Any hints ?
  
  Hardware (esp SRIOV) often has ways to do this check, too.
  
 Yes correct. Hw sriov and even switch in 802.1Qbh has anti-spoofing feature.
 In which case I am thinking having It at

Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-08 Thread Roopa Prabhu 



On 9/8/11 4:08 AM, Michael S. Tsirkin m...@redhat.com wrote:

 On Wed, Sep 07, 2011 at 10:20:28PM -0700, Roopa Prabhu wrote:
 On 9/7/11 5:34 AM, Michael S. Tsirkin m...@redhat.com wrote:
 
 On Tue, Sep 06, 2011 at 03:35:40PM -0700, Roopa Prabhu wrote:
 This patch is an attempt at providing address filtering support for macvtap
 devices in PASSTHRU mode. Its still a work in progress.
 Briefly tested for basic functionality. Wanted to get some feedback on the
 direction before proceeding.
 
 
 Good work, thanks.
 
 
 Thanks.
 
 I have hopefully CC'ed all concerned people.
 
 kvm crowd might also be interested.
 Try using ./scripts/get_maintainer.pl as well.
 
 Thanks for the tip. Expanded CC list a bit more.
 
 PASSTHRU mode today sets the lowerdev in promiscous mode. In PASSTHRU mode
 there is a 1-1 mapping between macvtap device and physical nic or VF. And
 all
 filtering is done in lowerdev hw. The lowerdev does not need to be in
 promiscous mode as long as the guest filters are passed down to the
 lowerdev.
 This patch tries to remove the need for putting the lowerdev in promiscous
 mode. 
 I have also referred to the thread below where TUNSETTXFILTER was mentioned
 in 
 this context: 
  http://patchwork.ozlabs.org/patch/69297/
 
 This patch basically passes the addresses got by TUNSETTXFILTER to macvlan
 lowerdev.
 
 I have looked at previous work and discussions on this for qemu-kvm
 by Michael Tsirkin, Alex Williamson and Dragos Tatulea
 http://patchwork.ozlabs.org/patch/78595/
 http://patchwork.ozlabs.org/patch/47160/
 https://patchwork.kernel.org/patch/474481/
 
 Redhat bugzilla by Michael Tsirkin:
 https://bugzilla.redhat.com/show_bug.cgi?id=655013
 
 I used Michael's qemu-kvm patch for testing the changes with KVM
 
 I would like to cover both MAC and vlan filtering in this work.
 
 Open Questions/Issues:
 - There is a need for vlan filtering to complete the patch. It will require
   a new tap ioctl cmd for vlans.
   Some ideas on this are:
 
   a) TUNSETVLANFILTER: This will entail we send the whole vlan bitmap
 filter
 (similar to tun_filter for addresses). Passing the vlan id's to lower
 device will mean going thru the whole list of vlans every time.
 
   OR
 
   b) TUNSETVLAN with vlan id and flag to set/unset
 
   Does option 'b' sound ok ?
 
 - In this implementation we make the macvlan address list same as the
 address
   list that came in the filter with TUNSETTXFILTER. This will not cover
 cases
   where the macvlan device needs to have other addresses that are not
   necessarily in the filter. Is this a problem ?
 
 What cases do you have in mind?
 
 This patch targets only macvlan PASSTHRU mode and for PASSTHRU mode I don't
 see a problem with uc/mc address list being the same in all the stacked
 netdevs in the path. I called that out above to make sure I was not missing
 any case in PASSTHRU mode where this might be invalid. Otherwise I don't see
 a problem in the simple PASSTHRU use case this patch supports.
 
 - The patch currently only supports passing of IFF_PROMISC and
 IFF_MULTICAST
 filter flags to lowerdev
 
 This patch series implements the following
 01/3 - macvlan: Add support for unicast filtering in macvlan
 02/3 - macvlan: Add function to set addr filter on lower device in passthru
 mode
 03/3 - macvtap: Add support for TUNSETTXFILTER
 
 Please comment. Thanks.
 
 Signed-off-by: Roopa Prabhu ropra...@cisco.com
 Signed-off-by: Christian Benvenuti be...@cisco.com
 Signed-off-by: David Wang dwa...@cisco.com
 
 The security isn't lower than with promisc, so I don't see
 a problem with this as such.
 
 There are more features we'll want down the road though,
 so let's see whether the interface will be able to
 satisfy them in a backwards compatible way before we
 set it in stone. Here's what I came up with:
 
 How will the filtering table be partitioned within guests?
 
 Since this patch supports macvlan PASSTHRU mode only, in which the lower
 device has 1-1 mapping to the guest nic, it does not require any
 partitioning of filtering table within guests. Unless I missed understanding
 something. 
 If the lower device were being shared by multiple guest network interfaces
 (non PASSTHRU mode), only then we will need to maintain separate filter
 tables for each guest network interface in macvlan and forward the pkt to
 respective guest interface after a filter lookup. This could affect
 performance too I think.
 
 Not with hardware filtering support. Which is where we'd need to
 partition the host nic mac table between guests.
 
I need to understand this more. In non passthru case when a VF or physical
nic is shared between guests, the nic does not really know about the guests,
so I was thinking we do the same thing as we do for the passthru case (ie
send all the address filters from macvlan to the physical nic). So at the
hardware, filtering is done for all guests sharing the nic. But if we want
each virtio-net nic or guest to get exactly what it asked for
macvlan/macvtap

Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-08 Thread Michael S. Tsirkin 
On Thu, Sep 08, 2011 at 12:23:56PM -0700, Roopa Prabhu wrote:
  
  I think the main usecase for passthru mode is to assign a SR-IOV VF to
  a single guest.
  
 Yes and for the passthru usecase this patch should be enough to enable
 filtering in hw (eventually like I indicated before I need to fix vlan
 filtering too).

So with filtering in hw, and in sriov VF case, VFs
actually share a filtering table. How will that
be partitioned?

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-08 Thread Sridhar Samudrala 
On Thu, 2011-09-08 at 09:19 -0700, Roopa Prabhu wrote:
 
 
 On 9/8/11 4:08 AM, Michael S. Tsirkin m...@redhat.com wrote:
 
  On Wed, Sep 07, 2011 at 10:20:28PM -0700, Roopa Prabhu wrote:
  On 9/7/11 5:34 AM, Michael S. Tsirkin m...@redhat.com wrote:
  
  On Tue, Sep 06, 2011 at 03:35:40PM -0700, Roopa Prabhu wrote:
  This patch is an attempt at providing address filtering support for 
  macvtap
  devices in PASSTHRU mode. Its still a work in progress.
  Briefly tested for basic functionality. Wanted to get some feedback on 
  the
  direction before proceeding.
  
  
  Good work, thanks.
  
  
  Thanks.
  
  I have hopefully CC'ed all concerned people.
  
  kvm crowd might also be interested.
  Try using ./scripts/get_maintainer.pl as well.
  
  Thanks for the tip. Expanded CC list a bit more.
  
  PASSTHRU mode today sets the lowerdev in promiscous mode. In PASSTHRU 
  mode
  there is a 1-1 mapping between macvtap device and physical nic or VF. And
  all
  filtering is done in lowerdev hw. The lowerdev does not need to be in
  promiscous mode as long as the guest filters are passed down to the
  lowerdev.
  This patch tries to remove the need for putting the lowerdev in 
  promiscous
  mode. 
  I have also referred to the thread below where TUNSETTXFILTER was 
  mentioned
  in 
  this context: 
   http://patchwork.ozlabs.org/patch/69297/
  
  This patch basically passes the addresses got by TUNSETTXFILTER to 
  macvlan
  lowerdev.
  
  I have looked at previous work and discussions on this for qemu-kvm
  by Michael Tsirkin, Alex Williamson and Dragos Tatulea
  http://patchwork.ozlabs.org/patch/78595/
  http://patchwork.ozlabs.org/patch/47160/
  https://patchwork.kernel.org/patch/474481/
  
  Redhat bugzilla by Michael Tsirkin:
  https://bugzilla.redhat.com/show_bug.cgi?id=655013
  
  I used Michael's qemu-kvm patch for testing the changes with KVM
  
  I would like to cover both MAC and vlan filtering in this work.
  
  Open Questions/Issues:
  - There is a need for vlan filtering to complete the patch. It will 
  require
a new tap ioctl cmd for vlans.
Some ideas on this are:
  
a) TUNSETVLANFILTER: This will entail we send the whole vlan bitmap
  filter
  (similar to tun_filter for addresses). Passing the vlan id's to lower
  device will mean going thru the whole list of vlans every time.
  
OR
  
b) TUNSETVLAN with vlan id and flag to set/unset
  
Does option 'b' sound ok ?
  
  - In this implementation we make the macvlan address list same as the
  address
list that came in the filter with TUNSETTXFILTER. This will not cover
  cases
where the macvlan device needs to have other addresses that are not
necessarily in the filter. Is this a problem ?
  
  What cases do you have in mind?
  
  This patch targets only macvlan PASSTHRU mode and for PASSTHRU mode I don't
  see a problem with uc/mc address list being the same in all the stacked
  netdevs in the path. I called that out above to make sure I was not missing
  any case in PASSTHRU mode where this might be invalid. Otherwise I don't 
  see
  a problem in the simple PASSTHRU use case this patch supports.
  
  - The patch currently only supports passing of IFF_PROMISC and
  IFF_MULTICAST
  filter flags to lowerdev
  
  This patch series implements the following
  01/3 - macvlan: Add support for unicast filtering in macvlan
  02/3 - macvlan: Add function to set addr filter on lower device in 
  passthru
  mode
  03/3 - macvtap: Add support for TUNSETTXFILTER
  
  Please comment. Thanks.
  
  Signed-off-by: Roopa Prabhu ropra...@cisco.com
  Signed-off-by: Christian Benvenuti be...@cisco.com
  Signed-off-by: David Wang dwa...@cisco.com
  
  The security isn't lower than with promisc, so I don't see
  a problem with this as such.
  
  There are more features we'll want down the road though,
  so let's see whether the interface will be able to
  satisfy them in a backwards compatible way before we
  set it in stone. Here's what I came up with:
  
  How will the filtering table be partitioned within guests?
  
  Since this patch supports macvlan PASSTHRU mode only, in which the lower
  device has 1-1 mapping to the guest nic, it does not require any
  partitioning of filtering table within guests. Unless I missed 
  understanding
  something. 
  If the lower device were being shared by multiple guest network interfaces
  (non PASSTHRU mode), only then we will need to maintain separate filter
  tables for each guest network interface in macvlan and forward the pkt to
  respective guest interface after a filter lookup. This could affect
  performance too I think.
  
  Not with hardware filtering support. Which is where we'd need to
  partition the host nic mac table between guests.
  
 I need to understand this more. In non passthru case when a VF or physical
 nic is shared between guests, the nic does not really know about the guests,
 so I was thinking we do the same thing as we do for the passthru case (ie
 send all the

Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-08 Thread Roopa Prabhu 



On 9/8/11 12:11 PM, Michael S. Tsirkin m...@redhat.com wrote:

 On Thu, Sep 08, 2011 at 09:19:32AM -0700, Roopa Prabhu wrote:
 There are more features we'll want down the road though,
 so let's see whether the interface will be able to
 satisfy them in a backwards compatible way before we
 set it in stone. Here's what I came up with:
 
 How will the filtering table be partitioned within guests?
 
 Since this patch supports macvlan PASSTHRU mode only, in which the lower
 device has 1-1 mapping to the guest nic, it does not require any
 partitioning of filtering table within guests. Unless I missed
 understanding
 something. 
 If the lower device were being shared by multiple guest network interfaces
 (non PASSTHRU mode), only then we will need to maintain separate filter
 tables for each guest network interface in macvlan and forward the pkt to
 respective guest interface after a filter lookup. This could affect
 performance too I think.
 
 Not with hardware filtering support. Which is where we'd need to
 partition the host nic mac table between guests.
 
 I need to understand this more. In non passthru case when a VF or physical
 nic is shared between guests,
 
 For example, consider a VF given to each guest. Hardware supports a fixed
 total number of filters, which can be partitioned between VFs.
 
O ok. But hw maintains VF filters separately for every VF as far as I know.
Filters received on a VF are programmed for that VF only. Am assuming all
hardware do this. Atleast our hardware does this.
What I was referring to was a single VF shared between guests using macvtap
(could be bridge mode for example). All guests sharing the VF will register
 filters with the VF via macvlan. Hw makes sure what ever the VF asked for
is received at the VF. VF in hw does not know that it is shared by guests.
Only at macvlan we might need to re-filter the pkts received on the VF and
steer pkts to the individual guests based on what they asked for.


 the nic does not really know about the guests,
 so I was thinking we do the same thing as we do for the passthru case (ie
 send all the address filters from macvlan to the physical nic). So at the
 hardware, filtering is done for all guests sharing the nic. But if we want
 each virtio-net nic or guest to get exactly what it asked for
 macvlan/macvtap needs to maintain a copy of each guest filter and do a
 lookup and send only the requested traffic to the guest. Here is the
 performance hit that I was seeing. Please see my next comment for further
 details. 
 
 It won't be any slower than attaching a non-passthrough macvlan
 to a device, will it?
 
Am not sure. The filter lookup in macvlan is the one I am concerned about.
Will need to try it out.

 
 I chose to support PASSTHRU Mode only at first because its simpler and all
 code additions are in control path only.
 
 I agree. It would be a bit silly to have a dedicated interface
 for passthough and a completely separate one for
 non passthrough.
 
 Agree. The reason I did not focus on non-passthru case in the initial
 version was because I was thinking things to do in the non-passthru case
 will be just add-ons to the passthru case. But true Better to flush out the
 non-pasthru case details.
 
 After dwelling on this a bit more how about the below:
 
 Phase 1: Goal: Enable hardware filtering for all macvlan modes
 - In macvlan passthru mode the single guest virtio-nic connected will
   receive traffic that he requested for
 - In macvlan non-passthru mode all guest virtio-nics sharing the
   physical nic will see all other guest traffic
   but the filtering at guest virtio-nic
 
 I don't think guests currently filter anything.
 
I was referring to Qemu-kvm virtio-net in
virtion_net_receive-receive_filter. I think It only passes pkts that the
guest OS is interested. It uses the filter table that I am passing to
macvtap in this patch.


   will make sure each guest
   eventually sees traffic he asked for. This is still better than
   putting the physical nic in promiscuous mode.
 
 (This is mainly what my patch does...but will need to remove the passthru
 check and see if there are any thing else needed for non-passthru case)
 
 I'm fine with sticking with passthrough, make non passthrough
 a separate phase.
 
Ok.

 
 Phase 2: Goal: Enable filtering at macvlan so that each guest virtio-nic
 receives only what he requested for.
 - In this case, in addition to pushing the filters down to the physical
   nic we will have to maintain the same filter in macvlan and do a filter
   lookup before forwarding the traffic to a virtio-nic.
 
 But I am thinking phase 2 might be redundant given virtio-nic already does
 filtering for the guest.
 
 It does? Do you mean the filter that qemu does in userspace?
 
Yes I meant the filter that qemu does in userspace qemu-kvm/hw/virtio-net.c
receive_filter(). 

 In which case we might not need phase 2 at all. I
 might have been over complicating things.

Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-08 Thread Sridhar Samudrala 

On 9/8/2011 8:00 PM, Roopa Prabhu wrote:



On 9/8/11 12:33 PM, Michael S. Tsirkinm...@redhat.com  wrote:


On Thu, Sep 08, 2011 at 12:23:56PM -0700, Roopa Prabhu wrote:

I think the main usecase for passthru mode is to assign a SR-IOV VF to
a single guest.


Yes and for the passthru usecase this patch should be enough to enable
filtering in hw (eventually like I indicated before I need to fix vlan
filtering too).

So with filtering in hw, and in sriov VF case, VFs
actually share a filtering table. How will that
be partitioned?

AFAIK, though it might maintain a single filter table space in hw, hw does
know which filter belongs to which VF. And the OS driver does not need to do
anything special. The VF driver exposes a VF netdev. And any uc/mc addresses
registered with a VF netdev are registered with the hw by the driver. And hw
will filter and send only pkts that the VF has expressed interest in.

Does your NIC  driver support adding multiple mac addresses to a VF?
I have tried a few other SR-IOV NICs sometime back and they didn't 
support this feature.


Currently, we don't have an interface to add multiple mac addresses to a 
netdev other than an

indirect way of creating a macvlan /if on top of it.

Thanks
Sridhar



No special filter partitioning in hw is required.

Thanks,
Roopa




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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-08 Thread Michael S. Tsirkin 
On Thu, Sep 08, 2011 at 07:53:11PM -0700, Roopa Prabhu wrote:
  Phase 1: Goal: Enable hardware filtering for all macvlan modes
  - In macvlan passthru mode the single guest virtio-nic connected will
receive traffic that he requested for
  - In macvlan non-passthru mode all guest virtio-nics sharing the
physical nic will see all other guest traffic
but the filtering at guest virtio-nic
  
  I don't think guests currently filter anything.
  
 I was referring to Qemu-kvm virtio-net in
 virtion_net_receive-receive_filter. I think It only passes pkts that the
 guest OS is interested. It uses the filter table that I am passing to
 macvtap in this patch.

This happens after userspace thread gets woken up and data
is copied there. So relying on filtering at that level is
going to be very inefficient on a system with
multiple active guests. Further, and for that reason, vhost-net
doesn't do filtering at all, relying on the backends
to pass it correct packets.

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Re: [net-next-2.6 PATCH 0/3 RFC] macvlan: MAC Address filtering support for passthru mode

2011-09-07 Thread Roopa Prabhu 
On 9/7/11 5:34 AM, Michael S. Tsirkin m...@redhat.com wrote:

 On Tue, Sep 06, 2011 at 03:35:40PM -0700, Roopa Prabhu wrote:
 This patch is an attempt at providing address filtering support for macvtap
 devices in PASSTHRU mode. Its still a work in progress.
 Briefly tested for basic functionality. Wanted to get some feedback on the
 direction before proceeding.
 
 
 Good work, thanks.
 

Thanks.

 I have hopefully CC'ed all concerned people.
 
 kvm crowd might also be interested.
 Try using ./scripts/get_maintainer.pl as well.
 
Thanks for the tip. Expanded CC list a bit more.

 PASSTHRU mode today sets the lowerdev in promiscous mode. In PASSTHRU mode
 there is a 1-1 mapping between macvtap device and physical nic or VF. And all
 filtering is done in lowerdev hw. The lowerdev does not need to be in
 promiscous mode as long as the guest filters are passed down to the lowerdev.
 This patch tries to remove the need for putting the lowerdev in promiscous
 mode. 
 I have also referred to the thread below where TUNSETTXFILTER was mentioned
 in 
 this context: 
  http://patchwork.ozlabs.org/patch/69297/
 
 This patch basically passes the addresses got by TUNSETTXFILTER to macvlan
 lowerdev.
 
 I have looked at previous work and discussions on this for qemu-kvm
 by Michael Tsirkin, Alex Williamson and Dragos Tatulea
 http://patchwork.ozlabs.org/patch/78595/
 http://patchwork.ozlabs.org/patch/47160/
 https://patchwork.kernel.org/patch/474481/
 
 Redhat bugzilla by Michael Tsirkin:
 https://bugzilla.redhat.com/show_bug.cgi?id=655013
 
 I used Michael's qemu-kvm patch for testing the changes with KVM
 
 I would like to cover both MAC and vlan filtering in this work.
 
 Open Questions/Issues:
 - There is a need for vlan filtering to complete the patch. It will require
   a new tap ioctl cmd for vlans.
   Some ideas on this are:
 
   a) TUNSETVLANFILTER: This will entail we send the whole vlan bitmap filter
 (similar to tun_filter for addresses). Passing the vlan id's to lower
 device will mean going thru the whole list of vlans every time.
 
   OR
 
   b) TUNSETVLAN with vlan id and flag to set/unset
 
   Does option 'b' sound ok ?
 
 - In this implementation we make the macvlan address list same as the address
   list that came in the filter with TUNSETTXFILTER. This will not cover cases
   where the macvlan device needs to have other addresses that are not
   necessarily in the filter. Is this a problem ?
 
 What cases do you have in mind?
 
This patch targets only macvlan PASSTHRU mode and for PASSTHRU mode I don't
see a problem with uc/mc address list being the same in all the stacked
netdevs in the path. I called that out above to make sure I was not missing
any case in PASSTHRU mode where this might be invalid. Otherwise I don't see
a problem in the simple PASSTHRU use case this patch supports.

 - The patch currently only supports passing of IFF_PROMISC and IFF_MULTICAST
 filter flags to lowerdev
 
 This patch series implements the following
 01/3 - macvlan: Add support for unicast filtering in macvlan
 02/3 - macvlan: Add function to set addr filter on lower device in passthru
 mode
 03/3 - macvtap: Add support for TUNSETTXFILTER
 
 Please comment. Thanks.
 
 Signed-off-by: Roopa Prabhu ropra...@cisco.com
 Signed-off-by: Christian Benvenuti be...@cisco.com
 Signed-off-by: David Wang dwa...@cisco.com
 
 The security isn't lower than with promisc, so I don't see
 a problem with this as such.
 
 There are more features we'll want down the road though,
 so let's see whether the interface will be able to
 satisfy them in a backwards compatible way before we
 set it in stone. Here's what I came up with:
 
 How will the filtering table be partitioned within guests?

Since this patch supports macvlan PASSTHRU mode only, in which the lower
device has 1-1 mapping to the guest nic, it does not require any
partitioning of filtering table within guests. Unless I missed understanding
something. 

If the lower device were being shared by multiple guest network interfaces
(non PASSTHRU mode), only then we will need to maintain separate filter
tables for each guest network interface in macvlan and forward the pkt to
respective guest interface after a filter lookup. This could affect
performance too I think.

I chose to support PASSTHRU Mode only at first because its simpler and all
code additions are in control path only.

 
 A way to limit what the guest can do would also be useful.
 How can this be done? selinux?

I vaguely remember a thread on the same context.. had a suggestion to
maintain pre-approved address lists and allow guest filter registration of
only those addresses for security. This seemed reasonable. Plus the ability
to support additional address registration from guest could be made
configurable (One of your ideas again from prior work).

I am not an selinux expert, but I am thinking we can use it to only allow or
disallow access or operations to the macvtap device. (?). I will check more
on this.

 
 Any