similar to: Questions about XSA39

We''ve been hitting the following issue on a variety of hosts and recent Xen/dom0 version combinations. Here''s an excerpt from our latest: Xen: 4.1.4 (xenbits @ 23432) Dom0: 3.7.1-x86_64 BUG: unable to handle kernel NULL pointer dereference at 000000000000001c IP: [<ffffffff8141a301>] evtchn_from_irq+0x11/0x40 PGD 0 Oops: 0000 [#1] SMP Modules linked in: ebt_comment

Tune xen_netbk_count_requests to not touch working array beyond limit, so that we can make working array size constant. Signed-off-by: Wei Liu <wei.liu2@citrix.com> --- drivers/net/xen-netback/netback.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index

A buggy or malicious frontend should not be able to confuse netback. If we spot anything which is not as it should be then shutdown the device and don''t try to continue with the ring in a potentially hostile state. Well behaved and non-hostile frontends will not be penalised. As well as making the existing checks for such errors fatal also add a new check that ensures that there

Hi Ian, Today i fired up an old VM with a bittorrent client, trying to download some torrents. I seem to be hitting the unlikely case of "xennet: skb rides the rocket: xx slots" and this results in some dropped packets in domU, I don''t see any warnings in dom0. I have added some extra info, but i don''t have enough knowledge if this could/should be prevented from

When I was preparing Xen''s netback driver for upstream one of the things I removed was the zero-copy guest transmit (i.e. netback receive) support. In this mode guest data pages ("foreign pages") were mapped into the backend domain (using Xen grant-table functionality) and placed into the skb''s paged frag list (skb_shinfo(skb)->frags, I hope I am using the right

Hi all I''m hacking on a netback trying to identify whether TLB flushes causes heavy performance penalty on Tx path. The hack is quite nasty (you would not want to know, trust me). Basically what is doesn''t is, 1) alter network protocol to pass along mfns instead of grant references, 2) when the backend sees a new mfn, map it RO and cache it in its own address space. With this

The code to detect fragments in checksum_setup() was missing for IPv4 and too eager for IPv6. (It transpires that Windows seems to send IPv6 packets with a fragment header even if they are not a fragment - i.e. offset is zero, and M bit is not set). Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com>

When counting required slots for skb, netback directly uses DIV_ROUND_UP to get slots required by header data. This is wrong when offset in the page of header data is not zero, and is also inconsistent with following calculation for required slot in netbk_gop_skb. In netbk_gop_skb, required slots are calculated based on offset and len in page of header data. It is possible that required slots

hyperv_net: - set min/max_mtu, per Haiyang, after rndis_filter_device_add virtio_net: - set min/max_mtu - remove virtnet_change_mtu vmxnet3: - set min/max_mtu xen-netback: - min_mtu = 0, max_mtu = 65517 xen-netfront: - min_mtu = 0, max_mtu = 65535 unisys/visor: - clean up defines a little to not clash with network core or add redundat definitions CC: netdev at vger.kernel.org CC:

hyperv_net: - set min/max_mtu, per Haiyang, after rndis_filter_device_add virtio_net: - set min/max_mtu - remove virtnet_change_mtu vmxnet3: - set min/max_mtu xen-netback: - min_mtu = 0, max_mtu = 65517 xen-netfront: - min_mtu = 0, max_mtu = 65535 unisys/visor: - clean up defines a little to not clash with network core or add redundat definitions CC: netdev at vger.kernel.org CC:

When counting required slots for skb, netback directly uses DIV_ROUND_UP to get slots required by header data. This is wrong when offset in the page of header data is not zero, and is also inconsistent with following calculation for required slot in netbk_gop_skb. In netbk_gop_skb, required slots are calculated based on offset and len in page of header data. It is possible that required slots

I''m trying to improve performance on the gpl pv drivers for windows, and am running into trouble with the sg stuff on the tx path. Taking an icmp packet as an example, windows formats the packet like this: sg entry 0 - Ethernet header sg entry 1 - IP header sg entry 2 - payload Those pieces could be anywhere inside the page. In netback.c, it appears that the sg magic happens inside

Hi Keir: These two patches remove the need for netloop by performing the copying in netback and only if it is necessary. The rationale is that most packets will be processed without delay allowing them to be freed without copying at all. So instead of copying every packet destined to dom0 we''ll only copy those that linger longer than a specified amount of time (currently 0.5s). As it

On 02/26/2014 02:32 PM, Qin Chuanyu wrote: > On 2014/2/26 13:53, Jason Wang wrote: >> On 02/25/2014 09:57 PM, Michael S. Tsirkin wrote: >>> On Tue, Feb 25, 2014 at 02:53:58PM +0800, Jason Wang wrote: >>>> We used to stop the handling of tx when the number of pending DMAs >>>> exceeds VHOST_MAX_PEND. This is used to reduce the memory occupation

On 02/26/2014 02:32 PM, Qin Chuanyu wrote: > On 2014/2/26 13:53, Jason Wang wrote: >> On 02/25/2014 09:57 PM, Michael S. Tsirkin wrote: >>> On Tue, Feb 25, 2014 at 02:53:58PM +0800, Jason Wang wrote: >>>> We used to stop the handling of tx when the number of pending DMAs >>>> exceeds VHOST_MAX_PEND. This is used to reduce the memory occupation

This dependence is undesirable and logically incorrect. It''s undesirable because Xen network protocol should not depend on a OS-specific constant. It''s incorrect because the ring slots required doesn''t correspond to the number of frags a SKB has (consider compound page frags). This patch removes this dependence by correctly counting the ring slots required.

VM traffic is already limited by a throughput limit, but there is no control over the maximum packet per second (PPS). In DDOS attack the major issue is rather PPS than throughput. With provider offering more bandwidth to VMs, it becames easy to coordinate a massive attack using VMs. Example: 100Mbits ~ 200kpps using 64B packets. This patch provides a new option to limit VMs maximum packets per

Instead of mixing printk and pr_<level> forms, just use pr_<level> Miscellaneous changes around these conversions: Add a missing newline to avoid message interleaving, coalesce formats, reflow modified lines to 80 columns. Signed-off-by: Joe Perches <joe at perches.com> --- drivers/net/xen-netback/netback.c | 7 +++---- drivers/net/xen-netfront.c | 28

Instead of mixing printk and pr_<level> forms, just use pr_<level> Miscellaneous changes around these conversions: Add a missing newline to avoid message interleaving, coalesce formats, reflow modified lines to 80 columns. Signed-off-by: Joe Perches <joe at perches.com> --- drivers/net/xen-netback/netback.c | 7 +++---- drivers/net/xen-netfront.c | 28

Instead of mixing printk and pr_<level> forms, just use pr_<level> Miscellaneous changes around these conversions: Add a missing newline to avoid message interleaving, coalesce formats, reflow modified lines to 80 columns. Signed-off-by: Joe Perches <joe at perches.com> --- drivers/net/xen-netback/netback.c | 7 +++---- drivers/net/xen-netfront.c | 28