stable inclusion
from stable-v5.10.88
commit d31b3379179d64724d3bbfa87bd4ada94e3237de
bugzilla: 186058 https://gitee.com/openeuler/kernel/issues/I4QW6A

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d31b3379179d64724d3bbfa87bd4ada94e3237de

--------------------------------

commit b27d4795 upstream.

The Xen netfront driver is still vulnerable for an attack via excessive
number of events sent by the backend. Fix that by using lateeoi event
channels.

For being able to detect the case of no rx responses being added while
the carrier is down a new lock is needed in order to update and test
rsp_cons and the number of seen unconsumed responses atomically.

This is part of XSA-391
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NJan Beulich <jbeulich@suse.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-v5.10.83
commit 1c5f722a8fdf19d383112fb701525e1b6870d8ca
bugzilla: 185879 https://gitee.com/openeuler/kernel/issues/I4QUVG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1c5f722a8fdf19d383112fb701525e1b6870d8ca

--------------------------------

commit a884daa6 upstream.

Today netfront will trust the backend to send only sane response data.
In order to avoid privilege escalations or crashes in case of malicious
backends verify the data to be within expected limits. Especially make
sure that the response always references an outstanding request.

Note that only the tx queue needs special id handling, as for the rx
queue the id is equal to the index in the ring page.

Introduce a new indicator for the device whether it is broken and let
the device stop working when it is set. Set this indicator in case the
backend sets any weird data.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NJan Beulich <jbeulich@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-v5.10.83
commit 334b0f278761a65718324137e87efe722d536700
bugzilla: 185879 https://gitee.com/openeuler/kernel/issues/I4QUVG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=334b0f278761a65718324137e87efe722d536700

--------------------------------

commit 21631d2d upstream.

The tx_skb_freelist elements are in a single linked list with the
request id used as link reference. The per element link field is in a
union with the skb pointer of an in use request.

Move the link reference out of the union in order to enable a later
reuse of it for requests which need a populated skb pointer.

Rename add_id_to_freelist() and get_id_from_freelist() to
add_id_to_list() and get_id_from_list() in order to prepare using
those for other lists as well. Define ~0 as value to indicate the end
of a list and place that value into the link for a request not being
on the list.

When freeing a skb zero the skb pointer in the request. Use a NULL
value of the skb pointer instead of skb_entry_is_link() for deciding
whether a request has a skb linked to it.

Remove skb_entry_set_link() and open code it instead as it is really
trivial now.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-v5.10.83
commit e17ee047eea7122c1d4196ed39032e517dad4152
bugzilla: 185879 https://gitee.com/openeuler/kernel/issues/I4QUVG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e17ee047eea7122c1d4196ed39032e517dad4152

--------------------------------

commit 162081ec upstream.

In order to avoid a malicious backend being able to influence the local
processing of a request build the request locally first and then copy
it to the ring page. Any reading from the request influencing the
processing in the frontend needs to be done on the local instance.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NJan Beulich <jbeulich@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-v5.10.83
commit f5e493709800243181e268ddbfae949d2cc37f0b
bugzilla: 185879 https://gitee.com/openeuler/kernel/issues/I4QUVG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f5e493709800243181e268ddbfae949d2cc37f0b

--------------------------------

commit 8446066b upstream.

In order to avoid problems in case the backend is modifying a response
on the ring page while the frontend has already seen it, just read the
response into a local buffer in one go and then operate on that buffer
only.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NJan Beulich <jbeulich@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-5.10.80
commit 0e86b727a94fc4d532a166c449ab96e3b15015ea
bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0e86b727a94fc4d532a166c449ab96e3b15015ea

--------------------------------

[ Upstream commit 042b2046 ]

The tx queues are not stopped during the live migration. As a result, the
ndo_start_xmit() may access netfront_info->queues which is freed by
talk_to_netback()->xennet_destroy_queues().

This patch is to netif_device_detach() at the beginning of xen-netfront
resuming, and netif_device_attach() at the end of resuming.

     CPU A                                CPU B

 talk_to_netback()
 -> if (info->queues)
        xennet_destroy_queues(info);
    to free netfront_info->queues

                                        xennet_start_xmit()
                                        to access netfront_info->queues

  -> err = xennet_create_queues(info, &num_queues);

The idea is borrowed from virtio-net.

Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: NDongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-throughSigned-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>

Now that BPF program/link management is centralized in generic net_device
code, kernel code never queries program id from drivers, so
XDP_QUERY_PROG/XDP_QUERY_PROG_HW commands are unnecessary.

This patch removes all the implementations of those commands in kernel, along
the xdp_attachment_query().

This patch was compile-tested on allyesconfig.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722064603.3350758-10-andriin@fb.com

There's a potential race in xennet_remove(); this is what the driver is
doing upon unregistering a network device:

  1. state = read bus state
  2. if state is not "Closed":
  3.    request to set state to "Closing"
  4.    wait for state to be set to "Closing"
  5.    request to set state to "Closed"
  6.    wait for state to be set to "Closed"

If the state changes to "Closed" immediately after step 1 we are stuck
forever in step 4, because the state will never go back from "Closed" to
"Closing".

Make sure to check also for state == "Closed" in step 4 to prevent the
deadlock.

Also add a 5 sec timeout any time we wait for the bus state to change,
to avoid getting stuck forever in wait_event().
Signed-off-by: NAndrea Righi <andrea.righi@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This adds kernel TX timestamps to the xen-netfront driver.  Tested with chrony
on an AWS EC2 instance.
Signed-off-by: NDaniel Drown <dan-netdev@drown.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The variable act is being initialized with a value that is
never read and it is being updated later with a new value. The
initialization is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The patch adds a basic XDP processing to xen-netfront driver.

We ran an XDP program for an RX response received from netback
driver. Also we request xen-netback to adjust data offset for
bpf_xdp_adjust_head() header space for custom headers.

synchronization between frontend and backend parts is done
by using xenbus state switching:
Reconfiguring -> Reconfigured- > Connected

UDP packets drop rate using xdp program is around 310 kpps
using ./pktgen_sample04_many_flows.sh and 160 kpps without the patch.
Signed-off-by: NDenis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

xennet_fill_frags() uses ~0U as return value when the sk_buff is not able
to cache extra fragments. This is incorrect because the return type of
xennet_fill_frags() is RING_IDX and 0xffffffff is an expected value for
ring buffer index.

In the situation when the rsp_cons is approaching 0xffffffff, the return
value of xennet_fill_frags() may become 0xffffffff which xennet_poll() (the
caller) would regard as error. As a result, queue->rx.rsp_cons is set
incorrectly because it is updated only when there is error. If there is no
error, xennet_poll() would be responsible to update queue->rx.rsp_cons.
Finally, queue->rx.rsp_cons would point to the rx ring buffer entries whose
queue->rx_skbs[i] and queue->grant_rx_ref[i] are already cleared to NULL.
This leads to NULL pointer access in the next iteration to process rx ring
buffer entries.

The symptom is similar to the one fixed in
commit 00b36850 ("xen-netfront: do not assume sk_buff_head list is
empty in error handling").

This patch changes the return type of xennet_fill_frags() to indicate
whether it is successful or failed. The queue->rx.rsp_cons will be
always updated inside this function.

Fixes: ad4f15dc ("xen/netfront: don't bug in case of too many frags")
Signed-off-by: NDongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When skb_shinfo(skb) is not able to cache extra fragment (that is,
skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS), xennet_fill_frags() assumes
the sk_buff_head list is already empty. As a result, cons is increased only
by 1 and returns to error handling path in xennet_poll().

However, if the sk_buff_head list is not empty, queue->rx.rsp_cons may be
set incorrectly. That is, queue->rx.rsp_cons would point to the rx ring
buffer entries whose queue->rx_skbs[i] and queue->grant_rx_ref[i] are
already cleared to NULL. This leads to NULL pointer access in the next
iteration to process rx ring buffer entries.

Below is how xennet_poll() does error handling. All remaining entries in
tmpq are accounted to queue->rx.rsp_cons without assuming how many
outstanding skbs are remained in the list.

 985 static int xennet_poll(struct napi_struct *napi, int budget)
... ...
1032           if (unlikely(xennet_set_skb_gso(skb, gso))) {
1033                   __skb_queue_head(&tmpq, skb);
1034                   queue->rx.rsp_cons += skb_queue_len(&tmpq);
1035                   goto err;
1036           }

It is better to always have the error handling in the same way.

Fixes: ad4f15dc ("xen/netfront: don't bug in case of too many frags")
Signed-off-by: NDongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use accessor functions for skb fragment's page_offset instead
of direct references, in preparation for bvec conversion.
Signed-off-by: NJonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warning:

drivers/net/xen-netfront.c: In function ‘netback_changed’:
drivers/net/xen-netfront.c:2038:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (dev->state == XenbusStateClosed)
      ^
drivers/net/xen-netfront.c:2041:2: note: here
  case XenbusStateClosing:
  ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

Notice that, in this particular case, the code comment is modified
in accordance with what GCC is expecting to find.

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>

In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warning:

drivers/net/xen-netfront.c: In function ‘netback_changed’:
drivers/net/xen-netfront.c:2038:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (dev->state == XenbusStateClosed)
      ^
drivers/net/xen-netfront.c:2041:2: note: here
  case XenbusStateClosing:
  ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

Notice that, in this particular case, the code comment is modified
in accordance with what GCC is expecting to find.

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After the previous patch, all the callers of ndo_select_queue()
provide as a 'fallback' argument netdev_pick_tx.
The only exceptions are nested calls to ndo_select_queue(),
which pass down the 'fallback' available in the current scope
- still netdev_pick_tx.

We can drop such argument and replace fallback() invocation with
netdev_pick_tx(). This avoids an indirect call per xmit packet
in some scenarios (TCP syn, UDP unconnected, XDP generic, pktgen)
with device drivers implementing such ndo. It also clean the code
a bit.

Tested with ixgbe and CONFIG_FCOE=m

With pktgen using queue xmit:
threads		vanilla 	patched
		(kpps)		(kpps)
1		2334		2428
2		4166		4278
4		7895		8100

 v1 -> v2:
 - rebased after helper's name change
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

At least old Xen net backends seem to send frags with no real data
sometimes. In case such a fragment happens to occur with the frag limit
already reached the frontend will BUG currently even if this situation
is easily recoverable.

Modify the BUG_ON() condition accordingly.
Tested-by: NDietmar Hahn <dietmar.hahn@ts.fujitsu.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RING_PUSH_REQUESTS_AND_CHECK_NOTIFY is already able to make sure backend sees
requests before req_prod is updated.
Signed-off-by: NJacob Wen <jian.w.wen@oracle.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 57f230ab ("xen/netfront: raise max number of slots in
xennet_get_responses()") raised the max number of allowed slots by one.
This seems to be problematic in some configurations with netback using
a larger MAX_SKB_FRAGS value (e.g. old Linux kernel with MAX_SKB_FRAGS
defined as 18 instead of nowadays 17).

Instead of BUG_ON() in this case just fall back to retransmission.

Fixes: 57f230ab ("xen/netfront: raise max number of slots in xennet_get_responses()")
Cc: stable@vger.kernel.org
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 822fb18a ("xen-netfront: wait xenbus state change when load
module manually") added a new wait queue to wait on for a state change
when the module is loaded manually. Unfortunately there is no wakeup
anywhere to stop that waiting.

Instead of introducing a new wait queue rename the existing
module_unload_q to module_wq and use it for both purposes (loading and
unloading).

As any state change of the backend might be intended to stop waiting
do the wake_up_all() in any case when netback_changed() is called.

Fixes: 822fb18a ("xen-netfront: wait xenbus state change when load module manually")
Cc: <stable@vger.kernel.org> #4.18
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is a call trace generated after commit 2d408c0d(
xen-netfront: fix queue name setting). There is no 'device/vif/xx-q0-tx' file found
under /proc/irq/xx/.

This patch only picks up device type and id as its name.

With the patch, now /proc/interrupts looks like below and the warning message gone:
 70:         21          0          0          0   xen-dyn    -event     vif0-q0-tx
 71:         15          0          0          0   xen-dyn    -event     vif0-q0-rx
 72:         14          0          0          0   xen-dyn    -event     vif0-q1-tx
 73:         33          0          0          0   xen-dyn    -event     vif0-q1-rx
 74:         12          0          0          0   xen-dyn    -event     vif0-q2-tx
 75:         24          0          0          0   xen-dyn    -event     vif0-q2-rx
 76:         19          0          0          0   xen-dyn    -event     vif0-q3-tx
 77:         21          0          0          0   xen-dyn    -event     vif0-q3-rx

Below is call trace information without this patch:

name 'device/vif/0-q0-tx'
WARNING: CPU: 2 PID: 37 at fs/proc/generic.c:174 __xlate_proc_name+0x85/0xa0
RIP: 0010:__xlate_proc_name+0x85/0xa0
RSP: 0018:ffffb85c40473c18 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000000006
RDX: 0000000000000007 RSI: 0000000000000096 RDI: ffff984c7f516930
RBP: ffffb85c40473cb8 R08: 000000000000002c R09: 0000000000000229
R10: 0000000000000000 R11: 0000000000000001 R12: ffffb85c40473c98
R13: ffffb85c40473cb8 R14: ffffb85c40473c50 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff984c7f500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f69b6899038 CR3: 000000001c20a006 CR4: 00000000001606e0
Call Trace:
__proc_create+0x45/0x230
? snprintf+0x49/0x60
proc_mkdir_data+0x35/0x90
register_handler_proc+0xef/0x110
? proc_register+0xfc/0x110
? proc_create_data+0x70/0xb0
__setup_irq+0x39b/0x660
? request_threaded_irq+0xad/0x160
request_threaded_irq+0xf5/0x160
? xennet_tx_buf_gc+0x1d0/0x1d0 [xen_netfront]
bind_evtchn_to_irqhandler+0x3d/0x70
? xenbus_alloc_evtchn+0x41/0xa0
netback_changed+0xa46/0xcda [xen_netfront]
? find_watch+0x40/0x40
xenwatch_thread+0xc5/0x160
? finish_wait+0x80/0x80
kthread+0x112/0x130
? kthread_create_worker_on_cpu+0x70/0x70
ret_from_fork+0x35/0x40
Code: 81 5c 00 48 85 c0 75 cc 5b 49 89 2e 31 c0 5d 4d 89 3c 24 41 5c 41 5d 41 5e 41 5f c3 4c 89 ee 48 c7 c7 40 4f 0e b4 e8 65 ea d8 ff <0f> 0b b8 fe ff ff ff 5b 5d 41 5c 41 5d 41 5e 41 5f c3 66 0f 1f
---[ end trace 650e5561b0caab3a ]---
Signed-off-by: NXiao Liang <xiliang@redhat.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

skb_shinfo() can change when calling __pskb_pull_tail(): Don't cache
its return value.

Cc: stable@vger.kernel.org
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When loading module manually, after call xenbus_switch_state to initializes
the state of the netfront device, the driver state did not change so fast
that may lead no dev created in latest kernel. This patch adds wait to make
sure xenbus knows the driver is not in closed/unknown state.

Current state:
[vm]# ethtool eth0
Settings for eth0:
	Link detected: yes
[vm]# modprobe -r xen_netfront
[vm]# modprobe  xen_netfront
[vm]# ethtool eth0
Settings for eth0:
Cannot get device settings: No such device
Cannot get wake-on-lan settings: No such device
Cannot get message level: No such device
Cannot get link status: No such device
No data available

With the patch installed.
[vm]# ethtool eth0
Settings for eth0:
	Link detected: yes
[vm]# modprobe -r xen_netfront
[vm]# modprobe xen_netfront
[vm]# ethtool eth0
Settings for eth0:
	Link detected: yes
Signed-off-by: NXiao Liang <xiliang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit f599c64f ("xen-netfront: Fix race between device setup and
open") changed the initialization order: xennet_create_queues() now
happens before we do register_netdev() so using netdev->name in
xennet_init_queue() is incorrect, we end up with the following in
/proc/interrupts:

 60:        139          0   xen-dyn    -event     eth%d-q0-tx
 61:        265          0   xen-dyn    -event     eth%d-q0-rx
 62:        234          0   xen-dyn    -event     eth%d-q1-tx
 63:          1          0   xen-dyn    -event     eth%d-q1-rx

and this looks ugly. Actually, using early netdev name (even when it's
already set) is also not ideal: nowadays we tend to rename eth devices
and queue name may end up not corresponding to the netdev name.

Use nodename from xenbus device for queue naming: this can't change in VM's
lifetime. Now /proc/interrupts looks like

 62:        202          0   xen-dyn    -event     device/vif/0-q0-tx
 63:        317          0   xen-dyn    -event     device/vif/0-q0-rx
 64:        262          0   xen-dyn    -event     device/vif/0-q1-tx
 65:         17          0   xen-dyn    -event     device/vif/0-q1-rx

Fixes: f599c64f ("xen-netfront: Fix race between device setup and open")
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: NRoss Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch makes it so that instead of passing a void pointer as the
accel_priv we instead pass a net_device pointer as sb_dev. Making this
change allows us to pass the subordinate device through to the fallback
function eventually so that we can keep the actual code in the
ndo_select_queue call as focused on possible on the exception cases.
Signed-off-by: NAlexander Duyck <alexander.h.duyck@intel.com>
Tested-by: NAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Update the features after calling register_netdev() otherwise the
device features are not set up correctly and it not possible to change
the MTU of the device. After this change, the features reported by
ethtool match the device's features before the commit which introduced
the issue and it is possible to change the device's MTU.

Fixes: f599c64f ("xen-netfront: Fix race between device setup and open")
Reported-by: NLiam Shepherd <liam@dancer.es>
Signed-off-by: NRoss Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes: f599c64f ("xen-netfront: Fix race between device setup and open")
Reported-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NRoss Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The max number of slots used in xennet_get_responses() is set to
MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD).

In old kernel-xen MAX_SKB_FRAGS was 18, while nowadays it is 17. This
difference is resulting in frequent messages "too many slots" and a
reduced network throughput for some workloads (factor 10 below that of
a kernel-xen based guest).

Replacing MAX_SKB_FRAGS by XEN_NETIF_NR_SLOTS_MIN for calculation of
the max number of slots to use solves that problem (tests showed no
more messages "too many slots" and throughput was as high as with the
kernel-xen based guest system).

Replace MAX_SKB_FRAGS-2 by XEN_NETIF_NR_SLOTS_MIN-1 in
netfront_tx_slot_available() for making it clearer what is really being
tested without actually modifying the tested value.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The method ndo_start_xmit() is defined as returning an 'netdev_tx_t',
which is a typedef for an enum type, but the implementation in this
driver returns an 'int'.

Fix this by returning 'netdev_tx_t' in this driver too.
Signed-off-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com>
Reviewed-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>

Prefer the direct use of octal for permissions.

Done with checkpatch -f --types=SYMBOLIC_PERMS --fix-inplace
and some typing.

Miscellanea:

o Whitespace neatening around these conversions.
Signed-off-by: NJoe Perches <joe@perches.com>
Reviewed-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A toolstack may delete the vif frontend and backend xenstore entries
while xen-netfront is in the removal code path.  In that case, the
checks for xenbus_read_driver_state would return XenbusStateUnknown, and
xennet_remove would hang indefinitely.  This hang prevents system
shutdown.

xennet_remove must be able to handle XenbusStateUnknown, and
netback_changed must also wake up the wake_queue for that state as well.

Fixes: 5b5971df ("xen-netfront: remove warning when unloading module")
Signed-off-by: NJason Andryuk <jandryuk@gmail.com>
Cc: Eduardo Otubo <otubo@redhat.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>

When a netfront device is set up it registers a netdev fairly early on,
before it has set up the queues and is actually usable. A userspace tool
like NetworkManager will immediately try to open it and access its state
as soon as it appears. The bug can be reproduced by hotplugging VIFs
until the VM runs out of grant refs. It registers the netdev but fails
to set up any queues (since there are no more grant refs). In the
meantime, NetworkManager opens the device and the kernel crashes trying
to access the queues (of which there are none).

Fix this in two ways:
* For initial setup, register the netdev much later, after the queues
are setup. This avoids the race entirely.
* During a suspend/resume cycle, the frontend reconnects to the backend
and the queues are recreated. It is possible (though highly unlikely) to
race with something opening the device and accessing the queues after
they have been destroyed but before they have been recreated. Extend the
region covered by the rtnl semaphore to protect against this race. There
is a possibility that we fail to recreate the queues so check for this
in the open function.
Signed-off-by: NRoss Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>

When loading the module after unloading it, the network interface would
not be enabled and thus wouldn't have a backend counterpart and unable
to be used by the guest.

The guest would face errors like:

  [root@guest ~]# ethtool -i eth0
  Cannot get driver information: No such device

  [root@guest ~]# ifconfig eth0
  eth0: error fetching interface information: Device not found

This patch initializes the state of the netfront device whenever it is
loaded manually, this state would communicate the netback to create its
device and establish the connection between them.
Signed-off-by: NEduardo Otubo <otubo@redhat.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

v2:
 * Replace busy wait with wait_event()/wake_up_all()
 * Cannot garantee that at the time xennet_remove is called, the
   xen_netback state will not be XenbusStateClosed, so added a
   condition for that
 * There's a small chance for the xen_netback state is
   XenbusStateUnknown by the time the xen_netfront switches to Closed,
   so added a condition for that.

When unloading module xen_netfront from guest, dmesg would output
warning messages like below:

  [  105.236836] xen:grant_table: WARNING: g.e. 0x903 still in use!
  [  105.236839] deferring g.e. 0x903 (pfn 0x35805)

This problem relies on netfront and netback being out of sync. By the time
netfront revokes the g.e.'s netback didn't have enough time to free all of
them, hence displaying the warnings on dmesg.

The trick here is to make netfront to wait until netback frees all the g.e.'s
and only then continue to cleanup for the module removal, and this is done by
manipulating both device states.
Signed-off-by: NEduardo Otubo <otubo@redhat.com>
Acked-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This converts all remaining cases of the old setup_timer() API into using
timer_setup(), where the callback argument is the structure already
holding the struct timer_list. These should have no behavioral changes,
since they just change which pointer is passed into the callback with
the same available pointers after conversion. It handles the following
examples, in addition to some other variations.

Casting from unsigned long:

    void my_callback(unsigned long data)
    {
        struct something *ptr = (struct something *)data;
    ...
    }
    ...
    setup_timer(&ptr->my_timer, my_callback, ptr);

and forced object casts:

    void my_callback(struct something *ptr)
    {
    ...
    }
    ...
    setup_timer(&ptr->my_timer, my_callback, (unsigned long)ptr);

become:

    void my_callback(struct timer_list *t)
    {
        struct something *ptr = from_timer(ptr, t, my_timer);
    ...
    }
    ...
    timer_setup(&ptr->my_timer, my_callback, 0);

Direct function assignments:

    void my_callback(unsigned long data)
    {
        struct something *ptr = (struct something *)data;
    ...
    }
    ...
    ptr->my_timer.function = my_callback;

have a temporary cast added, along with converting the args:

    void my_callback(struct timer_list *t)
    {
        struct something *ptr = from_timer(ptr, t, my_timer);
    ...
    }
    ...
    ptr->my_timer.function = (TIMER_FUNC_TYPE)my_callback;

And finally, callbacks without a data assignment:

    void my_callback(unsigned long data)
    {
    ...
    }
    ...
    setup_timer(&ptr->my_timer, my_callback, 0);

have their argument renamed to verify they're unused during conversion:

    void my_callback(struct timer_list *unused)
    {
    ...
    }
    ...
    timer_setup(&ptr->my_timer, my_callback, 0);

The conversion is done with the following Coccinelle script:

spatch --very-quiet --all-includes --include-headers \
	-I ./arch/x86/include -I ./arch/x86/include/generated \
	-I ./include -I ./arch/x86/include/uapi \
	-I ./arch/x86/include/generated/uapi -I ./include/uapi \
	-I ./include/generated/uapi --include ./include/linux/kconfig.h \
	--dir . \
	--cocci-file ~/src/data/timer_setup.cocci

@fix_address_of@
expression e;
@@

 setup_timer(
-&(e)
+&e
 , ...)

// Update any raw setup_timer() usages that have a NULL callback, but
// would otherwise match change_timer_function_usage, since the latter
// will update all function assignments done in the face of a NULL
// function initialization in setup_timer().
@change_timer_function_usage_NULL@
expression _E;
identifier _timer;
type _cast_data;
@@

(
-setup_timer(&_E->_timer, NULL, _E);
+timer_setup(&_E->_timer, NULL, 0);
|
-setup_timer(&_E->_timer, NULL, (_cast_data)_E);
+timer_setup(&_E->_timer, NULL, 0);
|
-setup_timer(&_E._timer, NULL, &_E);
+timer_setup(&_E._timer, NULL, 0);
|
-setup_timer(&_E._timer, NULL, (_cast_data)&_E);
+timer_setup(&_E._timer, NULL, 0);
)

@change_timer_function_usage@
expression _E;
identifier _timer;
struct timer_list _stl;
identifier _callback;
type _cast_func, _cast_data;
@@

(
-setup_timer(&_E->_timer, _callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, &_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, &_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)&_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)&_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, &_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, &_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)&_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)&_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
 _E->_timer@_stl.function = _callback;
|
 _E->_timer@_stl.function = &_callback;
|
 _E->_timer@_stl.function = (_cast_func)_callback;
|
 _E->_timer@_stl.function = (_cast_func)&_callback;
|
 _E._timer@_stl.function = _callback;
|
 _E._timer@_stl.function = &_callback;
|
 _E._timer@_stl.function = (_cast_func)_callback;
|
 _E._timer@_stl.function = (_cast_func)&_callback;
)

// callback(unsigned long arg)
@change_callback_handle_cast
 depends on change_timer_function_usage@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _origtype;
identifier _origarg;
type _handletype;
identifier _handle;
@@

 void _callback(
-_origtype _origarg
+struct timer_list *t
 )
 {
(
	... when != _origarg
	_handletype *_handle =
-(_handletype *)_origarg;
+from_timer(_handle, t, _timer);
	... when != _origarg
|
	... when != _origarg
	_handletype *_handle =
-(void *)_origarg;
+from_timer(_handle, t, _timer);
	... when != _origarg
|
	... when != _origarg
	_handletype *_handle;
	... when != _handle
	_handle =
-(_handletype *)_origarg;
+from_timer(_handle, t, _timer);
	... when != _origarg
|
	... when != _origarg
	_handletype *_handle;
	... when != _handle
	_handle =
-(void *)_origarg;
+from_timer(_handle, t, _timer);
	... when != _origarg
)
 }

// callback(unsigned long arg) without existing variable
@change_callback_handle_cast_no_arg
 depends on change_timer_function_usage &&
                     !change_callback_handle_cast@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _origtype;
identifier _origarg;
type _handletype;
@@

 void _callback(
-_origtype _origarg
+struct timer_list *t
 )
 {
+	_handletype *_origarg = from_timer(_origarg, t, _timer);
+
	... when != _origarg
-	(_handletype *)_origarg
+	_origarg
	... when != _origarg
 }

// Avoid already converted callbacks.
@match_callback_converted
 depends on change_timer_function_usage &&
            !change_callback_handle_cast &&
	    !change_callback_handle_cast_no_arg@
identifier change_timer_function_usage._callback;
identifier t;
@@

 void _callback(struct timer_list *t)
 { ... }

// callback(struct something *handle)
@change_callback_handle_arg
 depends on change_timer_function_usage &&
	    !match_callback_converted &&
            !change_callback_handle_cast &&
            !change_callback_handle_cast_no_arg@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _handletype;
identifier _handle;
@@

 void _callback(
-_handletype *_handle
+struct timer_list *t
 )
 {
+	_handletype *_handle = from_timer(_handle, t, _timer);
	...
 }

// If change_callback_handle_arg ran on an empty function, remove
// the added handler.
@unchange_callback_handle_arg
 depends on change_timer_function_usage &&
	    change_callback_handle_arg@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _handletype;
identifier _handle;
identifier t;
@@

 void _callback(struct timer_list *t)
 {
-	_handletype *_handle = from_timer(_handle, t, _timer);
 }

// We only want to refactor the setup_timer() data argument if we've found
// the matching callback. This undoes changes in change_timer_function_usage.
@unchange_timer_function_usage
 depends on change_timer_function_usage &&
            !change_callback_handle_cast &&
            !change_callback_handle_cast_no_arg &&
	    !change_callback_handle_arg@
expression change_timer_function_usage._E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type change_timer_function_usage._cast_data;
@@

(
-timer_setup(&_E->_timer, _callback, 0);
+setup_timer(&_E->_timer, _callback, (_cast_data)_E);
|
-timer_setup(&_E._timer, _callback, 0);
+setup_timer(&_E._timer, _callback, (_cast_data)&_E);
)

// If we fixed a callback from a .function assignment, fix the
// assignment cast now.
@change_timer_function_assignment
 depends on change_timer_function_usage &&
            (change_callback_handle_cast ||
             change_callback_handle_cast_no_arg ||
             change_callback_handle_arg)@
expression change_timer_function_usage._E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type _cast_func;
typedef TIMER_FUNC_TYPE;
@@

(
 _E->_timer.function =
-_callback
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E->_timer.function =
-&_callback
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E->_timer.function =
-(_cast_func)_callback;
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E->_timer.function =
-(_cast_func)&_callback
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E._timer.function =
-_callback
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E._timer.function =
-&_callback;
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E._timer.function =
-(_cast_func)_callback
+(TIMER_FUNC_TYPE)_callback
 ;
|
 _E._timer.function =
-(_cast_func)&_callback
+(TIMER_FUNC_TYPE)_callback
 ;
)

// Sometimes timer functions are called directly. Replace matched args.
@change_timer_function_calls
 depends on change_timer_function_usage &&
            (change_callback_handle_cast ||
             change_callback_handle_cast_no_arg ||
             change_callback_handle_arg)@
expression _E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type _cast_data;
@@

 _callback(
(
-(_cast_data)_E
+&_E->_timer
|
-(_cast_data)&_E
+&_E._timer
|
-_E
+&_E->_timer
)
 )

// If a timer has been configured without a data argument, it can be
// converted without regard to the callback argument, since it is unused.
@match_timer_function_unused_data@
expression _E;
identifier _timer;
identifier _callback;
@@

(
-setup_timer(&_E->_timer, _callback, 0);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, 0L);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, 0UL);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0L);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0UL);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0L);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0UL);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0);
+timer_setup(_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0L);
+timer_setup(_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0UL);
+timer_setup(_timer, _callback, 0);
)

@change_callback_unused_data
 depends on match_timer_function_unused_data@
identifier match_timer_function_unused_data._callback;
type _origtype;
identifier _origarg;
@@

 void _callback(
-_origtype _origarg
+struct timer_list *unused
 )
 {
	... when != _origarg
 }
Signed-off-by: NKees Cook <keescook@chromium.org>

RFC791 specifies the minimum MTU to be 68, while xen-net{front|back}
drivers use a minimum value of 0.

When set MTU to 0~67 with xen_net{front|back} driver, the network
will become unreachable immediately, the guest can no longer be pinged.

xen_net{front|back} should not allow the user to set this value which causes
network problems.
Reported-by: NChen Shi <cheshi@redhat.com>
Signed-off-by: NMohammed Gamal <mgamal@redhat.com>
Acked-by: NWei Liu <wei.liu2@citrix.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>

xennet_start_xmit() might copy skb with inappropriate layout
into a fresh one.

Old skb is freed, and at this point it is not a drop, but
a consume. New skb will then be either consumed or dropped.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Unavoidable crashes in netfront_resume() and netback_changed() after a
previous fail in talk_to_netback() (e.g. when we fail to read MAC from
xenstore) were discovered. The failure path in talk_to_netback() does
unregister/free for netdev but we don't reset drvdata and we try accessing
it after resume.

Fix the bug by removing the whole xen device completely with
device_unregister(), this guarantees we won't have any calls into netfront
after a failure.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>