* Re: [PATCH net] vhost: Use kzalloc() to allocate vhost_msg_node
From: Dmitry Vyukov via Virtualization @ 2018-05-07 13:12 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: Kevin Easton, KVM list, netdev, syzkaller-bugs, LKML,
virtualization
In-Reply-To: <20180507155534-mutt-send-email-mst@kernel.org>
On Mon, May 7, 2018 at 3:03 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> On Fri, Apr 27, 2018 at 11:45:02AM -0400, Kevin Easton wrote:
>> The struct vhost_msg within struct vhost_msg_node is copied to userspace,
>> so it should be allocated with kzalloc() to ensure all structure padding
>> is zeroed.
>>
>> Signed-off-by: Kevin Easton <kevin@guarana.org>
>> Reported-by: syzbot+87cfa083e727a224754b@syzkaller.appspotmail.com
>> ---
>> drivers/vhost/vhost.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
>> index f3bd8e9..1b84dcff 100644
>> --- a/drivers/vhost/vhost.c
>> +++ b/drivers/vhost/vhost.c
>> @@ -2339,7 +2339,7 @@ EXPORT_SYMBOL_GPL(vhost_disable_notify);
>> /* Create a new message. */
>> struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
>> {
>> - struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
>> + struct vhost_msg_node *node = kzalloc(sizeof *node, GFP_KERNEL);
>> if (!node)
>> return NULL;
>> node->vq = vq;
>
>
> Let's just init the msg though.
>
> OK it seems this is the best we can do for now,
> we need a new feature bit to fix it for 32 bit
> userspace on 64 bit kernels.
>
> Does the following help?
Hi Michael,
You can ask reporter (syzbot) to test:
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#kmsan-bugs
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index f3bd8e9..58d9aec 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -2342,6 +2342,9 @@ struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
> struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
> if (!node)
> return NULL;
> +
> + /* Make sure all padding within the structure is initialized. */
> + memset(&node->msg, 0, sizeof node->msg);
> node->vq = vq;
> node->msg.type = type;
> return node;
>
> --
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> For more options, visit https://groups.google.com/d/optout.
^ permalink raw reply
* [PATCH net-next v10 0/4] Enable virtio_net to act as a standby for a passthru device
From: Sridhar Samudrala @ 2018-05-07 22:10 UTC (permalink / raw)
To: mst, stephen, davem, netdev, virtualization, virtio-dev,
jesse.brandeburg, alexander.h.duyck, kubakici, sridhar.samudrala,
jasowang, loseweigh, jiri, aaron.f.brown
The main motivation for this patch is to enable cloud service providers
to provide an accelerated datapath to virtio-net enabled VMs in a
transparent manner with no/minimal guest userspace changes. This also
enables hypervisor controlled live migration to be supported with VMs that
have direct attached SR-IOV VF devices.
Patch 1 introduces a new feature bit VIRTIO_NET_F_STANDBY that can be
used by hypervisor to indicate that virtio_net interface should act as
a standby for another device with the same MAC address.
Patch 2 introduces a failover module that provides a generic interface for
paravirtual drivers to listen for netdev register/unregister/link change
events from pci ethernet devices with the same MAC and takeover their
datapath. The notifier and event handling code is based on the existing
netvsc implementation. It provides 2 sets of interfaces to paravirtual
drivers to support 2-netdev(netvsc) and 3-netdev(virtio_net) models.
Patch 3 extends virtio_net to use alternate datapath when available and
registered. When STANDBY feature is enabled, virtio_net driver creates
an additional 'failover' netdev that acts as a master device and controls
2 slave devices. The original virtio_net netdev is registered as
'standby' netdev and a passthru/vf device with the same MAC gets
registered as 'primary' netdev. Both 'standby' and 'failover' netdevs are
associated with the same 'pci' device. The user accesses the network
interface via 'failover' netdev. The 'failover' netdev chooses 'primary'
netdev as default for transmits when it is available with link up and
running.
Patch 4 refactors netvsc to use the registration/notification framework
supported by failover module.
As this patch series is initially focusing on usecases where hypervisor
fully controls the VM networking and the guest is not expected to directly
configure any hardware settings, it doesn't expose all the ndo/ethtool ops
that are supported by virtio_net at this time. To support additional usecases,
it should be possible to enable additional ops later by caching the state
in virtio netdev and replaying when the 'primary' netdev gets registered.
At the time of live migration, the hypervisor needs to unplug the VF device
from the guest on the source host and reset the MAC filter of the VF to
initiate failover of datapath to virtio before starting the migration. After
the migration is completed, the destination hypervisor sets the MAC filter
on the VF and plugs it back to the guest to switch over to VF datapath.
This patch is based on the discussion initiated by Jesse on this thread.
https://marc.info/?l=linux-virtualization&m=151189725224231&w=2
v10:
- Tested live migration with virtio-net/AVF(i40evf) configured in failover
mode while running iperf in background. Tried static ip and dhcp
configurations using 'network' scripts and Network Manager.
- To avoid dhcp requests to be sent over the lower 'standby' and 'primary'
netdevs, ifcfg-xxx scripts for the lower devices can be created.
- Build tested netvsc module.
Updates:
- fix net_failover_open() to update failover CARRIER correctly based on
standby and primary states.
- fix net_failover_handle_frame() to handle frames received on standby
when primary is present.
- replace netdev_upper_dev_link with netdev_master_upper_dev_link and
handle lower dev state changes.
- fix net_failver_create() and net_failover_register() interfaces to
use ERR_PTR and avoid arg **
- disable setting mac address when virtio-net in STANDBY mode
- document exported symbols
- added entry to MAINTAINERS file
v9:
Select NET_FAILOVER automatically when VIRTIO_NET/HYPERV_NET
are enabled. (stephen)
v8:
- Made the failover managment routines more robust by updating the feature
bits/other fields in the failover netdev when slave netdevs are
registered/unregistered. (mst)
- added support for handling vlans.
- Limited the changes in netvsc to only use the notifier/event/lookups
from the failover module. The slave register/unregister/link-change
handlers are only updated to use the getbymac routine to get the
upper netdev. There is no change in their functionality. (stephen)
- renamed structs/function/file names to use net_failover prefix. (mst)
v7
- Rename 'bypass/active/backup' terminology with 'failover/primary/standy'
(jiri, mst)
- re-arranged dev_open() and dev_set_mtu() calls in the register routines
so that they don't get called for 2-netdev model. (stephen)
- fixed select_queue() routine to do queue selection based on VF if it is
registered as primary. (stephen)
- minor bugfixes
v6 RFC:
Simplified virtio_net changes by moving all the ndo_ops of the
bypass_netdev and create/destroy of bypass_netdev to 'bypass' module.
avoided 2 phase registration(driver + instances).
introduced IFF_BYPASS/IFF_BYPASS_SLAVE dev->priv_flags
replaced mutex with a spinlock
v5 RFC:
Based on Jiri's comments, moved the common functionality to a 'bypass'
module so that the same notifier and event handlers to handle child
register/unregister/link change events can be shared between virtio_net
and netvsc.
Improved error handling based on Siwei's comments.
v4:
- Based on the review comments on the v3 version of the RFC patch and
Jakub's suggestion for the naming issue with 3 netdev solution,
proposed 3 netdev in-driver bonding solution for virtio-net.
v3 RFC:
- Introduced 3 netdev model and pointed out a couple of issues with
that model and proposed 2 netdev model to avoid these issues.
- Removed broadcast/multicast optimization and only use virtio as
backup path when VF is unplugged.
v2 RFC:
- Changed VIRTIO_NET_F_MASTER to VIRTIO_NET_F_BACKUP (mst)
- made a small change to the virtio-net xmit path to only use VF datapath
for unicasts. Broadcasts/multicasts use virtio datapath. This avoids
east-west broadcasts to go over the PCI link.
- added suppport for the feature bit in qemu
Sridhar Samudrala (4):
virtio_net: Introduce VIRTIO_NET_F_STANDBY feature bit
net: Introduce generic failover module
virtio_net: Extend virtio to use VF datapath when available
netvsc: refactor notifier/event handling code to use the failover
framework
MAINTAINERS | 7 +
drivers/net/Kconfig | 1 +
drivers/net/hyperv/Kconfig | 1 +
drivers/net/hyperv/hyperv_net.h | 2 +
drivers/net/hyperv/netvsc_drv.c | 134 +----
drivers/net/virtio_net.c | 40 +-
include/linux/netdevice.h | 16 +
include/net/net_failover.h | 52 ++
include/uapi/linux/virtio_net.h | 3 +
net/Kconfig | 10 +
net/core/Makefile | 1 +
net/core/net_failover.c | 1044 +++++++++++++++++++++++++++++++++++++++
12 files changed, 1198 insertions(+), 113 deletions(-)
create mode 100644 include/net/net_failover.h
create mode 100644 net/core/net_failover.c
--
2.14.3
^ permalink raw reply
* [PATCH net-next v10 1/4] virtio_net: Introduce VIRTIO_NET_F_STANDBY feature bit
From: Sridhar Samudrala @ 2018-05-07 22:10 UTC (permalink / raw)
To: mst, stephen, davem, netdev, virtualization, virtio-dev,
jesse.brandeburg, alexander.h.duyck, kubakici, sridhar.samudrala,
jasowang, loseweigh, jiri, aaron.f.brown
In-Reply-To: <1525731046-10989-1-git-send-email-sridhar.samudrala@intel.com>
This feature bit can be used by hypervisor to indicate virtio_net device to
act as a standby for another device with the same MAC address.
VIRTIO_NET_F_STANDBY is defined as bit 62 as it is a device feature bit.
Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
---
drivers/net/virtio_net.c | 2 +-
include/uapi/linux/virtio_net.h | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f34794a76c4d..213fddc70fd0 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2999,7 +2999,7 @@ static struct virtio_device_id id_table[] = {
VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, \
VIRTIO_NET_F_CTRL_MAC_ADDR, \
VIRTIO_NET_F_MTU, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, \
- VIRTIO_NET_F_SPEED_DUPLEX
+ VIRTIO_NET_F_SPEED_DUPLEX, VIRTIO_NET_F_STANDBY
static unsigned int features[] = {
VIRTNET_FEATURES,
diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index 5de6ed37695b..a3715a3224c1 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -57,6 +57,9 @@
* Steering */
#define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */
+#define VIRTIO_NET_F_STANDBY 62 /* Act as standby for another device
+ * with the same MAC.
+ */
#define VIRTIO_NET_F_SPEED_DUPLEX 63 /* Device set linkspeed and duplex */
#ifndef VIRTIO_NET_NO_LEGACY
--
2.14.3
^ permalink raw reply related
* [PATCH net-next v10 2/4] net: Introduce generic failover module
From: Sridhar Samudrala @ 2018-05-07 22:10 UTC (permalink / raw)
To: mst, stephen, davem, netdev, virtualization, virtio-dev,
jesse.brandeburg, alexander.h.duyck, kubakici, sridhar.samudrala,
jasowang, loseweigh, jiri, aaron.f.brown
In-Reply-To: <1525731046-10989-1-git-send-email-sridhar.samudrala@intel.com>
This provides a generic interface for paravirtual drivers to listen
for netdev register/unregister/link change events from pci ethernet
devices with the same MAC and takeover their datapath. The notifier and
event handling code is based on the existing netvsc implementation.
It exposes 2 sets of interfaces to the paravirtual drivers.
1. For paravirtual drivers like virtio_net that use 3 netdev model, the
the failover module provides interfaces to create/destroy additional
master netdev and all the slave events are managed internally.
net_failover_create()
net_failover_destroy()
A failover netdev is created that acts a master device and controls 2
slave devices. The original virtio_net netdev is registered as 'standby'
netdev and a passthru/vf device with the same MAC gets registered as
'primary' netdev. Both 'standby' and 'failover' netdevs are associated
with the same 'pci' device. The user accesses the network interface via
'failover' netdev. The 'failover' netdev chooses 'primary' netdev as
default for transmits when it is available with link up and running.
2. For existing netvsc driver that uses 2 netdev model, no master netdev
is created. The paravirtual driver registers each instance of netvsc
as a 'failover' netdev along with a set of ops to manage the slave
events. There is no 'standby' netdev in this model. A passthru/vf device
with the same MAC gets registered as 'primary' netdev.
net_failover_register()
net_failover_unregister()
Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
---
MAINTAINERS | 7 +
include/linux/netdevice.h | 16 +
include/net/net_failover.h | 52 +++
net/Kconfig | 10 +
net/core/Makefile | 1 +
net/core/net_failover.c | 1044 ++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 1130 insertions(+)
create mode 100644 include/net/net_failover.h
create mode 100644 net/core/net_failover.c
diff --git a/MAINTAINERS b/MAINTAINERS
index ebe0b9ed7805..83cbd99d8efa 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9638,6 +9638,13 @@ S: Maintained
F: Documentation/hwmon/nct6775
F: drivers/hwmon/nct6775.c
+NET_FAILOVER MODULE
+M: Sridhar Samudrala <sridhar.samudrala@intel.com>
+L: netdev@vger.kernel.org
+S: Supported
+F: net/core/net_failover.c
+F: include/net/net_failover.h
+
NETEFFECT IWARP RNIC DRIVER (IW_NES)
M: Faisal Latif <faisal.latif@intel.com>
L: linux-rdma@vger.kernel.org
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 46dcb5f7522f..4fff9b5d079e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1421,6 +1421,8 @@ struct net_device_ops {
* entity (i.e. the master device for bridged veth)
* @IFF_MACSEC: device is a MACsec device
* @IFF_NO_RX_HANDLER: device doesn't support the rx_handler hook
+ * @IFF_FAILOVER: device is a failover master device
+ * @IFF_FAILOVER_SLAVE: device is lower dev of a failover master device
*/
enum netdev_priv_flags {
IFF_802_1Q_VLAN = 1<<0,
@@ -1450,6 +1452,8 @@ enum netdev_priv_flags {
IFF_PHONY_HEADROOM = 1<<24,
IFF_MACSEC = 1<<25,
IFF_NO_RX_HANDLER = 1<<26,
+ IFF_FAILOVER = 1<<27,
+ IFF_FAILOVER_SLAVE = 1<<28,
};
#define IFF_802_1Q_VLAN IFF_802_1Q_VLAN
@@ -1478,6 +1482,8 @@ enum netdev_priv_flags {
#define IFF_RXFH_CONFIGURED IFF_RXFH_CONFIGURED
#define IFF_MACSEC IFF_MACSEC
#define IFF_NO_RX_HANDLER IFF_NO_RX_HANDLER
+#define IFF_FAILOVER IFF_FAILOVER
+#define IFF_FAILOVER_SLAVE IFF_FAILOVER_SLAVE
/**
* struct net_device - The DEVICE structure.
@@ -4320,6 +4326,16 @@ static inline bool netif_is_rxfh_configured(const struct net_device *dev)
return dev->priv_flags & IFF_RXFH_CONFIGURED;
}
+static inline bool netif_is_failover(const struct net_device *dev)
+{
+ return dev->priv_flags & IFF_FAILOVER;
+}
+
+static inline bool netif_is_failover_slave(const struct net_device *dev)
+{
+ return dev->priv_flags & IFF_FAILOVER_SLAVE;
+}
+
/* This device needs to keep skb dst for qdisc enqueue or ndo_start_xmit() */
static inline void netif_keep_dst(struct net_device *dev)
{
diff --git a/include/net/net_failover.h b/include/net/net_failover.h
new file mode 100644
index 000000000000..221c2aff7531
--- /dev/null
+++ b/include/net/net_failover.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2018, Intel Corporation. */
+
+#ifndef _NET_FAILOVER_H
+#define _NET_FAILOVER_H
+
+#include <linux/netdevice.h>
+
+struct net_failover_ops {
+ int (*slave_register)(struct net_device *slave_dev,
+ struct net_device *failover_dev);
+ int (*slave_unregister)(struct net_device *slave_dev,
+ struct net_device *failover_dev);
+ int (*slave_link_change)(struct net_device *slave_dev,
+ struct net_device *failover_dev);
+};
+
+struct net_failover {
+ struct list_head list;
+ struct net_device __rcu *failover_dev;
+ struct net_failover_ops __rcu *ops;
+};
+
+/* failover state */
+struct net_failover_info {
+ /* primary netdev with same MAC */
+ struct net_device __rcu *primary_dev;
+
+ /* standby netdev */
+ struct net_device __rcu *standby_dev;
+
+ /* primary netdev stats */
+ struct rtnl_link_stats64 primary_stats;
+
+ /* standby netdev stats */
+ struct rtnl_link_stats64 standby_stats;
+
+ /* aggregated stats */
+ struct rtnl_link_stats64 failover_stats;
+
+ /* spinlock while updating stats */
+ spinlock_t stats_lock;
+};
+
+struct net_failover *net_failover_create(struct net_device *standby_dev);
+void net_failover_destroy(struct net_failover *failover);
+struct net_failover *net_failover_register(struct net_device *dev,
+ struct net_failover_ops *ops);
+void net_failover_unregister(struct net_failover *failover);
+int net_failover_slave_unregister(struct net_device *slave_dev);
+
+#endif /* _NET_FAILOVER_H */
diff --git a/net/Kconfig b/net/Kconfig
index b62089fb1332..0540856676de 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -429,6 +429,16 @@ config MAY_USE_DEVLINK
config PAGE_POOL
bool
+config NET_FAILOVER
+ tristate "Failover interface"
+ default m
+ help
+ This provides a generic interface for paravirtual drivers to listen
+ for netdev register/unregister/link change events from pci ethernet
+ devices with the same MAC and takeover their datapath. This also
+ enables live migration of a VM with direct attached VF by failing
+ over to the paravirtual datapath when the VF is unplugged.
+
endif # if NET
# Used by archs to tell that they support BPF JIT compiler plus which flavour.
diff --git a/net/core/Makefile b/net/core/Makefile
index 7080417f8bc8..283ed9b0e581 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -31,3 +31,4 @@ obj-$(CONFIG_DST_CACHE) += dst_cache.o
obj-$(CONFIG_HWBM) += hwbm.o
obj-$(CONFIG_NET_DEVLINK) += devlink.o
obj-$(CONFIG_GRO_CELLS) += gro_cells.o
+obj-$(CONFIG_NET_FAILOVER) += net_failover.o
diff --git a/net/core/net_failover.c b/net/core/net_failover.c
new file mode 100644
index 000000000000..8d60e74e3034
--- /dev/null
+++ b/net/core/net_failover.c
@@ -0,0 +1,1044 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2018, Intel Corporation. */
+
+/* A common module to handle registrations and notifications for paravirtual
+ * drivers to enable accelerated datapath and support VF live migration.
+ *
+ * The notifier and event handling code is based on netvsc driver and failover
+ * netdev management routines are based on bond/team driver.
+ *
+ */
+
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/ethtool.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/netdevice.h>
+#include <linux/netpoll.h>
+#include <linux/rtnetlink.h>
+#include <linux/if_vlan.h>
+#include <linux/pci.h>
+#include <net/sch_generic.h>
+#include <uapi/linux/if_arp.h>
+#include <net/net_failover.h>
+
+static LIST_HEAD(net_failover_list);
+static DEFINE_SPINLOCK(net_failover_lock);
+
+static bool net_failover_xmit_ready(struct net_device *dev)
+{
+ return netif_running(dev) && netif_carrier_ok(dev);
+}
+
+static int net_failover_open(struct net_device *dev)
+{
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *primary_dev, *standby_dev;
+ int err;
+
+ primary_dev = rtnl_dereference(nfo_info->primary_dev);
+ if (primary_dev) {
+ err = dev_open(primary_dev);
+ if (err)
+ goto err_primary_open;
+ }
+
+ standby_dev = rtnl_dereference(nfo_info->standby_dev);
+ if (standby_dev) {
+ err = dev_open(standby_dev);
+ if (err)
+ goto err_standby_open;
+ }
+
+ if ((primary_dev && net_failover_xmit_ready(primary_dev)) ||
+ (standby_dev && net_failover_xmit_ready(standby_dev))) {
+ netif_carrier_on(dev);
+ netif_tx_wake_all_queues(dev);
+ }
+
+ return 0;
+
+err_standby_open:
+ dev_close(primary_dev);
+err_primary_open:
+ netif_tx_disable(dev);
+ return err;
+}
+
+static int net_failover_close(struct net_device *dev)
+{
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *slave_dev;
+
+ netif_tx_disable(dev);
+
+ slave_dev = rtnl_dereference(nfo_info->primary_dev);
+ if (slave_dev)
+ dev_close(slave_dev);
+
+ slave_dev = rtnl_dereference(nfo_info->standby_dev);
+ if (slave_dev)
+ dev_close(slave_dev);
+
+ return 0;
+}
+
+static netdev_tx_t net_failover_drop_xmit(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ atomic_long_inc(&dev->tx_dropped);
+ dev_kfree_skb_any(skb);
+ return NETDEV_TX_OK;
+}
+
+static netdev_tx_t net_failover_start_xmit(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *xmit_dev;
+
+ /* Try xmit via primary netdev followed by standby netdev */
+ xmit_dev = rcu_dereference_bh(nfo_info->primary_dev);
+ if (!xmit_dev || !net_failover_xmit_ready(xmit_dev)) {
+ xmit_dev = rcu_dereference_bh(nfo_info->standby_dev);
+ if (!xmit_dev || !net_failover_xmit_ready(xmit_dev))
+ return net_failover_drop_xmit(skb, dev);
+ }
+
+ skb->dev = xmit_dev;
+ skb->queue_mapping = qdisc_skb_cb(skb)->slave_dev_queue_mapping;
+
+ return dev_queue_xmit(skb);
+}
+
+static u16 net_failover_select_queue(struct net_device *dev,
+ struct sk_buff *skb, void *accel_priv,
+ select_queue_fallback_t fallback)
+{
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *primary_dev;
+ u16 txq;
+
+ rcu_read_lock();
+ primary_dev = rcu_dereference(nfo_info->primary_dev);
+ if (primary_dev) {
+ const struct net_device_ops *ops = primary_dev->netdev_ops;
+
+ if (ops->ndo_select_queue)
+ txq = ops->ndo_select_queue(primary_dev, skb,
+ accel_priv, fallback);
+ else
+ txq = fallback(primary_dev, skb);
+
+ qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping;
+
+ return txq;
+ }
+
+ txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : 0;
+
+ /* Save the original txq to restore before passing to the driver */
+ qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping;
+
+ if (unlikely(txq >= dev->real_num_tx_queues)) {
+ do {
+ txq -= dev->real_num_tx_queues;
+ } while (txq >= dev->real_num_tx_queues);
+ }
+
+ return txq;
+}
+
+/* fold stats, assuming all rtnl_link_stats64 fields are u64, but
+ * that some drivers can provide 32bit values only.
+ */
+static void net_failover_fold_stats(struct rtnl_link_stats64 *_res,
+ const struct rtnl_link_stats64 *_new,
+ const struct rtnl_link_stats64 *_old)
+{
+ const u64 *new = (const u64 *)_new;
+ const u64 *old = (const u64 *)_old;
+ u64 *res = (u64 *)_res;
+ int i;
+
+ for (i = 0; i < sizeof(*_res) / sizeof(u64); i++) {
+ u64 nv = new[i];
+ u64 ov = old[i];
+ s64 delta = nv - ov;
+
+ /* detects if this particular field is 32bit only */
+ if (((nv | ov) >> 32) == 0)
+ delta = (s64)(s32)((u32)nv - (u32)ov);
+
+ /* filter anomalies, some drivers reset their stats
+ * at down/up events.
+ */
+ if (delta > 0)
+ res[i] += delta;
+ }
+}
+
+static void net_failover_get_stats(struct net_device *dev,
+ struct rtnl_link_stats64 *stats)
+{
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ const struct rtnl_link_stats64 *new;
+ struct rtnl_link_stats64 temp;
+ struct net_device *slave_dev;
+
+ spin_lock(&nfo_info->stats_lock);
+ memcpy(stats, &nfo_info->failover_stats, sizeof(*stats));
+
+ rcu_read_lock();
+
+ slave_dev = rcu_dereference(nfo_info->primary_dev);
+ if (slave_dev) {
+ new = dev_get_stats(slave_dev, &temp);
+ net_failover_fold_stats(stats, new, &nfo_info->primary_stats);
+ memcpy(&nfo_info->primary_stats, new, sizeof(*new));
+ }
+
+ slave_dev = rcu_dereference(nfo_info->standby_dev);
+ if (slave_dev) {
+ new = dev_get_stats(slave_dev, &temp);
+ net_failover_fold_stats(stats, new, &nfo_info->standby_stats);
+ memcpy(&nfo_info->standby_stats, new, sizeof(*new));
+ }
+
+ rcu_read_unlock();
+
+ memcpy(&nfo_info->failover_stats, stats, sizeof(*stats));
+ spin_unlock(&nfo_info->stats_lock);
+}
+
+static int net_failover_change_mtu(struct net_device *dev, int new_mtu)
+{
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *primary_dev, *standby_dev;
+ int ret = 0;
+
+ primary_dev = rcu_dereference(nfo_info->primary_dev);
+ if (primary_dev) {
+ ret = dev_set_mtu(primary_dev, new_mtu);
+ if (ret)
+ return ret;
+ }
+
+ standby_dev = rcu_dereference(nfo_info->standby_dev);
+ if (standby_dev) {
+ ret = dev_set_mtu(standby_dev, new_mtu);
+ if (ret) {
+ if (primary_dev)
+ dev_set_mtu(primary_dev, dev->mtu);
+ return ret;
+ }
+ }
+
+ dev->mtu = new_mtu;
+
+ return 0;
+}
+
+static void net_failover_set_rx_mode(struct net_device *dev)
+{
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *slave_dev;
+
+ rcu_read_lock();
+
+ slave_dev = rcu_dereference(nfo_info->primary_dev);
+ if (slave_dev) {
+ dev_uc_sync_multiple(slave_dev, dev);
+ dev_mc_sync_multiple(slave_dev, dev);
+ }
+
+ slave_dev = rcu_dereference(nfo_info->standby_dev);
+ if (slave_dev) {
+ dev_uc_sync_multiple(slave_dev, dev);
+ dev_mc_sync_multiple(slave_dev, dev);
+ }
+
+ rcu_read_unlock();
+}
+
+static int net_failover_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
+ u16 vid)
+{
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *primary_dev, *standby_dev;
+ int ret = 0;
+
+ primary_dev = rcu_dereference(nfo_info->primary_dev);
+ if (primary_dev) {
+ ret = vlan_vid_add(primary_dev, proto, vid);
+ if (ret)
+ return ret;
+ }
+
+ standby_dev = rcu_dereference(nfo_info->standby_dev);
+ if (standby_dev) {
+ ret = vlan_vid_add(standby_dev, proto, vid);
+ if (ret)
+ if (primary_dev)
+ vlan_vid_del(primary_dev, proto, vid);
+ }
+
+ return ret;
+}
+
+static int net_failover_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
+ u16 vid)
+{
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *slave_dev;
+
+ slave_dev = rcu_dereference(nfo_info->primary_dev);
+ if (slave_dev)
+ vlan_vid_del(slave_dev, proto, vid);
+
+ slave_dev = rcu_dereference(nfo_info->standby_dev);
+ if (slave_dev)
+ vlan_vid_del(slave_dev, proto, vid);
+
+ return 0;
+}
+
+static const struct net_device_ops failover_dev_ops = {
+ .ndo_open = net_failover_open,
+ .ndo_stop = net_failover_close,
+ .ndo_start_xmit = net_failover_start_xmit,
+ .ndo_select_queue = net_failover_select_queue,
+ .ndo_get_stats64 = net_failover_get_stats,
+ .ndo_change_mtu = net_failover_change_mtu,
+ .ndo_set_rx_mode = net_failover_set_rx_mode,
+ .ndo_vlan_rx_add_vid = net_failover_vlan_rx_add_vid,
+ .ndo_vlan_rx_kill_vid = net_failover_vlan_rx_kill_vid,
+ .ndo_validate_addr = eth_validate_addr,
+ .ndo_features_check = passthru_features_check,
+};
+
+#define FAILOVER_NAME "net_failover"
+#define FAILOVER_VERSION "0.1"
+
+static void nfo_ethtool_get_drvinfo(struct net_device *dev,
+ struct ethtool_drvinfo *drvinfo)
+{
+ strlcpy(drvinfo->driver, FAILOVER_NAME, sizeof(drvinfo->driver));
+ strlcpy(drvinfo->version, FAILOVER_VERSION, sizeof(drvinfo->version));
+}
+
+static int nfo_ethtool_get_link_ksettings(struct net_device *dev,
+ struct ethtool_link_ksettings *cmd)
+{
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *slave_dev;
+
+ slave_dev = rtnl_dereference(nfo_info->primary_dev);
+ if (!slave_dev || !net_failover_xmit_ready(slave_dev)) {
+ slave_dev = rtnl_dereference(nfo_info->standby_dev);
+ if (!slave_dev || !net_failover_xmit_ready(slave_dev)) {
+ cmd->base.duplex = DUPLEX_UNKNOWN;
+ cmd->base.port = PORT_OTHER;
+ cmd->base.speed = SPEED_UNKNOWN;
+
+ return 0;
+ }
+ }
+
+ return __ethtool_get_link_ksettings(slave_dev, cmd);
+}
+
+static const struct ethtool_ops failover_ethtool_ops = {
+ .get_drvinfo = nfo_ethtool_get_drvinfo,
+ .get_link = ethtool_op_get_link,
+ .get_link_ksettings = nfo_ethtool_get_link_ksettings,
+};
+
+static struct net_device *net_failover_get_bymac(u8 *mac,
+ struct net_failover_ops **ops)
+{
+ struct net_device *failover_dev;
+ struct net_failover *failover;
+
+ spin_lock(&net_failover_lock);
+ list_for_each_entry(failover, &net_failover_list, list) {
+ failover_dev = rtnl_dereference(failover->failover_dev);
+ if (ether_addr_equal(failover_dev->perm_addr, mac)) {
+ *ops = rtnl_dereference(failover->ops);
+ spin_unlock(&net_failover_lock);
+ return failover_dev;
+ }
+ }
+ spin_unlock(&net_failover_lock);
+ return NULL;
+}
+
+/* Called when slave dev is injecting data into network stack.
+ * Change the associated network device from lower dev to failover dev.
+ * note: already called with rcu_read_lock
+ */
+static rx_handler_result_t net_failover_handle_frame(struct sk_buff **pskb)
+{
+ struct sk_buff *skb = *pskb;
+ struct net_device *dev = rcu_dereference(skb->dev->rx_handler_data);
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *primary_dev, *standby_dev;
+
+ primary_dev = rcu_dereference(nfo_info->primary_dev);
+ standby_dev = rcu_dereference(nfo_info->standby_dev);
+
+ if (primary_dev && skb->dev == standby_dev)
+ return RX_HANDLER_EXACT;
+
+ skb->dev = dev;
+
+ return RX_HANDLER_ANOTHER;
+}
+
+#define FAILOVER_VLAN_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | \
+ NETIF_F_FRAGLIST | NETIF_F_ALL_TSO | \
+ NETIF_F_HIGHDMA | NETIF_F_LRO)
+
+#define FAILOVER_ENC_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | \
+ NETIF_F_RXCSUM | NETIF_F_ALL_TSO)
+
+static void net_failover_compute_features(struct net_device *dev)
+{
+ u32 vlan_features = FAILOVER_VLAN_FEATURES & NETIF_F_ALL_FOR_ALL;
+ netdev_features_t enc_features = FAILOVER_ENC_FEATURES;
+ unsigned short max_hard_header_len = ETH_HLEN;
+ unsigned int dst_release_flag = IFF_XMIT_DST_RELEASE |
+ IFF_XMIT_DST_RELEASE_PERM;
+ struct net_failover_info *nfo_info = netdev_priv(dev);
+ struct net_device *primary_dev, *standby_dev;
+
+ primary_dev = rcu_dereference(nfo_info->primary_dev);
+ if (primary_dev) {
+ vlan_features =
+ netdev_increment_features(vlan_features,
+ primary_dev->vlan_features,
+ FAILOVER_VLAN_FEATURES);
+ enc_features =
+ netdev_increment_features(enc_features,
+ primary_dev->hw_enc_features,
+ FAILOVER_ENC_FEATURES);
+
+ dst_release_flag &= primary_dev->priv_flags;
+ if (primary_dev->hard_header_len > max_hard_header_len)
+ max_hard_header_len = primary_dev->hard_header_len;
+ }
+
+ standby_dev = rcu_dereference(nfo_info->standby_dev);
+ if (standby_dev) {
+ vlan_features =
+ netdev_increment_features(vlan_features,
+ standby_dev->vlan_features,
+ FAILOVER_VLAN_FEATURES);
+ enc_features =
+ netdev_increment_features(enc_features,
+ standby_dev->hw_enc_features,
+ FAILOVER_ENC_FEATURES);
+
+ dst_release_flag &= standby_dev->priv_flags;
+ if (standby_dev->hard_header_len > max_hard_header_len)
+ max_hard_header_len = standby_dev->hard_header_len;
+ }
+
+ dev->vlan_features = vlan_features;
+ dev->hw_enc_features = enc_features | NETIF_F_GSO_ENCAP_ALL;
+ dev->hard_header_len = max_hard_header_len;
+
+ dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+ if (dst_release_flag == (IFF_XMIT_DST_RELEASE |
+ IFF_XMIT_DST_RELEASE_PERM))
+ dev->priv_flags |= IFF_XMIT_DST_RELEASE;
+
+ netdev_change_features(dev);
+}
+
+static void net_failover_lower_state_changed(struct net_device *slave_dev,
+ struct net_device *primary_dev,
+ struct net_device *standby_dev)
+{
+ struct netdev_lag_lower_state_info info;
+
+ if (netif_carrier_ok(slave_dev))
+ info.link_up = true;
+ else
+ info.link_up = false;
+
+ if (slave_dev == primary_dev) {
+ if (netif_running(primary_dev))
+ info.tx_enabled = true;
+ else
+ info.tx_enabled = false;
+ } else {
+ if ((primary_dev && netif_running(primary_dev)) ||
+ (!netif_running(standby_dev)))
+ info.tx_enabled = false;
+ else
+ info.tx_enabled = true;
+ }
+
+ netdev_lower_state_changed(slave_dev, &info);
+}
+
+/**
+ * net_failover_slave_register - Register a slave netdev
+ *
+ * @slave_dev: slave netdev that is being registered
+ *
+ * Registers a slave device to a failover instance. For a 2 netdev model,
+ * this will be primary netdev. In case of a 3 netdev model, it can be a
+ * standby or a primary netdev.
+ *
+ */
+static int net_failover_slave_register(struct net_device *slave_dev)
+{
+ struct net_device *standby_dev, *primary_dev, *failover_dev;
+ struct netdev_lag_upper_info lag_upper_info;
+ struct net_failover_info *nfo_info;
+ struct net_failover_ops *nfo_ops;
+ bool slave_is_standby;
+ u32 orig_mtu;
+ int err;
+
+ ASSERT_RTNL();
+
+ failover_dev = net_failover_get_bymac(slave_dev->perm_addr, &nfo_ops);
+ if (!failover_dev)
+ goto done;
+
+ if (failover_dev->type != slave_dev->type)
+ goto done;
+
+ if (nfo_ops && nfo_ops->slave_register)
+ return nfo_ops->slave_register(slave_dev, failover_dev);
+
+ nfo_info = netdev_priv(failover_dev);
+ standby_dev = rtnl_dereference(nfo_info->standby_dev);
+ primary_dev = rtnl_dereference(nfo_info->primary_dev);
+ slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
+ if (slave_is_standby ? standby_dev : primary_dev) {
+ netdev_err(failover_dev, "%s attempting to register as slave dev when %s already present\n",
+ slave_dev->name,
+ slave_is_standby ? "standby" : "primary");
+ goto done;
+ }
+
+ /* We want to allow only a direct attached VF device as a primary
+ * netdev. As there is no easy way to check for a VF device, restrict
+ * this to a pci device.
+ */
+ if (!slave_is_standby && (!slave_dev->dev.parent ||
+ !dev_is_pci(slave_dev->dev.parent)))
+ goto done;
+
+ if (failover_dev->features & NETIF_F_VLAN_CHALLENGED &&
+ vlan_uses_dev(failover_dev)) {
+ netdev_err(failover_dev, "Device %s is VLAN challenged and failover device has VLAN set up\n",
+ failover_dev->name);
+ goto done;
+ }
+
+ /* Align MTU of slave with failover dev */
+ orig_mtu = slave_dev->mtu;
+ err = dev_set_mtu(slave_dev, failover_dev->mtu);
+ if (err) {
+ netdev_err(failover_dev, "unable to change mtu of %s to %u register failed\n",
+ slave_dev->name, failover_dev->mtu);
+ goto done;
+ }
+
+ dev_hold(slave_dev);
+
+ if (netif_running(failover_dev)) {
+ err = dev_open(slave_dev);
+ if (err && (err != -EBUSY)) {
+ netdev_err(failover_dev, "Opening slave %s failed err:%d\n",
+ slave_dev->name, err);
+ goto err_dev_open;
+ }
+ }
+
+ netif_addr_lock_bh(failover_dev);
+ dev_uc_sync_multiple(slave_dev, failover_dev);
+ dev_uc_sync_multiple(slave_dev, failover_dev);
+ netif_addr_unlock_bh(failover_dev);
+
+ err = vlan_vids_add_by_dev(slave_dev, failover_dev);
+ if (err) {
+ netdev_err(failover_dev, "Failed to add vlan ids to device %s err:%d\n",
+ slave_dev->name, err);
+ goto err_vlan_add;
+ }
+
+ err = netdev_rx_handler_register(slave_dev, net_failover_handle_frame,
+ failover_dev);
+ if (err) {
+ netdev_err(slave_dev, "can not register failover rx handler (err = %d)\n",
+ err);
+ goto err_handler_register;
+ }
+
+ lag_upper_info.tx_type = NETDEV_LAG_TX_TYPE_ACTIVEBACKUP;
+ err = netdev_master_upper_dev_link(slave_dev, failover_dev, NULL,
+ &lag_upper_info, NULL);
+ if (err) {
+ netdev_err(slave_dev, "can not set failover device %s (err = %d)\n",
+ failover_dev->name, err);
+ goto err_upper_link;
+ }
+
+ slave_dev->priv_flags |= IFF_FAILOVER_SLAVE;
+
+ if (slave_is_standby) {
+ rcu_assign_pointer(nfo_info->standby_dev, slave_dev);
+ standby_dev = slave_dev;
+ dev_get_stats(standby_dev, &nfo_info->standby_stats);
+ } else {
+ rcu_assign_pointer(nfo_info->primary_dev, slave_dev);
+ primary_dev = slave_dev;
+ dev_get_stats(primary_dev, &nfo_info->primary_stats);
+ failover_dev->min_mtu = slave_dev->min_mtu;
+ failover_dev->max_mtu = slave_dev->max_mtu;
+ }
+
+ net_failover_lower_state_changed(slave_dev, primary_dev, standby_dev);
+ net_failover_compute_features(failover_dev);
+
+ call_netdevice_notifiers(NETDEV_JOIN, slave_dev);
+
+ netdev_info(failover_dev, "failover %s slave:%s registered\n",
+ slave_is_standby ? "standby" : "primary", slave_dev->name);
+
+ goto done;
+
+err_upper_link:
+ netdev_rx_handler_unregister(slave_dev);
+err_handler_register:
+ vlan_vids_del_by_dev(slave_dev, failover_dev);
+err_vlan_add:
+ dev_uc_unsync(slave_dev, failover_dev);
+ dev_mc_unsync(slave_dev, failover_dev);
+ dev_close(slave_dev);
+err_dev_open:
+ dev_put(slave_dev);
+ dev_set_mtu(slave_dev, orig_mtu);
+done:
+ return NOTIFY_DONE;
+}
+
+/**
+ * net_failover_slave_unregister - Unregister a slave netdev
+ *
+ * @slave_dev: slave netdev that is being unregistered
+ *
+ * Unregisters a slave device from a failover instance. For a 2 netdev model,
+ * this will be primary netdev. In case of a 3 netdev model, it can be a
+ * standby or a primary netdev.
+ *
+ */
+int net_failover_slave_unregister(struct net_device *slave_dev)
+{
+ struct net_device *standby_dev, *primary_dev, *failover_dev;
+ struct net_failover_info *nfo_info;
+ struct net_failover_ops *nfo_ops;
+ bool slave_is_standby;
+
+ if (!netif_is_failover_slave(slave_dev))
+ goto done;
+
+ ASSERT_RTNL();
+
+ failover_dev = net_failover_get_bymac(slave_dev->perm_addr, &nfo_ops);
+ if (!failover_dev)
+ goto done;
+
+ if (nfo_ops && nfo_ops->slave_unregister)
+ return nfo_ops->slave_unregister(slave_dev, failover_dev);
+
+ nfo_info = netdev_priv(failover_dev);
+ primary_dev = rtnl_dereference(nfo_info->primary_dev);
+ standby_dev = rtnl_dereference(nfo_info->standby_dev);
+
+ if (slave_dev != primary_dev && slave_dev != standby_dev)
+ goto done;
+
+ slave_is_standby = slave_dev->dev.parent == failover_dev->dev.parent;
+
+ netdev_rx_handler_unregister(slave_dev);
+ netdev_upper_dev_unlink(slave_dev, failover_dev);
+ vlan_vids_del_by_dev(slave_dev, failover_dev);
+ dev_uc_unsync(slave_dev, failover_dev);
+ dev_mc_unsync(slave_dev, failover_dev);
+ dev_close(slave_dev);
+ slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE;
+
+ nfo_info = netdev_priv(failover_dev);
+ net_failover_get_stats(failover_dev, &nfo_info->failover_stats);
+
+ if (slave_is_standby) {
+ RCU_INIT_POINTER(nfo_info->standby_dev, NULL);
+ } else {
+ RCU_INIT_POINTER(nfo_info->primary_dev, NULL);
+ if (standby_dev) {
+ failover_dev->min_mtu = standby_dev->min_mtu;
+ failover_dev->max_mtu = standby_dev->max_mtu;
+ }
+ }
+
+ dev_put(slave_dev);
+
+ net_failover_compute_features(failover_dev);
+
+ netdev_info(failover_dev, "failover %s slave:%s unregistered\n",
+ slave_is_standby ? "standby" : "primary", slave_dev->name);
+
+done:
+ return NOTIFY_DONE;
+}
+EXPORT_SYMBOL_GPL(net_failover_slave_unregister);
+
+static int net_failover_slave_link_change(struct net_device *slave_dev)
+{
+ struct net_device *failover_dev, *primary_dev, *standby_dev;
+ struct net_failover_info *nfo_info;
+ struct net_failover_ops *nfo_ops;
+
+ if (!netif_is_failover_slave(slave_dev))
+ goto done;
+
+ ASSERT_RTNL();
+
+ failover_dev = net_failover_get_bymac(slave_dev->perm_addr, &nfo_ops);
+ if (!failover_dev)
+ goto done;
+
+ if (nfo_ops && nfo_ops->slave_link_change)
+ return nfo_ops->slave_link_change(slave_dev, failover_dev);
+
+ if (!netif_running(failover_dev))
+ goto done;
+
+ nfo_info = netdev_priv(failover_dev);
+
+ primary_dev = rtnl_dereference(nfo_info->primary_dev);
+ standby_dev = rtnl_dereference(nfo_info->standby_dev);
+
+ if (slave_dev != primary_dev && slave_dev != standby_dev)
+ goto done;
+
+ if ((primary_dev && net_failover_xmit_ready(primary_dev)) ||
+ (standby_dev && net_failover_xmit_ready(standby_dev))) {
+ netif_carrier_on(failover_dev);
+ netif_tx_wake_all_queues(failover_dev);
+ } else {
+ net_failover_get_stats(failover_dev, &nfo_info->failover_stats);
+ netif_carrier_off(failover_dev);
+ netif_tx_stop_all_queues(failover_dev);
+ }
+
+ net_failover_lower_state_changed(slave_dev, primary_dev, standby_dev);
+
+done:
+ return NOTIFY_DONE;
+}
+
+static int net_failover_slave_change_name(struct net_device *slave_dev)
+{
+ struct net_device *failover_dev, *primary_dev, *standby_dev;
+ struct net_failover_info *nfo_info;
+ struct net_failover_ops *nfo_ops;
+
+ if (!netif_is_failover_slave(slave_dev))
+ goto done;
+
+ ASSERT_RTNL();
+
+ failover_dev = net_failover_get_bymac(slave_dev->perm_addr, &nfo_ops);
+ if (!failover_dev)
+ goto done;
+
+ if (!netif_running(failover_dev))
+ goto done;
+
+ nfo_info = netdev_priv(failover_dev);
+
+ primary_dev = rtnl_dereference(nfo_info->primary_dev);
+ standby_dev = rtnl_dereference(nfo_info->standby_dev);
+
+ if (slave_dev != primary_dev && slave_dev != standby_dev)
+ goto done;
+
+ /* We need to bring up the slave after the rename by udev in case
+ * open failed with EBUSY when it was registered.
+ */
+ dev_open(slave_dev);
+
+done:
+ return NOTIFY_DONE;
+}
+
+static int
+net_failover_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+ struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
+
+ /* Skip parent events */
+ if (netif_is_failover(event_dev))
+ return NOTIFY_DONE;
+
+ switch (event) {
+ case NETDEV_REGISTER:
+ return net_failover_slave_register(event_dev);
+ case NETDEV_UNREGISTER:
+ return net_failover_slave_unregister(event_dev);
+ case NETDEV_UP:
+ case NETDEV_DOWN:
+ case NETDEV_CHANGE:
+ return net_failover_slave_link_change(event_dev);
+ case NETDEV_CHANGENAME:
+ return net_failover_slave_change_name(event_dev);
+ default:
+ return NOTIFY_DONE;
+ }
+}
+
+static struct notifier_block net_failover_notifier = {
+ .notifier_call = net_failover_event,
+};
+
+static void
+net_failover_existing_slave_register(struct net_device *failover_dev)
+{
+ struct net *net = dev_net(failover_dev);
+ struct net_device *dev;
+
+ rtnl_lock();
+ for_each_netdev(net, dev) {
+ if (netif_is_failover(dev))
+ continue;
+ if (ether_addr_equal(failover_dev->perm_addr, dev->perm_addr))
+ net_failover_slave_register(dev);
+ }
+ rtnl_unlock();
+}
+
+/**
+ * net_failover_register - Register a failover instance
+ *
+ * @dev: failover or standby netdev
+ * @ops: failover ops
+ *
+ * Paravirtual drivers supporting 3-netdev model call this routine indirectly
+ * via net_failover_create(). It passes failover netdev and ops will be NULL
+ * as the slave events are handled internally.
+ * Paravirtual drivers supporting 2-netdev model call this routine by passing
+ * standby netdev and ops that are called to handle slave register/unregister/
+ * link change events.
+ *
+ * Return: pointer to failover instance
+ */
+struct net_failover *net_failover_register(struct net_device *dev,
+ struct net_failover_ops *ops)
+{
+ struct net_failover *failover;
+
+ failover = kzalloc(sizeof(*failover), GFP_KERNEL);
+ if (!failover)
+ return ERR_PTR(-ENOMEM);
+
+ rcu_assign_pointer(failover->ops, ops);
+ dev_hold(dev);
+ dev->priv_flags |= IFF_FAILOVER;
+ rcu_assign_pointer(failover->failover_dev, dev);
+
+ spin_lock(&net_failover_lock);
+ list_add_tail(&failover->list, &net_failover_list);
+ spin_unlock(&net_failover_lock);
+
+ netdev_info(dev, "failover master:%s registered\n", dev->name);
+
+ net_failover_existing_slave_register(dev);
+
+ return failover;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(net_failover_register);
+
+/**
+ * net_failover_unregister - Unregister a failover instance
+ *
+ * @failover: pointer to failover instance
+ *
+ * Unregisters and frees a failover instance.
+ */
+void net_failover_unregister(struct net_failover *failover)
+{
+ struct net_device *failover_dev;
+
+ failover_dev = rcu_dereference(failover->failover_dev);
+
+ netdev_info(failover_dev, "failover master:%s unregistered\n",
+ failover_dev->name);
+
+ failover_dev->priv_flags &= ~IFF_FAILOVER;
+ dev_put(failover_dev);
+
+ spin_lock(&net_failover_lock);
+ list_del(&failover->list);
+ spin_unlock(&net_failover_lock);
+
+ kfree(failover);
+}
+EXPORT_SYMBOL_GPL(net_failover_unregister);
+
+/**
+ * net_failover_create - Create and register a failover instance
+ *
+ * @dev: standby netdev
+ *
+ * Creates a failover netdev and registers a failover instance for a standby
+ * netdev. Used by paravirtual drivers that use 3-netdev model.
+ * The failover netdev acts as a master device and controls 2 slave devices -
+ * the original standby netdev and a VF netdev with the same MAC gets
+ * registered as primary netdev.
+ *
+ * Return: pointer to failover instance
+ */
+struct net_failover *net_failover_create(struct net_device *standby_dev)
+{
+ struct device *dev = standby_dev->dev.parent;
+ struct net_device *failover_dev;
+ struct net_failover *failover;
+ int err;
+
+ /* Alloc at least 2 queues, for now we are going with 16 assuming
+ * that VF devices being enslaved won't have too many queues.
+ */
+ failover_dev = alloc_etherdev_mq(sizeof(struct net_failover_info), 16);
+ if (!failover_dev) {
+ dev_err(dev, "Unable to allocate failover_netdev!\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ dev_net_set(failover_dev, dev_net(standby_dev));
+ SET_NETDEV_DEV(failover_dev, dev);
+
+ failover_dev->netdev_ops = &failover_dev_ops;
+ failover_dev->ethtool_ops = &failover_ethtool_ops;
+
+ /* Initialize the device options */
+ failover_dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE;
+ failover_dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE |
+ IFF_TX_SKB_SHARING);
+
+ /* don't acquire failover netdev's netif_tx_lock when transmitting */
+ failover_dev->features |= NETIF_F_LLTX;
+
+ /* Don't allow failover devices to change network namespaces. */
+ failover_dev->features |= NETIF_F_NETNS_LOCAL;
+
+ failover_dev->hw_features = FAILOVER_VLAN_FEATURES |
+ NETIF_F_HW_VLAN_CTAG_TX |
+ NETIF_F_HW_VLAN_CTAG_RX |
+ NETIF_F_HW_VLAN_CTAG_FILTER;
+
+ failover_dev->hw_features |= NETIF_F_GSO_ENCAP_ALL;
+ failover_dev->features |= failover_dev->hw_features;
+
+ memcpy(failover_dev->dev_addr, standby_dev->dev_addr,
+ failover_dev->addr_len);
+
+ failover_dev->min_mtu = standby_dev->min_mtu;
+ failover_dev->max_mtu = standby_dev->max_mtu;
+
+ err = register_netdev(failover_dev);
+ if (err) {
+ dev_err(dev, "Unable to register failover_dev!\n");
+ goto err_register_netdev;
+ }
+
+ netif_carrier_off(failover_dev);
+
+ failover = net_failover_register(failover_dev, NULL);
+ if (IS_ERR(failover))
+ goto err_failover_register;
+
+ return failover;
+
+err_failover_register:
+ unregister_netdev(failover_dev);
+err_register_netdev:
+ free_netdev(failover_dev);
+
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(net_failover_create);
+
+/**
+ * net_failover_destroy - Destroy a failover instance
+ *
+ * @failover: pointer to failover instance
+ *
+ * Unregisters any slave netdevs associated with the failover instance by
+ * calling net_failover_slave_unregister().
+ * unregisters the failover instance itself and finally frees the failover
+ * netdev. Used by paravirtual drivers that use 3-netdev model.
+ *
+ */
+void net_failover_destroy(struct net_failover *failover)
+{
+ struct net_failover_info *nfo_info;
+ struct net_device *failover_dev;
+ struct net_device *slave_dev;
+
+ if (!failover)
+ return;
+
+ failover_dev = rcu_dereference(failover->failover_dev);
+ nfo_info = netdev_priv(failover_dev);
+
+ netif_device_detach(failover_dev);
+
+ rtnl_lock();
+
+ slave_dev = rtnl_dereference(nfo_info->primary_dev);
+ if (slave_dev)
+ net_failover_slave_unregister(slave_dev);
+
+ slave_dev = rtnl_dereference(nfo_info->standby_dev);
+ if (slave_dev)
+ net_failover_slave_unregister(slave_dev);
+
+ net_failover_unregister(failover);
+
+ unregister_netdevice(failover_dev);
+
+ rtnl_unlock();
+
+ free_netdev(failover_dev);
+}
+EXPORT_SYMBOL_GPL(net_failover_destroy);
+
+static __init int
+net_failover_init(void)
+{
+ register_netdevice_notifier(&net_failover_notifier);
+
+ return 0;
+}
+module_init(net_failover_init);
+
+static __exit
+void net_failover_exit(void)
+{
+ unregister_netdevice_notifier(&net_failover_notifier);
+}
+module_exit(net_failover_exit);
+
+MODULE_DESCRIPTION("Failover infrastructure/interface for Paravirtual drivers");
+MODULE_LICENSE("GPL v2");
--
2.14.3
^ permalink raw reply related
* [PATCH net-next v10 3/4] virtio_net: Extend virtio to use VF datapath when available
From: Sridhar Samudrala @ 2018-05-07 22:10 UTC (permalink / raw)
To: mst, stephen, davem, netdev, virtualization, virtio-dev,
jesse.brandeburg, alexander.h.duyck, kubakici, sridhar.samudrala,
jasowang, loseweigh, jiri, aaron.f.brown
In-Reply-To: <1525731046-10989-1-git-send-email-sridhar.samudrala@intel.com>
This patch enables virtio_net to switch over to a VF datapath when a VF
netdev is present with the same MAC address. It allows live migration
of a VM with a direct attached VF without the need to setup a bond/team
between a VF and virtio net device in the guest.
The hypervisor needs to unplug the VF device from the guest on the source
host and reset the MAC filter of the VF to initiate failover of datapath
to virtio before starting the migration. After the migration is completed,
the destination hypervisor sets the MAC filter on the VF and plugs it back
to the guest to switch over to VF datapath.
It uses the generic failover framework that provides 2 functions to create
and destroy a master failover netdev. When STANDBY feature is enabled, an
additional netdev(failover netdev) is created that acts as a master device
and tracks the state of the 2 lower netdevs. The original virtio_net netdev
is marked as 'standby' netdev and a passthru device with the same MAC is
registered as 'primary' netdev.
This patch is based on the discussion initiated by Jesse on this thread.
https://marc.info/?l=linux-virtualization&m=151189725224231&w=2
Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
---
drivers/net/Kconfig | 1 +
drivers/net/virtio_net.c | 38 +++++++++++++++++++++++++++++++++++++-
2 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index a029b27fd002..30e3bb0532e4 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -332,6 +332,7 @@ config VETH
config VIRTIO_NET
tristate "Virtio network driver"
depends on VIRTIO
+ select NET_FAILOVER
---help---
This is the virtual network driver for virtio. It can be used with
QEMU based VMMs (like KVM or Xen). Say Y or M.
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 213fddc70fd0..e7428d20763c 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -30,8 +30,11 @@
#include <linux/cpu.h>
#include <linux/average.h>
#include <linux/filter.h>
+#include <linux/netdevice.h>
+#include <linux/pci.h>
#include <net/route.h>
#include <net/xdp.h>
+#include <net/net_failover.h>
static int napi_weight = NAPI_POLL_WEIGHT;
module_param(napi_weight, int, 0444);
@@ -210,6 +213,9 @@ struct virtnet_info {
u32 speed;
unsigned long guest_offloads;
+
+ /* failover when STANDBY feature enabled */
+ struct net_failover *failover;
};
struct padded_vnet_hdr {
@@ -1523,6 +1529,9 @@ static int virtnet_set_mac_address(struct net_device *dev, void *p)
struct sockaddr *addr;
struct scatterlist sg;
+ if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STANDBY))
+ return -EOPNOTSUPP;
+
addr = kmemdup(p, sizeof(*addr), GFP_KERNEL);
if (!addr)
return -ENOMEM;
@@ -2306,6 +2315,22 @@ static int virtnet_xdp(struct net_device *dev, struct netdev_bpf *xdp)
}
}
+static int virtnet_get_phys_port_name(struct net_device *dev, char *buf,
+ size_t len)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+ int ret;
+
+ if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_STANDBY))
+ return -EOPNOTSUPP;
+
+ ret = snprintf(buf, len, "sby");
+ if (ret >= len)
+ return -EOPNOTSUPP;
+
+ return 0;
+}
+
static const struct net_device_ops virtnet_netdev = {
.ndo_open = virtnet_open,
.ndo_stop = virtnet_close,
@@ -2323,6 +2348,7 @@ static const struct net_device_ops virtnet_netdev = {
.ndo_xdp_xmit = virtnet_xdp_xmit,
.ndo_xdp_flush = virtnet_xdp_flush,
.ndo_features_check = passthru_features_check,
+ .ndo_get_phys_port_name = virtnet_get_phys_port_name,
};
static void virtnet_config_changed_work(struct work_struct *work)
@@ -2876,10 +2902,16 @@ static int virtnet_probe(struct virtio_device *vdev)
virtnet_init_settings(dev);
+ if (virtio_has_feature(vdev, VIRTIO_NET_F_STANDBY)) {
+ vi->failover = net_failover_create(vi->dev);
+ if (IS_ERR(vi->failover))
+ goto free_vqs;
+ }
+
err = register_netdev(dev);
if (err) {
pr_debug("virtio_net: registering device failed\n");
- goto free_vqs;
+ goto free_failover;
}
virtio_device_ready(vdev);
@@ -2916,6 +2948,8 @@ static int virtnet_probe(struct virtio_device *vdev)
vi->vdev->config->reset(vdev);
unregister_netdev(dev);
+free_failover:
+ net_failover_destroy(vi->failover);
free_vqs:
cancel_delayed_work_sync(&vi->refill);
free_receive_page_frags(vi);
@@ -2950,6 +2984,8 @@ static void virtnet_remove(struct virtio_device *vdev)
unregister_netdev(vi->dev);
+ net_failover_destroy(vi->failover);
+
remove_vq_common(vi);
free_netdev(vi->dev);
--
2.14.3
^ permalink raw reply related
* [PATCH net-next v10 4/4] netvsc: refactor notifier/event handling code to use the failover framework
From: Sridhar Samudrala @ 2018-05-07 22:10 UTC (permalink / raw)
To: mst, stephen, davem, netdev, virtualization, virtio-dev,
jesse.brandeburg, alexander.h.duyck, kubakici, sridhar.samudrala,
jasowang, loseweigh, jiri, aaron.f.brown
In-Reply-To: <1525731046-10989-1-git-send-email-sridhar.samudrala@intel.com>
Use the registration/notification framework supported by the generic
failover infrastructure.
Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
---
drivers/net/hyperv/Kconfig | 1 +
drivers/net/hyperv/hyperv_net.h | 2 +
drivers/net/hyperv/netvsc_drv.c | 134 +++++++---------------------------------
3 files changed, 26 insertions(+), 111 deletions(-)
diff --git a/drivers/net/hyperv/Kconfig b/drivers/net/hyperv/Kconfig
index 0765d5f61714..1f8419fc7c7f 100644
--- a/drivers/net/hyperv/Kconfig
+++ b/drivers/net/hyperv/Kconfig
@@ -2,5 +2,6 @@ config HYPERV_NET
tristate "Microsoft Hyper-V virtual network driver"
depends on HYPERV
select UCS2_STRING
+ select NET_FAILOVER
help
Select this option to enable the Hyper-V virtual network driver.
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 6ebe39a3dde6..2ec18344c0e8 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -932,6 +932,8 @@ struct net_device_context {
u32 vf_alloc;
/* Serial number of the VF to team with */
u32 vf_serial;
+
+ struct net_failover *failover;
};
/* Per channel data */
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index ecc84954c511..f852b3a9403a 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -43,6 +43,7 @@
#include <net/pkt_sched.h>
#include <net/checksum.h>
#include <net/ip6_checksum.h>
+#include <net/net_failover.h>
#include "hyperv_net.h"
@@ -1763,46 +1764,6 @@ static void netvsc_link_change(struct work_struct *w)
rtnl_unlock();
}
-static struct net_device *get_netvsc_bymac(const u8 *mac)
-{
- struct net_device *dev;
-
- ASSERT_RTNL();
-
- for_each_netdev(&init_net, dev) {
- if (dev->netdev_ops != &device_ops)
- continue; /* not a netvsc device */
-
- if (ether_addr_equal(mac, dev->perm_addr))
- return dev;
- }
-
- return NULL;
-}
-
-static struct net_device *get_netvsc_byref(struct net_device *vf_netdev)
-{
- struct net_device *dev;
-
- ASSERT_RTNL();
-
- for_each_netdev(&init_net, dev) {
- struct net_device_context *net_device_ctx;
-
- if (dev->netdev_ops != &device_ops)
- continue; /* not a netvsc device */
-
- net_device_ctx = netdev_priv(dev);
- if (!rtnl_dereference(net_device_ctx->nvdev))
- continue; /* device is removed */
-
- if (rtnl_dereference(net_device_ctx->vf_netdev) == vf_netdev)
- return dev; /* a match */
- }
-
- return NULL;
-}
-
/* Called when VF is injecting data into network stack.
* Change the associated network device from VF to netvsc.
* note: already called with rcu_read_lock
@@ -1914,24 +1875,15 @@ static void netvsc_vf_setup(struct work_struct *w)
rtnl_unlock();
}
-static int netvsc_register_vf(struct net_device *vf_netdev)
+static int netvsc_register_vf(struct net_device *vf_netdev,
+ struct net_device *ndev)
{
- struct net_device *ndev;
struct net_device_context *net_device_ctx;
struct netvsc_device *netvsc_dev;
if (vf_netdev->addr_len != ETH_ALEN)
return NOTIFY_DONE;
- /*
- * We will use the MAC address to locate the synthetic interface to
- * associate with the VF interface. If we don't find a matching
- * synthetic interface, move on.
- */
- ndev = get_netvsc_bymac(vf_netdev->perm_addr);
- if (!ndev)
- return NOTIFY_DONE;
-
net_device_ctx = netdev_priv(ndev);
netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);
if (!netvsc_dev || rtnl_dereference(net_device_ctx->vf_netdev))
@@ -1948,17 +1900,13 @@ static int netvsc_register_vf(struct net_device *vf_netdev)
}
/* VF up/down change detected, schedule to change data path */
-static int netvsc_vf_changed(struct net_device *vf_netdev)
+static int netvsc_vf_changed(struct net_device *vf_netdev,
+ struct net_device *ndev)
{
struct net_device_context *net_device_ctx;
struct netvsc_device *netvsc_dev;
- struct net_device *ndev;
bool vf_is_up = netif_running(vf_netdev);
- ndev = get_netvsc_byref(vf_netdev);
- if (!ndev)
- return NOTIFY_DONE;
-
net_device_ctx = netdev_priv(ndev);
netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);
if (!netvsc_dev)
@@ -1971,15 +1919,11 @@ static int netvsc_vf_changed(struct net_device *vf_netdev)
return NOTIFY_OK;
}
-static int netvsc_unregister_vf(struct net_device *vf_netdev)
+static int netvsc_unregister_vf(struct net_device *vf_netdev,
+ struct net_device *ndev)
{
- struct net_device *ndev;
struct net_device_context *net_device_ctx;
- ndev = get_netvsc_byref(vf_netdev);
- if (!ndev)
- return NOTIFY_DONE;
-
net_device_ctx = netdev_priv(ndev);
cancel_delayed_work_sync(&net_device_ctx->vf_takeover);
@@ -1993,6 +1937,12 @@ static int netvsc_unregister_vf(struct net_device *vf_netdev)
return NOTIFY_OK;
}
+static struct net_failover_ops netvsc_failover_ops = {
+ .slave_register = netvsc_register_vf,
+ .slave_unregister = netvsc_unregister_vf,
+ .slave_link_change = netvsc_vf_changed,
+};
+
static int netvsc_probe(struct hv_device *dev,
const struct hv_vmbus_device_id *dev_id)
{
@@ -2082,8 +2032,15 @@ static int netvsc_probe(struct hv_device *dev,
goto register_failed;
}
+ net_device_ctx->failover = net_failover_register(net,
+ &netvsc_failover_ops);
+ if (IS_ERR(net_device_ctx->failover))
+ goto err_failover;
+
return ret;
+err_failover:
+ unregister_netdev(net);
register_failed:
rndis_filter_device_remove(dev, nvdev);
rndis_failed:
@@ -2124,13 +2081,15 @@ static int netvsc_remove(struct hv_device *dev)
rtnl_lock();
vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
if (vf_netdev)
- netvsc_unregister_vf(vf_netdev);
+ net_failover_slave_unregister(vf_netdev);
if (nvdev)
rndis_filter_device_remove(dev, nvdev);
unregister_netdevice(net);
+ net_failover_unregister(ndev_ctx->failover);
+
rtnl_unlock();
rcu_read_unlock();
@@ -2157,54 +2116,8 @@ static struct hv_driver netvsc_drv = {
.remove = netvsc_remove,
};
-/*
- * On Hyper-V, every VF interface is matched with a corresponding
- * synthetic interface. The synthetic interface is presented first
- * to the guest. When the corresponding VF instance is registered,
- * we will take care of switching the data path.
- */
-static int netvsc_netdev_event(struct notifier_block *this,
- unsigned long event, void *ptr)
-{
- struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
-
- /* Skip our own events */
- if (event_dev->netdev_ops == &device_ops)
- return NOTIFY_DONE;
-
- /* Avoid non-Ethernet type devices */
- if (event_dev->type != ARPHRD_ETHER)
- return NOTIFY_DONE;
-
- /* Avoid Vlan dev with same MAC registering as VF */
- if (is_vlan_dev(event_dev))
- return NOTIFY_DONE;
-
- /* Avoid Bonding master dev with same MAC registering as VF */
- if ((event_dev->priv_flags & IFF_BONDING) &&
- (event_dev->flags & IFF_MASTER))
- return NOTIFY_DONE;
-
- switch (event) {
- case NETDEV_REGISTER:
- return netvsc_register_vf(event_dev);
- case NETDEV_UNREGISTER:
- return netvsc_unregister_vf(event_dev);
- case NETDEV_UP:
- case NETDEV_DOWN:
- return netvsc_vf_changed(event_dev);
- default:
- return NOTIFY_DONE;
- }
-}
-
-static struct notifier_block netvsc_netdev_notifier = {
- .notifier_call = netvsc_netdev_event,
-};
-
static void __exit netvsc_drv_exit(void)
{
- unregister_netdevice_notifier(&netvsc_netdev_notifier);
vmbus_driver_unregister(&netvsc_drv);
}
@@ -2224,7 +2137,6 @@ static int __init netvsc_drv_init(void)
if (ret)
return ret;
- register_netdevice_notifier(&netvsc_netdev_notifier);
return 0;
}
--
2.14.3
^ permalink raw reply related
* Re: [PATCH net-next v10 2/4] net: Introduce generic failover module
From: Randy Dunlap @ 2018-05-07 22:39 UTC (permalink / raw)
To: Sridhar Samudrala, mst, stephen, davem, netdev, virtualization,
virtio-dev, jesse.brandeburg, alexander.h.duyck, kubakici,
jasowang, loseweigh, jiri, aaron.f.brown
In-Reply-To: <1525731046-10989-3-git-send-email-sridhar.samudrala@intel.com>
Hi,
On 05/07/2018 03:10 PM, Sridhar Samudrala wrote:
>
> Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
> ---
> MAINTAINERS | 7 +
> include/linux/netdevice.h | 16 +
> include/net/net_failover.h | 52 +++
> net/Kconfig | 10 +
> net/core/Makefile | 1 +
> net/core/net_failover.c | 1044 ++++++++++++++++++++++++++++++++++++++++++++
> 6 files changed, 1130 insertions(+)
> create mode 100644 include/net/net_failover.h
> create mode 100644 net/core/net_failover.c
> diff --git a/net/Kconfig b/net/Kconfig
> index b62089fb1332..0540856676de 100644
> --- a/net/Kconfig
> +++ b/net/Kconfig
> @@ -429,6 +429,16 @@ config MAY_USE_DEVLINK
> config PAGE_POOL
> bool
>
> +config NET_FAILOVER
> + tristate "Failover interface"
> + default m
Need some justification for default m (as opposed to n).
> + help
> + This provides a generic interface for paravirtual drivers to listen
> + for netdev register/unregister/link change events from pci ethernet
PCI
> + devices with the same MAC and takeover their datapath. This also
> + enables live migration of a VM with direct attached VF by failing
> + over to the paravirtual datapath when the VF is unplugged.
> +
> endif # if NET
>
> # Used by archs to tell that they support BPF JIT compiler plus which flavour.
> diff --git a/net/core/net_failover.c b/net/core/net_failover.c
> new file mode 100644
> index 000000000000..8d60e74e3034
> --- /dev/null
> +++ b/net/core/net_failover.c
> @@ -0,0 +1,1044 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2018, Intel Corporation. */
> +
> +/* A common module to handle registrations and notifications for paravirtual
> + * drivers to enable accelerated datapath and support VF live migration.
> + *
> + * The notifier and event handling code is based on netvsc driver and failover
> + * netdev management routines are based on bond/team driver.
> + *
> + */
> +/**
> + * net_failover_create - Create and register a failover instance
> + *
> + * @dev: standby netdev
* @standby_dev: standby netdev
> + *
> + * Creates a failover netdev and registers a failover instance for a standby
> + * netdev. Used by paravirtual drivers that use 3-netdev model.
> + * The failover netdev acts as a master device and controls 2 slave devices -
> + * the original standby netdev and a VF netdev with the same MAC gets
> + * registered as primary netdev.
> + *
> + * Return: pointer to failover instance
> + */
> +struct net_failover *net_failover_create(struct net_device *standby_dev)
> +{
> + struct device *dev = standby_dev->dev.parent;
> + struct net_device *failover_dev;
> + struct net_failover *failover;
> + int err;
> +
> + /* Alloc at least 2 queues, for now we are going with 16 assuming
> + * that VF devices being enslaved won't have too many queues.
> + */
> + failover_dev = alloc_etherdev_mq(sizeof(struct net_failover_info), 16);
> + if (!failover_dev) {
> + dev_err(dev, "Unable to allocate failover_netdev!\n");
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + dev_net_set(failover_dev, dev_net(standby_dev));
> + SET_NETDEV_DEV(failover_dev, dev);
> +
> + failover_dev->netdev_ops = &failover_dev_ops;
> + failover_dev->ethtool_ops = &failover_ethtool_ops;
> +
> + /* Initialize the device options */
> + failover_dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE;
> + failover_dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE |
> + IFF_TX_SKB_SHARING);
> +
> + /* don't acquire failover netdev's netif_tx_lock when transmitting */
> + failover_dev->features |= NETIF_F_LLTX;
> +
> + /* Don't allow failover devices to change network namespaces. */
> + failover_dev->features |= NETIF_F_NETNS_LOCAL;
> +
> + failover_dev->hw_features = FAILOVER_VLAN_FEATURES |
> + NETIF_F_HW_VLAN_CTAG_TX |
> + NETIF_F_HW_VLAN_CTAG_RX |
> + NETIF_F_HW_VLAN_CTAG_FILTER;
> +
> + failover_dev->hw_features |= NETIF_F_GSO_ENCAP_ALL;
> + failover_dev->features |= failover_dev->hw_features;
> +
> + memcpy(failover_dev->dev_addr, standby_dev->dev_addr,
> + failover_dev->addr_len);
> +
> + failover_dev->min_mtu = standby_dev->min_mtu;
> + failover_dev->max_mtu = standby_dev->max_mtu;
> +
> + err = register_netdev(failover_dev);
> + if (err) {
> + dev_err(dev, "Unable to register failover_dev!\n");
> + goto err_register_netdev;
> + }
> +
> + netif_carrier_off(failover_dev);
> +
> + failover = net_failover_register(failover_dev, NULL);
> + if (IS_ERR(failover))
> + goto err_failover_register;
> +
> + return failover;
> +
> +err_failover_register:
> + unregister_netdev(failover_dev);
> +err_register_netdev:
> + free_netdev(failover_dev);
> +
> + return ERR_PTR(err);
> +}
> +EXPORT_SYMBOL_GPL(net_failover_create);
--
~Randy
^ permalink raw reply
* [PATCH] qemu: Introduce VIRTIO_NET_F_STANDBY feature bit to virtio_net
From: Sridhar Samudrala @ 2018-05-07 23:09 UTC (permalink / raw)
To: mst, netdev, virtualization, virtio-dev, jesse.brandeburg,
alexander.h.duyck, kubakici, sridhar.samudrala, jasowang,
loseweigh, jiri, aaron.f.brown, qemu-devel
This feature bit can be used by hypervisor to indicate virtio_net device to
act as a standby for another device with the same MAC address.
I tested this with a small change to the patch to mark the STANDBY feature 'true'
by default as i am using libvirt to start the VMs.
Is there a way to pass the newly added feature bit 'standby' to qemu via libvirt
XML file?
Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
---
hw/net/virtio-net.c | 2 ++
include/standard-headers/linux/virtio_net.h | 3 +++
2 files changed, 5 insertions(+)
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 90502fca7c..38b3140670 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -2198,6 +2198,8 @@ static Property virtio_net_properties[] = {
true),
DEFINE_PROP_INT32("speed", VirtIONet, net_conf.speed, SPEED_UNKNOWN),
DEFINE_PROP_STRING("duplex", VirtIONet, net_conf.duplex_str),
+ DEFINE_PROP_BIT64("standby", VirtIONet, host_features, VIRTIO_NET_F_STANDBY,
+ false),
DEFINE_PROP_END_OF_LIST(),
};
diff --git a/include/standard-headers/linux/virtio_net.h b/include/standard-headers/linux/virtio_net.h
index e9f255ea3f..01ec09684c 100644
--- a/include/standard-headers/linux/virtio_net.h
+++ b/include/standard-headers/linux/virtio_net.h
@@ -57,6 +57,9 @@
* Steering */
#define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */
+#define VIRTIO_NET_F_STANDBY 62 /* Act as standby for another device
+ * with the same MAC.
+ */
#define VIRTIO_NET_F_SPEED_DUPLEX 63 /* Device set linkspeed and duplex */
#ifndef VIRTIO_NET_NO_LEGACY
--
2.14.3
^ permalink raw reply related
* Re: [PATCH net-next v10 2/4] net: Introduce generic failover module
From: Stephen Hemminger @ 2018-05-07 23:46 UTC (permalink / raw)
To: Sridhar Samudrala
Cc: alexander.h.duyck, virtio-dev, jiri, mst, kubakici, netdev,
virtualization, loseweigh, aaron.f.brown, davem
In-Reply-To: <1525731046-10989-3-git-send-email-sridhar.samudrala@intel.com>
On Mon, 7 May 2018 15:10:44 -0700
Sridhar Samudrala <sridhar.samudrala@intel.com> wrote:
> This provides a generic interface for paravirtual drivers to listen
> for netdev register/unregister/link change events from pci ethernet
> devices with the same MAC and takeover their datapath. The notifier and
> event handling code is based on the existing netvsc implementation.
>
> It exposes 2 sets of interfaces to the paravirtual drivers.
> 1. For paravirtual drivers like virtio_net that use 3 netdev model, the
> the failover module provides interfaces to create/destroy additional
> master netdev and all the slave events are managed internally.
> net_failover_create()
> net_failover_destroy()
> A failover netdev is created that acts a master device and controls 2
> slave devices. The original virtio_net netdev is registered as 'standby'
> netdev and a passthru/vf device with the same MAC gets registered as
> 'primary' netdev. Both 'standby' and 'failover' netdevs are associated
> with the same 'pci' device. The user accesses the network interface via
> 'failover' netdev. The 'failover' netdev chooses 'primary' netdev as
> default for transmits when it is available with link up and running.
> 2. For existing netvsc driver that uses 2 netdev model, no master netdev
> is created. The paravirtual driver registers each instance of netvsc
> as a 'failover' netdev along with a set of ops to manage the slave
> events. There is no 'standby' netdev in this model. A passthru/vf device
> with the same MAC gets registered as 'primary' netdev.
> net_failover_register()
> net_failover_unregister()
>
> Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
You are conflating the net_failover device (3 device model) with
the generic network failover infrastructure into one file. There should be two
seperate files net/core/failover.c and drivers/net/failover.c which splits
the work into two parts (and acts a check for the api).
^ permalink raw reply
* Re: [PATCH net-next v10 2/4] net: Introduce generic failover module
From: Stephen Hemminger @ 2018-05-07 23:53 UTC (permalink / raw)
To: Sridhar Samudrala
Cc: alexander.h.duyck, virtio-dev, jiri, mst, kubakici, netdev,
virtualization, loseweigh, aaron.f.brown, davem
In-Reply-To: <1525731046-10989-3-git-send-email-sridhar.samudrala@intel.com>
On Mon, 7 May 2018 15:10:44 -0700
Sridhar Samudrala <sridhar.samudrala@intel.com> wrote:
> +static struct net_device *net_failover_get_bymac(u8 *mac,
> + struct net_failover_ops **ops)
> +{
> + struct net_device *failover_dev;
> + struct net_failover *failover;
> +
> + spin_lock(&net_failover_lock);
> + list_for_each_entry(failover, &net_failover_list, list) {
> + failover_dev = rtnl_dereference(failover->failover_dev);
> + if (ether_addr_equal(failover_dev->perm_addr, mac)) {
> + *ops = rtnl_dereference(failover->ops);
> + spin_unlock(&net_failover_lock);
> + return failover_dev;
> + }
> + }
> + spin_unlock(&net_failover_lock);
> + return NULL;
> +}
This is broken if non-ethernet devices such as Infiniband are present.
^ permalink raw reply
* Re: [PATCH net-next v10 2/4] net: Introduce generic failover module
From: Stephen Hemminger @ 2018-05-07 23:59 UTC (permalink / raw)
To: Sridhar Samudrala
Cc: alexander.h.duyck, virtio-dev, jiri, mst, kubakici, netdev,
virtualization, loseweigh, aaron.f.brown, davem
In-Reply-To: <1525731046-10989-3-git-send-email-sridhar.samudrala@intel.com>
On Mon, 7 May 2018 15:10:44 -0700
Sridhar Samudrala <sridhar.samudrala@intel.com> wrote:
> + if (netif_running(failover_dev)) {
> + err = dev_open(slave_dev);
> + if (err && (err != -EBUSY)) {
> + netdev_err(failover_dev, "Opening slave %s failed err:%d\n",
> + slave_dev->name, err);
> + goto err_dev_open;
> + }
> + }
> +
> + netif_addr_lock_bh(failover_dev);
> + dev_uc_sync_multiple(slave_dev, failover_dev);
> + dev_uc_sync_multiple(slave_dev, failover_dev);
> + netif_addr_unlock_bh(failover_dev);
> +
The order of these is backwards, you want to sync addresses before bringing up.
Also, doing it this way does not allow udev/systemd the chance to rename VF devices.
The complexity of this whole failover mechanism does not make life easier,
more reliable, or safer for netvsc. I though that was the whole reason for having
common code.
^ permalink raw reply
* Re: [PATCH net-next v10 2/4] net: Introduce generic failover module
From: Samudrala, Sridhar @ 2018-05-08 0:11 UTC (permalink / raw)
To: Stephen Hemminger
Cc: alexander.h.duyck, virtio-dev, jiri, mst, kubakici, netdev,
virtualization, loseweigh, aaron.f.brown, davem
In-Reply-To: <20180507165911.45b14c58@xeon-e3>
On 5/7/2018 4:59 PM, Stephen Hemminger wrote:
> On Mon, 7 May 2018 15:10:44 -0700
> Sridhar Samudrala <sridhar.samudrala@intel.com> wrote:
>
>> + if (netif_running(failover_dev)) {
>> + err = dev_open(slave_dev);
>> + if (err && (err != -EBUSY)) {
>> + netdev_err(failover_dev, "Opening slave %s failed err:%d\n",
>> + slave_dev->name, err);
>> + goto err_dev_open;
>> + }
>> + }
>> +
>> + netif_addr_lock_bh(failover_dev);
>> + dev_uc_sync_multiple(slave_dev, failover_dev);
>> + dev_uc_sync_multiple(slave_dev, failover_dev);
>> + netif_addr_unlock_bh(failover_dev);
>> +
> The order of these is backwards, you want to sync addresses before bringing up.
> Also, doing it this way does not allow udev/systemd the chance to rename VF devices.
During my testing, i noticed that dev_open() may fail with EBUSY in certain scenarios,
If so, the opening of the slave is handled after the rename via the NETDEV_CHANGENAME
event handler.
>
> The complexity of this whole failover mechanism does not make life easier,
> more reliable, or safer for netvsc. I though that was the whole reason for having
> common code.
netvsc doesn't go through this code.
if (nfo_ops && nfo_ops->slave_register)
return nfo_ops->slave_register(slave_dev, failover_dev);
So there is no change in event handling for netvsc 2-netdev model.
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^ permalink raw reply
* Re: [PATCH net-next v10 2/4] net: Introduce generic failover module
From: Samudrala, Sridhar @ 2018-05-08 0:24 UTC (permalink / raw)
To: Stephen Hemminger
Cc: alexander.h.duyck, virtio-dev, jiri, mst, kubakici, netdev,
virtualization, loseweigh, aaron.f.brown, davem
In-Reply-To: <20180507165306.541bd1f2@xeon-e3>
On 5/7/2018 4:53 PM, Stephen Hemminger wrote:
> On Mon, 7 May 2018 15:10:44 -0700
> Sridhar Samudrala <sridhar.samudrala@intel.com> wrote:
>
>> +static struct net_device *net_failover_get_bymac(u8 *mac,
>> + struct net_failover_ops **ops)
>> +{
>> + struct net_device *failover_dev;
>> + struct net_failover *failover;
>> +
>> + spin_lock(&net_failover_lock);
>> + list_for_each_entry(failover, &net_failover_list, list) {
>> + failover_dev = rtnl_dereference(failover->failover_dev);
>> + if (ether_addr_equal(failover_dev->perm_addr, mac)) {
>> + *ops = rtnl_dereference(failover->ops);
>> + spin_unlock(&net_failover_lock);
>> + return failover_dev;
>> + }
>> + }
>> + spin_unlock(&net_failover_lock);
>> + return NULL;
>> +}
> This is broken if non-ethernet devices such as Infiniband are present.
There is check to make sure that a slave and failover devices are of the same type in
net_failover_slave_register()
failover_dev = net_failover_get_bymac(slave_dev->perm_addr, &nfo_ops);
if (!failover_dev)
goto done;
if (failover_dev->type != slave_dev->type)
goto done;
Do you think this is not good enough? I had an explicit check for ARPHRD_ETHER in
earlier patchsets, but removed it based on Jiri's comment.
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^ permalink raw reply
* Re: [RFC v3 4/5] virtio_ring: add event idx support in packed ring
From: Jason Wang @ 2018-05-08 3:05 UTC (permalink / raw)
To: Tiwei Bie; +Cc: Michael S. Tsirkin, netdev, linux-kernel, virtualization, wexu
In-Reply-To: <20180503135430.lbtvn4p4lyu3ksqo@debian>
On 2018年05月03日 21:54, Tiwei Bie wrote:
> On Thu, May 03, 2018 at 03:25:29PM +0800, Jason Wang wrote:
>> On 2018年05月03日 10:09, Tiwei Bie wrote:
>>>>>> So how about we use the straightforward way then?
>>>>> You mean we do new += vq->vring_packed.num instead
>>>>> of event_idx -= vq->vring_packed.num before calling
>>>>> vring_need_event()?
>>>>>
>>>>> The problem is that, the second param (new_idx) of
>>>>> vring_need_event() will be used for:
>>>>>
>>>>> (__u16)(new_idx - event_idx - 1)
>>>>> (__u16)(new_idx - old)
>>>>>
>>>>> So if we change new, we will need to change old too.
>>>> I think that since we have a branch there anyway,
>>>> we are better off just special-casing if (wrap_counter != vq->wrap_counter).
>>>> Treat is differenty and avoid casts.
>>>>
>>>>> And that would be an ugly hack..
>>>>>
>>>>> Best regards,
>>>>> Tiwei Bie
>>>> I consider casts and huge numbers with two's complement
>>>> games even uglier.
>>> The dependency on two's complement game is introduced
>>> since the split ring.
>>>
>>> In packed ring, old is calculated via:
>>>
>>> old = vq->next_avail_idx - vq->num_added;
>>>
>>> In split ring, old is calculated via:
>>>
>>> old = vq->avail_idx_shadow - vq->num_added;
>>>
>>> In both cases, when vq->num_added is bigger, old will
>>> be a big number.
>>>
>>> Best regards,
>>> Tiwei Bie
>>>
>> How about just do something like vhost:
>>
>> static u16 vhost_idx_diff(struct vhost_virtqueue *vq, u16 old, u16 new)
>> {
>> if (new > old)
>> return new - old;
>> return (new + vq->num - old);
>> }
>>
>> static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
>> __u16 event_off, __u16 new,
>> __u16 old)
>> {
>> return (__u16)(vhost_idx_diff(vq, new, event_off) - 1) <
>> (__u16)vhost_idx_diff(vq, new, old);
>> }
>>
>> ?
> It seems that there is a typo in above code. The second
> param of vhost_idx_diff() is `old`, but when calling this
> function in vhost_vring_packed_need_event(), `new` is
> passed as the second param.
Right.
>
> If we assume the second param of vhost_idx_diff() is new
> and the third one is old, i.e.:
>
> static u16 vhost_idx_diff(struct vhost_virtqueue *vq, u16 new, u16 old)
> {
> if (new > old)
> return new - old;
> return (new + vq->num - old);
> }
>
> I think it's still not right.
>
> Because in virtqueue_enable_cb_delayed(), we may set an
> event_off which is bigger than new and both of them have
> wrapped. And in this case, although new is smaller than
> event_off (i.e. the third param -- old), new shouldn't
> add vq->num, and actually we are expecting a very big
> idx diff.
Yes, so to calculate distance correctly between event and new, we just
need to compare the warp counter and return false if it doesn't match
without the need to try to add vq.num here.
Thanks
>
> Best regards,
> Tiwei Bie
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^ permalink raw reply
* Re: [RFC v3 4/5] virtio_ring: add event idx support in packed ring
From: Jason Wang @ 2018-05-08 5:40 UTC (permalink / raw)
To: Tiwei Bie; +Cc: Michael S. Tsirkin, netdev, linux-kernel, virtualization, wexu
In-Reply-To: <fbe06940-1618-5d34-7321-f4888c5dd1ee@redhat.com>
On 2018年05月08日 11:05, Jason Wang wrote:
>>
>> Because in virtqueue_enable_cb_delayed(), we may set an
>> event_off which is bigger than new and both of them have
>> wrapped. And in this case, although new is smaller than
>> event_off (i.e. the third param -- old), new shouldn't
>> add vq->num, and actually we are expecting a very big
>> idx diff.
>
> Yes, so to calculate distance correctly between event and new, we just
> need to compare the warp counter and return false if it doesn't match
> without the need to try to add vq.num here.
>
> Thanks
Sorry, looks like the following should work, we need add vq.num if
used_wrap_counter does not match:
static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
__u16 off_wrap, __u16 new,
__u16 old)
{
bool wrap = off_wrap >> 15;
int off = off_wrap & ~(1 << 15);
__u16 d1, d2;
if (wrap != vq->used_wrap_counter)
d1 = new + vq->num - off - 1;
else
d1 = new - off - 1;
if (new > old)
d2 = new - old;
else
d2 = new + vq->num - old;
return d1 < d2;
}
Thanks
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^ permalink raw reply
* Re: [RFC v3 4/5] virtio_ring: add event idx support in packed ring
From: Tiwei Bie @ 2018-05-08 6:44 UTC (permalink / raw)
To: Jason Wang; +Cc: Michael S. Tsirkin, netdev, linux-kernel, virtualization, wexu
In-Reply-To: <12ede490-f674-2b89-d639-266b5fe15466@redhat.com>
On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote:
> On 2018年05月08日 11:05, Jason Wang wrote:
> > >
> > > Because in virtqueue_enable_cb_delayed(), we may set an
> > > event_off which is bigger than new and both of them have
> > > wrapped. And in this case, although new is smaller than
> > > event_off (i.e. the third param -- old), new shouldn't
> > > add vq->num, and actually we are expecting a very big
> > > idx diff.
> >
> > Yes, so to calculate distance correctly between event and new, we just
> > need to compare the warp counter and return false if it doesn't match
> > without the need to try to add vq.num here.
> >
> > Thanks
>
> Sorry, looks like the following should work, we need add vq.num if
> used_wrap_counter does not match:
>
> static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
> __u16 off_wrap, __u16 new,
> __u16 old)
> {
> bool wrap = off_wrap >> 15;
> int off = off_wrap & ~(1 << 15);
> __u16 d1, d2;
>
> if (wrap != vq->used_wrap_counter)
> d1 = new + vq->num - off - 1;
Just to draw your attention (maybe you have already
noticed this).
In this case (i.e. wrap != vq->used_wrap_counter),
it's also possible that (off < new) is true. Because,
when virtqueue_enable_cb_delayed_packed() is used,
`off` is calculated in driver in a way like this:
off = vq->last_used_idx + bufs;
if (off >= vq->vring_packed.num) {
off -= vq->vring_packed.num;
wrap_counter ^= 1;
}
And when `new` (in vhost) is close to vq->num. The
vq->last_used_idx + bufs (in driver) can be bigger
than vq->vring_packed.num, and:
1. `off` will wrap;
2. wrap counters won't match;
3. off < new;
And d1 (i.e. new + vq->num - off - 1) will be a value
bigger than vq->num. I'm okay with this, although it's
a bit weird.
Best regards,
Tiwei Bie
> else
> d1 = new - off - 1;
>
> if (new > old)
> d2 = new - old;
> else
> d2 = new + vq->num - old;
>
> return d1 < d2;
> }
>
> Thanks
>
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
^ permalink raw reply
* Re: [RFC v3 4/5] virtio_ring: add event idx support in packed ring
From: Jason Wang @ 2018-05-08 7:16 UTC (permalink / raw)
To: Tiwei Bie; +Cc: Michael S. Tsirkin, netdev, linux-kernel, virtualization, wexu
In-Reply-To: <20180508064409.kcn6amhsxu7nkuuc@debian>
On 2018年05月08日 14:44, Tiwei Bie wrote:
> On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote:
>> On 2018年05月08日 11:05, Jason Wang wrote:
>>>> Because in virtqueue_enable_cb_delayed(), we may set an
>>>> event_off which is bigger than new and both of them have
>>>> wrapped. And in this case, although new is smaller than
>>>> event_off (i.e. the third param -- old), new shouldn't
>>>> add vq->num, and actually we are expecting a very big
>>>> idx diff.
>>> Yes, so to calculate distance correctly between event and new, we just
>>> need to compare the warp counter and return false if it doesn't match
>>> without the need to try to add vq.num here.
>>>
>>> Thanks
>> Sorry, looks like the following should work, we need add vq.num if
>> used_wrap_counter does not match:
>>
>> static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
>> __u16 off_wrap, __u16 new,
>> __u16 old)
>> {
>> bool wrap = off_wrap >> 15;
>> int off = off_wrap & ~(1 << 15);
>> __u16 d1, d2;
>>
>> if (wrap != vq->used_wrap_counter)
>> d1 = new + vq->num - off - 1;
> Just to draw your attention (maybe you have already
> noticed this).
I miss this, thanks!
>
> In this case (i.e. wrap != vq->used_wrap_counter),
> it's also possible that (off < new) is true. Because,
>
> when virtqueue_enable_cb_delayed_packed() is used,
> `off` is calculated in driver in a way like this:
>
> off = vq->last_used_idx + bufs;
> if (off >= vq->vring_packed.num) {
> off -= vq->vring_packed.num;
> wrap_counter ^= 1;
> }
>
> And when `new` (in vhost) is close to vq->num. The
> vq->last_used_idx + bufs (in driver) can be bigger
> than vq->vring_packed.num, and:
>
> 1. `off` will wrap;
> 2. wrap counters won't match;
> 3. off < new;
>
> And d1 (i.e. new + vq->num - off - 1) will be a value
> bigger than vq->num. I'm okay with this, although it's
> a bit weird.
So I'm considering something more compact by reusing vring_need_event()
by pretending a larger queue size and adding vq->num back when necessary:
static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
__u16 off_wrap, __u16 new,
__u16 old)
{
bool wrap = vq->used_wrap_counter;
int off = off_wrap & ~(1 << 15);
__u16 d1, d2;
if (new < old) {
new += vq->num;
wrap ^= 1;
}
if (wrap != off_wrap >> 15)
off += vq->num;
return vring_need_event(off, new, old);
}
>
> Best regards,
> Tiwei Bie
>
>> else
>> d1 = new - off - 1;
>>
>> if (new > old)
>> d2 = new - old;
>> else
>> d2 = new + vq->num - old;
>>
>> return d1 < d2;
>> }
>>
>> Thanks
>>
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Virtualization mailing list
Virtualization@lists.linux-foundation.org
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^ permalink raw reply
* Re: [PATCH net-next v10 2/4] net: Introduce generic failover module
From: kbuild test robot @ 2018-05-08 9:02 UTC (permalink / raw)
Cc: alexander.h.duyck, virtio-dev, jiri, mst, kubakici, netdev,
virtualization, loseweigh, kbuild-all, sridhar.samudrala,
aaron.f.brown, davem
In-Reply-To: <1525731046-10989-3-git-send-email-sridhar.samudrala@intel.com>
Hi Sridhar,
I love your patch! Perhaps something to improve:
[auto build test WARNING on net-next/master]
url: https://github.com/0day-ci/linux/commits/Sridhar-Samudrala/Enable-virtio_net-to-act-as-a-standby-for-a-passthru-device/20180508-123531
reproduce:
# apt-get install sparse
make ARCH=x86_64 allmodconfig
make C=1 CF=-D__CHECK_ENDIAN__
sparse warnings: (new ones prefixed by >>)
>> net/core/net_failover.c:868:16: sparse: Using plain integer as NULL pointer
net/core/net_failover.c:115:12: sparse: context imbalance in 'net_failover_select_queue' - wrong count at exit
vim +868 net/core/net_failover.c
828
829 /**
830 * net_failover_register - Register a failover instance
831 *
832 * @dev: failover or standby netdev
833 * @ops: failover ops
834 *
835 * Paravirtual drivers supporting 3-netdev model call this routine indirectly
836 * via net_failover_create(). It passes failover netdev and ops will be NULL
837 * as the slave events are handled internally.
838 * Paravirtual drivers supporting 2-netdev model call this routine by passing
839 * standby netdev and ops that are called to handle slave register/unregister/
840 * link change events.
841 *
842 * Return: pointer to failover instance
843 */
844 struct net_failover *net_failover_register(struct net_device *dev,
845 struct net_failover_ops *ops)
846 {
847 struct net_failover *failover;
848
849 failover = kzalloc(sizeof(*failover), GFP_KERNEL);
850 if (!failover)
851 return ERR_PTR(-ENOMEM);
852
853 rcu_assign_pointer(failover->ops, ops);
854 dev_hold(dev);
855 dev->priv_flags |= IFF_FAILOVER;
856 rcu_assign_pointer(failover->failover_dev, dev);
857
858 spin_lock(&net_failover_lock);
859 list_add_tail(&failover->list, &net_failover_list);
860 spin_unlock(&net_failover_lock);
861
862 netdev_info(dev, "failover master:%s registered\n", dev->name);
863
864 net_failover_existing_slave_register(dev);
865
866 return failover;
867
> 868 return 0;
869 }
870 EXPORT_SYMBOL_GPL(net_failover_register);
871
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
^ permalink raw reply
* Re: [RFC v3 4/5] virtio_ring: add event idx support in packed ring
From: Tiwei Bie @ 2018-05-08 9:16 UTC (permalink / raw)
To: Jason Wang; +Cc: Michael S. Tsirkin, netdev, linux-kernel, virtualization, wexu
In-Reply-To: <34f2c690-7cb2-f9ea-2ce9-40f4ccb594c9@redhat.com>
On Tue, May 08, 2018 at 03:16:53PM +0800, Jason Wang wrote:
> On 2018年05月08日 14:44, Tiwei Bie wrote:
> > On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote:
> > > On 2018年05月08日 11:05, Jason Wang wrote:
> > > > > Because in virtqueue_enable_cb_delayed(), we may set an
> > > > > event_off which is bigger than new and both of them have
> > > > > wrapped. And in this case, although new is smaller than
> > > > > event_off (i.e. the third param -- old), new shouldn't
> > > > > add vq->num, and actually we are expecting a very big
> > > > > idx diff.
> > > > Yes, so to calculate distance correctly between event and new, we just
> > > > need to compare the warp counter and return false if it doesn't match
> > > > without the need to try to add vq.num here.
> > > >
> > > > Thanks
> > > Sorry, looks like the following should work, we need add vq.num if
> > > used_wrap_counter does not match:
> > >
> > > static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
> > > __u16 off_wrap, __u16 new,
> > > __u16 old)
> > > {
> > > bool wrap = off_wrap >> 15;
> > > int off = off_wrap & ~(1 << 15);
> > > __u16 d1, d2;
> > >
> > > if (wrap != vq->used_wrap_counter)
> > > d1 = new + vq->num - off - 1;
> > Just to draw your attention (maybe you have already
> > noticed this).
>
> I miss this, thanks!
>
> >
> > In this case (i.e. wrap != vq->used_wrap_counter),
> > it's also possible that (off < new) is true. Because,
> >
> > when virtqueue_enable_cb_delayed_packed() is used,
> > `off` is calculated in driver in a way like this:
> >
> > off = vq->last_used_idx + bufs;
> > if (off >= vq->vring_packed.num) {
> > off -= vq->vring_packed.num;
> > wrap_counter ^= 1;
> > }
> >
> > And when `new` (in vhost) is close to vq->num. The
> > vq->last_used_idx + bufs (in driver) can be bigger
> > than vq->vring_packed.num, and:
> >
> > 1. `off` will wrap;
> > 2. wrap counters won't match;
> > 3. off < new;
> >
> > And d1 (i.e. new + vq->num - off - 1) will be a value
> > bigger than vq->num. I'm okay with this, although it's
> > a bit weird.
>
>
> So I'm considering something more compact by reusing vring_need_event() by
> pretending a larger queue size and adding vq->num back when necessary:
>
> static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
> __u16 off_wrap, __u16 new,
> __u16 old)
> {
> bool wrap = vq->used_wrap_counter;
If the wrap counter is obtained from the vq,
I think `new` should also be obtained from
the vq. Or the wrap counter should be carried
in `new`.
> int off = off_wrap & ~(1 << 15);
> __u16 d1, d2;
>
> if (new < old) {
> new += vq->num;
> wrap ^= 1;
> }
>
> if (wrap != off_wrap >> 15)
> off += vq->num;
When `new` and `old` wraps, and `off` doesn't wrap,
wrap != (off_wrap >> 15) will be true. In this case,
`off` is bigger than `new`, and what we should do
is `off -= vq->num` instead of `off += vq->num`.
Best regards,
Tiwei Bie
>
> return vring_need_event(off, new, old);
> }
>
>
> >
> > Best regards,
> > Tiwei Bie
> >
> > > else
> > > d1 = new - off - 1;
> > >
> > > if (new > old)
> > > d2 = new - old;
> > > else
> > > d2 = new + vq->num - old;
> > >
> > > return d1 < d2;
> > > }
> > >
> > > Thanks
> > >
>
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
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^ permalink raw reply
* Re: [RFC v3 4/5] virtio_ring: add event idx support in packed ring
From: Jason Wang @ 2018-05-08 9:34 UTC (permalink / raw)
To: Tiwei Bie; +Cc: Michael S. Tsirkin, netdev, linux-kernel, virtualization, wexu
In-Reply-To: <20180508091628.d7jzpopqopq4abhy@debian>
On 2018年05月08日 17:16, Tiwei Bie wrote:
> On Tue, May 08, 2018 at 03:16:53PM +0800, Jason Wang wrote:
>> On 2018年05月08日 14:44, Tiwei Bie wrote:
>>> On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote:
>>>> On 2018年05月08日 11:05, Jason Wang wrote:
>>>>>> Because in virtqueue_enable_cb_delayed(), we may set an
>>>>>> event_off which is bigger than new and both of them have
>>>>>> wrapped. And in this case, although new is smaller than
>>>>>> event_off (i.e. the third param -- old), new shouldn't
>>>>>> add vq->num, and actually we are expecting a very big
>>>>>> idx diff.
>>>>> Yes, so to calculate distance correctly between event and new, we just
>>>>> need to compare the warp counter and return false if it doesn't match
>>>>> without the need to try to add vq.num here.
>>>>>
>>>>> Thanks
>>>> Sorry, looks like the following should work, we need add vq.num if
>>>> used_wrap_counter does not match:
>>>>
>>>> static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
>>>> __u16 off_wrap, __u16 new,
>>>> __u16 old)
>>>> {
>>>> bool wrap = off_wrap >> 15;
>>>> int off = off_wrap & ~(1 << 15);
>>>> __u16 d1, d2;
>>>>
>>>> if (wrap != vq->used_wrap_counter)
>>>> d1 = new + vq->num - off - 1;
>>> Just to draw your attention (maybe you have already
>>> noticed this).
>> I miss this, thanks!
>>
>>> In this case (i.e. wrap != vq->used_wrap_counter),
>>> it's also possible that (off < new) is true. Because,
>>>
>>> when virtqueue_enable_cb_delayed_packed() is used,
>>> `off` is calculated in driver in a way like this:
>>>
>>> off = vq->last_used_idx + bufs;
>>> if (off >= vq->vring_packed.num) {
>>> off -= vq->vring_packed.num;
>>> wrap_counter ^= 1;
>>> }
>>>
>>> And when `new` (in vhost) is close to vq->num. The
>>> vq->last_used_idx + bufs (in driver) can be bigger
>>> than vq->vring_packed.num, and:
>>>
>>> 1. `off` will wrap;
>>> 2. wrap counters won't match;
>>> 3. off < new;
>>>
>>> And d1 (i.e. new + vq->num - off - 1) will be a value
>>> bigger than vq->num. I'm okay with this, although it's
>>> a bit weird.
>>
>> So I'm considering something more compact by reusing vring_need_event() by
>> pretending a larger queue size and adding vq->num back when necessary:
>>
>> static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
>> __u16 off_wrap, __u16 new,
>> __u16 old)
>> {
>> bool wrap = vq->used_wrap_counter;
> If the wrap counter is obtained from the vq,
> I think `new` should also be obtained from
> the vq. Or the wrap counter should be carried
> in `new`.
>
>> int off = off_wrap & ~(1 << 15);
>> __u16 d1, d2;
>>
>> if (new < old) {
>> new += vq->num;
>> wrap ^= 1;
>> }
>>
>> if (wrap != off_wrap >> 15)
>> off += vq->num;
> When `new` and `old` wraps, and `off` doesn't wrap,
> wrap != (off_wrap >> 15) will be true. In this case,
> `off` is bigger than `new`, and what we should do
> is `off -= vq->num` instead of `off += vq->num`.
If I understand this correctly, if we track old correctly, it won't
happen if guest driver behave correctly. That means it should only
happen for a buggy driver (e.g trying to move off_wrap back).
Thanks
>
> Best regards,
> Tiwei Bie
>
>> return vring_need_event(off, new, old);
>> }
>>
>>
>>> Best regards,
>>> Tiwei Bie
>>>
>>>> else
>>>> d1 = new - off - 1;
>>>>
>>>> if (new > old)
>>>> d2 = new - old;
>>>> else
>>>> d2 = new + vq->num - old;
>>>>
>>>> return d1 < d2;
>>>> }
>>>>
>>>> Thanks
>>>>
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Virtualization mailing list
Virtualization@lists.linux-foundation.org
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^ permalink raw reply
* Re: [RFC v3 4/5] virtio_ring: add event idx support in packed ring
From: Tiwei Bie @ 2018-05-08 9:44 UTC (permalink / raw)
To: Jason Wang; +Cc: Michael S. Tsirkin, netdev, linux-kernel, virtualization, wexu
In-Reply-To: <122277c6-d103-e1f6-d695-4d64e6934a51@redhat.com>
On Tue, May 08, 2018 at 05:34:40PM +0800, Jason Wang wrote:
> On 2018年05月08日 17:16, Tiwei Bie wrote:
> > On Tue, May 08, 2018 at 03:16:53PM +0800, Jason Wang wrote:
> > > On 2018年05月08日 14:44, Tiwei Bie wrote:
> > > > On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote:
> > > > > On 2018年05月08日 11:05, Jason Wang wrote:
> > > > > > > Because in virtqueue_enable_cb_delayed(), we may set an
> > > > > > > event_off which is bigger than new and both of them have
> > > > > > > wrapped. And in this case, although new is smaller than
> > > > > > > event_off (i.e. the third param -- old), new shouldn't
> > > > > > > add vq->num, and actually we are expecting a very big
> > > > > > > idx diff.
> > > > > > Yes, so to calculate distance correctly between event and new, we just
> > > > > > need to compare the warp counter and return false if it doesn't match
> > > > > > without the need to try to add vq.num here.
> > > > > >
> > > > > > Thanks
> > > > > Sorry, looks like the following should work, we need add vq.num if
> > > > > used_wrap_counter does not match:
> > > > >
> > > > > static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
> > > > > __u16 off_wrap, __u16 new,
> > > > > __u16 old)
> > > > > {
> > > > > bool wrap = off_wrap >> 15;
> > > > > int off = off_wrap & ~(1 << 15);
> > > > > __u16 d1, d2;
> > > > >
> > > > > if (wrap != vq->used_wrap_counter)
> > > > > d1 = new + vq->num - off - 1;
> > > > Just to draw your attention (maybe you have already
> > > > noticed this).
> > > I miss this, thanks!
> > >
> > > > In this case (i.e. wrap != vq->used_wrap_counter),
> > > > it's also possible that (off < new) is true. Because,
> > > >
> > > > when virtqueue_enable_cb_delayed_packed() is used,
> > > > `off` is calculated in driver in a way like this:
> > > >
> > > > off = vq->last_used_idx + bufs;
> > > > if (off >= vq->vring_packed.num) {
> > > > off -= vq->vring_packed.num;
> > > > wrap_counter ^= 1;
> > > > }
> > > >
> > > > And when `new` (in vhost) is close to vq->num. The
> > > > vq->last_used_idx + bufs (in driver) can be bigger
> > > > than vq->vring_packed.num, and:
> > > >
> > > > 1. `off` will wrap;
> > > > 2. wrap counters won't match;
> > > > 3. off < new;
> > > >
> > > > And d1 (i.e. new + vq->num - off - 1) will be a value
> > > > bigger than vq->num. I'm okay with this, although it's
> > > > a bit weird.
> > >
> > > So I'm considering something more compact by reusing vring_need_event() by
> > > pretending a larger queue size and adding vq->num back when necessary:
> > >
> > > static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
> > > __u16 off_wrap, __u16 new,
> > > __u16 old)
> > > {
> > > bool wrap = vq->used_wrap_counter;
> > If the wrap counter is obtained from the vq,
> > I think `new` should also be obtained from
> > the vq. Or the wrap counter should be carried
> > in `new`.
> >
> > > int off = off_wrap & ~(1 << 15);
> > > __u16 d1, d2;
> > >
> > > if (new < old) {
> > > new += vq->num;
> > > wrap ^= 1;
> > > }
> > >
> > > if (wrap != off_wrap >> 15)
> > > off += vq->num;
> > When `new` and `old` wraps, and `off` doesn't wrap,
> > wrap != (off_wrap >> 15) will be true. In this case,
> > `off` is bigger than `new`, and what we should do
> > is `off -= vq->num` instead of `off += vq->num`.
>
> If I understand this correctly, if we track old correctly, it won't happen
> if guest driver behave correctly. That means it should only happen for a
> buggy driver (e.g trying to move off_wrap back).
If vhost is faster than virtio driver, I guess above
case may happen. The `old` and `new` will be updated
each time we want to notify the driver. If the driver
is slower, `old` and `new` in vhost may wrap before
the `off` which is set by driver wraps.
Best regards,
Tiwei Bie
>
> Thanks
>
> >
> > Best regards,
> > Tiwei Bie
> >
> > > return vring_need_event(off, new, old);
> > > }
> > >
> > >
> > > > Best regards,
> > > > Tiwei Bie
> > > >
> > > > > else
> > > > > d1 = new - off - 1;
> > > > >
> > > > > if (new > old)
> > > > > d2 = new - old;
> > > > > else
> > > > > d2 = new + vq->num - old;
> > > > >
> > > > > return d1 < d2;
> > > > > }
> > > > >
> > > > > Thanks
> > > > >
>
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Virtualization mailing list
Virtualization@lists.linux-foundation.org
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^ permalink raw reply
* Re: [RFC v3 4/5] virtio_ring: add event idx support in packed ring
From: Jason Wang @ 2018-05-09 3:43 UTC (permalink / raw)
To: Tiwei Bie; +Cc: Michael S. Tsirkin, netdev, linux-kernel, virtualization, wexu
In-Reply-To: <20180508094406.qjlaism3hqy4hvjd@debian>
On 2018年05月08日 17:44, Tiwei Bie wrote:
> On Tue, May 08, 2018 at 05:34:40PM +0800, Jason Wang wrote:
>> On 2018年05月08日 17:16, Tiwei Bie wrote:
>>> On Tue, May 08, 2018 at 03:16:53PM +0800, Jason Wang wrote:
>>>> On 2018年05月08日 14:44, Tiwei Bie wrote:
>>>>> On Tue, May 08, 2018 at 01:40:40PM +0800, Jason Wang wrote:
>>>>>> On 2018年05月08日 11:05, Jason Wang wrote:
>>>>>>>> Because in virtqueue_enable_cb_delayed(), we may set an
>>>>>>>> event_off which is bigger than new and both of them have
>>>>>>>> wrapped. And in this case, although new is smaller than
>>>>>>>> event_off (i.e. the third param -- old), new shouldn't
>>>>>>>> add vq->num, and actually we are expecting a very big
>>>>>>>> idx diff.
>>>>>>> Yes, so to calculate distance correctly between event and new, we just
>>>>>>> need to compare the warp counter and return false if it doesn't match
>>>>>>> without the need to try to add vq.num here.
>>>>>>>
>>>>>>> Thanks
>>>>>> Sorry, looks like the following should work, we need add vq.num if
>>>>>> used_wrap_counter does not match:
>>>>>>
>>>>>> static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
>>>>>> __u16 off_wrap, __u16 new,
>>>>>> __u16 old)
>>>>>> {
>>>>>> bool wrap = off_wrap >> 15;
>>>>>> int off = off_wrap & ~(1 << 15);
>>>>>> __u16 d1, d2;
>>>>>>
>>>>>> if (wrap != vq->used_wrap_counter)
>>>>>> d1 = new + vq->num - off - 1;
>>>>> Just to draw your attention (maybe you have already
>>>>> noticed this).
>>>> I miss this, thanks!
>>>>
>>>>> In this case (i.e. wrap != vq->used_wrap_counter),
>>>>> it's also possible that (off < new) is true. Because,
>>>>>
>>>>> when virtqueue_enable_cb_delayed_packed() is used,
>>>>> `off` is calculated in driver in a way like this:
>>>>>
>>>>> off = vq->last_used_idx + bufs;
>>>>> if (off >= vq->vring_packed.num) {
>>>>> off -= vq->vring_packed.num;
>>>>> wrap_counter ^= 1;
>>>>> }
>>>>>
>>>>> And when `new` (in vhost) is close to vq->num. The
>>>>> vq->last_used_idx + bufs (in driver) can be bigger
>>>>> than vq->vring_packed.num, and:
>>>>>
>>>>> 1. `off` will wrap;
>>>>> 2. wrap counters won't match;
>>>>> 3. off < new;
>>>>>
>>>>> And d1 (i.e. new + vq->num - off - 1) will be a value
>>>>> bigger than vq->num. I'm okay with this, although it's
>>>>> a bit weird.
>>>> So I'm considering something more compact by reusing vring_need_event() by
>>>> pretending a larger queue size and adding vq->num back when necessary:
>>>>
>>>> static bool vhost_vring_packed_need_event(struct vhost_virtqueue *vq,
>>>> __u16 off_wrap, __u16 new,
>>>> __u16 old)
>>>> {
>>>> bool wrap = vq->used_wrap_counter;
>>> If the wrap counter is obtained from the vq,
>>> I think `new` should also be obtained from
>>> the vq. Or the wrap counter should be carried
>>> in `new`.
>>>
>>>> int off = off_wrap & ~(1 << 15);
>>>> __u16 d1, d2;
>>>>
>>>> if (new < old) {
>>>> new += vq->num;
>>>> wrap ^= 1;
>>>> }
>>>>
>>>> if (wrap != off_wrap >> 15)
>>>> off += vq->num;
>>> When `new` and `old` wraps, and `off` doesn't wrap,
>>> wrap != (off_wrap >> 15) will be true. In this case,
>>> `off` is bigger than `new`, and what we should do
>>> is `off -= vq->num` instead of `off += vq->num`.
>> If I understand this correctly, if we track old correctly, it won't happen
>> if guest driver behave correctly. That means it should only happen for a
>> buggy driver (e.g trying to move off_wrap back).
> If vhost is faster than virtio driver, I guess above
> case may happen. The `old` and `new` will be updated
> each time we want to notify the driver. If the driver
> is slower, `old` and `new` in vhost may wrap before
> the `off` which is set by driver wraps.
>
> Best regards,
> Tiwei Bie
>
Oh, right.
But the code still work (in this case new - event_idx - 1 will
underflow). (And I admit it still looks ugly).
Thanks
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* Re: [RFC v3 3/5] virtio_ring: add packed ring support
From: Jason Wang @ 2018-05-10 7:32 UTC (permalink / raw)
To: Tiwei Bie, mst, virtualization, linux-kernel, netdev; +Cc: wexu
In-Reply-To: <20180425051550.24342-4-tiwei.bie@intel.com>
On 2018年04月25日 13:15, Tiwei Bie wrote:
> + /* We're using some buffers from the free list. */
> + vq->vq.num_free -= descs_used;
> +
> + /* Update free pointer */
> + if (indirect) {
> + n = head + 1;
> + if (n >= vq->vring_packed.num) {
> + n = 0;
> + vq->wrap_counter ^= 1;
> + }
> + vq->next_avail_idx = n;
> + } else
> + vq->next_avail_idx = i;
During testing zerocopy (out of order completion), I found driver may
submit two identical buffer id to vhost. So the above code may not work
well.
Consider the case that driver adds 3 buffer and virtqueue size is 8.
a) id = 0,count = 2,next_avail = 2
b) id = 2,count = 4,next_avail = 2
c) id = 4,count = 2,next_avail = 0
if packet b is done before packet a, driver may think buffer id 0 is
available and try to use it if even if the real buffer 0 was not done.
Thanks
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* Re: [RFC v3 3/5] virtio_ring: add packed ring support
From: Jason Wang @ 2018-05-10 7:34 UTC (permalink / raw)
To: Tiwei Bie, mst, virtualization, linux-kernel, netdev; +Cc: wexu
In-Reply-To: <927f4478-5a81-31d4-ac69-f9ec26248591@redhat.com>
On 2018年05月10日 15:32, Jason Wang wrote:
>
>
> On 2018年04月25日 13:15, Tiwei Bie wrote:
>> + /* We're using some buffers from the free list. */
>> + vq->vq.num_free -= descs_used;
>> +
>> + /* Update free pointer */
>> + if (indirect) {
>> + n = head + 1;
>> + if (n >= vq->vring_packed.num) {
>> + n = 0;
>> + vq->wrap_counter ^= 1;
>> + }
>> + vq->next_avail_idx = n;
>> + } else
>> + vq->next_avail_idx = i;
>
> During testing zerocopy (out of order completion), I found driver may
> submit two identical buffer id to vhost. So the above code may not
> work well.
>
> Consider the case that driver adds 3 buffer and virtqueue size is 8.
>
> a) id = 0,count = 2,next_avail = 2
>
> b) id = 2,count = 4,next_avail = 2
next_avail should be 6 here.
>
> c) id = 4,count = 2,next_avail = 0
>
id should be 6 here.
Thanks
> if packet b is done before packet a, driver may think buffer id 0 is
> available and try to use it if even if the real buffer 0 was not done.
>
> Thanks
> _______________________________________________
> Virtualization mailing list
> Virtualization@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization
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* Re: [RFC v3 3/5] virtio_ring: add packed ring support
From: Tiwei Bie @ 2018-05-10 8:56 UTC (permalink / raw)
To: Jason Wang; +Cc: netdev, wexu, virtualization, linux-kernel, mst
In-Reply-To: <5885acac-e9e3-3abf-b6a2-7347f4d55be2@redhat.com>
On Thu, May 10, 2018 at 03:34:50PM +0800, Jason Wang wrote:
> On 2018年05月10日 15:32, Jason Wang wrote:
> > On 2018年04月25日 13:15, Tiwei Bie wrote:
> > > + /* We're using some buffers from the free list. */
> > > + vq->vq.num_free -= descs_used;
> > > +
> > > + /* Update free pointer */
> > > + if (indirect) {
> > > + n = head + 1;
> > > + if (n >= vq->vring_packed.num) {
> > > + n = 0;
> > > + vq->wrap_counter ^= 1;
> > > + }
> > > + vq->next_avail_idx = n;
> > > + } else
> > > + vq->next_avail_idx = i;
> >
> > During testing zerocopy (out of order completion), I found driver may
> > submit two identical buffer id to vhost. So the above code may not work
> > well.
> >
> > Consider the case that driver adds 3 buffer and virtqueue size is 8.
> >
> > a) id = 0,count = 2,next_avail = 2
> >
> > b) id = 2,count = 4,next_avail = 2
>
> next_avail should be 6 here.
>
> >
> > c) id = 4,count = 2,next_avail = 0
> >
>
> id should be 6 here.
>
> Thanks
>
> > if packet b is done before packet a, driver may think buffer id 0 is
> > available and try to use it if even if the real buffer 0 was not done.
> >
> > Thanks
Nice catch! Thanks a lot!
I'll implement an ID allocator.
Best regards,
Tiwei Bie
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