| 1d7e2a8f | 13-Oct-2023 |
Hawkins Jiawei <yin31149@gmail.com> |
vdpa: Introduce cursors to vhost_vdpa_net_loadx()
This patch introduces two new arugments, `out_cursor`
and `in_cursor`, to vhost_vdpa_net_loadx(). Addtionally,
it includes a helper function
vhost_v
vdpa: Introduce cursors to vhost_vdpa_net_loadx()
This patch introduces two new arugments, `out_cursor`
and `in_cursor`, to vhost_vdpa_net_loadx(). Addtionally,
it includes a helper function
vhost_vdpa_net_load_cursor_reset() for resetting these
cursors.
Furthermore, this patch refactors vhost_vdpa_net_load_cmd()
so that vhost_vdpa_net_load_cmd() prepares buffers
for the device using the cursors arguments, instead
of directly accesses `s->cvq_cmd_out_buffer` and
`s->status` fields.
By making these change, next patches in this series
can refactor vhost_vdpa_net_load_cmd() directly to
iterate through the control commands shadow buffers,
allowing QEMU to send CVQ state load commands in parallel
at device startup.
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Message-Id: <1c6516e233a14cc222f0884e148e4e1adceda78d.1697165821.git.yin31149@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| 24e59cfe | 13-Oct-2023 |
Hawkins Jiawei <yin31149@gmail.com> |
vdpa: Check device ack in vhost_vdpa_net_load_rx_mode()
Considering that vhost_vdpa_net_load_rx_mode() is only called
within vhost_vdpa_net_load_rx() now, this patch refactors
vhost_vdpa_net_load_rx
vdpa: Check device ack in vhost_vdpa_net_load_rx_mode()
Considering that vhost_vdpa_net_load_rx_mode() is only called
within vhost_vdpa_net_load_rx() now, this patch refactors
vhost_vdpa_net_load_rx_mode() to include a check for the
device's ack, simplifying the code and improving its maintainability.
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <68811d52f96ae12d68f0d67d996ac1642a623943.1697165821.git.yin31149@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| 327dedb8 | 13-Oct-2023 |
Hawkins Jiawei <yin31149@gmail.com> |
vdpa: Avoid using vhost_vdpa_net_load_*() outside vhost_vdpa_net_load()
Next patches in this series will refactor vhost_vdpa_net_load_cmd()
to iterate through the control commands shadow buffers, al
vdpa: Avoid using vhost_vdpa_net_load_*() outside vhost_vdpa_net_load()
Next patches in this series will refactor vhost_vdpa_net_load_cmd()
to iterate through the control commands shadow buffers, allowing QEMU
to send CVQ state load commands in parallel at device startup.
Considering that QEMU always forwards the CVQ command serialized
outside of vhost_vdpa_net_load(), it is more elegant to send the
CVQ commands directly without invoking vhost_vdpa_net_load_*() helpers.
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <254f0618efde7af7229ba4fdada667bb9d318991.1697165821.git.yin31149@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| 73071f19 | 04-Oct-2023 |
Philippe Mathieu-Daudé <philmd@linaro.org> |
net/net: Clean up global variable shadowing
Fix:
net/net.c:1680:35: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
bool netdev_is_modern(const char *optarg)
net/net: Clean up global variable shadowing
Fix:
net/net.c:1680:35: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
bool netdev_is_modern(const char *optarg)
^
net/net.c:1714:38: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
void netdev_parse_modern(const char *optarg)
^
net/net.c:1728:60: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
void net_client_parse(QemuOptsList *opts_list, const char *optarg)
^
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/getopt.h:77:14: note: previous declaration is here
extern char *optarg; /* getopt(3) external variables */
^
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20231004120019.93101-4-philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
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| 0a7a164b | 13-Sep-2023 |
Eugenio Pérez <eperezma@redhat.com> |
vdpa net: zero vhost_vdpa iova_tree pointer at cleanup
Not zeroing it causes a SIGSEGV if the live migration is cancelled, at
net device restart.
This is caused because CVQ tries to reuse the iova_
vdpa net: zero vhost_vdpa iova_tree pointer at cleanup
Not zeroing it causes a SIGSEGV if the live migration is cancelled, at
net device restart.
This is caused because CVQ tries to reuse the iova_tree that is present
in the first vhost_vdpa device at the end of vhost_vdpa_net_cvq_start.
As a consequence, it tries to access an iova_tree that has been already
free.
Fixes: 00ef422e9fbf ("vdpa net: move iova tree creation from init to start")
Reported-by: Yanhui Ma <yama@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20230913123408.2819185-1-eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| b0de17a2 | 29-Aug-2023 |
Hawkins Jiawei <yin31149@gmail.com> |
vhost: Add count argument to vhost_svq_poll()
Next patches in this series will no longer perform an
immediate poll and check of the device's used buffers
for each CVQ state load command. Instead, th
vhost: Add count argument to vhost_svq_poll()
Next patches in this series will no longer perform an
immediate poll and check of the device's used buffers
for each CVQ state load command. Instead, they will
send CVQ state load commands in parallel by polling
multiple pending buffers at once.
To achieve this, this patch refactoring vhost_svq_poll()
to accept a new argument `num`, which allows vhost_svq_poll()
to wait for the device to use multiple elements,
rather than polling for a single element.
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <950b3bfcfc5d446168b9d6a249d554a013a691d4.1693287885.git.yin31149@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| f13f5f64 | 22-Aug-2023 |
Eugenio Pérez <eperezma@redhat.com> |
vdpa: remove net cvq migration blocker
Now that we have add migration blockers if the device does not support
all the needed features, remove the general blocker applied to all net
devices with CVQ.
vdpa: remove net cvq migration blocker
Now that we have add migration blockers if the device does not support
all the needed features, remove the general blocker applied to all net
devices with CVQ.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20230822085330.3978829-6-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| 6c482547 | 22-Aug-2023 |
Eugenio Pérez <eperezma@redhat.com> |
vdpa: move vhost_vdpa_set_vring_ready to the caller
Doing that way allows CVQ to be enabled before the dataplane vqs,
restoring the state as MQ or MAC addresses properly in the case of a
migration.
vdpa: move vhost_vdpa_set_vring_ready to the caller
Doing that way allows CVQ to be enabled before the dataplane vqs,
restoring the state as MQ or MAC addresses properly in the case of a
migration.
The patch does it by defining a ->load NetClientInfo callback also for
dataplane. Ideally, this should be done by an independent patch, but
the function is already static so it would only add an empty
vhost_vdpa_net_data_load stub.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20230822085330.3978829-5-eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| b40eba9c | 22-Aug-2023 |
Eugenio Pérez <eperezma@redhat.com> |
vdpa: use first queue SVQ state for CVQ default
Previous to this patch the only way CVQ would be shadowed is if it does
support to isolate CVQ group or if all vqs were shadowed from the
beginning.
vdpa: use first queue SVQ state for CVQ default
Previous to this patch the only way CVQ would be shadowed is if it does
support to isolate CVQ group or if all vqs were shadowed from the
beginning. The second condition was checked at the beginning, and no
more configuration was done.
After this series we need to check if data queues are shadowed because
they are in the middle of the migration. As checking if they are
shadowed already covers the previous case, let's just mimic it.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20230822085330.3978829-2-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| 6d7a53e9 | 24-Aug-2023 |
Peter Maydell <peter.maydell@linaro.org> |
net/tap: Avoid variable-length array
Use a heap allocation instead of a variable length array in
tap_receive_iov().
The codebase has very few VLAs, and if we can get rid of them all we
can make the
net/tap: Avoid variable-length array
Use a heap allocation instead of a variable length array in
tap_receive_iov().
The codebase has very few VLAs, and if we can get rid of them all we
can make the compiler error on new additions. This is a defensive
measure against security bugs where an on-stack dynamic allocation
isn't correctly size-checked (e.g. CVE-2021-3527).
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Francisco Iglesias <frasse.iglesias@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
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| cb039ef3 | 13-Sep-2023 |
Ilya Maximets <i.maximets@ovn.org> |
net: add initial support for AF_XDP network backend
AF_XDP is a network socket family that allows communication directly
with the network device driver in the kernel, bypassing most or all
of the ke
net: add initial support for AF_XDP network backend
AF_XDP is a network socket family that allows communication directly
with the network device driver in the kernel, bypassing most or all
of the kernel networking stack. In the essence, the technology is
pretty similar to netmap. But, unlike netmap, AF_XDP is Linux-native
and works with any network interfaces without driver modifications.
Unlike vhost-based backends (kernel, user, vdpa), AF_XDP doesn't
require access to character devices or unix sockets. Only access to
the network interface itself is necessary.
This patch implements a network backend that communicates with the
kernel by creating an AF_XDP socket. A chunk of userspace memory
is shared between QEMU and the host kernel. 4 ring buffers (Tx, Rx,
Fill and Completion) are placed in that memory along with a pool of
memory buffers for the packet data. Data transmission is done by
allocating one of the buffers, copying packet data into it and
placing the pointer into Tx ring. After transmission, device will
return the buffer via Completion ring. On Rx, device will take
a buffer form a pre-populated Fill ring, write the packet data into
it and place the buffer into Rx ring.
AF_XDP network backend takes on the communication with the host
kernel and the network interface and forwards packets to/from the
peer device in QEMU.
Usage example:
-device virtio-net-pci,netdev=guest1,mac=00:16:35:AF:AA:5C
-netdev af-xdp,ifname=ens6f1np1,id=guest1,mode=native,queues=1
XDP program bridges the socket with a network interface. It can be
attached to the interface in 2 different modes:
1. skb - this mode should work for any interface and doesn't require
driver support. With a caveat of lower performance.
2. native - this does require support from the driver and allows to
bypass skb allocation in the kernel and potentially use
zero-copy while getting packets in/out userspace.
By default, QEMU will try to use native mode and fall back to skb.
Mode can be forced via 'mode' option. To force 'copy' even in native
mode, use 'force-copy=on' option. This might be useful if there is
some issue with the driver.
Option 'queues=N' allows to specify how many device queues should
be open. Note that all the queues that are not open are still
functional and can receive traffic, but it will not be delivered to
QEMU. So, the number of device queues should generally match the
QEMU configuration, unless the device is shared with something
else and the traffic re-direction to appropriate queues is correctly
configured on a device level (e.g. with ethtool -N).
'start-queue=M' option can be used to specify from which queue id
QEMU should start configuring 'N' queues. It might also be necessary
to use this option with certain NICs, e.g. MLX5 NICs. See the docs
for examples.
In a general case QEMU will need CAP_NET_ADMIN and CAP_SYS_ADMIN
or CAP_BPF capabilities in order to load default XSK/XDP programs to
the network interface and configure BPF maps. It is possible, however,
to run with no capabilities. For that to work, an external process
with enough capabilities will need to pre-load default XSK program,
create AF_XDP sockets and pass their file descriptors to QEMU process
on startup via 'sock-fds' option. Network backend will need to be
configured with 'inhibit=on' to avoid loading of the program.
QEMU will need 32 MB of locked memory (RLIMIT_MEMLOCK) per queue
or CAP_IPC_LOCK.
There are few performance challenges with the current network backends.
First is that they do not support IO threads. This means that data
path is handled by the main thread in QEMU and may slow down other
work or may be slowed down by some other work. This also means that
taking advantage of multi-queue is generally not possible today.
Another thing is that data path is going through the device emulation
code, which is not really optimized for performance. The fastest
"frontend" device is virtio-net. But it's not optimized for heavy
traffic either, because it expects such use-cases to be handled via
some implementation of vhost (user, kernel, vdpa). In practice, we
have virtio notifications and rcu lock/unlock on a per-packet basis
and not very efficient accesses to the guest memory. Communication
channels between backend and frontend devices do not allow passing
more than one packet at a time as well.
Some of these challenges can be avoided in the future by adding better
batching into device emulation or by implementing vhost-af-xdp variant.
There are also a few kernel limitations. AF_XDP sockets do not
support any kinds of checksum or segmentation offloading. Buffers
are limited to a page size (4K), i.e. MTU is limited. Multi-buffer
support implementation for AF_XDP is in progress, but not ready yet.
Also, transmission in all non-zero-copy modes is synchronous, i.e.
done in a syscall. That doesn't allow high packet rates on virtual
interfaces.
However, keeping in mind all of these challenges, current implementation
of the AF_XDP backend shows a decent performance while running on top
of a physical NIC with zero-copy support.
Test setup:
2 VMs running on 2 physical hosts connected via ConnectX6-Dx card.
Network backend is configured to open the NIC directly in native mode.
The driver supports zero-copy. NIC is configured to use 1 queue.
Inside a VM - iperf3 for basic TCP performance testing and dpdk-testpmd
for PPS testing.
iperf3 result:
TCP stream : 19.1 Gbps
dpdk-testpmd (single queue, single CPU core, 64 B packets) results:
Tx only : 3.4 Mpps
Rx only : 2.0 Mpps
L2 FWD Loopback : 1.5 Mpps
In skb mode the same setup shows much lower performance, similar to
the setup where pair of physical NICs is replaced with veth pair:
iperf3 result:
TCP stream : 9 Gbps
dpdk-testpmd (single queue, single CPU core, 64 B packets) results:
Tx only : 1.2 Mpps
Rx only : 1.0 Mpps
L2 FWD Loopback : 0.7 Mpps
Results in skb mode or over the veth are close to results of a tap
backend with vhost=on and disabled segmentation offloading bridged
with a NIC.
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> (docker/lcitool)
Signed-off-by: Jason Wang <jasowang@redhat.com>
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