* [PATCH RFC net-next v2 0/6] Device memory TCP TX
@ 2025-01-30 21:15 Mina Almasry
2025-01-30 21:15 ` [PATCH RFC net-next v2 1/6] net: add devmem TCP TX documentation Mina Almasry
` (5 more replies)
0 siblings, 6 replies; 17+ messages in thread
From: Mina Almasry @ 2025-01-30 21:15 UTC (permalink / raw)
To: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest
Cc: Mina Almasry, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
RFC v2: https://patchwork.kernel.org/project/netdevbpf/list/?series=920056&state=*
=======
RFC v2 addresses much of the feedback from RFC v1. I plan on sending
something close to this as net-next reopens, sending it slightly early
to get feedback if any.
Major changes:
--------------
- much improved UAPI as suggested by Stan. We now interpret the iov_base
of the passed in iov from userspace as the offset into the dmabuf to
send from. This removes the need to set iov.iov_base = NULL which may
be confusing to users, and enables us to send multiple iovs in the
same sendmsg() call. ncdevmem and the docs show a sample use of that.
- Removed the duplicate dmabuf iov_iter in binding->iov_iter. I think
this is good improvment as it was confusing to keep track of
2 iterators for the same sendmsg, and mistracking both iterators
caused a couple of bugs reported in the last iteration that are now
resolved with this streamlining.
- Improved test coverage in ncdevmem. Now muliple sendmsg() are tested,
and sending multiple iovs in the same sendmsg() is tested.
- Fixed issue where dmabuf unmapping was happening in invalid context
(Stan).
====================================================================
The TX path had been dropped from the Device Memory TCP patch series
post RFCv1 [1], to make that series slightly easier to review. This
series rebases the implementation of the TX path on top of the
net_iov/netmem framework agreed upon and merged. The motivation for
the feature is thoroughly described in the docs & cover letter of the
original proposal, so I don't repeat the lengthy descriptions here, but
they are available in [1].
Sending this series as RFC as the winder closure is immenient. I plan on
reposting as non-RFC once the tree re-opens, addressing any feedback
I receive in the meantime.
Full outline on usage of the TX path is detailed in the documentation
added in the first patch.
Test example is available via the kselftest included in the series as well.
The series is relatively small, as the TX path for this feature largely
piggybacks on the existing MSG_ZEROCOPY implementation.
Patch Overview:
---------------
1. Documentation & tests to give high level overview of the feature
being added.
2. Add netmem refcounting needed for the TX path.
3. Devmem TX netlink API.
4. Devmem TX net stack implementation.
Testing:
--------
Testing is very similar to devmem TCP RX path. The ncdevmem test used
for the RX path is now augemented with client functionality to test TX
path.
* Test Setup:
Kernel: net-next with this RFC and memory provider API cherry-picked
locally.
Hardware: Google Cloud A3 VMs.
NIC: GVE with header split & RSS & flow steering support.
Performance results are not included with this version, unfortunately.
I'm having issues running the dma-buf exporter driver against the
upstream kernel on my test setup. The issues are specific to that
dma-buf exporter and do not affect this patch series. I plan to follow
up this series with perf fixes if the tests point to issues once they're
up and running.
Special thanks to Stan who took a stab at rebasing the TX implementation
on top of the netmem/net_iov framework merged. Parts of his proposal [2]
that are reused as-is are forked off into their own patches to give full
credit.
[1] https://lore.kernel.org/netdev/20240909054318.1809580-1-almasrymina@google.com/
[2] https://lore.kernel.org/netdev/20240913150913.1280238-2-sdf@fomichev.me/T/#m066dd407fbed108828e2c40ae50e3f4376ef57fd
Cc: sdf@fomichev.me
Cc: asml.silence@gmail.com
Cc: dw@davidwei.uk
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Victor Nogueira <victor@mojatatu.com>
Cc: Pedro Tammela <pctammela@mojatatu.com>
Mina Almasry (5):
net: add devmem TCP TX documentation
selftests: ncdevmem: Implement devmem TCP TX
net: add get_netmem/put_netmem support
net: devmem: Implement TX path
net: devmem: make dmabuf unbinding scheduled work
Stanislav Fomichev (1):
net: devmem: TCP tx netlink api
Documentation/netlink/specs/netdev.yaml | 12 +
Documentation/networking/devmem.rst | 144 ++++++++-
include/linux/skbuff.h | 15 +-
include/linux/skbuff_ref.h | 4 +-
include/net/netmem.h | 3 +
include/net/sock.h | 1 +
include/uapi/linux/netdev.h | 1 +
include/uapi/linux/uio.h | 6 +-
net/core/datagram.c | 41 ++-
net/core/devmem.c | 110 ++++++-
net/core/devmem.h | 70 ++++-
net/core/netdev-genl-gen.c | 13 +
net/core/netdev-genl-gen.h | 1 +
net/core/netdev-genl.c | 67 ++++-
net/core/skbuff.c | 36 ++-
net/core/sock.c | 8 +
net/ipv4/tcp.c | 36 ++-
net/vmw_vsock/virtio_transport_common.c | 3 +-
tools/include/uapi/linux/netdev.h | 1 +
.../selftests/drivers/net/hw/ncdevmem.c | 276 +++++++++++++++++-
20 files changed, 802 insertions(+), 46 deletions(-)
--
2.48.1.362.g079036d154-goog
^ permalink raw reply [flat|nested] 17+ messages in thread
* [PATCH RFC net-next v2 1/6] net: add devmem TCP TX documentation
2025-01-30 21:15 [PATCH RFC net-next v2 0/6] Device memory TCP TX Mina Almasry
@ 2025-01-30 21:15 ` Mina Almasry
2025-01-30 22:59 ` Stanislav Fomichev
2025-01-30 21:15 ` [PATCH RFC net-next v2 2/6] selftests: ncdevmem: Implement devmem TCP TX Mina Almasry
` (4 subsequent siblings)
5 siblings, 1 reply; 17+ messages in thread
From: Mina Almasry @ 2025-01-30 21:15 UTC (permalink / raw)
To: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest
Cc: Mina Almasry, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
Add documentation outlining the usage and details of the devmem TCP TX
API.
Signed-off-by: Mina Almasry <almasrymina@google.com>
---
v2:
- Update documentation for iov_base is the dmabuf offset (Stan)
---
Documentation/networking/devmem.rst | 144 +++++++++++++++++++++++++++-
1 file changed, 140 insertions(+), 4 deletions(-)
diff --git a/Documentation/networking/devmem.rst b/Documentation/networking/devmem.rst
index d95363645331..8166fe09da13 100644
--- a/Documentation/networking/devmem.rst
+++ b/Documentation/networking/devmem.rst
@@ -62,15 +62,15 @@ More Info
https://lore.kernel.org/netdev/20240831004313.3713467-1-almasrymina@google.com/
-Interface
-=========
+RX Interface
+============
Example
-------
-tools/testing/selftests/net/ncdevmem.c:do_server shows an example of setting up
-the RX path of this API.
+./tools/testing/selftests/drivers/net/hw/ncdevmem:do_server shows an example of
+setting up the RX path of this API.
NIC Setup
@@ -235,6 +235,142 @@ can be less than the tokens provided by the user in case of:
(a) an internal kernel leak bug.
(b) the user passed more than 1024 frags.
+TX Interface
+============
+
+
+Example
+-------
+
+./tools/testing/selftests/drivers/net/hw/ncdevmem:do_client shows an example of
+setting up the TX path of this API.
+
+
+NIC Setup
+---------
+
+The user must bind a TX dmabuf to a given NIC using the netlink API::
+
+ struct netdev_bind_tx_req *req = NULL;
+ struct netdev_bind_tx_rsp *rsp = NULL;
+ struct ynl_error yerr;
+
+ *ys = ynl_sock_create(&ynl_netdev_family, &yerr);
+
+ req = netdev_bind_tx_req_alloc();
+ netdev_bind_tx_req_set_ifindex(req, ifindex);
+ netdev_bind_tx_req_set_fd(req, dmabuf_fd);
+
+ rsp = netdev_bind_tx(*ys, req);
+
+ tx_dmabuf_id = rsp->id;
+
+
+The netlink API returns a dmabuf_id: a unique ID that refers to this dmabuf
+that has been bound.
+
+The user can unbind the dmabuf from the netdevice by closing the netlink socket
+that established the binding. We do this so that the binding is automatically
+unbound even if the userspace process crashes.
+
+Note that any reasonably well-behaved dmabuf from any exporter should work with
+devmem TCP, even if the dmabuf is not actually backed by devmem. An example of
+this is udmabuf, which wraps user memory (non-devmem) in a dmabuf.
+
+Socket Setup
+------------
+
+The user application must use MSG_ZEROCOPY flag when sending devmem TCP. Devmem
+cannot be copied by the kernel, so the semantics of the devmem TX are similar
+to the semantics of MSG_ZEROCOPY.
+
+ ret = setsockopt(socket_fd, SOL_SOCKET, SO_ZEROCOPY, &opt, sizeof(opt));
+
+Sending data
+--------------
+
+Devmem data is sent using the SCM_DEVMEM_DMABUF cmsg.
+
+The user should create a msghdr where,
+
+iov_base is set to the offset into the dmabuf to start sending from.
+iov_len is set to the number of bytes to be sent from the dmabuf.
+
+The user passes the dma-buf id to send from via the dmabuf_tx_cmsg.dmabuf_id.
+
+The example below sends 1024 bytes from offset 100 into the dmabuf, and 2048
+from offset 2000 into the dmabuf. The dmabuf to send from is tx_dmabuf_id::
+
+ char ctrl_data[CMSG_SPACE(sizeof(struct dmabuf_tx_cmsg))];
+ struct dmabuf_tx_cmsg ddmabuf;
+ struct msghdr msg = {};
+ struct cmsghdr *cmsg;
+ struct iovec iov[2];
+
+ iov[0].iov_base = (void*)100;
+ iov[0].iov_len = 1024;
+ iov[1].iov_base = (void*)2000;
+ iov[1].iov_len = 2048;
+
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 2;
+
+ msg.msg_control = ctrl_data;
+ msg.msg_controllen = sizeof(ctrl_data);
+
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_DEVMEM_DMABUF;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(struct dmabuf_tx_cmsg));
+
+ ddmabuf.dmabuf_id = tx_dmabuf_id;
+
+ *((struct dmabuf_tx_cmsg *)CMSG_DATA(cmsg)) = ddmabuf;
+
+ sendmsg(socket_fd, &msg, MSG_ZEROCOPY);
+
+
+Reusing TX dmabufs
+------------------
+
+Similar to MSG_ZEROCOPY with regular memory, the user should not modify the
+contents of the dma-buf while a send operation is in progress. This is because
+the kernel does not keep a copy of the dmabuf contents. Instead, the kernel
+will pin and send data from the buffer available to the userspace.
+
+Just as in MSG_ZEROCOPY, the kernel notifies the userspace of send completions
+using MSG_ERRQUEUE::
+
+ int64_t tstop = gettimeofday_ms() + waittime_ms;
+ char control[CMSG_SPACE(100)] = {};
+ struct sock_extended_err *serr;
+ struct msghdr msg = {};
+ struct cmsghdr *cm;
+ int retries = 10;
+ __u32 hi, lo;
+
+ msg.msg_control = control;
+ msg.msg_controllen = sizeof(control);
+
+ while (gettimeofday_ms() < tstop) {
+ if (!do_poll(fd)) continue;
+
+ ret = recvmsg(fd, &msg, MSG_ERRQUEUE);
+
+ for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm)) {
+ serr = (void *)CMSG_DATA(cm);
+
+ hi = serr->ee_data;
+ lo = serr->ee_info;
+
+ fprintf(stdout, "tx complete [%d,%d]\n", lo, hi);
+ }
+ }
+
+After the associated sendmsg has been completed, the dmabuf can be reused by
+the userspace.
+
+
Implementation & Caveats
========================
--
2.48.1.362.g079036d154-goog
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH RFC net-next v2 2/6] selftests: ncdevmem: Implement devmem TCP TX
2025-01-30 21:15 [PATCH RFC net-next v2 0/6] Device memory TCP TX Mina Almasry
2025-01-30 21:15 ` [PATCH RFC net-next v2 1/6] net: add devmem TCP TX documentation Mina Almasry
@ 2025-01-30 21:15 ` Mina Almasry
2025-01-30 23:05 ` Stanislav Fomichev
2025-01-31 17:45 ` Stanislav Fomichev
2025-01-30 21:15 ` [PATCH RFC net-next v2 3/6] net: add get_netmem/put_netmem support Mina Almasry
` (3 subsequent siblings)
5 siblings, 2 replies; 17+ messages in thread
From: Mina Almasry @ 2025-01-30 21:15 UTC (permalink / raw)
To: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest
Cc: Mina Almasry, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
Add support for devmem TX in ncdevmem.
This is a combination of the ncdevmem from the devmem TCP series RFCv1
which included the TX path, and work by Stan to include the netlink API
and refactored on top of his generic memory_provider support.
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
---
v2:
- make errors a static variable so that we catch instances where there
are less than 20 errors across different buffers.
- Fix the issue where the seed is reset to 0 instead of its starting
value 1.
- Use 1000ULL instead of 1000 to guard against overflow (Willem).
- Do not set POLLERR (Willem).
- Update the test to use the new interface where iov_base is the
dmabuf_offset.
- Update the test to send 2 iov instead of 1, so we get some test
coverage over sending multiple iovs at once.
- Print the ifindex the test is using, useful for debugging issues where
maybe the test may fail because the ifindex of the socket is different
from the dmabuf binding.
---
.../selftests/drivers/net/hw/ncdevmem.c | 276 +++++++++++++++++-
1 file changed, 272 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
index 19a6969643f4..8455f19ecd1a 100644
--- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
+++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
@@ -40,15 +40,18 @@
#include <fcntl.h>
#include <malloc.h>
#include <error.h>
+#include <poll.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
+#include <sys/time.h>
#include <linux/memfd.h>
#include <linux/dma-buf.h>
+#include <linux/errqueue.h>
#include <linux/udmabuf.h>
#include <libmnl/libmnl.h>
#include <linux/types.h>
@@ -80,6 +83,8 @@ static int num_queues = -1;
static char *ifname;
static unsigned int ifindex;
static unsigned int dmabuf_id;
+static uint32_t tx_dmabuf_id;
+static int waittime_ms = 500;
struct memory_buffer {
int fd;
@@ -93,6 +98,8 @@ struct memory_buffer {
struct memory_provider {
struct memory_buffer *(*alloc)(size_t size);
void (*free)(struct memory_buffer *ctx);
+ void (*memcpy_to_device)(struct memory_buffer *dst, size_t off,
+ void *src, int n);
void (*memcpy_from_device)(void *dst, struct memory_buffer *src,
size_t off, int n);
};
@@ -153,6 +160,20 @@ static void udmabuf_free(struct memory_buffer *ctx)
free(ctx);
}
+static void udmabuf_memcpy_to_device(struct memory_buffer *dst, size_t off,
+ void *src, int n)
+{
+ struct dma_buf_sync sync = {};
+
+ sync.flags = DMA_BUF_SYNC_START | DMA_BUF_SYNC_WRITE;
+ ioctl(dst->fd, DMA_BUF_IOCTL_SYNC, &sync);
+
+ memcpy(dst->buf_mem + off, src, n);
+
+ sync.flags = DMA_BUF_SYNC_END | DMA_BUF_SYNC_WRITE;
+ ioctl(dst->fd, DMA_BUF_IOCTL_SYNC, &sync);
+}
+
static void udmabuf_memcpy_from_device(void *dst, struct memory_buffer *src,
size_t off, int n)
{
@@ -170,6 +191,7 @@ static void udmabuf_memcpy_from_device(void *dst, struct memory_buffer *src,
static struct memory_provider udmabuf_memory_provider = {
.alloc = udmabuf_alloc,
.free = udmabuf_free,
+ .memcpy_to_device = udmabuf_memcpy_to_device,
.memcpy_from_device = udmabuf_memcpy_from_device,
};
@@ -188,7 +210,7 @@ void validate_buffer(void *line, size_t size)
{
static unsigned char seed = 1;
unsigned char *ptr = line;
- int errors = 0;
+ static int errors;
size_t i;
for (i = 0; i < size; i++) {
@@ -202,7 +224,7 @@ void validate_buffer(void *line, size_t size)
}
seed++;
if (seed == do_validation)
- seed = 0;
+ seed = 1;
}
fprintf(stdout, "Validated buffer\n");
@@ -394,6 +416,49 @@ static int bind_rx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
return -1;
}
+static int bind_tx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
+ struct ynl_sock **ys)
+{
+ struct netdev_bind_tx_req *req = NULL;
+ struct netdev_bind_tx_rsp *rsp = NULL;
+ struct ynl_error yerr;
+
+ *ys = ynl_sock_create(&ynl_netdev_family, &yerr);
+ if (!*ys) {
+ fprintf(stderr, "YNL: %s\n", yerr.msg);
+ return -1;
+ }
+
+ req = netdev_bind_tx_req_alloc();
+ netdev_bind_tx_req_set_ifindex(req, ifindex);
+ netdev_bind_tx_req_set_fd(req, dmabuf_fd);
+
+ rsp = netdev_bind_tx(*ys, req);
+ if (!rsp) {
+ perror("netdev_bind_tx");
+ goto err_close;
+ }
+
+ if (!rsp->_present.id) {
+ perror("id not present");
+ goto err_close;
+ }
+
+ fprintf(stderr, "got tx dmabuf id=%d\n", rsp->id);
+ tx_dmabuf_id = rsp->id;
+
+ netdev_bind_tx_req_free(req);
+ netdev_bind_tx_rsp_free(rsp);
+
+ return 0;
+
+err_close:
+ fprintf(stderr, "YNL failed: %s\n", (*ys)->err.msg);
+ netdev_bind_tx_req_free(req);
+ ynl_sock_destroy(*ys);
+ return -1;
+}
+
static void enable_reuseaddr(int fd)
{
int opt = 1;
@@ -432,7 +497,7 @@ static int parse_address(const char *str, int port, struct sockaddr_in6 *sin6)
return 0;
}
-int do_server(struct memory_buffer *mem)
+static int do_server(struct memory_buffer *mem)
{
char ctrl_data[sizeof(int) * 20000];
struct netdev_queue_id *queues;
@@ -686,6 +751,207 @@ void run_devmem_tests(void)
provider->free(mem);
}
+static uint64_t gettimeofday_ms(void)
+{
+ struct timeval tv;
+
+ gettimeofday(&tv, NULL);
+ return (tv.tv_sec * 1000ULL) + (tv.tv_usec / 1000ULL);
+}
+
+static int do_poll(int fd)
+{
+ struct pollfd pfd;
+ int ret;
+
+ pfd.revents = 0;
+ pfd.fd = fd;
+
+ ret = poll(&pfd, 1, waittime_ms);
+ if (ret == -1)
+ error(1, errno, "poll");
+
+ return ret && (pfd.revents & POLLERR);
+}
+
+static void wait_compl(int fd)
+{
+ int64_t tstop = gettimeofday_ms() + waittime_ms;
+ char control[CMSG_SPACE(100)] = {};
+ struct sock_extended_err *serr;
+ struct msghdr msg = {};
+ struct cmsghdr *cm;
+ int retries = 10;
+ __u32 hi, lo;
+ int ret;
+
+ msg.msg_control = control;
+ msg.msg_controllen = sizeof(control);
+
+ while (gettimeofday_ms() < tstop) {
+ if (!do_poll(fd))
+ continue;
+
+ ret = recvmsg(fd, &msg, MSG_ERRQUEUE);
+ if (ret < 0) {
+ if (errno == EAGAIN)
+ continue;
+ error(1, ret, "recvmsg(MSG_ERRQUEUE)");
+ return;
+ }
+ if (msg.msg_flags & MSG_CTRUNC)
+ error(1, 0, "MSG_CTRUNC\n");
+
+ for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm)) {
+ if (cm->cmsg_level != SOL_IP &&
+ cm->cmsg_level != SOL_IPV6)
+ continue;
+ if (cm->cmsg_level == SOL_IP &&
+ cm->cmsg_type != IP_RECVERR)
+ continue;
+ if (cm->cmsg_level == SOL_IPV6 &&
+ cm->cmsg_type != IPV6_RECVERR)
+ continue;
+
+ serr = (void *)CMSG_DATA(cm);
+ if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY)
+ error(1, 0, "wrong origin %u", serr->ee_origin);
+ if (serr->ee_errno != 0)
+ error(1, 0, "wrong errno %d", serr->ee_errno);
+
+ hi = serr->ee_data;
+ lo = serr->ee_info;
+
+ fprintf(stderr, "tx complete [%d,%d]\n", lo, hi);
+ return;
+ }
+ }
+
+ error(1, 0, "did not receive tx completion");
+}
+
+static int do_client(struct memory_buffer *mem)
+{
+ char ctrl_data[CMSG_SPACE(sizeof(struct dmabuf_tx_cmsg))];
+ struct sockaddr_in6 server_sin;
+ struct sockaddr_in6 client_sin;
+ struct dmabuf_tx_cmsg ddmabuf;
+ struct ynl_sock *ys = NULL;
+ struct msghdr msg = {};
+ ssize_t line_size = 0;
+ struct cmsghdr *cmsg;
+ struct iovec iov[2];
+ uint64_t off = 100;
+ char *line = NULL;
+ size_t len = 0;
+ int socket_fd;
+ int ret, mid;
+ int opt = 1;
+
+ ret = parse_address(server_ip, atoi(port), &server_sin);
+ if (ret < 0)
+ error(1, 0, "parse server address");
+
+ socket_fd = socket(AF_INET6, SOCK_STREAM, 0);
+ if (socket_fd < 0)
+ error(1, socket_fd, "create socket");
+
+ enable_reuseaddr(socket_fd);
+
+ ret = setsockopt(socket_fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
+ strlen(ifname) + 1);
+ if (ret)
+ error(1, ret, "bindtodevice");
+
+ if (bind_tx_queue(ifindex, mem->fd, &ys))
+ error(1, 0, "Failed to bind\n");
+
+ ret = parse_address(client_ip, atoi(port), &client_sin);
+ if (ret < 0)
+ error(1, 0, "parse client address");
+
+ ret = bind(socket_fd, &client_sin, sizeof(client_sin));
+ if (ret)
+ error(1, ret, "bind");
+
+ ret = setsockopt(socket_fd, SOL_SOCKET, SO_ZEROCOPY, &opt, sizeof(opt));
+ if (ret)
+ error(1, ret, "set sock opt");
+
+ fprintf(stderr, "Connect to %s %d (via %s)\n", server_ip,
+ ntohs(server_sin.sin6_port), ifname);
+
+ ret = connect(socket_fd, &server_sin, sizeof(server_sin));
+ if (ret)
+ error(1, ret, "connect");
+
+ while (1) {
+ free(line);
+ line = NULL;
+ /* Subtract 1 from line_size to remove trailing newlines that
+ * get_line are surely to parse...
+ */
+ line_size = getline(&line, &len, stdin) - 1;
+
+ if (line_size < 0)
+ break;
+
+ mid = (line_size / 2) + 1;
+
+ iov[0].iov_base = (void *)100;
+ iov[0].iov_len = mid;
+ iov[1].iov_base = (void *)2000;
+ iov[1].iov_len = line_size - mid;
+
+ provider->memcpy_to_device(mem, (size_t)iov[0].iov_base, line,
+ iov[0].iov_len);
+ provider->memcpy_to_device(mem, (size_t)iov[1].iov_base,
+ line + iov[0].iov_len,
+ iov[1].iov_len);
+
+ fprintf(stderr,
+ "read line_size=%ld off=%d iov[0].iov_base=%d, iov[0].iov_len=%d, iov[1].iov_base=%d, iov[1].iov_len=%d\n",
+ line_size, off, iov[0].iov_base, iov[0].iov_len,
+ iov[1].iov_base, iov[1].iov_len);
+
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 2;
+
+ msg.msg_control = ctrl_data;
+ msg.msg_controllen = sizeof(ctrl_data);
+
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_DEVMEM_DMABUF;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(struct dmabuf_tx_cmsg));
+
+ ddmabuf.dmabuf_id = tx_dmabuf_id;
+
+ *((struct dmabuf_tx_cmsg *)CMSG_DATA(cmsg)) = ddmabuf;
+
+ ret = sendmsg(socket_fd, &msg, MSG_ZEROCOPY);
+ if (ret < 0)
+ error(1, errno, "Failed sendmsg");
+
+ fprintf(stderr, "sendmsg_ret=%d\n", ret);
+
+ if (ret != line_size)
+ error(1, errno, "Did not send all bytes");
+
+ wait_compl(socket_fd);
+ }
+
+ fprintf(stderr, "%s: tx ok\n", TEST_PREFIX);
+
+ free(line);
+ close(socket_fd);
+
+ if (ys)
+ ynl_sock_destroy(ys);
+
+ return 0;
+}
+
int main(int argc, char *argv[])
{
struct memory_buffer *mem;
@@ -729,6 +995,8 @@ int main(int argc, char *argv[])
ifindex = if_nametoindex(ifname);
+ fprintf(stderr, "using ifindex=%u\n", ifindex);
+
if (!server_ip && !client_ip) {
if (start_queue < 0 && num_queues < 0) {
num_queues = rxq_num(ifindex);
@@ -779,7 +1047,7 @@ int main(int argc, char *argv[])
error(1, 0, "Missing -p argument\n");
mem = provider->alloc(getpagesize() * NUM_PAGES);
- ret = is_server ? do_server(mem) : 1;
+ ret = is_server ? do_server(mem) : do_client(mem);
provider->free(mem);
return ret;
--
2.48.1.362.g079036d154-goog
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH RFC net-next v2 3/6] net: add get_netmem/put_netmem support
2025-01-30 21:15 [PATCH RFC net-next v2 0/6] Device memory TCP TX Mina Almasry
2025-01-30 21:15 ` [PATCH RFC net-next v2 1/6] net: add devmem TCP TX documentation Mina Almasry
2025-01-30 21:15 ` [PATCH RFC net-next v2 2/6] selftests: ncdevmem: Implement devmem TCP TX Mina Almasry
@ 2025-01-30 21:15 ` Mina Almasry
2025-01-30 21:15 ` [PATCH RFC net-next v2 4/6] net: devmem: TCP tx netlink api Mina Almasry
` (2 subsequent siblings)
5 siblings, 0 replies; 17+ messages in thread
From: Mina Almasry @ 2025-01-30 21:15 UTC (permalink / raw)
To: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest
Cc: Mina Almasry, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
Currently net_iovs support only pp ref counts, and do not support a
page ref equivalent.
This is fine for the RX path as net_iovs are used exclusively with the
pp and only pp refcounting is needed there. The TX path however does not
use pp ref counts, thus, support for get_page/put_page equivalent is
needed for netmem.
Support get_netmem/put_netmem. Check the type of the netmem before
passing it to page or net_iov specific code to obtain a page ref
equivalent.
For dmabuf net_iovs, we obtain a ref on the underlying binding. This
ensures the entire binding doesn't disappear until all the net_iovs have
been put_netmem'ed. We do not need to track the refcount of individual
dmabuf net_iovs as we don't allocate/free them from a pool similar to
what the buddy allocator does for pages.
This code is written to be extensible by other net_iov implementers.
get_netmem/put_netmem will check the type of the netmem and route it to
the correct helper:
pages -> [get|put]_page()
dmabuf net_iovs -> net_devmem_[get|put]_net_iov()
new net_iovs -> new helpers
Signed-off-by: Mina Almasry <almasrymina@google.com>
---
v2:
- Add comment on top of refcount_t ref explaining the usage in the XT
path.
- Fix missing definition of net_devmem_dmabuf_binding_put in this patch.
---
include/linux/skbuff_ref.h | 4 ++--
include/net/netmem.h | 3 +++
net/core/devmem.c | 10 ++++++++++
net/core/devmem.h | 20 ++++++++++++++++++++
net/core/skbuff.c | 30 ++++++++++++++++++++++++++++++
5 files changed, 65 insertions(+), 2 deletions(-)
diff --git a/include/linux/skbuff_ref.h b/include/linux/skbuff_ref.h
index 0f3c58007488..9e49372ef1a0 100644
--- a/include/linux/skbuff_ref.h
+++ b/include/linux/skbuff_ref.h
@@ -17,7 +17,7 @@
*/
static inline void __skb_frag_ref(skb_frag_t *frag)
{
- get_page(skb_frag_page(frag));
+ get_netmem(skb_frag_netmem(frag));
}
/**
@@ -40,7 +40,7 @@ static inline void skb_page_unref(netmem_ref netmem, bool recycle)
if (recycle && napi_pp_put_page(netmem))
return;
#endif
- put_page(netmem_to_page(netmem));
+ put_netmem(netmem);
}
/**
diff --git a/include/net/netmem.h b/include/net/netmem.h
index 1b58faa4f20f..d30f31878a09 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h
@@ -245,4 +245,7 @@ static inline unsigned long netmem_get_dma_addr(netmem_ref netmem)
return __netmem_clear_lsb(netmem)->dma_addr;
}
+void get_netmem(netmem_ref netmem);
+void put_netmem(netmem_ref netmem);
+
#endif /* _NET_NETMEM_H */
diff --git a/net/core/devmem.c b/net/core/devmem.c
index 3bba3f018df0..20985a570662 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -333,6 +333,16 @@ void dev_dmabuf_uninstall(struct net_device *dev)
}
}
+void net_devmem_get_net_iov(struct net_iov *niov)
+{
+ net_devmem_dmabuf_binding_get(niov->owner->binding);
+}
+
+void net_devmem_put_net_iov(struct net_iov *niov)
+{
+ net_devmem_dmabuf_binding_put(niov->owner->binding);
+}
+
/*** "Dmabuf devmem memory provider" ***/
int mp_dmabuf_devmem_init(struct page_pool *pool)
diff --git a/net/core/devmem.h b/net/core/devmem.h
index 76099ef9c482..8b51caff5a0e 100644
--- a/net/core/devmem.h
+++ b/net/core/devmem.h
@@ -27,6 +27,10 @@ struct net_devmem_dmabuf_binding {
* The binding undos itself and unmaps the underlying dmabuf once all
* those refs are dropped and the binding is no longer desired or in
* use.
+ *
+ * net_devmem_get_net_iov() on dmabuf net_iovs will increment this
+ * reference, making sure that the binding remains alive until all the
+ * net_iovs are no longer used.
*/
refcount_t ref;
@@ -119,6 +123,9 @@ net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding)
__net_devmem_dmabuf_binding_free(binding);
}
+void net_devmem_get_net_iov(struct net_iov *niov);
+void net_devmem_put_net_iov(struct net_iov *niov);
+
struct net_iov *
net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding);
void net_devmem_free_dmabuf(struct net_iov *ppiov);
@@ -126,6 +133,19 @@ void net_devmem_free_dmabuf(struct net_iov *ppiov);
#else
struct net_devmem_dmabuf_binding;
+static inline void
+net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding)
+{
+}
+
+static inline void net_devmem_get_net_iov(struct net_iov *niov)
+{
+}
+
+static inline void net_devmem_put_net_iov(struct net_iov *niov)
+{
+}
+
static inline void
__net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
{
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a441613a1e6c..815245d5c36b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -88,6 +88,7 @@
#include <linux/textsearch.h>
#include "dev.h"
+#include "devmem.h"
#include "netmem_priv.h"
#include "sock_destructor.h"
@@ -7290,3 +7291,32 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
return false;
}
EXPORT_SYMBOL(csum_and_copy_from_iter_full);
+
+void get_netmem(netmem_ref netmem)
+{
+ if (netmem_is_net_iov(netmem)) {
+ /* Assume any net_iov is devmem and route it to
+ * net_devmem_get_net_iov. As new net_iov types are added they
+ * need to be checked here.
+ */
+ net_devmem_get_net_iov(netmem_to_net_iov(netmem));
+ return;
+ }
+ get_page(netmem_to_page(netmem));
+}
+EXPORT_SYMBOL(get_netmem);
+
+void put_netmem(netmem_ref netmem)
+{
+ if (netmem_is_net_iov(netmem)) {
+ /* Assume any net_iov is devmem and route it to
+ * net_devmem_put_net_iov. As new net_iov types are added they
+ * need to be checked here.
+ */
+ net_devmem_put_net_iov(netmem_to_net_iov(netmem));
+ return;
+ }
+
+ put_page(netmem_to_page(netmem));
+}
+EXPORT_SYMBOL(put_netmem);
--
2.48.1.362.g079036d154-goog
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH RFC net-next v2 4/6] net: devmem: TCP tx netlink api
2025-01-30 21:15 [PATCH RFC net-next v2 0/6] Device memory TCP TX Mina Almasry
` (2 preceding siblings ...)
2025-01-30 21:15 ` [PATCH RFC net-next v2 3/6] net: add get_netmem/put_netmem support Mina Almasry
@ 2025-01-30 21:15 ` Mina Almasry
2025-01-31 8:29 ` Simon Horman
2025-01-30 21:15 ` [PATCH RFC net-next v2 5/6] net: devmem: Implement TX path Mina Almasry
2025-01-30 21:15 ` [PATCH RFC net-next v2 6/6] net: devmem: make dmabuf unbinding scheduled work Mina Almasry
5 siblings, 1 reply; 17+ messages in thread
From: Mina Almasry @ 2025-01-30 21:15 UTC (permalink / raw)
To: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest
Cc: Mina Almasry, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
From: Stanislav Fomichev <sdf@fomichev.me>
Add bind-tx netlink call to attach dmabuf for TX; queue is not
required, only ifindex and dmabuf fd for attachment.
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Mina Almasry <almasrymina@google.com>
---
Documentation/netlink/specs/netdev.yaml | 12 ++++++++++++
include/uapi/linux/netdev.h | 1 +
net/core/netdev-genl-gen.c | 13 +++++++++++++
net/core/netdev-genl-gen.h | 1 +
net/core/netdev-genl.c | 6 ++++++
tools/include/uapi/linux/netdev.h | 1 +
6 files changed, 34 insertions(+)
diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index cbb544bd6c84..93f4333e7bc6 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -711,6 +711,18 @@ operations:
- defer-hard-irqs
- gro-flush-timeout
- irq-suspend-timeout
+ -
+ name: bind-tx
+ doc: Bind dmabuf to netdev for TX
+ attribute-set: dmabuf
+ do:
+ request:
+ attributes:
+ - ifindex
+ - fd
+ reply:
+ attributes:
+ - id
kernel-family:
headers: [ "linux/list.h"]
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index e4be227d3ad6..04364ef5edbe 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -203,6 +203,7 @@ enum {
NETDEV_CMD_QSTATS_GET,
NETDEV_CMD_BIND_RX,
NETDEV_CMD_NAPI_SET,
+ NETDEV_CMD_BIND_TX,
__NETDEV_CMD_MAX,
NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c
index 996ac6a449eb..9e947284e42d 100644
--- a/net/core/netdev-genl-gen.c
+++ b/net/core/netdev-genl-gen.c
@@ -99,6 +99,12 @@ static const struct nla_policy netdev_napi_set_nl_policy[NETDEV_A_NAPI_IRQ_SUSPE
[NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT] = { .type = NLA_UINT, },
};
+/* NETDEV_CMD_BIND_TX - do */
+static const struct nla_policy netdev_bind_tx_nl_policy[NETDEV_A_DMABUF_FD + 1] = {
+ [NETDEV_A_DMABUF_IFINDEX] = NLA_POLICY_MIN(NLA_U32, 1),
+ [NETDEV_A_DMABUF_FD] = { .type = NLA_U32, },
+};
+
/* Ops table for netdev */
static const struct genl_split_ops netdev_nl_ops[] = {
{
@@ -190,6 +196,13 @@ static const struct genl_split_ops netdev_nl_ops[] = {
.maxattr = NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT,
.flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
},
+ {
+ .cmd = NETDEV_CMD_BIND_TX,
+ .doit = netdev_nl_bind_tx_doit,
+ .policy = netdev_bind_tx_nl_policy,
+ .maxattr = NETDEV_A_DMABUF_FD,
+ .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+ },
};
static const struct genl_multicast_group netdev_nl_mcgrps[] = {
diff --git a/net/core/netdev-genl-gen.h b/net/core/netdev-genl-gen.h
index e09dd7539ff2..c1fed66e92b9 100644
--- a/net/core/netdev-genl-gen.h
+++ b/net/core/netdev-genl-gen.h
@@ -34,6 +34,7 @@ int netdev_nl_qstats_get_dumpit(struct sk_buff *skb,
struct netlink_callback *cb);
int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info);
int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info);
+int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info);
enum {
NETDEV_NLGRP_MGMT,
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 715f85c6b62e..0e41699df419 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -911,6 +911,12 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
return err;
}
+/* stub */
+int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
+{
+ return 0;
+}
+
void netdev_nl_sock_priv_init(struct list_head *priv)
{
INIT_LIST_HEAD(priv);
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index e4be227d3ad6..04364ef5edbe 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -203,6 +203,7 @@ enum {
NETDEV_CMD_QSTATS_GET,
NETDEV_CMD_BIND_RX,
NETDEV_CMD_NAPI_SET,
+ NETDEV_CMD_BIND_TX,
__NETDEV_CMD_MAX,
NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
--
2.48.1.362.g079036d154-goog
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH RFC net-next v2 5/6] net: devmem: Implement TX path
2025-01-30 21:15 [PATCH RFC net-next v2 0/6] Device memory TCP TX Mina Almasry
` (3 preceding siblings ...)
2025-01-30 21:15 ` [PATCH RFC net-next v2 4/6] net: devmem: TCP tx netlink api Mina Almasry
@ 2025-01-30 21:15 ` Mina Almasry
2025-01-30 23:07 ` Stanislav Fomichev
2025-01-31 9:09 ` Simon Horman
2025-01-30 21:15 ` [PATCH RFC net-next v2 6/6] net: devmem: make dmabuf unbinding scheduled work Mina Almasry
5 siblings, 2 replies; 17+ messages in thread
From: Mina Almasry @ 2025-01-30 21:15 UTC (permalink / raw)
To: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest
Cc: Mina Almasry, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela, Kaiyuan Zhang
Augment dmabuf binding to be able to handle TX. Additional to all the RX
binding, we also create tx_vec needed for the TX path.
Provide API for sendmsg to be able to send dmabufs bound to this device:
- Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from.
- MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf.
Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY
implementation, while disabling instances where MSG_ZEROCOPY falls back
to copying.
We additionally pipe the binding down to the new
zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems
instead of the traditional page netmems.
We also special case skb_frag_dma_map to return the dma-address of these
dmabuf net_iovs instead of attempting to map pages.
Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat
of the implementation came from devmem TCP RFC v1[1], which included the
TX path, but Stan did all the rebasing on top of netmem/net_iov.
Cc: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com>
Signed-off-by: Mina Almasry <almasrymina@google.com>
---
v2:
- Remove dmabuf_offset from the dmabuf cmsg.
- Update zerocopy_fill_skb_from_devmem to interpret the
iov_base/iter_iov_addr as the offset into the dmabuf to send from
(Stan).
- Remove the confusing binding->tx_iter which is not needed if we
interpret the iov_base/iter_iov_addr as offset into the dmabuf (Stan).
- Remove check for binding->sgt and binding->sgt->nents in dmabuf
binding.
- Simplify the calculation of binding->tx_vec.
- Check in net_devmem_get_binding that the binding we're returning
has ifindex matching the sending socket (Willem).
---
include/linux/skbuff.h | 15 +++-
include/net/sock.h | 1 +
include/uapi/linux/uio.h | 6 +-
net/core/datagram.c | 41 ++++++++++-
net/core/devmem.c | 96 +++++++++++++++++++++++--
net/core/devmem.h | 42 +++++++++--
net/core/netdev-genl.c | 65 ++++++++++++++++-
net/core/skbuff.c | 6 +-
net/core/sock.c | 8 +++
net/ipv4/tcp.c | 36 +++++++---
net/vmw_vsock/virtio_transport_common.c | 3 +-
11 files changed, 285 insertions(+), 34 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index bb2b751d274a..3ff8f568c382 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1711,9 +1711,12 @@ struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
void msg_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref);
+struct net_devmem_dmabuf_binding;
+
int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb, struct iov_iter *from,
- size_t length);
+ size_t length,
+ struct net_devmem_dmabuf_binding *binding);
int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
struct iov_iter *from, size_t length);
@@ -1721,12 +1724,14 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
static inline int skb_zerocopy_iter_dgram(struct sk_buff *skb,
struct msghdr *msg, int len)
{
- return __zerocopy_sg_from_iter(msg, skb->sk, skb, &msg->msg_iter, len);
+ return __zerocopy_sg_from_iter(msg, skb->sk, skb, &msg->msg_iter, len,
+ NULL);
}
int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
struct msghdr *msg, int len,
- struct ubuf_info *uarg);
+ struct ubuf_info *uarg,
+ struct net_devmem_dmabuf_binding *binding);
/* Internal */
#define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
@@ -3697,6 +3702,10 @@ static inline dma_addr_t __skb_frag_dma_map(struct device *dev,
size_t offset, size_t size,
enum dma_data_direction dir)
{
+ if (skb_frag_is_net_iov(frag)) {
+ return netmem_to_net_iov(frag->netmem)->dma_addr + offset +
+ frag->offset;
+ }
return dma_map_page(dev, skb_frag_page(frag),
skb_frag_off(frag) + offset, size, dir);
}
diff --git a/include/net/sock.h b/include/net/sock.h
index 8036b3b79cd8..09eb918525b6 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1822,6 +1822,7 @@ struct sockcm_cookie {
u32 tsflags;
u32 ts_opt_id;
u32 priority;
+ u32 dmabuf_id;
};
static inline void sockcm_init(struct sockcm_cookie *sockc,
diff --git a/include/uapi/linux/uio.h b/include/uapi/linux/uio.h
index 649739e0c404..866bd5dfe39f 100644
--- a/include/uapi/linux/uio.h
+++ b/include/uapi/linux/uio.h
@@ -38,10 +38,14 @@ struct dmabuf_token {
__u32 token_count;
};
+struct dmabuf_tx_cmsg {
+ __u32 dmabuf_id;
+};
+
/*
* UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1)
*/
-
+
#define UIO_FASTIOV 8
#define UIO_MAXIOV 1024
diff --git a/net/core/datagram.c b/net/core/datagram.c
index f0693707aece..c989606ff58d 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -63,6 +63,8 @@
#include <net/busy_poll.h>
#include <crypto/hash.h>
+#include "devmem.h"
+
/*
* Is a socket 'connection oriented' ?
*/
@@ -692,9 +694,42 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
return 0;
}
+static int
+zerocopy_fill_skb_from_devmem(struct sk_buff *skb, struct iov_iter *from,
+ int length,
+ struct net_devmem_dmabuf_binding *binding)
+{
+ int i = skb_shinfo(skb)->nr_frags;
+ size_t virt_addr, size, off;
+ struct net_iov *niov;
+
+ while (length && iov_iter_count(from)) {
+ if (i == MAX_SKB_FRAGS)
+ return -EMSGSIZE;
+
+ virt_addr = (size_t)iter_iov_addr(from);
+ niov = net_devmem_get_niov_at(binding, virt_addr, &off, &size);
+ if (!niov)
+ return -EFAULT;
+
+ size = min_t(size_t, size, length);
+ size = min_t(size_t, size, iter_iov_len(from));
+
+ get_netmem(net_iov_to_netmem(niov));
+ skb_add_rx_frag_netmem(skb, i, net_iov_to_netmem(niov), off,
+ size, PAGE_SIZE);
+ iov_iter_advance(from, size);
+ length -= size;
+ i++;
+ }
+
+ return 0;
+}
+
int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb, struct iov_iter *from,
- size_t length)
+ size_t length,
+ struct net_devmem_dmabuf_binding *binding)
{
unsigned long orig_size = skb->truesize;
unsigned long truesize;
@@ -702,6 +737,8 @@ int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
if (msg && msg->msg_ubuf && msg->sg_from_iter)
ret = msg->sg_from_iter(skb, from, length);
+ else if (unlikely(binding))
+ ret = zerocopy_fill_skb_from_devmem(skb, from, length, binding);
else
ret = zerocopy_fill_skb_from_iter(skb, from, length);
@@ -735,7 +772,7 @@ int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *from)
if (skb_copy_datagram_from_iter(skb, 0, from, copy))
return -EFAULT;
- return __zerocopy_sg_from_iter(NULL, NULL, skb, from, ~0U);
+ return __zerocopy_sg_from_iter(NULL, NULL, skb, from, ~0U, NULL);
}
EXPORT_SYMBOL(zerocopy_sg_from_iter);
diff --git a/net/core/devmem.c b/net/core/devmem.c
index 20985a570662..796338b1599e 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -16,6 +16,7 @@
#include <net/netdev_queues.h>
#include <net/netdev_rx_queue.h>
#include <net/page_pool/helpers.h>
+#include <net/sock.h>
#include <trace/events/page_pool.h>
#include "devmem.h"
@@ -64,8 +65,10 @@ void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
dma_buf_detach(binding->dmabuf, binding->attachment);
dma_buf_put(binding->dmabuf);
xa_destroy(&binding->bound_rxqs);
+ kfree(binding->tx_vec);
kfree(binding);
}
+EXPORT_SYMBOL(__net_devmem_dmabuf_binding_free);
struct net_iov *
net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
@@ -110,6 +113,13 @@ void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
unsigned long xa_idx;
unsigned int rxq_idx;
+ xa_erase(&net_devmem_dmabuf_bindings, binding->id);
+
+ /* Ensure no tx net_devmem_lookup_dmabuf() are in flight after the
+ * erase.
+ */
+ synchronize_net();
+
if (binding->list.next)
list_del(&binding->list);
@@ -123,8 +133,6 @@ void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
WARN_ON(netdev_rx_queue_restart(binding->dev, rxq_idx));
}
- xa_erase(&net_devmem_dmabuf_bindings, binding->id);
-
net_devmem_dmabuf_binding_put(binding);
}
@@ -185,8 +193,9 @@ int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
}
struct net_devmem_dmabuf_binding *
-net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
- struct netlink_ext_ack *extack)
+net_devmem_bind_dmabuf(struct net_device *dev,
+ enum dma_data_direction direction,
+ unsigned int dmabuf_fd, struct netlink_ext_ack *extack)
{
struct net_devmem_dmabuf_binding *binding;
static u32 id_alloc_next;
@@ -229,7 +238,7 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
}
binding->sgt = dma_buf_map_attachment_unlocked(binding->attachment,
- DMA_FROM_DEVICE);
+ direction);
if (IS_ERR(binding->sgt)) {
err = PTR_ERR(binding->sgt);
NL_SET_ERR_MSG(extack, "Failed to map dmabuf attachment");
@@ -240,13 +249,22 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
* binding can be much more flexible than that. We may be able to
* allocate MTU sized chunks here. Leave that for future work...
*/
- binding->chunk_pool =
- gen_pool_create(PAGE_SHIFT, dev_to_node(&dev->dev));
+ binding->chunk_pool = gen_pool_create(PAGE_SHIFT,
+ dev_to_node(&dev->dev));
if (!binding->chunk_pool) {
err = -ENOMEM;
goto err_unmap;
}
+ if (direction == DMA_TO_DEVICE) {
+ binding->tx_vec = kcalloc(dmabuf->size / PAGE_SIZE,
+ sizeof(struct net_iov *), GFP_KERNEL);
+ if (!binding->tx_vec) {
+ err = -ENOMEM;
+ goto err_free_chunks;
+ }
+ }
+
virtual = 0;
for_each_sgtable_dma_sg(binding->sgt, sg, sg_idx) {
dma_addr_t dma_addr = sg_dma_address(sg);
@@ -288,6 +306,8 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
niov->owner = owner;
page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov),
net_devmem_get_dma_addr(niov));
+ if (direction == DMA_TO_DEVICE)
+ binding->tx_vec[owner->base_virtual / PAGE_SIZE + i] = niov;
}
virtual += len;
@@ -313,6 +333,21 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
return ERR_PTR(err);
}
+struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id)
+{
+ struct net_devmem_dmabuf_binding *binding;
+
+ rcu_read_lock();
+ binding = xa_load(&net_devmem_dmabuf_bindings, id);
+ if (binding) {
+ if (!net_devmem_dmabuf_binding_get(binding))
+ binding = NULL;
+ }
+ rcu_read_unlock();
+
+ return binding;
+}
+
void dev_dmabuf_uninstall(struct net_device *dev)
{
struct net_devmem_dmabuf_binding *binding;
@@ -343,6 +378,53 @@ void net_devmem_put_net_iov(struct net_iov *niov)
net_devmem_dmabuf_binding_put(niov->owner->binding);
}
+struct net_devmem_dmabuf_binding *net_devmem_get_binding(struct sock *sk,
+ unsigned int dmabuf_id)
+{
+ struct net_devmem_dmabuf_binding *binding;
+ struct dst_entry *dst = __sk_dst_get(sk);
+ int err = 0;
+
+ binding = net_devmem_lookup_dmabuf(dmabuf_id);
+ if (!binding || !binding->tx_vec) {
+ err = -EINVAL;
+ goto out_err;
+ }
+
+ /* The dma-addrs in this binding are only reachable to the corresponding
+ * net_device.
+ */
+ if (!dst || !dst->dev || dst->dev->ifindex != binding->dev->ifindex) {
+ err = -ENODEV;
+ goto out_err;
+ }
+
+ return binding;
+
+out_err:
+ if (binding)
+ net_devmem_dmabuf_binding_put(binding);
+
+ return ERR_PTR(err);
+}
+
+struct net_iov *
+net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding,
+ size_t virt_addr, size_t *off, size_t *size)
+{
+ size_t idx;
+
+ if (virt_addr >= binding->dmabuf->size)
+ return NULL;
+
+ idx = virt_addr / PAGE_SIZE;
+
+ *off = virt_addr % PAGE_SIZE;
+ *size = PAGE_SIZE - *off;
+
+ return binding->tx_vec[idx];
+}
+
/*** "Dmabuf devmem memory provider" ***/
int mp_dmabuf_devmem_init(struct page_pool *pool)
diff --git a/net/core/devmem.h b/net/core/devmem.h
index 8b51caff5a0e..874e891e70e0 100644
--- a/net/core/devmem.h
+++ b/net/core/devmem.h
@@ -46,6 +46,12 @@ struct net_devmem_dmabuf_binding {
* active.
*/
u32 id;
+
+ /* Array of net_iov pointers for this binding, sorted by virtual
+ * address. This array is convenient to map the virtual addresses to
+ * net_iovs in the TX path.
+ */
+ struct net_iov **tx_vec;
};
#if defined(CONFIG_NET_DEVMEM)
@@ -70,12 +76,15 @@ struct dmabuf_genpool_chunk_owner {
void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding);
struct net_devmem_dmabuf_binding *
-net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
- struct netlink_ext_ack *extack);
+net_devmem_bind_dmabuf(struct net_device *dev,
+ enum dma_data_direction direction,
+ unsigned int dmabuf_fd, struct netlink_ext_ack *extack);
+struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id);
void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding);
int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
struct net_devmem_dmabuf_binding *binding,
struct netlink_ext_ack *extack);
+void net_devmem_bind_tx_release(struct sock *sk);
void dev_dmabuf_uninstall(struct net_device *dev);
static inline struct dmabuf_genpool_chunk_owner *
@@ -108,10 +117,10 @@ static inline u32 net_iov_binding_id(const struct net_iov *niov)
return net_iov_owner(niov)->binding->id;
}
-static inline void
+static inline bool
net_devmem_dmabuf_binding_get(struct net_devmem_dmabuf_binding *binding)
{
- refcount_inc(&binding->ref);
+ return refcount_inc_not_zero(&binding->ref);
}
static inline void
@@ -130,6 +139,12 @@ struct net_iov *
net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding);
void net_devmem_free_dmabuf(struct net_iov *ppiov);
+struct net_devmem_dmabuf_binding *
+net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id);
+struct net_iov *
+net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr,
+ size_t *off, size_t *size);
+
#else
struct net_devmem_dmabuf_binding;
@@ -153,11 +168,17 @@ __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
static inline struct net_devmem_dmabuf_binding *
net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
+ enum dma_data_direction direction,
struct netlink_ext_ack *extack)
{
return ERR_PTR(-EOPNOTSUPP);
}
+static inline struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id)
+{
+ return NULL;
+}
+
static inline void
net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
{
@@ -195,6 +216,19 @@ static inline u32 net_iov_binding_id(const struct net_iov *niov)
{
return 0;
}
+
+static inline struct net_devmem_dmabuf_binding *
+net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id)
+{
+ return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline struct net_iov *
+net_devmem_get_niov_at(struct net_devmem_dmabuf_binding *binding, size_t addr,
+ size_t *off, size_t *size)
+{
+ return NULL;
+}
#endif
#endif /* _NET_DEVMEM_H */
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 0e41699df419..9ba6994e2a05 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -854,7 +854,8 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
goto err_unlock;
}
- binding = net_devmem_bind_dmabuf(netdev, dmabuf_fd, info->extack);
+ binding = net_devmem_bind_dmabuf(netdev, DMA_FROM_DEVICE, dmabuf_fd,
+ info->extack);
if (IS_ERR(binding)) {
err = PTR_ERR(binding);
goto err_unlock;
@@ -911,10 +912,68 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
return err;
}
-/* stub */
int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
{
- return 0;
+ struct net_devmem_dmabuf_binding *binding;
+ struct list_head *sock_binding_list;
+ struct net_device *netdev;
+ u32 ifindex, dmabuf_fd;
+ struct sk_buff *rsp;
+ int err = 0;
+ void *hdr;
+
+ if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_DEV_IFINDEX) ||
+ GENL_REQ_ATTR_CHECK(info, NETDEV_A_DMABUF_FD))
+ return -EINVAL;
+
+ ifindex = nla_get_u32(info->attrs[NETDEV_A_DEV_IFINDEX]);
+ dmabuf_fd = nla_get_u32(info->attrs[NETDEV_A_DMABUF_FD]);
+
+ sock_binding_list =
+ genl_sk_priv_get(&netdev_nl_family, NETLINK_CB(skb).sk);
+ if (IS_ERR(sock_binding_list))
+ return PTR_ERR(sock_binding_list);
+
+ rsp = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ if (!rsp)
+ return -ENOMEM;
+
+ hdr = genlmsg_iput(rsp, info);
+ if (!hdr) {
+ err = -EMSGSIZE;
+ goto err_genlmsg_free;
+ }
+
+ rtnl_lock();
+
+ netdev = __dev_get_by_index(genl_info_net(info), ifindex);
+ if (!netdev || !netif_device_present(netdev)) {
+ err = -ENODEV;
+ goto err_unlock;
+ }
+
+ binding = net_devmem_bind_dmabuf(netdev, DMA_TO_DEVICE, dmabuf_fd,
+ info->extack);
+ if (IS_ERR(binding)) {
+ err = PTR_ERR(binding);
+ goto err_unlock;
+ }
+
+ list_add(&binding->list, sock_binding_list);
+
+ nla_put_u32(rsp, NETDEV_A_DMABUF_ID, binding->id);
+ genlmsg_end(rsp, hdr);
+
+ rtnl_unlock();
+
+ return genlmsg_reply(rsp, info);
+
+ net_devmem_unbind_dmabuf(binding);
+err_unlock:
+ rtnl_unlock();
+err_genlmsg_free:
+ nlmsg_free(rsp);
+ return err;
}
void netdev_nl_sock_priv_init(struct list_head *priv)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 815245d5c36b..6289ffcbb20b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1882,7 +1882,8 @@ EXPORT_SYMBOL_GPL(msg_zerocopy_ubuf_ops);
int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
struct msghdr *msg, int len,
- struct ubuf_info *uarg)
+ struct ubuf_info *uarg,
+ struct net_devmem_dmabuf_binding *binding)
{
int err, orig_len = skb->len;
@@ -1901,7 +1902,8 @@ int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
return -EEXIST;
}
- err = __zerocopy_sg_from_iter(msg, sk, skb, &msg->msg_iter, len);
+ err = __zerocopy_sg_from_iter(msg, sk, skb, &msg->msg_iter, len,
+ binding);
if (err == -EFAULT || (err == -EMSGSIZE && skb->len == orig_len)) {
struct sock *save_sk = skb->sk;
diff --git a/net/core/sock.c b/net/core/sock.c
index eae2ae70a2e0..353669f124ab 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2911,6 +2911,7 @@ EXPORT_SYMBOL(sock_alloc_send_pskb);
int __sock_cmsg_send(struct sock *sk, struct cmsghdr *cmsg,
struct sockcm_cookie *sockc)
{
+ struct dmabuf_tx_cmsg dmabuf_tx;
u32 tsflags;
BUILD_BUG_ON(SOF_TIMESTAMPING_LAST == (1 << 31));
@@ -2964,6 +2965,13 @@ int __sock_cmsg_send(struct sock *sk, struct cmsghdr *cmsg,
if (!sk_set_prio_allowed(sk, *(u32 *)CMSG_DATA(cmsg)))
return -EPERM;
sockc->priority = *(u32 *)CMSG_DATA(cmsg);
+ break;
+ case SCM_DEVMEM_DMABUF:
+ if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct dmabuf_tx_cmsg)))
+ return -EINVAL;
+ dmabuf_tx = *(struct dmabuf_tx_cmsg *)CMSG_DATA(cmsg);
+ sockc->dmabuf_id = dmabuf_tx.dmabuf_id;
+
break;
default:
return -EINVAL;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 0d704bda6c41..44198ae7e44c 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1051,6 +1051,7 @@ int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied,
int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
{
+ struct net_devmem_dmabuf_binding *binding = NULL;
struct tcp_sock *tp = tcp_sk(sk);
struct ubuf_info *uarg = NULL;
struct sk_buff *skb;
@@ -1063,6 +1064,15 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
flags = msg->msg_flags;
+ sockcm_init(&sockc, sk);
+ if (msg->msg_controllen) {
+ err = sock_cmsg_send(sk, msg, &sockc);
+ if (unlikely(err)) {
+ err = -EINVAL;
+ goto out_err;
+ }
+ }
+
if ((flags & MSG_ZEROCOPY) && size) {
if (msg->msg_ubuf) {
uarg = msg->msg_ubuf;
@@ -1080,6 +1090,15 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
else
uarg_to_msgzc(uarg)->zerocopy = 0;
}
+
+ if (sockc.dmabuf_id != 0) {
+ binding = net_devmem_get_binding(sk, sockc.dmabuf_id);
+ if (IS_ERR(binding)) {
+ err = PTR_ERR(binding);
+ binding = NULL;
+ goto out_err;
+ }
+ }
} else if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES) && size) {
if (sk->sk_route_caps & NETIF_F_SG)
zc = MSG_SPLICE_PAGES;
@@ -1123,15 +1142,6 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
/* 'common' sending to sendq */
}
- sockcm_init(&sockc, sk);
- if (msg->msg_controllen) {
- err = sock_cmsg_send(sk, msg, &sockc);
- if (unlikely(err)) {
- err = -EINVAL;
- goto out_err;
- }
- }
-
/* This should be in poll */
sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
@@ -1248,7 +1258,8 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
goto wait_for_space;
}
- err = skb_zerocopy_iter_stream(sk, skb, msg, copy, uarg);
+ err = skb_zerocopy_iter_stream(sk, skb, msg, copy, uarg,
+ binding);
if (err == -EMSGSIZE || err == -EEXIST) {
tcp_mark_push(tp, skb);
goto new_segment;
@@ -1329,6 +1340,8 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
/* msg->msg_ubuf is pinned by the caller so we don't take extra refs */
if (uarg && !msg->msg_ubuf)
net_zcopy_put(uarg);
+ if (binding)
+ net_devmem_dmabuf_binding_put(binding);
return copied + copied_syn;
do_error:
@@ -1346,6 +1359,9 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
sk->sk_write_space(sk);
tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
}
+ if (binding)
+ net_devmem_dmabuf_binding_put(binding);
+
return err;
}
EXPORT_SYMBOL_GPL(tcp_sendmsg_locked);
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 7f7de6d88096..f6d4bb798517 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -107,8 +107,7 @@ static int virtio_transport_fill_skb(struct sk_buff *skb,
{
if (zcopy)
return __zerocopy_sg_from_iter(info->msg, NULL, skb,
- &info->msg->msg_iter,
- len);
+ &info->msg->msg_iter, len, NULL);
return memcpy_from_msg(skb_put(skb, len), info->msg, len);
}
--
2.48.1.362.g079036d154-goog
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH RFC net-next v2 6/6] net: devmem: make dmabuf unbinding scheduled work
2025-01-30 21:15 [PATCH RFC net-next v2 0/6] Device memory TCP TX Mina Almasry
` (4 preceding siblings ...)
2025-01-30 21:15 ` [PATCH RFC net-next v2 5/6] net: devmem: Implement TX path Mina Almasry
@ 2025-01-30 21:15 ` Mina Almasry
5 siblings, 0 replies; 17+ messages in thread
From: Mina Almasry @ 2025-01-30 21:15 UTC (permalink / raw)
To: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest
Cc: Mina Almasry, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
The TX path may release the dmabuf in a context where we cannot wait.
This happens when the user unbinds a TX dmabuf while there are still
references to its netmems in the TX path. In that case, the netmems will
be put_netmem'd from a context where we can't unmap the dmabuf,
resulting in a BUG like seen by Stan:
[ 1.548495] BUG: sleeping function called from invalid context at drivers/dma-buf/dma-buf.c:1255
[ 1.548741] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 149, name: ncdevmem
[ 1.548926] preempt_count: 201, expected: 0
[ 1.549026] RCU nest depth: 0, expected: 0
[ 1.549197]
[ 1.549237] =============================
[ 1.549331] [ BUG: Invalid wait context ]
[ 1.549425] 6.13.0-rc3-00770-gbc9ef9606dc9-dirty #15 Tainted: G W
[ 1.549609] -----------------------------
[ 1.549704] ncdevmem/149 is trying to lock:
[ 1.549801] ffff8880066701c0 (reservation_ww_class_mutex){+.+.}-{4:4}, at: dma_buf_unmap_attachment_unlocked+0x4b/0x90
[ 1.550051] other info that might help us debug this:
[ 1.550167] context-{5:5}
[ 1.550229] 3 locks held by ncdevmem/149:
[ 1.550322] #0: ffff888005730208 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: sock_close+0x40/0xf0
[ 1.550530] #1: ffff88800b148f98 (sk_lock-AF_INET6){+.+.}-{0:0}, at: tcp_close+0x19/0x80
[ 1.550731] #2: ffff88800b148f18 (slock-AF_INET6){+.-.}-{3:3}, at: __tcp_close+0x185/0x4b0
[ 1.550921] stack backtrace:
[ 1.550990] CPU: 0 UID: 0 PID: 149 Comm: ncdevmem Tainted: G W 6.13.0-rc3-00770-gbc9ef9606dc9-dirty #15
[ 1.551233] Tainted: [W]=WARN
[ 1.551304] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[ 1.551518] Call Trace:
[ 1.551584] <TASK>
[ 1.551636] dump_stack_lvl+0x86/0xc0
[ 1.551723] __lock_acquire+0xb0f/0xc30
[ 1.551814] ? dma_buf_unmap_attachment_unlocked+0x4b/0x90
[ 1.551941] lock_acquire+0xf1/0x2a0
[ 1.552026] ? dma_buf_unmap_attachment_unlocked+0x4b/0x90
[ 1.552152] ? dma_buf_unmap_attachment_unlocked+0x4b/0x90
[ 1.552281] ? dma_buf_unmap_attachment_unlocked+0x4b/0x90
[ 1.552408] __ww_mutex_lock+0x121/0x1060
[ 1.552503] ? dma_buf_unmap_attachment_unlocked+0x4b/0x90
[ 1.552648] ww_mutex_lock+0x3d/0xa0
[ 1.552733] dma_buf_unmap_attachment_unlocked+0x4b/0x90
[ 1.552857] __net_devmem_dmabuf_binding_free+0x56/0xb0
[ 1.552979] skb_release_data+0x120/0x1f0
[ 1.553074] __kfree_skb+0x29/0xa0
[ 1.553156] tcp_write_queue_purge+0x41/0x310
[ 1.553259] tcp_v4_destroy_sock+0x127/0x320
[ 1.553363] ? __tcp_close+0x169/0x4b0
[ 1.553452] inet_csk_destroy_sock+0x53/0x130
[ 1.553560] __tcp_close+0x421/0x4b0
[ 1.553646] tcp_close+0x24/0x80
[ 1.553724] inet_release+0x5d/0x90
[ 1.553806] sock_close+0x4a/0xf0
[ 1.553886] __fput+0x9c/0x2b0
[ 1.553960] task_work_run+0x89/0xc0
[ 1.554046] do_exit+0x27f/0x980
[ 1.554125] do_group_exit+0xa4/0xb0
[ 1.554211] __x64_sys_exit_group+0x17/0x20
[ 1.554309] x64_sys_call+0x21a0/0x21a0
[ 1.554400] do_syscall_64+0xec/0x1d0
[ 1.554487] ? exc_page_fault+0x8a/0xf0
[ 1.554585] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 1.554703] RIP: 0033:0x7f2f8a27abcd
Resolve this by making __net_devmem_dmabuf_binding_free schedule_work'd.
Suggested-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Mina Almasry <almasrymina@google.com>
---
net/core/devmem.c | 4 +++-
net/core/devmem.h | 10 ++++++----
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/net/core/devmem.c b/net/core/devmem.c
index 796338b1599e..58fcae0c0c69 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -46,8 +46,10 @@ static dma_addr_t net_devmem_get_dma_addr(const struct net_iov *niov)
((dma_addr_t)net_iov_idx(niov) << PAGE_SHIFT);
}
-void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
+void __net_devmem_dmabuf_binding_free(struct work_struct *wq)
{
+ struct net_devmem_dmabuf_binding *binding = container_of(wq, typeof(*binding), unbind_w);
+
size_t size, avail;
gen_pool_for_each_chunk(binding->chunk_pool,
diff --git a/net/core/devmem.h b/net/core/devmem.h
index 874e891e70e0..63d16dbaca2d 100644
--- a/net/core/devmem.h
+++ b/net/core/devmem.h
@@ -52,6 +52,8 @@ struct net_devmem_dmabuf_binding {
* net_iovs in the TX path.
*/
struct net_iov **tx_vec;
+
+ struct work_struct unbind_w;
};
#if defined(CONFIG_NET_DEVMEM)
@@ -74,7 +76,7 @@ struct dmabuf_genpool_chunk_owner {
struct net_devmem_dmabuf_binding *binding;
};
-void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding);
+void __net_devmem_dmabuf_binding_free(struct work_struct *wq);
struct net_devmem_dmabuf_binding *
net_devmem_bind_dmabuf(struct net_device *dev,
enum dma_data_direction direction,
@@ -129,7 +131,8 @@ net_devmem_dmabuf_binding_put(struct net_devmem_dmabuf_binding *binding)
if (!refcount_dec_and_test(&binding->ref))
return;
- __net_devmem_dmabuf_binding_free(binding);
+ INIT_WORK(&binding->unbind_w, __net_devmem_dmabuf_binding_free);
+ schedule_work(&binding->unbind_w);
}
void net_devmem_get_net_iov(struct net_iov *niov);
@@ -161,8 +164,7 @@ static inline void net_devmem_put_net_iov(struct net_iov *niov)
{
}
-static inline void
-__net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
+static inline void __net_devmem_dmabuf_binding_free(struct work_struct *wq)
{
}
--
2.48.1.362.g079036d154-goog
^ permalink raw reply related [flat|nested] 17+ messages in thread
* Re: [PATCH RFC net-next v2 1/6] net: add devmem TCP TX documentation
2025-01-30 21:15 ` [PATCH RFC net-next v2 1/6] net: add devmem TCP TX documentation Mina Almasry
@ 2025-01-30 22:59 ` Stanislav Fomichev
2025-01-30 23:22 ` Mina Almasry
0 siblings, 1 reply; 17+ messages in thread
From: Stanislav Fomichev @ 2025-01-30 22:59 UTC (permalink / raw)
To: Mina Almasry
Cc: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
On 01/30, Mina Almasry wrote:
> Add documentation outlining the usage and details of the devmem TCP TX
> API.
>
> Signed-off-by: Mina Almasry <almasrymina@google.com>
>
> ---
>
> v2:
> - Update documentation for iov_base is the dmabuf offset (Stan)
> ---
> Documentation/networking/devmem.rst | 144 +++++++++++++++++++++++++++-
> 1 file changed, 140 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/networking/devmem.rst b/Documentation/networking/devmem.rst
> index d95363645331..8166fe09da13 100644
> --- a/Documentation/networking/devmem.rst
> +++ b/Documentation/networking/devmem.rst
> @@ -62,15 +62,15 @@ More Info
> https://lore.kernel.org/netdev/20240831004313.3713467-1-almasrymina@google.com/
>
>
> -Interface
> -=========
> +RX Interface
> +============
>
>
> Example
> -------
>
> -tools/testing/selftests/net/ncdevmem.c:do_server shows an example of setting up
> -the RX path of this API.
> +./tools/testing/selftests/drivers/net/hw/ncdevmem:do_server shows an example of
> +setting up the RX path of this API.
>
>
> NIC Setup
> @@ -235,6 +235,142 @@ can be less than the tokens provided by the user in case of:
> (a) an internal kernel leak bug.
> (b) the user passed more than 1024 frags.
>
> +TX Interface
> +============
> +
> +
> +Example
> +-------
> +
> +./tools/testing/selftests/drivers/net/hw/ncdevmem:do_client shows an example of
> +setting up the TX path of this API.
> +
> +
> +NIC Setup
> +---------
> +
> +The user must bind a TX dmabuf to a given NIC using the netlink API::
> +
> + struct netdev_bind_tx_req *req = NULL;
> + struct netdev_bind_tx_rsp *rsp = NULL;
> + struct ynl_error yerr;
> +
> + *ys = ynl_sock_create(&ynl_netdev_family, &yerr);
> +
> + req = netdev_bind_tx_req_alloc();
> + netdev_bind_tx_req_set_ifindex(req, ifindex);
> + netdev_bind_tx_req_set_fd(req, dmabuf_fd);
> +
> + rsp = netdev_bind_tx(*ys, req);
> +
> + tx_dmabuf_id = rsp->id;
> +
> +
> +The netlink API returns a dmabuf_id: a unique ID that refers to this dmabuf
> +that has been bound.
> +
> +The user can unbind the dmabuf from the netdevice by closing the netlink socket
> +that established the binding. We do this so that the binding is automatically
> +unbound even if the userspace process crashes.
> +
> +Note that any reasonably well-behaved dmabuf from any exporter should work with
> +devmem TCP, even if the dmabuf is not actually backed by devmem. An example of
> +this is udmabuf, which wraps user memory (non-devmem) in a dmabuf.
> +
> +Socket Setup
> +------------
> +
> +The user application must use MSG_ZEROCOPY flag when sending devmem TCP. Devmem
> +cannot be copied by the kernel, so the semantics of the devmem TX are similar
> +to the semantics of MSG_ZEROCOPY.
> +
> + ret = setsockopt(socket_fd, SOL_SOCKET, SO_ZEROCOPY, &opt, sizeof(opt));
> +
> +Sending data
> +--------------
> +
> +Devmem data is sent using the SCM_DEVMEM_DMABUF cmsg.
> +
> +The user should create a msghdr where,
> +
> +iov_base is set to the offset into the dmabuf to start sending from.
> +iov_len is set to the number of bytes to be sent from the dmabuf.
> +
> +The user passes the dma-buf id to send from via the dmabuf_tx_cmsg.dmabuf_id.
> +
> +The example below sends 1024 bytes from offset 100 into the dmabuf, and 2048
> +from offset 2000 into the dmabuf. The dmabuf to send from is tx_dmabuf_id::
> +
> + char ctrl_data[CMSG_SPACE(sizeof(struct dmabuf_tx_cmsg))];
> + struct dmabuf_tx_cmsg ddmabuf;
> + struct msghdr msg = {};
> + struct cmsghdr *cmsg;
> + struct iovec iov[2];
> +
> + iov[0].iov_base = (void*)100;
> + iov[0].iov_len = 1024;
> + iov[1].iov_base = (void*)2000;
> + iov[1].iov_len = 2048;
> +
> + msg.msg_iov = iov;
> + msg.msg_iovlen = 2;
> +
> + msg.msg_control = ctrl_data;
> + msg.msg_controllen = sizeof(ctrl_data);
> +
> + cmsg = CMSG_FIRSTHDR(&msg);
> + cmsg->cmsg_level = SOL_SOCKET;
> + cmsg->cmsg_type = SCM_DEVMEM_DMABUF;
> + cmsg->cmsg_len = CMSG_LEN(sizeof(struct dmabuf_tx_cmsg));
> +
> + ddmabuf.dmabuf_id = tx_dmabuf_id;
> +
> + *((struct dmabuf_tx_cmsg *)CMSG_DATA(cmsg)) = ddmabuf;
[..]
> + sendmsg(socket_fd, &msg, MSG_ZEROCOPY);
Not super important, but any reason not to use MSG_SOCK_DEVMEM as a
flag? We already use it for recvmsg, seems logical to mirror the same
flag on the transmit side?
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH RFC net-next v2 2/6] selftests: ncdevmem: Implement devmem TCP TX
2025-01-30 21:15 ` [PATCH RFC net-next v2 2/6] selftests: ncdevmem: Implement devmem TCP TX Mina Almasry
@ 2025-01-30 23:05 ` Stanislav Fomichev
2025-01-30 23:29 ` Mina Almasry
2025-01-31 17:45 ` Stanislav Fomichev
1 sibling, 1 reply; 17+ messages in thread
From: Stanislav Fomichev @ 2025-01-30 23:05 UTC (permalink / raw)
To: Mina Almasry
Cc: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
On 01/30, Mina Almasry wrote:
> Add support for devmem TX in ncdevmem.
>
> This is a combination of the ncdevmem from the devmem TCP series RFCv1
> which included the TX path, and work by Stan to include the netlink API
> and refactored on top of his generic memory_provider support.
>
> Signed-off-by: Mina Almasry <almasrymina@google.com>
> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
>
> ---
>
> v2:
> - make errors a static variable so that we catch instances where there
> are less than 20 errors across different buffers.
> - Fix the issue where the seed is reset to 0 instead of its starting
> value 1.
> - Use 1000ULL instead of 1000 to guard against overflow (Willem).
> - Do not set POLLERR (Willem).
> - Update the test to use the new interface where iov_base is the
> dmabuf_offset.
> - Update the test to send 2 iov instead of 1, so we get some test
> coverage over sending multiple iovs at once.
> - Print the ifindex the test is using, useful for debugging issues where
> maybe the test may fail because the ifindex of the socket is different
> from the dmabuf binding.
> ---
> .../selftests/drivers/net/hw/ncdevmem.c | 276 +++++++++++++++++-
> 1 file changed, 272 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> index 19a6969643f4..8455f19ecd1a 100644
> --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> @@ -40,15 +40,18 @@
> #include <fcntl.h>
> #include <malloc.h>
> #include <error.h>
> +#include <poll.h>
>
> #include <arpa/inet.h>
> #include <sys/socket.h>
> #include <sys/mman.h>
> #include <sys/ioctl.h>
> #include <sys/syscall.h>
> +#include <sys/time.h>
>
> #include <linux/memfd.h>
> #include <linux/dma-buf.h>
> +#include <linux/errqueue.h>
> #include <linux/udmabuf.h>
> #include <libmnl/libmnl.h>
> #include <linux/types.h>
> @@ -80,6 +83,8 @@ static int num_queues = -1;
> static char *ifname;
> static unsigned int ifindex;
> static unsigned int dmabuf_id;
> +static uint32_t tx_dmabuf_id;
> +static int waittime_ms = 500;
>
> struct memory_buffer {
> int fd;
> @@ -93,6 +98,8 @@ struct memory_buffer {
> struct memory_provider {
> struct memory_buffer *(*alloc)(size_t size);
> void (*free)(struct memory_buffer *ctx);
> + void (*memcpy_to_device)(struct memory_buffer *dst, size_t off,
> + void *src, int n);
> void (*memcpy_from_device)(void *dst, struct memory_buffer *src,
> size_t off, int n);
> };
> @@ -153,6 +160,20 @@ static void udmabuf_free(struct memory_buffer *ctx)
> free(ctx);
> }
>
> +static void udmabuf_memcpy_to_device(struct memory_buffer *dst, size_t off,
> + void *src, int n)
> +{
> + struct dma_buf_sync sync = {};
> +
> + sync.flags = DMA_BUF_SYNC_START | DMA_BUF_SYNC_WRITE;
> + ioctl(dst->fd, DMA_BUF_IOCTL_SYNC, &sync);
> +
> + memcpy(dst->buf_mem + off, src, n);
> +
> + sync.flags = DMA_BUF_SYNC_END | DMA_BUF_SYNC_WRITE;
> + ioctl(dst->fd, DMA_BUF_IOCTL_SYNC, &sync);
> +}
> +
> static void udmabuf_memcpy_from_device(void *dst, struct memory_buffer *src,
> size_t off, int n)
> {
> @@ -170,6 +191,7 @@ static void udmabuf_memcpy_from_device(void *dst, struct memory_buffer *src,
> static struct memory_provider udmabuf_memory_provider = {
> .alloc = udmabuf_alloc,
> .free = udmabuf_free,
> + .memcpy_to_device = udmabuf_memcpy_to_device,
> .memcpy_from_device = udmabuf_memcpy_from_device,
> };
>
> @@ -188,7 +210,7 @@ void validate_buffer(void *line, size_t size)
> {
> static unsigned char seed = 1;
> unsigned char *ptr = line;
> - int errors = 0;
> + static int errors;
> size_t i;
>
> for (i = 0; i < size; i++) {
> @@ -202,7 +224,7 @@ void validate_buffer(void *line, size_t size)
> }
> seed++;
> if (seed == do_validation)
> - seed = 0;
> + seed = 1;
> }
>
> fprintf(stdout, "Validated buffer\n");
> @@ -394,6 +416,49 @@ static int bind_rx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
> return -1;
> }
>
> +static int bind_tx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
> + struct ynl_sock **ys)
> +{
> + struct netdev_bind_tx_req *req = NULL;
> + struct netdev_bind_tx_rsp *rsp = NULL;
> + struct ynl_error yerr;
> +
> + *ys = ynl_sock_create(&ynl_netdev_family, &yerr);
> + if (!*ys) {
> + fprintf(stderr, "YNL: %s\n", yerr.msg);
> + return -1;
> + }
> +
> + req = netdev_bind_tx_req_alloc();
> + netdev_bind_tx_req_set_ifindex(req, ifindex);
> + netdev_bind_tx_req_set_fd(req, dmabuf_fd);
> +
> + rsp = netdev_bind_tx(*ys, req);
> + if (!rsp) {
> + perror("netdev_bind_tx");
> + goto err_close;
> + }
> +
> + if (!rsp->_present.id) {
> + perror("id not present");
> + goto err_close;
> + }
> +
> + fprintf(stderr, "got tx dmabuf id=%d\n", rsp->id);
> + tx_dmabuf_id = rsp->id;
> +
> + netdev_bind_tx_req_free(req);
> + netdev_bind_tx_rsp_free(rsp);
> +
> + return 0;
> +
> +err_close:
> + fprintf(stderr, "YNL failed: %s\n", (*ys)->err.msg);
> + netdev_bind_tx_req_free(req);
> + ynl_sock_destroy(*ys);
> + return -1;
> +}
> +
> static void enable_reuseaddr(int fd)
> {
> int opt = 1;
> @@ -432,7 +497,7 @@ static int parse_address(const char *str, int port, struct sockaddr_in6 *sin6)
> return 0;
> }
>
> -int do_server(struct memory_buffer *mem)
> +static int do_server(struct memory_buffer *mem)
> {
> char ctrl_data[sizeof(int) * 20000];
> struct netdev_queue_id *queues;
> @@ -686,6 +751,207 @@ void run_devmem_tests(void)
> provider->free(mem);
> }
>
> +static uint64_t gettimeofday_ms(void)
> +{
> + struct timeval tv;
> +
> + gettimeofday(&tv, NULL);
> + return (tv.tv_sec * 1000ULL) + (tv.tv_usec / 1000ULL);
> +}
> +
> +static int do_poll(int fd)
> +{
> + struct pollfd pfd;
> + int ret;
> +
> + pfd.revents = 0;
> + pfd.fd = fd;
> +
> + ret = poll(&pfd, 1, waittime_ms);
> + if (ret == -1)
> + error(1, errno, "poll");
> +
> + return ret && (pfd.revents & POLLERR);
> +}
> +
> +static void wait_compl(int fd)
> +{
> + int64_t tstop = gettimeofday_ms() + waittime_ms;
> + char control[CMSG_SPACE(100)] = {};
> + struct sock_extended_err *serr;
> + struct msghdr msg = {};
> + struct cmsghdr *cm;
> + int retries = 10;
> + __u32 hi, lo;
> + int ret;
> +
> + msg.msg_control = control;
> + msg.msg_controllen = sizeof(control);
> +
> + while (gettimeofday_ms() < tstop) {
> + if (!do_poll(fd))
> + continue;
> +
> + ret = recvmsg(fd, &msg, MSG_ERRQUEUE);
> + if (ret < 0) {
> + if (errno == EAGAIN)
> + continue;
> + error(1, ret, "recvmsg(MSG_ERRQUEUE)");
> + return;
> + }
> + if (msg.msg_flags & MSG_CTRUNC)
> + error(1, 0, "MSG_CTRUNC\n");
> +
> + for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm)) {
> + if (cm->cmsg_level != SOL_IP &&
> + cm->cmsg_level != SOL_IPV6)
> + continue;
> + if (cm->cmsg_level == SOL_IP &&
> + cm->cmsg_type != IP_RECVERR)
> + continue;
> + if (cm->cmsg_level == SOL_IPV6 &&
> + cm->cmsg_type != IPV6_RECVERR)
> + continue;
> +
> + serr = (void *)CMSG_DATA(cm);
> + if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY)
> + error(1, 0, "wrong origin %u", serr->ee_origin);
> + if (serr->ee_errno != 0)
> + error(1, 0, "wrong errno %d", serr->ee_errno);
> +
> + hi = serr->ee_data;
> + lo = serr->ee_info;
> +
> + fprintf(stderr, "tx complete [%d,%d]\n", lo, hi);
> + return;
> + }
> + }
> +
> + error(1, 0, "did not receive tx completion");
> +}
> +
> +static int do_client(struct memory_buffer *mem)
> +{
> + char ctrl_data[CMSG_SPACE(sizeof(struct dmabuf_tx_cmsg))];
> + struct sockaddr_in6 server_sin;
> + struct sockaddr_in6 client_sin;
> + struct dmabuf_tx_cmsg ddmabuf;
> + struct ynl_sock *ys = NULL;
> + struct msghdr msg = {};
> + ssize_t line_size = 0;
> + struct cmsghdr *cmsg;
> + struct iovec iov[2];
> + uint64_t off = 100;
> + char *line = NULL;
> + size_t len = 0;
> + int socket_fd;
> + int ret, mid;
> + int opt = 1;
> +
> + ret = parse_address(server_ip, atoi(port), &server_sin);
> + if (ret < 0)
> + error(1, 0, "parse server address");
> +
> + socket_fd = socket(AF_INET6, SOCK_STREAM, 0);
> + if (socket_fd < 0)
> + error(1, socket_fd, "create socket");
> +
> + enable_reuseaddr(socket_fd);
> +
> + ret = setsockopt(socket_fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
> + strlen(ifname) + 1);
> + if (ret)
> + error(1, ret, "bindtodevice");
> +
> + if (bind_tx_queue(ifindex, mem->fd, &ys))
> + error(1, 0, "Failed to bind\n");
> +
> + ret = parse_address(client_ip, atoi(port), &client_sin);
> + if (ret < 0)
> + error(1, 0, "parse client address");
> +
> + ret = bind(socket_fd, &client_sin, sizeof(client_sin));
> + if (ret)
> + error(1, ret, "bind");
> +
> + ret = setsockopt(socket_fd, SOL_SOCKET, SO_ZEROCOPY, &opt, sizeof(opt));
> + if (ret)
> + error(1, ret, "set sock opt");
> +
> + fprintf(stderr, "Connect to %s %d (via %s)\n", server_ip,
> + ntohs(server_sin.sin6_port), ifname);
> +
> + ret = connect(socket_fd, &server_sin, sizeof(server_sin));
> + if (ret)
> + error(1, ret, "connect");
> +
> + while (1) {
> + free(line);
> + line = NULL;
> + /* Subtract 1 from line_size to remove trailing newlines that
> + * get_line are surely to parse...
> + */
> + line_size = getline(&line, &len, stdin) - 1;
Why not send the '\n' as well? If we skip the '\n', it's not keeping
netcat-like behavior :-(
> +
> + if (line_size < 0)
> + break;
[..]
> + mid = (line_size / 2) + 1;
> +
> + iov[0].iov_base = (void *)100;
> + iov[0].iov_len = mid;
> + iov[1].iov_base = (void *)2000;
> + iov[1].iov_len = line_size - mid;
This seems a bit hard-coded. We should at least test that mid is < 2000?
But ideally we should have two modes for tx with a flag (and run them
both from the selftest):
- pass one big iov, this will test the sendmsg path which creates
multiple skbs internally
- break 'line' into N sections (as you do here), but maybe have more
control over the number of sections?
Maybe let's have a new --max-iov-size flag? Then we can call ncdevmem
with --max-iov-size <some prime number close to 4k> to exercise all
sorts of weird offsets?
(seems ok to also follow up on that separately)
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH RFC net-next v2 5/6] net: devmem: Implement TX path
2025-01-30 21:15 ` [PATCH RFC net-next v2 5/6] net: devmem: Implement TX path Mina Almasry
@ 2025-01-30 23:07 ` Stanislav Fomichev
2025-01-31 9:09 ` Simon Horman
1 sibling, 0 replies; 17+ messages in thread
From: Stanislav Fomichev @ 2025-01-30 23:07 UTC (permalink / raw)
To: Mina Almasry
Cc: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela, Kaiyuan Zhang
On 01/30, Mina Almasry wrote:
> Augment dmabuf binding to be able to handle TX. Additional to all the RX
> binding, we also create tx_vec needed for the TX path.
>
> Provide API for sendmsg to be able to send dmabufs bound to this device:
>
> - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from.
> - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf.
>
> Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY
> implementation, while disabling instances where MSG_ZEROCOPY falls back
> to copying.
>
> We additionally pipe the binding down to the new
> zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems
> instead of the traditional page netmems.
>
> We also special case skb_frag_dma_map to return the dma-address of these
> dmabuf net_iovs instead of attempting to map pages.
>
> Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat
> of the implementation came from devmem TCP RFC v1[1], which included the
> TX path, but Stan did all the rebasing on top of netmem/net_iov.
>
> Cc: Stanislav Fomichev <sdf@fomichev.me>
> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com>
> Signed-off-by: Mina Almasry <almasrymina@google.com>
>
>
> ---
>
> v2:
> - Remove dmabuf_offset from the dmabuf cmsg.
> - Update zerocopy_fill_skb_from_devmem to interpret the
> iov_base/iter_iov_addr as the offset into the dmabuf to send from
> (Stan).
> - Remove the confusing binding->tx_iter which is not needed if we
> interpret the iov_base/iter_iov_addr as offset into the dmabuf (Stan).
> - Remove check for binding->sgt and binding->sgt->nents in dmabuf
> binding.
> - Simplify the calculation of binding->tx_vec.
> - Check in net_devmem_get_binding that the binding we're returning
> has ifindex matching the sending socket (Willem).
> ---
> include/linux/skbuff.h | 15 +++-
> include/net/sock.h | 1 +
> include/uapi/linux/uio.h | 6 +-
> net/core/datagram.c | 41 ++++++++++-
> net/core/devmem.c | 96 +++++++++++++++++++++++--
> net/core/devmem.h | 42 +++++++++--
> net/core/netdev-genl.c | 65 ++++++++++++++++-
> net/core/skbuff.c | 6 +-
> net/core/sock.c | 8 +++
> net/ipv4/tcp.c | 36 +++++++---
> net/vmw_vsock/virtio_transport_common.c | 3 +-
> 11 files changed, 285 insertions(+), 34 deletions(-)
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index bb2b751d274a..3ff8f568c382 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -1711,9 +1711,12 @@ struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size,
>
> void msg_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref);
>
> +struct net_devmem_dmabuf_binding;
> +
> int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
> struct sk_buff *skb, struct iov_iter *from,
> - size_t length);
> + size_t length,
> + struct net_devmem_dmabuf_binding *binding);
>
> int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
> struct iov_iter *from, size_t length);
> @@ -1721,12 +1724,14 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
> static inline int skb_zerocopy_iter_dgram(struct sk_buff *skb,
> struct msghdr *msg, int len)
> {
> - return __zerocopy_sg_from_iter(msg, skb->sk, skb, &msg->msg_iter, len);
> + return __zerocopy_sg_from_iter(msg, skb->sk, skb, &msg->msg_iter, len,
> + NULL);
> }
>
> int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
> struct msghdr *msg, int len,
> - struct ubuf_info *uarg);
> + struct ubuf_info *uarg,
> + struct net_devmem_dmabuf_binding *binding);
>
> /* Internal */
> #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
> @@ -3697,6 +3702,10 @@ static inline dma_addr_t __skb_frag_dma_map(struct device *dev,
> size_t offset, size_t size,
> enum dma_data_direction dir)
> {
> + if (skb_frag_is_net_iov(frag)) {
> + return netmem_to_net_iov(frag->netmem)->dma_addr + offset +
> + frag->offset;
> + }
> return dma_map_page(dev, skb_frag_page(frag),
> skb_frag_off(frag) + offset, size, dir);
> }
> diff --git a/include/net/sock.h b/include/net/sock.h
> index 8036b3b79cd8..09eb918525b6 100644
> --- a/include/net/sock.h
> +++ b/include/net/sock.h
> @@ -1822,6 +1822,7 @@ struct sockcm_cookie {
> u32 tsflags;
> u32 ts_opt_id;
> u32 priority;
> + u32 dmabuf_id;
> };
>
> static inline void sockcm_init(struct sockcm_cookie *sockc,
> diff --git a/include/uapi/linux/uio.h b/include/uapi/linux/uio.h
> index 649739e0c404..866bd5dfe39f 100644
> --- a/include/uapi/linux/uio.h
> +++ b/include/uapi/linux/uio.h
> @@ -38,10 +38,14 @@ struct dmabuf_token {
> __u32 token_count;
> };
>
> +struct dmabuf_tx_cmsg {
> + __u32 dmabuf_id;
> +};
> +
> /*
> * UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1)
> */
> -
> +
> #define UIO_FASTIOV 8
> #define UIO_MAXIOV 1024
>
> diff --git a/net/core/datagram.c b/net/core/datagram.c
> index f0693707aece..c989606ff58d 100644
> --- a/net/core/datagram.c
> +++ b/net/core/datagram.c
> @@ -63,6 +63,8 @@
> #include <net/busy_poll.h>
> #include <crypto/hash.h>
>
> +#include "devmem.h"
> +
> /*
> * Is a socket 'connection oriented' ?
> */
> @@ -692,9 +694,42 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
> return 0;
> }
>
> +static int
> +zerocopy_fill_skb_from_devmem(struct sk_buff *skb, struct iov_iter *from,
> + int length,
> + struct net_devmem_dmabuf_binding *binding)
> +{
> + int i = skb_shinfo(skb)->nr_frags;
> + size_t virt_addr, size, off;
> + struct net_iov *niov;
> +
> + while (length && iov_iter_count(from)) {
> + if (i == MAX_SKB_FRAGS)
> + return -EMSGSIZE;
> +
> + virt_addr = (size_t)iter_iov_addr(from);
> + niov = net_devmem_get_niov_at(binding, virt_addr, &off, &size);
> + if (!niov)
> + return -EFAULT;
> +
> + size = min_t(size_t, size, length);
> + size = min_t(size_t, size, iter_iov_len(from));
> +
> + get_netmem(net_iov_to_netmem(niov));
> + skb_add_rx_frag_netmem(skb, i, net_iov_to_netmem(niov), off,
> + size, PAGE_SIZE);
> + iov_iter_advance(from, size);
> + length -= size;
> + i++;
> + }
> +
> + return 0;
> +}
> +
> int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
> struct sk_buff *skb, struct iov_iter *from,
> - size_t length)
> + size_t length,
> + struct net_devmem_dmabuf_binding *binding)
> {
> unsigned long orig_size = skb->truesize;
> unsigned long truesize;
> @@ -702,6 +737,8 @@ int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk,
>
> if (msg && msg->msg_ubuf && msg->sg_from_iter)
> ret = msg->sg_from_iter(skb, from, length);
> + else if (unlikely(binding))
> + ret = zerocopy_fill_skb_from_devmem(skb, from, length, binding);
> else
> ret = zerocopy_fill_skb_from_iter(skb, from, length);
>
> @@ -735,7 +772,7 @@ int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *from)
> if (skb_copy_datagram_from_iter(skb, 0, from, copy))
> return -EFAULT;
>
> - return __zerocopy_sg_from_iter(NULL, NULL, skb, from, ~0U);
> + return __zerocopy_sg_from_iter(NULL, NULL, skb, from, ~0U, NULL);
> }
> EXPORT_SYMBOL(zerocopy_sg_from_iter);
>
> diff --git a/net/core/devmem.c b/net/core/devmem.c
> index 20985a570662..796338b1599e 100644
> --- a/net/core/devmem.c
> +++ b/net/core/devmem.c
> @@ -16,6 +16,7 @@
> #include <net/netdev_queues.h>
> #include <net/netdev_rx_queue.h>
> #include <net/page_pool/helpers.h>
> +#include <net/sock.h>
> #include <trace/events/page_pool.h>
>
> #include "devmem.h"
> @@ -64,8 +65,10 @@ void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding)
> dma_buf_detach(binding->dmabuf, binding->attachment);
> dma_buf_put(binding->dmabuf);
> xa_destroy(&binding->bound_rxqs);
> + kfree(binding->tx_vec);
> kfree(binding);
> }
> +EXPORT_SYMBOL(__net_devmem_dmabuf_binding_free);
>
> struct net_iov *
> net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
> @@ -110,6 +113,13 @@ void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
> unsigned long xa_idx;
> unsigned int rxq_idx;
>
> + xa_erase(&net_devmem_dmabuf_bindings, binding->id);
> +
> + /* Ensure no tx net_devmem_lookup_dmabuf() are in flight after the
> + * erase.
> + */
> + synchronize_net();
> +
> if (binding->list.next)
> list_del(&binding->list);
>
> @@ -123,8 +133,6 @@ void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
> WARN_ON(netdev_rx_queue_restart(binding->dev, rxq_idx));
> }
>
> - xa_erase(&net_devmem_dmabuf_bindings, binding->id);
> -
> net_devmem_dmabuf_binding_put(binding);
> }
>
> @@ -185,8 +193,9 @@ int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx,
> }
>
> struct net_devmem_dmabuf_binding *
> -net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
> - struct netlink_ext_ack *extack)
> +net_devmem_bind_dmabuf(struct net_device *dev,
> + enum dma_data_direction direction,
> + unsigned int dmabuf_fd, struct netlink_ext_ack *extack)
> {
> struct net_devmem_dmabuf_binding *binding;
> static u32 id_alloc_next;
> @@ -229,7 +238,7 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
> }
>
> binding->sgt = dma_buf_map_attachment_unlocked(binding->attachment,
> - DMA_FROM_DEVICE);
> + direction);
> if (IS_ERR(binding->sgt)) {
> err = PTR_ERR(binding->sgt);
> NL_SET_ERR_MSG(extack, "Failed to map dmabuf attachment");
> @@ -240,13 +249,22 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,
> * binding can be much more flexible than that. We may be able to
> * allocate MTU sized chunks here. Leave that for future work...
> */
> - binding->chunk_pool =
> - gen_pool_create(PAGE_SHIFT, dev_to_node(&dev->dev));
> + binding->chunk_pool = gen_pool_create(PAGE_SHIFT,
> + dev_to_node(&dev->dev));
> if (!binding->chunk_pool) {
> err = -ENOMEM;
> goto err_unmap;
> }
>
> + if (direction == DMA_TO_DEVICE) {
> + binding->tx_vec = kcalloc(dmabuf->size / PAGE_SIZE,
> + sizeof(struct net_iov *), GFP_KERNEL);
Let's make this kvcalloc (and kvfree in the release path)? Otherwise
we'll get ENOMEM here for a reasonably sized dmabufs..
The rest looks good, I'll try to run it on my side today/tomorrow..
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH RFC net-next v2 1/6] net: add devmem TCP TX documentation
2025-01-30 22:59 ` Stanislav Fomichev
@ 2025-01-30 23:22 ` Mina Almasry
2025-01-31 17:39 ` Stanislav Fomichev
0 siblings, 1 reply; 17+ messages in thread
From: Mina Almasry @ 2025-01-30 23:22 UTC (permalink / raw)
To: Stanislav Fomichev
Cc: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
On Thu, Jan 30, 2025 at 2:59 PM Stanislav Fomichev <stfomichev@gmail.com> wrote:
>
> On 01/30, Mina Almasry wrote:
> > Add documentation outlining the usage and details of the devmem TCP TX
> > API.
> >
> > Signed-off-by: Mina Almasry <almasrymina@google.com>
> >
> > ---
> >
> > v2:
> > - Update documentation for iov_base is the dmabuf offset (Stan)
> > ---
> > Documentation/networking/devmem.rst | 144 +++++++++++++++++++++++++++-
> > 1 file changed, 140 insertions(+), 4 deletions(-)
> >
> > diff --git a/Documentation/networking/devmem.rst b/Documentation/networking/devmem.rst
> > index d95363645331..8166fe09da13 100644
> > --- a/Documentation/networking/devmem.rst
> > +++ b/Documentation/networking/devmem.rst
> > @@ -62,15 +62,15 @@ More Info
> > https://lore.kernel.org/netdev/20240831004313.3713467-1-almasrymina@google.com/
> >
> >
> > -Interface
> > -=========
> > +RX Interface
> > +============
> >
> >
> > Example
> > -------
> >
> > -tools/testing/selftests/net/ncdevmem.c:do_server shows an example of setting up
> > -the RX path of this API.
> > +./tools/testing/selftests/drivers/net/hw/ncdevmem:do_server shows an example of
> > +setting up the RX path of this API.
> >
> >
> > NIC Setup
> > @@ -235,6 +235,142 @@ can be less than the tokens provided by the user in case of:
> > (a) an internal kernel leak bug.
> > (b) the user passed more than 1024 frags.
> >
> > +TX Interface
> > +============
> > +
> > +
> > +Example
> > +-------
> > +
> > +./tools/testing/selftests/drivers/net/hw/ncdevmem:do_client shows an example of
> > +setting up the TX path of this API.
> > +
> > +
> > +NIC Setup
> > +---------
> > +
> > +The user must bind a TX dmabuf to a given NIC using the netlink API::
> > +
> > + struct netdev_bind_tx_req *req = NULL;
> > + struct netdev_bind_tx_rsp *rsp = NULL;
> > + struct ynl_error yerr;
> > +
> > + *ys = ynl_sock_create(&ynl_netdev_family, &yerr);
> > +
> > + req = netdev_bind_tx_req_alloc();
> > + netdev_bind_tx_req_set_ifindex(req, ifindex);
> > + netdev_bind_tx_req_set_fd(req, dmabuf_fd);
> > +
> > + rsp = netdev_bind_tx(*ys, req);
> > +
> > + tx_dmabuf_id = rsp->id;
> > +
> > +
> > +The netlink API returns a dmabuf_id: a unique ID that refers to this dmabuf
> > +that has been bound.
> > +
> > +The user can unbind the dmabuf from the netdevice by closing the netlink socket
> > +that established the binding. We do this so that the binding is automatically
> > +unbound even if the userspace process crashes.
> > +
> > +Note that any reasonably well-behaved dmabuf from any exporter should work with
> > +devmem TCP, even if the dmabuf is not actually backed by devmem. An example of
> > +this is udmabuf, which wraps user memory (non-devmem) in a dmabuf.
> > +
> > +Socket Setup
> > +------------
> > +
> > +The user application must use MSG_ZEROCOPY flag when sending devmem TCP. Devmem
> > +cannot be copied by the kernel, so the semantics of the devmem TX are similar
> > +to the semantics of MSG_ZEROCOPY.
> > +
> > + ret = setsockopt(socket_fd, SOL_SOCKET, SO_ZEROCOPY, &opt, sizeof(opt));
> > +
> > +Sending data
> > +--------------
> > +
> > +Devmem data is sent using the SCM_DEVMEM_DMABUF cmsg.
> > +
> > +The user should create a msghdr where,
> > +
> > +iov_base is set to the offset into the dmabuf to start sending from.
> > +iov_len is set to the number of bytes to be sent from the dmabuf.
> > +
> > +The user passes the dma-buf id to send from via the dmabuf_tx_cmsg.dmabuf_id.
> > +
> > +The example below sends 1024 bytes from offset 100 into the dmabuf, and 2048
> > +from offset 2000 into the dmabuf. The dmabuf to send from is tx_dmabuf_id::
> > +
> > + char ctrl_data[CMSG_SPACE(sizeof(struct dmabuf_tx_cmsg))];
> > + struct dmabuf_tx_cmsg ddmabuf;
> > + struct msghdr msg = {};
> > + struct cmsghdr *cmsg;
> > + struct iovec iov[2];
> > +
> > + iov[0].iov_base = (void*)100;
> > + iov[0].iov_len = 1024;
> > + iov[1].iov_base = (void*)2000;
> > + iov[1].iov_len = 2048;
> > +
> > + msg.msg_iov = iov;
> > + msg.msg_iovlen = 2;
> > +
> > + msg.msg_control = ctrl_data;
> > + msg.msg_controllen = sizeof(ctrl_data);
> > +
> > + cmsg = CMSG_FIRSTHDR(&msg);
> > + cmsg->cmsg_level = SOL_SOCKET;
> > + cmsg->cmsg_type = SCM_DEVMEM_DMABUF;
> > + cmsg->cmsg_len = CMSG_LEN(sizeof(struct dmabuf_tx_cmsg));
> > +
> > + ddmabuf.dmabuf_id = tx_dmabuf_id;
> > +
> > + *((struct dmabuf_tx_cmsg *)CMSG_DATA(cmsg)) = ddmabuf;
>
> [..]
>
> > + sendmsg(socket_fd, &msg, MSG_ZEROCOPY);
>
> Not super important, but any reason not to use MSG_SOCK_DEVMEM as a
> flag? We already use it for recvmsg, seems logical to mirror the same
> flag on the transmit side?
Only to remove redundancy, and the possible confusion that could
arise, and the extra checks needed to catch invalid input.
With this, the user tells the kernel to send from the dmabuf by
supplying the SCM_DEVMEM_DMABUF cmsg. If we add another signal like
MSG_SOCK_DEVMEM, there is room for the user to supply the cmg but not
the flag (confusion), and the kernel needs to have the code and
overhead to check that both the flag and the cmsg are provided.
--
Thanks,
Mina
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH RFC net-next v2 2/6] selftests: ncdevmem: Implement devmem TCP TX
2025-01-30 23:05 ` Stanislav Fomichev
@ 2025-01-30 23:29 ` Mina Almasry
2025-01-31 17:41 ` Stanislav Fomichev
0 siblings, 1 reply; 17+ messages in thread
From: Mina Almasry @ 2025-01-30 23:29 UTC (permalink / raw)
To: Stanislav Fomichev
Cc: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
On Thu, Jan 30, 2025 at 3:05 PM Stanislav Fomichev <stfomichev@gmail.com> wrote:
>
> On 01/30, Mina Almasry wrote:
> > Add support for devmem TX in ncdevmem.
> >
> > This is a combination of the ncdevmem from the devmem TCP series RFCv1
> > which included the TX path, and work by Stan to include the netlink API
> > and refactored on top of his generic memory_provider support.
> >
> > Signed-off-by: Mina Almasry <almasrymina@google.com>
> > Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
> >
> > ---
> >
> > v2:
> > - make errors a static variable so that we catch instances where there
> > are less than 20 errors across different buffers.
> > - Fix the issue where the seed is reset to 0 instead of its starting
> > value 1.
> > - Use 1000ULL instead of 1000 to guard against overflow (Willem).
> > - Do not set POLLERR (Willem).
> > - Update the test to use the new interface where iov_base is the
> > dmabuf_offset.
> > - Update the test to send 2 iov instead of 1, so we get some test
> > coverage over sending multiple iovs at once.
> > - Print the ifindex the test is using, useful for debugging issues where
> > maybe the test may fail because the ifindex of the socket is different
> > from the dmabuf binding.
> > ---
> > .../selftests/drivers/net/hw/ncdevmem.c | 276 +++++++++++++++++-
> > 1 file changed, 272 insertions(+), 4 deletions(-)
> >
> > diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > index 19a6969643f4..8455f19ecd1a 100644
> > --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > @@ -40,15 +40,18 @@
> > #include <fcntl.h>
> > #include <malloc.h>
> > #include <error.h>
> > +#include <poll.h>
> >
> > #include <arpa/inet.h>
> > #include <sys/socket.h>
> > #include <sys/mman.h>
> > #include <sys/ioctl.h>
> > #include <sys/syscall.h>
> > +#include <sys/time.h>
> >
> > #include <linux/memfd.h>
> > #include <linux/dma-buf.h>
> > +#include <linux/errqueue.h>
> > #include <linux/udmabuf.h>
> > #include <libmnl/libmnl.h>
> > #include <linux/types.h>
> > @@ -80,6 +83,8 @@ static int num_queues = -1;
> > static char *ifname;
> > static unsigned int ifindex;
> > static unsigned int dmabuf_id;
> > +static uint32_t tx_dmabuf_id;
> > +static int waittime_ms = 500;
> >
> > struct memory_buffer {
> > int fd;
> > @@ -93,6 +98,8 @@ struct memory_buffer {
> > struct memory_provider {
> > struct memory_buffer *(*alloc)(size_t size);
> > void (*free)(struct memory_buffer *ctx);
> > + void (*memcpy_to_device)(struct memory_buffer *dst, size_t off,
> > + void *src, int n);
> > void (*memcpy_from_device)(void *dst, struct memory_buffer *src,
> > size_t off, int n);
> > };
> > @@ -153,6 +160,20 @@ static void udmabuf_free(struct memory_buffer *ctx)
> > free(ctx);
> > }
> >
> > +static void udmabuf_memcpy_to_device(struct memory_buffer *dst, size_t off,
> > + void *src, int n)
> > +{
> > + struct dma_buf_sync sync = {};
> > +
> > + sync.flags = DMA_BUF_SYNC_START | DMA_BUF_SYNC_WRITE;
> > + ioctl(dst->fd, DMA_BUF_IOCTL_SYNC, &sync);
> > +
> > + memcpy(dst->buf_mem + off, src, n);
> > +
> > + sync.flags = DMA_BUF_SYNC_END | DMA_BUF_SYNC_WRITE;
> > + ioctl(dst->fd, DMA_BUF_IOCTL_SYNC, &sync);
> > +}
> > +
> > static void udmabuf_memcpy_from_device(void *dst, struct memory_buffer *src,
> > size_t off, int n)
> > {
> > @@ -170,6 +191,7 @@ static void udmabuf_memcpy_from_device(void *dst, struct memory_buffer *src,
> > static struct memory_provider udmabuf_memory_provider = {
> > .alloc = udmabuf_alloc,
> > .free = udmabuf_free,
> > + .memcpy_to_device = udmabuf_memcpy_to_device,
> > .memcpy_from_device = udmabuf_memcpy_from_device,
> > };
> >
> > @@ -188,7 +210,7 @@ void validate_buffer(void *line, size_t size)
> > {
> > static unsigned char seed = 1;
> > unsigned char *ptr = line;
> > - int errors = 0;
> > + static int errors;
> > size_t i;
> >
> > for (i = 0; i < size; i++) {
> > @@ -202,7 +224,7 @@ void validate_buffer(void *line, size_t size)
> > }
> > seed++;
> > if (seed == do_validation)
> > - seed = 0;
> > + seed = 1;
> > }
> >
> > fprintf(stdout, "Validated buffer\n");
> > @@ -394,6 +416,49 @@ static int bind_rx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
> > return -1;
> > }
> >
> > +static int bind_tx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
> > + struct ynl_sock **ys)
> > +{
> > + struct netdev_bind_tx_req *req = NULL;
> > + struct netdev_bind_tx_rsp *rsp = NULL;
> > + struct ynl_error yerr;
> > +
> > + *ys = ynl_sock_create(&ynl_netdev_family, &yerr);
> > + if (!*ys) {
> > + fprintf(stderr, "YNL: %s\n", yerr.msg);
> > + return -1;
> > + }
> > +
> > + req = netdev_bind_tx_req_alloc();
> > + netdev_bind_tx_req_set_ifindex(req, ifindex);
> > + netdev_bind_tx_req_set_fd(req, dmabuf_fd);
> > +
> > + rsp = netdev_bind_tx(*ys, req);
> > + if (!rsp) {
> > + perror("netdev_bind_tx");
> > + goto err_close;
> > + }
> > +
> > + if (!rsp->_present.id) {
> > + perror("id not present");
> > + goto err_close;
> > + }
> > +
> > + fprintf(stderr, "got tx dmabuf id=%d\n", rsp->id);
> > + tx_dmabuf_id = rsp->id;
> > +
> > + netdev_bind_tx_req_free(req);
> > + netdev_bind_tx_rsp_free(rsp);
> > +
> > + return 0;
> > +
> > +err_close:
> > + fprintf(stderr, "YNL failed: %s\n", (*ys)->err.msg);
> > + netdev_bind_tx_req_free(req);
> > + ynl_sock_destroy(*ys);
> > + return -1;
> > +}
> > +
> > static void enable_reuseaddr(int fd)
> > {
> > int opt = 1;
> > @@ -432,7 +497,7 @@ static int parse_address(const char *str, int port, struct sockaddr_in6 *sin6)
> > return 0;
> > }
> >
> > -int do_server(struct memory_buffer *mem)
> > +static int do_server(struct memory_buffer *mem)
> > {
> > char ctrl_data[sizeof(int) * 20000];
> > struct netdev_queue_id *queues;
> > @@ -686,6 +751,207 @@ void run_devmem_tests(void)
> > provider->free(mem);
> > }
> >
> > +static uint64_t gettimeofday_ms(void)
> > +{
> > + struct timeval tv;
> > +
> > + gettimeofday(&tv, NULL);
> > + return (tv.tv_sec * 1000ULL) + (tv.tv_usec / 1000ULL);
> > +}
> > +
> > +static int do_poll(int fd)
> > +{
> > + struct pollfd pfd;
> > + int ret;
> > +
> > + pfd.revents = 0;
> > + pfd.fd = fd;
> > +
> > + ret = poll(&pfd, 1, waittime_ms);
> > + if (ret == -1)
> > + error(1, errno, "poll");
> > +
> > + return ret && (pfd.revents & POLLERR);
> > +}
> > +
> > +static void wait_compl(int fd)
> > +{
> > + int64_t tstop = gettimeofday_ms() + waittime_ms;
> > + char control[CMSG_SPACE(100)] = {};
> > + struct sock_extended_err *serr;
> > + struct msghdr msg = {};
> > + struct cmsghdr *cm;
> > + int retries = 10;
> > + __u32 hi, lo;
> > + int ret;
> > +
> > + msg.msg_control = control;
> > + msg.msg_controllen = sizeof(control);
> > +
> > + while (gettimeofday_ms() < tstop) {
> > + if (!do_poll(fd))
> > + continue;
> > +
> > + ret = recvmsg(fd, &msg, MSG_ERRQUEUE);
> > + if (ret < 0) {
> > + if (errno == EAGAIN)
> > + continue;
> > + error(1, ret, "recvmsg(MSG_ERRQUEUE)");
> > + return;
> > + }
> > + if (msg.msg_flags & MSG_CTRUNC)
> > + error(1, 0, "MSG_CTRUNC\n");
> > +
> > + for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm)) {
> > + if (cm->cmsg_level != SOL_IP &&
> > + cm->cmsg_level != SOL_IPV6)
> > + continue;
> > + if (cm->cmsg_level == SOL_IP &&
> > + cm->cmsg_type != IP_RECVERR)
> > + continue;
> > + if (cm->cmsg_level == SOL_IPV6 &&
> > + cm->cmsg_type != IPV6_RECVERR)
> > + continue;
> > +
> > + serr = (void *)CMSG_DATA(cm);
> > + if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY)
> > + error(1, 0, "wrong origin %u", serr->ee_origin);
> > + if (serr->ee_errno != 0)
> > + error(1, 0, "wrong errno %d", serr->ee_errno);
> > +
> > + hi = serr->ee_data;
> > + lo = serr->ee_info;
> > +
> > + fprintf(stderr, "tx complete [%d,%d]\n", lo, hi);
> > + return;
> > + }
> > + }
> > +
> > + error(1, 0, "did not receive tx completion");
> > +}
> > +
> > +static int do_client(struct memory_buffer *mem)
> > +{
> > + char ctrl_data[CMSG_SPACE(sizeof(struct dmabuf_tx_cmsg))];
> > + struct sockaddr_in6 server_sin;
> > + struct sockaddr_in6 client_sin;
> > + struct dmabuf_tx_cmsg ddmabuf;
> > + struct ynl_sock *ys = NULL;
> > + struct msghdr msg = {};
> > + ssize_t line_size = 0;
> > + struct cmsghdr *cmsg;
> > + struct iovec iov[2];
> > + uint64_t off = 100;
> > + char *line = NULL;
> > + size_t len = 0;
> > + int socket_fd;
> > + int ret, mid;
> > + int opt = 1;
> > +
> > + ret = parse_address(server_ip, atoi(port), &server_sin);
> > + if (ret < 0)
> > + error(1, 0, "parse server address");
> > +
> > + socket_fd = socket(AF_INET6, SOCK_STREAM, 0);
> > + if (socket_fd < 0)
> > + error(1, socket_fd, "create socket");
> > +
> > + enable_reuseaddr(socket_fd);
> > +
> > + ret = setsockopt(socket_fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
> > + strlen(ifname) + 1);
> > + if (ret)
> > + error(1, ret, "bindtodevice");
> > +
> > + if (bind_tx_queue(ifindex, mem->fd, &ys))
> > + error(1, 0, "Failed to bind\n");
> > +
> > + ret = parse_address(client_ip, atoi(port), &client_sin);
> > + if (ret < 0)
> > + error(1, 0, "parse client address");
> > +
> > + ret = bind(socket_fd, &client_sin, sizeof(client_sin));
> > + if (ret)
> > + error(1, ret, "bind");
> > +
> > + ret = setsockopt(socket_fd, SOL_SOCKET, SO_ZEROCOPY, &opt, sizeof(opt));
> > + if (ret)
> > + error(1, ret, "set sock opt");
> > +
> > + fprintf(stderr, "Connect to %s %d (via %s)\n", server_ip,
> > + ntohs(server_sin.sin6_port), ifname);
> > +
> > + ret = connect(socket_fd, &server_sin, sizeof(server_sin));
> > + if (ret)
> > + error(1, ret, "connect");
> > +
> > + while (1) {
> > + free(line);
> > + line = NULL;
> > + /* Subtract 1 from line_size to remove trailing newlines that
> > + * get_line are surely to parse...
> > + */
> > + line_size = getline(&line, &len, stdin) - 1;
>
> Why not send the '\n' as well? If we skip the '\n', it's not keeping
> netcat-like behavior :-(
>
Ah, this is to make the validation on the RX side work. The validation
expects a repeating pattern:
1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, ....
With no newlines.
But it does become weird that TX doesn't match netcat. Let me think on
this a bit. Maybe I can resolve this in a way where the validation
works but also the tx side behaves like netcat. Maybe the RX
validation can skip newlines or something. Maybe I can massage how I
invoke the test.
This can become a rabbit hole because I do want to invoke multiple
sendmsg() in one iteration of the test as well, and not overcomplicate
the series.
> > +
> > + if (line_size < 0)
> > + break;
>
> [..]
>
> > + mid = (line_size / 2) + 1;
> > +
> > + iov[0].iov_base = (void *)100;
> > + iov[0].iov_len = mid;
> > + iov[1].iov_base = (void *)2000;
> > + iov[1].iov_len = line_size - mid;
>
> This seems a bit hard-coded. We should at least test that mid is < 2000?
>
Yep, I should do at least do that. FWIW (although missed it in this
iteration), at the top of the file I put docs that list exactly what I
run for others to repro the results (and nipa should eventually run
similar, I have that on my todo list), but the test should be more
flexible to at least catch instances where mid is too large.
> But ideally we should have two modes for tx with a flag (and run them
> both from the selftest):
> - pass one big iov, this will test the sendmsg path which creates
> multiple skbs internally
> - break 'line' into N sections (as you do here), but maybe have more
> control over the number of sections?
>
> Maybe let's have a new --max-iov-size flag? Then we can call ncdevmem
> with --max-iov-size <some prime number close to 4k> to exercise all
> sorts of weird offsets?
>
> (seems ok to also follow up on that separately)
Yeah, improvements to tests are always possible, lets have some
reasonable tests in the first iteration and expand.
--
Thanks,
Mina
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH RFC net-next v2 4/6] net: devmem: TCP tx netlink api
2025-01-30 21:15 ` [PATCH RFC net-next v2 4/6] net: devmem: TCP tx netlink api Mina Almasry
@ 2025-01-31 8:29 ` Simon Horman
0 siblings, 0 replies; 17+ messages in thread
From: Simon Horman @ 2025-01-31 8:29 UTC (permalink / raw)
To: Mina Almasry
Cc: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Donald Hunter, Jonathan Corbet, Andrew Lunn,
David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
On Thu, Jan 30, 2025 at 09:15:37PM +0000, Mina Almasry wrote:
> From: Stanislav Fomichev <sdf@fomichev.me>
>
> Add bind-tx netlink call to attach dmabuf for TX; queue is not
> required, only ifindex and dmabuf fd for attachment.
>
> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
> Signed-off-by: Mina Almasry <almasrymina@google.com>
Hi Mina,
I noticed minor issue relating to generated code.
...
> diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
> index cbb544bd6c84..93f4333e7bc6 100644
> --- a/Documentation/netlink/specs/netdev.yaml
> +++ b/Documentation/netlink/specs/netdev.yaml
The lines preceding the hunk below are:
name: napi-set
doc: Set configurable NAPI instance settings.
attribute-set: napi
flags: [ admin-perm ]
do:
request:
attributes:
- id
> @@ -711,6 +711,18 @@ operations:
> - defer-hard-irqs
> - gro-flush-timeout
> - irq-suspend-timeout
> + -
> + name: bind-tx
> + doc: Bind dmabuf to netdev for TX
> + attribute-set: dmabuf
Unlike the entry for napi-set there is no "flags: [ admin-perm ]" fpr
bind-tx...
> + do:
> + request:
> + attributes:
> + - ifindex
> + - fd
> + reply:
> + attributes:
> + - id
>
> kernel-family:
> headers: [ "linux/list.h"]
...
> diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c
...
> @@ -190,6 +196,13 @@ static const struct genl_split_ops netdev_nl_ops[] = {
The lines preceding this hunk are:
{
.cmd = NETDEV_CMD_NAPI_SET,
.doit = netdev_nl_napi_set_doit,
.policy = netdev_napi_set_nl_policy,
> .maxattr = NETDEV_A_NAPI_IRQ_SUSPEND_TIMEOUT,
> .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
> },
> + {
> + .cmd = NETDEV_CMD_BIND_TX,
> + .doit = netdev_nl_bind_tx_doit,
> + .policy = netdev_bind_tx_nl_policy,
> + .maxattr = NETDEV_A_DMABUF_FD,
> + .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
... so I don't think GENL_ADMIN_PERM should be here.
Flagged by running tools/net/ynl/ynl-regen.sh -f && git diff
> + },
> };
>
> static const struct genl_multicast_group netdev_nl_mcgrps[] = {
...
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH RFC net-next v2 5/6] net: devmem: Implement TX path
2025-01-30 21:15 ` [PATCH RFC net-next v2 5/6] net: devmem: Implement TX path Mina Almasry
2025-01-30 23:07 ` Stanislav Fomichev
@ 2025-01-31 9:09 ` Simon Horman
1 sibling, 0 replies; 17+ messages in thread
From: Simon Horman @ 2025-01-31 9:09 UTC (permalink / raw)
To: Mina Almasry
Cc: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Donald Hunter, Jonathan Corbet, Andrew Lunn,
David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela, Kaiyuan Zhang
On Thu, Jan 30, 2025 at 09:15:38PM +0000, Mina Almasry wrote:
> Augment dmabuf binding to be able to handle TX. Additional to all the RX
> binding, we also create tx_vec needed for the TX path.
>
> Provide API for sendmsg to be able to send dmabufs bound to this device:
>
> - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from.
> - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf.
>
> Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY
> implementation, while disabling instances where MSG_ZEROCOPY falls back
> to copying.
>
> We additionally pipe the binding down to the new
> zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems
> instead of the traditional page netmems.
>
> We also special case skb_frag_dma_map to return the dma-address of these
> dmabuf net_iovs instead of attempting to map pages.
>
> Based on work by Stanislav Fomichev <sdf@fomichev.me>. A lot of the meat
> of the implementation came from devmem TCP RFC v1[1], which included the
> TX path, but Stan did all the rebasing on top of netmem/net_iov.
>
> Cc: Stanislav Fomichev <sdf@fomichev.me>
> Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com>
> Signed-off-by: Mina Almasry <almasrymina@google.com>
...
> diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
> index 0e41699df419..9ba6994e2a05 100644
> --- a/net/core/netdev-genl.c
> +++ b/net/core/netdev-genl.c
...
> @@ -911,10 +912,68 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
> return err;
> }
>
> -/* stub */
> int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
> {
> - return 0;
> + struct net_devmem_dmabuf_binding *binding;
> + struct list_head *sock_binding_list;
> + struct net_device *netdev;
> + u32 ifindex, dmabuf_fd;
> + struct sk_buff *rsp;
> + int err = 0;
> + void *hdr;
> +
> + if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_DEV_IFINDEX) ||
> + GENL_REQ_ATTR_CHECK(info, NETDEV_A_DMABUF_FD))
> + return -EINVAL;
> +
> + ifindex = nla_get_u32(info->attrs[NETDEV_A_DEV_IFINDEX]);
> + dmabuf_fd = nla_get_u32(info->attrs[NETDEV_A_DMABUF_FD]);
> +
> + sock_binding_list =
> + genl_sk_priv_get(&netdev_nl_family, NETLINK_CB(skb).sk);
> + if (IS_ERR(sock_binding_list))
> + return PTR_ERR(sock_binding_list);
> +
> + rsp = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
> + if (!rsp)
> + return -ENOMEM;
> +
> + hdr = genlmsg_iput(rsp, info);
> + if (!hdr) {
> + err = -EMSGSIZE;
> + goto err_genlmsg_free;
> + }
> +
> + rtnl_lock();
> +
> + netdev = __dev_get_by_index(genl_info_net(info), ifindex);
> + if (!netdev || !netif_device_present(netdev)) {
> + err = -ENODEV;
> + goto err_unlock;
> + }
> +
> + binding = net_devmem_bind_dmabuf(netdev, DMA_TO_DEVICE, dmabuf_fd,
> + info->extack);
> + if (IS_ERR(binding)) {
> + err = PTR_ERR(binding);
> + goto err_unlock;
> + }
> +
> + list_add(&binding->list, sock_binding_list);
> +
> + nla_put_u32(rsp, NETDEV_A_DMABUF_ID, binding->id);
> + genlmsg_end(rsp, hdr);
> +
> + rtnl_unlock();
> +
> + return genlmsg_reply(rsp, info);
> +
> + net_devmem_unbind_dmabuf(binding);
Hi Mina,
It appears that the line above is unreachable.
I guess it was part of an unwind that is no-longer needed
and thus can now be removed.
Flagged by Smatch.
> +err_unlock:
> + rtnl_unlock();
> +err_genlmsg_free:
> + nlmsg_free(rsp);
> + return err;
> }
...
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH RFC net-next v2 1/6] net: add devmem TCP TX documentation
2025-01-30 23:22 ` Mina Almasry
@ 2025-01-31 17:39 ` Stanislav Fomichev
0 siblings, 0 replies; 17+ messages in thread
From: Stanislav Fomichev @ 2025-01-31 17:39 UTC (permalink / raw)
To: Mina Almasry
Cc: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
On 01/30, Mina Almasry wrote:
> On Thu, Jan 30, 2025 at 2:59 PM Stanislav Fomichev <stfomichev@gmail.com> wrote:
> >
> > On 01/30, Mina Almasry wrote:
> > > Add documentation outlining the usage and details of the devmem TCP TX
> > > API.
> > >
> > > Signed-off-by: Mina Almasry <almasrymina@google.com>
> > >
> > > ---
> > >
> > > v2:
> > > - Update documentation for iov_base is the dmabuf offset (Stan)
> > > ---
> > > Documentation/networking/devmem.rst | 144 +++++++++++++++++++++++++++-
> > > 1 file changed, 140 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/Documentation/networking/devmem.rst b/Documentation/networking/devmem.rst
> > > index d95363645331..8166fe09da13 100644
> > > --- a/Documentation/networking/devmem.rst
> > > +++ b/Documentation/networking/devmem.rst
> > > @@ -62,15 +62,15 @@ More Info
> > > https://lore.kernel.org/netdev/20240831004313.3713467-1-almasrymina@google.com/
> > >
> > >
> > > -Interface
> > > -=========
> > > +RX Interface
> > > +============
> > >
> > >
> > > Example
> > > -------
> > >
> > > -tools/testing/selftests/net/ncdevmem.c:do_server shows an example of setting up
> > > -the RX path of this API.
> > > +./tools/testing/selftests/drivers/net/hw/ncdevmem:do_server shows an example of
> > > +setting up the RX path of this API.
> > >
> > >
> > > NIC Setup
> > > @@ -235,6 +235,142 @@ can be less than the tokens provided by the user in case of:
> > > (a) an internal kernel leak bug.
> > > (b) the user passed more than 1024 frags.
> > >
> > > +TX Interface
> > > +============
> > > +
> > > +
> > > +Example
> > > +-------
> > > +
> > > +./tools/testing/selftests/drivers/net/hw/ncdevmem:do_client shows an example of
> > > +setting up the TX path of this API.
> > > +
> > > +
> > > +NIC Setup
> > > +---------
> > > +
> > > +The user must bind a TX dmabuf to a given NIC using the netlink API::
> > > +
> > > + struct netdev_bind_tx_req *req = NULL;
> > > + struct netdev_bind_tx_rsp *rsp = NULL;
> > > + struct ynl_error yerr;
> > > +
> > > + *ys = ynl_sock_create(&ynl_netdev_family, &yerr);
> > > +
> > > + req = netdev_bind_tx_req_alloc();
> > > + netdev_bind_tx_req_set_ifindex(req, ifindex);
> > > + netdev_bind_tx_req_set_fd(req, dmabuf_fd);
> > > +
> > > + rsp = netdev_bind_tx(*ys, req);
> > > +
> > > + tx_dmabuf_id = rsp->id;
> > > +
> > > +
> > > +The netlink API returns a dmabuf_id: a unique ID that refers to this dmabuf
> > > +that has been bound.
> > > +
> > > +The user can unbind the dmabuf from the netdevice by closing the netlink socket
> > > +that established the binding. We do this so that the binding is automatically
> > > +unbound even if the userspace process crashes.
> > > +
> > > +Note that any reasonably well-behaved dmabuf from any exporter should work with
> > > +devmem TCP, even if the dmabuf is not actually backed by devmem. An example of
> > > +this is udmabuf, which wraps user memory (non-devmem) in a dmabuf.
> > > +
> > > +Socket Setup
> > > +------------
> > > +
> > > +The user application must use MSG_ZEROCOPY flag when sending devmem TCP. Devmem
> > > +cannot be copied by the kernel, so the semantics of the devmem TX are similar
> > > +to the semantics of MSG_ZEROCOPY.
> > > +
> > > + ret = setsockopt(socket_fd, SOL_SOCKET, SO_ZEROCOPY, &opt, sizeof(opt));
> > > +
> > > +Sending data
> > > +--------------
> > > +
> > > +Devmem data is sent using the SCM_DEVMEM_DMABUF cmsg.
> > > +
> > > +The user should create a msghdr where,
> > > +
> > > +iov_base is set to the offset into the dmabuf to start sending from.
> > > +iov_len is set to the number of bytes to be sent from the dmabuf.
> > > +
> > > +The user passes the dma-buf id to send from via the dmabuf_tx_cmsg.dmabuf_id.
> > > +
> > > +The example below sends 1024 bytes from offset 100 into the dmabuf, and 2048
> > > +from offset 2000 into the dmabuf. The dmabuf to send from is tx_dmabuf_id::
> > > +
> > > + char ctrl_data[CMSG_SPACE(sizeof(struct dmabuf_tx_cmsg))];
> > > + struct dmabuf_tx_cmsg ddmabuf;
> > > + struct msghdr msg = {};
> > > + struct cmsghdr *cmsg;
> > > + struct iovec iov[2];
> > > +
> > > + iov[0].iov_base = (void*)100;
> > > + iov[0].iov_len = 1024;
> > > + iov[1].iov_base = (void*)2000;
> > > + iov[1].iov_len = 2048;
> > > +
> > > + msg.msg_iov = iov;
> > > + msg.msg_iovlen = 2;
> > > +
> > > + msg.msg_control = ctrl_data;
> > > + msg.msg_controllen = sizeof(ctrl_data);
> > > +
> > > + cmsg = CMSG_FIRSTHDR(&msg);
> > > + cmsg->cmsg_level = SOL_SOCKET;
> > > + cmsg->cmsg_type = SCM_DEVMEM_DMABUF;
> > > + cmsg->cmsg_len = CMSG_LEN(sizeof(struct dmabuf_tx_cmsg));
> > > +
> > > + ddmabuf.dmabuf_id = tx_dmabuf_id;
> > > +
> > > + *((struct dmabuf_tx_cmsg *)CMSG_DATA(cmsg)) = ddmabuf;
> >
> > [..]
> >
> > > + sendmsg(socket_fd, &msg, MSG_ZEROCOPY);
> >
> > Not super important, but any reason not to use MSG_SOCK_DEVMEM as a
> > flag? We already use it for recvmsg, seems logical to mirror the same
> > flag on the transmit side?
>
> Only to remove redundancy, and the possible confusion that could
> arise, and the extra checks needed to catch invalid input.
>
> With this, the user tells the kernel to send from the dmabuf by
> supplying the SCM_DEVMEM_DMABUF cmsg. If we add another signal like
> MSG_SOCK_DEVMEM, there is room for the user to supply the cmg but not
> the flag (confusion), and the kernel needs to have the code and
> overhead to check that both the flag and the cmsg are provided.
SG! Having another 'if' doesn't seem like a big overhead to me (given that
we already spend a ton of time copying all the cmsg stuff), but no
strong preference on my side..
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH RFC net-next v2 2/6] selftests: ncdevmem: Implement devmem TCP TX
2025-01-30 23:29 ` Mina Almasry
@ 2025-01-31 17:41 ` Stanislav Fomichev
0 siblings, 0 replies; 17+ messages in thread
From: Stanislav Fomichev @ 2025-01-31 17:41 UTC (permalink / raw)
To: Mina Almasry
Cc: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
On 01/30, Mina Almasry wrote:
> On Thu, Jan 30, 2025 at 3:05 PM Stanislav Fomichev <stfomichev@gmail.com> wrote:
> >
> > On 01/30, Mina Almasry wrote:
> > > Add support for devmem TX in ncdevmem.
> > >
> > > This is a combination of the ncdevmem from the devmem TCP series RFCv1
> > > which included the TX path, and work by Stan to include the netlink API
> > > and refactored on top of his generic memory_provider support.
> > >
> > > Signed-off-by: Mina Almasry <almasrymina@google.com>
> > > Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
> > >
> > > ---
> > >
> > > v2:
> > > - make errors a static variable so that we catch instances where there
> > > are less than 20 errors across different buffers.
> > > - Fix the issue where the seed is reset to 0 instead of its starting
> > > value 1.
> > > - Use 1000ULL instead of 1000 to guard against overflow (Willem).
> > > - Do not set POLLERR (Willem).
> > > - Update the test to use the new interface where iov_base is the
> > > dmabuf_offset.
> > > - Update the test to send 2 iov instead of 1, so we get some test
> > > coverage over sending multiple iovs at once.
> > > - Print the ifindex the test is using, useful for debugging issues where
> > > maybe the test may fail because the ifindex of the socket is different
> > > from the dmabuf binding.
> > > ---
> > > .../selftests/drivers/net/hw/ncdevmem.c | 276 +++++++++++++++++-
> > > 1 file changed, 272 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > > index 19a6969643f4..8455f19ecd1a 100644
> > > --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > > +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> > > @@ -40,15 +40,18 @@
> > > #include <fcntl.h>
> > > #include <malloc.h>
> > > #include <error.h>
> > > +#include <poll.h>
> > >
> > > #include <arpa/inet.h>
> > > #include <sys/socket.h>
> > > #include <sys/mman.h>
> > > #include <sys/ioctl.h>
> > > #include <sys/syscall.h>
> > > +#include <sys/time.h>
> > >
> > > #include <linux/memfd.h>
> > > #include <linux/dma-buf.h>
> > > +#include <linux/errqueue.h>
> > > #include <linux/udmabuf.h>
> > > #include <libmnl/libmnl.h>
> > > #include <linux/types.h>
> > > @@ -80,6 +83,8 @@ static int num_queues = -1;
> > > static char *ifname;
> > > static unsigned int ifindex;
> > > static unsigned int dmabuf_id;
> > > +static uint32_t tx_dmabuf_id;
> > > +static int waittime_ms = 500;
> > >
> > > struct memory_buffer {
> > > int fd;
> > > @@ -93,6 +98,8 @@ struct memory_buffer {
> > > struct memory_provider {
> > > struct memory_buffer *(*alloc)(size_t size);
> > > void (*free)(struct memory_buffer *ctx);
> > > + void (*memcpy_to_device)(struct memory_buffer *dst, size_t off,
> > > + void *src, int n);
> > > void (*memcpy_from_device)(void *dst, struct memory_buffer *src,
> > > size_t off, int n);
> > > };
> > > @@ -153,6 +160,20 @@ static void udmabuf_free(struct memory_buffer *ctx)
> > > free(ctx);
> > > }
> > >
> > > +static void udmabuf_memcpy_to_device(struct memory_buffer *dst, size_t off,
> > > + void *src, int n)
> > > +{
> > > + struct dma_buf_sync sync = {};
> > > +
> > > + sync.flags = DMA_BUF_SYNC_START | DMA_BUF_SYNC_WRITE;
> > > + ioctl(dst->fd, DMA_BUF_IOCTL_SYNC, &sync);
> > > +
> > > + memcpy(dst->buf_mem + off, src, n);
> > > +
> > > + sync.flags = DMA_BUF_SYNC_END | DMA_BUF_SYNC_WRITE;
> > > + ioctl(dst->fd, DMA_BUF_IOCTL_SYNC, &sync);
> > > +}
> > > +
> > > static void udmabuf_memcpy_from_device(void *dst, struct memory_buffer *src,
> > > size_t off, int n)
> > > {
> > > @@ -170,6 +191,7 @@ static void udmabuf_memcpy_from_device(void *dst, struct memory_buffer *src,
> > > static struct memory_provider udmabuf_memory_provider = {
> > > .alloc = udmabuf_alloc,
> > > .free = udmabuf_free,
> > > + .memcpy_to_device = udmabuf_memcpy_to_device,
> > > .memcpy_from_device = udmabuf_memcpy_from_device,
> > > };
> > >
> > > @@ -188,7 +210,7 @@ void validate_buffer(void *line, size_t size)
> > > {
> > > static unsigned char seed = 1;
> > > unsigned char *ptr = line;
> > > - int errors = 0;
> > > + static int errors;
> > > size_t i;
> > >
> > > for (i = 0; i < size; i++) {
> > > @@ -202,7 +224,7 @@ void validate_buffer(void *line, size_t size)
> > > }
> > > seed++;
> > > if (seed == do_validation)
> > > - seed = 0;
> > > + seed = 1;
> > > }
> > >
> > > fprintf(stdout, "Validated buffer\n");
> > > @@ -394,6 +416,49 @@ static int bind_rx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
> > > return -1;
> > > }
> > >
> > > +static int bind_tx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
> > > + struct ynl_sock **ys)
> > > +{
> > > + struct netdev_bind_tx_req *req = NULL;
> > > + struct netdev_bind_tx_rsp *rsp = NULL;
> > > + struct ynl_error yerr;
> > > +
> > > + *ys = ynl_sock_create(&ynl_netdev_family, &yerr);
> > > + if (!*ys) {
> > > + fprintf(stderr, "YNL: %s\n", yerr.msg);
> > > + return -1;
> > > + }
> > > +
> > > + req = netdev_bind_tx_req_alloc();
> > > + netdev_bind_tx_req_set_ifindex(req, ifindex);
> > > + netdev_bind_tx_req_set_fd(req, dmabuf_fd);
> > > +
> > > + rsp = netdev_bind_tx(*ys, req);
> > > + if (!rsp) {
> > > + perror("netdev_bind_tx");
> > > + goto err_close;
> > > + }
> > > +
> > > + if (!rsp->_present.id) {
> > > + perror("id not present");
> > > + goto err_close;
> > > + }
> > > +
> > > + fprintf(stderr, "got tx dmabuf id=%d\n", rsp->id);
> > > + tx_dmabuf_id = rsp->id;
> > > +
> > > + netdev_bind_tx_req_free(req);
> > > + netdev_bind_tx_rsp_free(rsp);
> > > +
> > > + return 0;
> > > +
> > > +err_close:
> > > + fprintf(stderr, "YNL failed: %s\n", (*ys)->err.msg);
> > > + netdev_bind_tx_req_free(req);
> > > + ynl_sock_destroy(*ys);
> > > + return -1;
> > > +}
> > > +
> > > static void enable_reuseaddr(int fd)
> > > {
> > > int opt = 1;
> > > @@ -432,7 +497,7 @@ static int parse_address(const char *str, int port, struct sockaddr_in6 *sin6)
> > > return 0;
> > > }
> > >
> > > -int do_server(struct memory_buffer *mem)
> > > +static int do_server(struct memory_buffer *mem)
> > > {
> > > char ctrl_data[sizeof(int) * 20000];
> > > struct netdev_queue_id *queues;
> > > @@ -686,6 +751,207 @@ void run_devmem_tests(void)
> > > provider->free(mem);
> > > }
> > >
> > > +static uint64_t gettimeofday_ms(void)
> > > +{
> > > + struct timeval tv;
> > > +
> > > + gettimeofday(&tv, NULL);
> > > + return (tv.tv_sec * 1000ULL) + (tv.tv_usec / 1000ULL);
> > > +}
> > > +
> > > +static int do_poll(int fd)
> > > +{
> > > + struct pollfd pfd;
> > > + int ret;
> > > +
> > > + pfd.revents = 0;
> > > + pfd.fd = fd;
> > > +
> > > + ret = poll(&pfd, 1, waittime_ms);
> > > + if (ret == -1)
> > > + error(1, errno, "poll");
> > > +
> > > + return ret && (pfd.revents & POLLERR);
> > > +}
> > > +
> > > +static void wait_compl(int fd)
> > > +{
> > > + int64_t tstop = gettimeofday_ms() + waittime_ms;
> > > + char control[CMSG_SPACE(100)] = {};
> > > + struct sock_extended_err *serr;
> > > + struct msghdr msg = {};
> > > + struct cmsghdr *cm;
> > > + int retries = 10;
> > > + __u32 hi, lo;
> > > + int ret;
> > > +
> > > + msg.msg_control = control;
> > > + msg.msg_controllen = sizeof(control);
> > > +
> > > + while (gettimeofday_ms() < tstop) {
> > > + if (!do_poll(fd))
> > > + continue;
> > > +
> > > + ret = recvmsg(fd, &msg, MSG_ERRQUEUE);
> > > + if (ret < 0) {
> > > + if (errno == EAGAIN)
> > > + continue;
> > > + error(1, ret, "recvmsg(MSG_ERRQUEUE)");
> > > + return;
> > > + }
> > > + if (msg.msg_flags & MSG_CTRUNC)
> > > + error(1, 0, "MSG_CTRUNC\n");
> > > +
> > > + for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm)) {
> > > + if (cm->cmsg_level != SOL_IP &&
> > > + cm->cmsg_level != SOL_IPV6)
> > > + continue;
> > > + if (cm->cmsg_level == SOL_IP &&
> > > + cm->cmsg_type != IP_RECVERR)
> > > + continue;
> > > + if (cm->cmsg_level == SOL_IPV6 &&
> > > + cm->cmsg_type != IPV6_RECVERR)
> > > + continue;
> > > +
> > > + serr = (void *)CMSG_DATA(cm);
> > > + if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY)
> > > + error(1, 0, "wrong origin %u", serr->ee_origin);
> > > + if (serr->ee_errno != 0)
> > > + error(1, 0, "wrong errno %d", serr->ee_errno);
> > > +
> > > + hi = serr->ee_data;
> > > + lo = serr->ee_info;
> > > +
> > > + fprintf(stderr, "tx complete [%d,%d]\n", lo, hi);
> > > + return;
> > > + }
> > > + }
> > > +
> > > + error(1, 0, "did not receive tx completion");
> > > +}
> > > +
> > > +static int do_client(struct memory_buffer *mem)
> > > +{
> > > + char ctrl_data[CMSG_SPACE(sizeof(struct dmabuf_tx_cmsg))];
> > > + struct sockaddr_in6 server_sin;
> > > + struct sockaddr_in6 client_sin;
> > > + struct dmabuf_tx_cmsg ddmabuf;
> > > + struct ynl_sock *ys = NULL;
> > > + struct msghdr msg = {};
> > > + ssize_t line_size = 0;
> > > + struct cmsghdr *cmsg;
> > > + struct iovec iov[2];
> > > + uint64_t off = 100;
> > > + char *line = NULL;
> > > + size_t len = 0;
> > > + int socket_fd;
> > > + int ret, mid;
> > > + int opt = 1;
> > > +
> > > + ret = parse_address(server_ip, atoi(port), &server_sin);
> > > + if (ret < 0)
> > > + error(1, 0, "parse server address");
> > > +
> > > + socket_fd = socket(AF_INET6, SOCK_STREAM, 0);
> > > + if (socket_fd < 0)
> > > + error(1, socket_fd, "create socket");
> > > +
> > > + enable_reuseaddr(socket_fd);
> > > +
> > > + ret = setsockopt(socket_fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
> > > + strlen(ifname) + 1);
> > > + if (ret)
> > > + error(1, ret, "bindtodevice");
> > > +
> > > + if (bind_tx_queue(ifindex, mem->fd, &ys))
> > > + error(1, 0, "Failed to bind\n");
> > > +
> > > + ret = parse_address(client_ip, atoi(port), &client_sin);
> > > + if (ret < 0)
> > > + error(1, 0, "parse client address");
> > > +
> > > + ret = bind(socket_fd, &client_sin, sizeof(client_sin));
> > > + if (ret)
> > > + error(1, ret, "bind");
> > > +
> > > + ret = setsockopt(socket_fd, SOL_SOCKET, SO_ZEROCOPY, &opt, sizeof(opt));
> > > + if (ret)
> > > + error(1, ret, "set sock opt");
> > > +
> > > + fprintf(stderr, "Connect to %s %d (via %s)\n", server_ip,
> > > + ntohs(server_sin.sin6_port), ifname);
> > > +
> > > + ret = connect(socket_fd, &server_sin, sizeof(server_sin));
> > > + if (ret)
> > > + error(1, ret, "connect");
> > > +
> > > + while (1) {
> > > + free(line);
> > > + line = NULL;
> > > + /* Subtract 1 from line_size to remove trailing newlines that
> > > + * get_line are surely to parse...
> > > + */
> > > + line_size = getline(&line, &len, stdin) - 1;
> >
> > Why not send the '\n' as well? If we skip the '\n', it's not keeping
> > netcat-like behavior :-(
> >
>
> Ah, this is to make the validation on the RX side work. The validation
> expects a repeating pattern:
>
> 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, ....
>
> With no newlines.
>
> But it does become weird that TX doesn't match netcat. Let me think on
> this a bit. Maybe I can resolve this in a way where the validation
> works but also the tx side behaves like netcat. Maybe the RX
> validation can skip newlines or something. Maybe I can massage how I
> invoke the test.
>
> This can become a rabbit hole because I do want to invoke multiple
> sendmsg() in one iteration of the test as well, and not overcomplicate
> the series.
Then let's do it for validation mode only? FWIW, my existing (python
wrapper) tests pass with your series. I'll be sending a bunch of minor
comments about the selftest part separately shortly..
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH RFC net-next v2 2/6] selftests: ncdevmem: Implement devmem TCP TX
2025-01-30 21:15 ` [PATCH RFC net-next v2 2/6] selftests: ncdevmem: Implement devmem TCP TX Mina Almasry
2025-01-30 23:05 ` Stanislav Fomichev
@ 2025-01-31 17:45 ` Stanislav Fomichev
1 sibling, 0 replies; 17+ messages in thread
From: Stanislav Fomichev @ 2025-01-31 17:45 UTC (permalink / raw)
To: Mina Almasry
Cc: netdev, linux-kernel, linux-doc, kvm, virtualization,
linux-kselftest, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, Donald Hunter, Jonathan Corbet,
Andrew Lunn, David Ahern, Stefan Hajnoczi, Stefano Garzarella,
Michael S. Tsirkin, Jason Wang, Xuan Zhuo, Eugenio Pérez,
Shuah Khan, sdf, asml.silence, dw, Jamal Hadi Salim,
Victor Nogueira, Pedro Tammela
On 01/30, Mina Almasry wrote:
> Add support for devmem TX in ncdevmem.
>
> This is a combination of the ncdevmem from the devmem TCP series RFCv1
> which included the TX path, and work by Stan to include the netlink API
> and refactored on top of his generic memory_provider support.
>
> Signed-off-by: Mina Almasry <almasrymina@google.com>
> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
>
> ---
>
> v2:
> - make errors a static variable so that we catch instances where there
> are less than 20 errors across different buffers.
> - Fix the issue where the seed is reset to 0 instead of its starting
> value 1.
> - Use 1000ULL instead of 1000 to guard against overflow (Willem).
> - Do not set POLLERR (Willem).
> - Update the test to use the new interface where iov_base is the
> dmabuf_offset.
> - Update the test to send 2 iov instead of 1, so we get some test
> coverage over sending multiple iovs at once.
> - Print the ifindex the test is using, useful for debugging issues where
> maybe the test may fail because the ifindex of the socket is different
> from the dmabuf binding.
> ---
> .../selftests/drivers/net/hw/ncdevmem.c | 276 +++++++++++++++++-
> 1 file changed, 272 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> index 19a6969643f4..8455f19ecd1a 100644
> --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> @@ -40,15 +40,18 @@
> #include <fcntl.h>
> #include <malloc.h>
> #include <error.h>
> +#include <poll.h>
>
> #include <arpa/inet.h>
> #include <sys/socket.h>
> #include <sys/mman.h>
> #include <sys/ioctl.h>
> #include <sys/syscall.h>
> +#include <sys/time.h>
>
> #include <linux/memfd.h>
> #include <linux/dma-buf.h>
> +#include <linux/errqueue.h>
> #include <linux/udmabuf.h>
> #include <libmnl/libmnl.h>
> #include <linux/types.h>
> @@ -80,6 +83,8 @@ static int num_queues = -1;
> static char *ifname;
> static unsigned int ifindex;
> static unsigned int dmabuf_id;
> +static uint32_t tx_dmabuf_id;
> +static int waittime_ms = 500;
>
> struct memory_buffer {
> int fd;
> @@ -93,6 +98,8 @@ struct memory_buffer {
> struct memory_provider {
> struct memory_buffer *(*alloc)(size_t size);
> void (*free)(struct memory_buffer *ctx);
> + void (*memcpy_to_device)(struct memory_buffer *dst, size_t off,
> + void *src, int n);
> void (*memcpy_from_device)(void *dst, struct memory_buffer *src,
> size_t off, int n);
> };
> @@ -153,6 +160,20 @@ static void udmabuf_free(struct memory_buffer *ctx)
> free(ctx);
> }
>
> +static void udmabuf_memcpy_to_device(struct memory_buffer *dst, size_t off,
> + void *src, int n)
> +{
> + struct dma_buf_sync sync = {};
> +
> + sync.flags = DMA_BUF_SYNC_START | DMA_BUF_SYNC_WRITE;
> + ioctl(dst->fd, DMA_BUF_IOCTL_SYNC, &sync);
> +
> + memcpy(dst->buf_mem + off, src, n);
> +
> + sync.flags = DMA_BUF_SYNC_END | DMA_BUF_SYNC_WRITE;
> + ioctl(dst->fd, DMA_BUF_IOCTL_SYNC, &sync);
> +}
> +
> static void udmabuf_memcpy_from_device(void *dst, struct memory_buffer *src,
> size_t off, int n)
> {
> @@ -170,6 +191,7 @@ static void udmabuf_memcpy_from_device(void *dst, struct memory_buffer *src,
> static struct memory_provider udmabuf_memory_provider = {
> .alloc = udmabuf_alloc,
> .free = udmabuf_free,
> + .memcpy_to_device = udmabuf_memcpy_to_device,
> .memcpy_from_device = udmabuf_memcpy_from_device,
> };
>
> @@ -188,7 +210,7 @@ void validate_buffer(void *line, size_t size)
> {
> static unsigned char seed = 1;
> unsigned char *ptr = line;
> - int errors = 0;
> + static int errors;
> size_t i;
>
> for (i = 0; i < size; i++) {
> @@ -202,7 +224,7 @@ void validate_buffer(void *line, size_t size)
> }
> seed++;
> if (seed == do_validation)
> - seed = 0;
> + seed = 1;
> }
>
> fprintf(stdout, "Validated buffer\n");
> @@ -394,6 +416,49 @@ static int bind_rx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
> return -1;
> }
>
> +static int bind_tx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
> + struct ynl_sock **ys)
> +{
> + struct netdev_bind_tx_req *req = NULL;
> + struct netdev_bind_tx_rsp *rsp = NULL;
> + struct ynl_error yerr;
> +
> + *ys = ynl_sock_create(&ynl_netdev_family, &yerr);
> + if (!*ys) {
> + fprintf(stderr, "YNL: %s\n", yerr.msg);
> + return -1;
> + }
> +
> + req = netdev_bind_tx_req_alloc();
> + netdev_bind_tx_req_set_ifindex(req, ifindex);
> + netdev_bind_tx_req_set_fd(req, dmabuf_fd);
> +
> + rsp = netdev_bind_tx(*ys, req);
> + if (!rsp) {
> + perror("netdev_bind_tx");
> + goto err_close;
> + }
> +
> + if (!rsp->_present.id) {
> + perror("id not present");
> + goto err_close;
> + }
> +
> + fprintf(stderr, "got tx dmabuf id=%d\n", rsp->id);
> + tx_dmabuf_id = rsp->id;
> +
> + netdev_bind_tx_req_free(req);
> + netdev_bind_tx_rsp_free(rsp);
> +
> + return 0;
> +
> +err_close:
> + fprintf(stderr, "YNL failed: %s\n", (*ys)->err.msg);
> + netdev_bind_tx_req_free(req);
> + ynl_sock_destroy(*ys);
> + return -1;
> +}
> +
> static void enable_reuseaddr(int fd)
> {
> int opt = 1;
> @@ -432,7 +497,7 @@ static int parse_address(const char *str, int port, struct sockaddr_in6 *sin6)
> return 0;
> }
>
> -int do_server(struct memory_buffer *mem)
> +static int do_server(struct memory_buffer *mem)
> {
> char ctrl_data[sizeof(int) * 20000];
> struct netdev_queue_id *queues;
> @@ -686,6 +751,207 @@ void run_devmem_tests(void)
> provider->free(mem);
> }
>
> +static uint64_t gettimeofday_ms(void)
> +{
> + struct timeval tv;
> +
> + gettimeofday(&tv, NULL);
> + return (tv.tv_sec * 1000ULL) + (tv.tv_usec / 1000ULL);
> +}
> +
> +static int do_poll(int fd)
> +{
> + struct pollfd pfd;
> + int ret;
> +
> + pfd.revents = 0;
> + pfd.fd = fd;
> +
> + ret = poll(&pfd, 1, waittime_ms);
> + if (ret == -1)
> + error(1, errno, "poll");
> +
> + return ret && (pfd.revents & POLLERR);
> +}
> +
> +static void wait_compl(int fd)
> +{
> + int64_t tstop = gettimeofday_ms() + waittime_ms;
> + char control[CMSG_SPACE(100)] = {};
> + struct sock_extended_err *serr;
> + struct msghdr msg = {};
> + struct cmsghdr *cm;
> + int retries = 10;
> + __u32 hi, lo;
> + int ret;
> +
> + msg.msg_control = control;
> + msg.msg_controllen = sizeof(control);
> +
> + while (gettimeofday_ms() < tstop) {
> + if (!do_poll(fd))
> + continue;
> +
> + ret = recvmsg(fd, &msg, MSG_ERRQUEUE);
> + if (ret < 0) {
> + if (errno == EAGAIN)
> + continue;
> + error(1, ret, "recvmsg(MSG_ERRQUEUE)");
> + return;
> + }
> + if (msg.msg_flags & MSG_CTRUNC)
> + error(1, 0, "MSG_CTRUNC\n");
> +
> + for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm)) {
> + if (cm->cmsg_level != SOL_IP &&
> + cm->cmsg_level != SOL_IPV6)
> + continue;
> + if (cm->cmsg_level == SOL_IP &&
> + cm->cmsg_type != IP_RECVERR)
> + continue;
> + if (cm->cmsg_level == SOL_IPV6 &&
> + cm->cmsg_type != IPV6_RECVERR)
> + continue;
> +
> + serr = (void *)CMSG_DATA(cm);
> + if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY)
> + error(1, 0, "wrong origin %u", serr->ee_origin);
> + if (serr->ee_errno != 0)
> + error(1, 0, "wrong errno %d", serr->ee_errno);
> +
> + hi = serr->ee_data;
> + lo = serr->ee_info;
> +
> + fprintf(stderr, "tx complete [%d,%d]\n", lo, hi);
> + return;
> + }
> + }
> +
> + error(1, 0, "did not receive tx completion");
> +}
> +
> +static int do_client(struct memory_buffer *mem)
> +{
> + char ctrl_data[CMSG_SPACE(sizeof(struct dmabuf_tx_cmsg))];
> + struct sockaddr_in6 server_sin;
> + struct sockaddr_in6 client_sin;
> + struct dmabuf_tx_cmsg ddmabuf;
> + struct ynl_sock *ys = NULL;
> + struct msghdr msg = {};
> + ssize_t line_size = 0;
> + struct cmsghdr *cmsg;
> + struct iovec iov[2];
> + uint64_t off = 100;
> + char *line = NULL;
> + size_t len = 0;
> + int socket_fd;
> + int ret, mid;
> + int opt = 1;
> +
> + ret = parse_address(server_ip, atoi(port), &server_sin);
> + if (ret < 0)
> + error(1, 0, "parse server address");
> +
> + socket_fd = socket(AF_INET6, SOCK_STREAM, 0);
> + if (socket_fd < 0)
> + error(1, socket_fd, "create socket");
> +
> + enable_reuseaddr(socket_fd);
> +
> + ret = setsockopt(socket_fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
> + strlen(ifname) + 1);
> + if (ret)
> + error(1, ret, "bindtodevice");
> +
> + if (bind_tx_queue(ifindex, mem->fd, &ys))
> + error(1, 0, "Failed to bind\n");
> +
[..]
> + ret = parse_address(client_ip, atoi(port), &client_sin);
> + if (ret < 0)
> + error(1, 0, "parse client address");
> +
> + ret = bind(socket_fd, &client_sin, sizeof(client_sin));
> + if (ret)
> + error(1, ret, "bind");
> +
Can we wrap the two above in 'if (client_ip) {}'? For my case, as long as
we do SO_BINDTODEVICE, the autobind will do the right thing and I don't
have to explicitly pass '-c' (ncdemem crashes right now if it's
not passed).
> + ret = setsockopt(socket_fd, SOL_SOCKET, SO_ZEROCOPY, &opt, sizeof(opt));
> + if (ret)
> + error(1, ret, "set sock opt");
> +
> + fprintf(stderr, "Connect to %s %d (via %s)\n", server_ip,
> + ntohs(server_sin.sin6_port), ifname);
> +
[..]
> + ret = connect(socket_fd, &server_sin, sizeof(server_sin));
> + if (ret)
> + error(1, ret, "connect");
The most new error() invocations, you pass 'ret' as a second argument.
We need to use 'errno' instead where possible to give the users correct errors
for diagnostics.
> +
> + while (1) {
> + free(line);
> + line = NULL;
> + /* Subtract 1 from line_size to remove trailing newlines that
> + * get_line are surely to parse...
> + */
> + line_size = getline(&line, &len, stdin) - 1;
> +
> + if (line_size < 0)
> + break;
> +
> + mid = (line_size / 2) + 1;
> +
> + iov[0].iov_base = (void *)100;
> + iov[0].iov_len = mid;
> + iov[1].iov_base = (void *)2000;
> + iov[1].iov_len = line_size - mid;
> +
> + provider->memcpy_to_device(mem, (size_t)iov[0].iov_base, line,
> + iov[0].iov_len);
This generates the following on my side:
ncdevmem.c:911:15: warning: format specifies type 'int' but the argument has type 'uint64_t' (aka 'unsigned long') [-Wformat]
910 | "read line_size=%ld off=%d iov[0].iov_base=%d, iov[0].iov_len=%d, iov[1].iov_base=%d, iov[1].iov_len=%d\n",
| ~~
| %lu
911 | line_size, off, iov[0].iov_base, iov[0].iov_len,
| ^~~
ncdevmem.c:911:20: warning: format specifies type 'int' but the argument has type 'void *' [-Wformat]
910 | "read line_size=%ld off=%d iov[0].iov_base=%d, iov[0].iov_len=%d, iov[1].iov_base=%d, iov[1].iov_len=%d\n",
| ~~
911 | line_size, off, iov[0].iov_base, iov[0].iov_len,
| ^~~~~~~~~~~~~~~
ncdevmem.c:911:37: warning: format specifies type 'int' but the argument has type '__kernel_size_t' (aka 'unsigned long') [-Wformat]
910 | "read line_size=%ld off=%d iov[0].iov_base=%d, iov[0].iov_len=%d, iov[1].iov_base=%d, iov[1].iov_len=%d\n",
| ~~
| %lu
911 | line_size, off, iov[0].iov_base, iov[0].iov_len,
| ^~~~~~~~~~~~~~
ncdevmem.c:912:4: warning: format specifies type 'int' but the argument has type 'void *' [-Wformat]
910 | "read line_size=%ld off=%d iov[0].iov_base=%d, iov[0].iov_len=%d, iov[1].iov_base=%d, iov[1].iov_len=%d\n",
| ~~
911 | line_size, off, iov[0].iov_base, iov[0].iov_len,
912 | iov[1].iov_base, iov[1].iov_len);
| ^~~~~~~~~~~~~~~
ncdevmem.c:912:21: warning: format specifies type 'int' but the argument has type '__kernel_size_t' (aka 'unsigned long') [-Wformat]
910 | "read line_size=%ld off=%d iov[0].iov_base=%d, iov[0].iov_len=%d, iov[1].iov_base=%d, iov[1].iov_len=%d\n",
| ~~
| %lu
911 | line_size, off, iov[0].iov_base, iov[0].iov_len,
912 | iov[1].iov_base, iov[1].iov_len);
| ^~~~~~~~~~~~~~
^ permalink raw reply [flat|nested] 17+ messages in thread
end of thread, other threads:[~2025-01-31 17:45 UTC | newest]
Thread overview: 17+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-01-30 21:15 [PATCH RFC net-next v2 0/6] Device memory TCP TX Mina Almasry
2025-01-30 21:15 ` [PATCH RFC net-next v2 1/6] net: add devmem TCP TX documentation Mina Almasry
2025-01-30 22:59 ` Stanislav Fomichev
2025-01-30 23:22 ` Mina Almasry
2025-01-31 17:39 ` Stanislav Fomichev
2025-01-30 21:15 ` [PATCH RFC net-next v2 2/6] selftests: ncdevmem: Implement devmem TCP TX Mina Almasry
2025-01-30 23:05 ` Stanislav Fomichev
2025-01-30 23:29 ` Mina Almasry
2025-01-31 17:41 ` Stanislav Fomichev
2025-01-31 17:45 ` Stanislav Fomichev
2025-01-30 21:15 ` [PATCH RFC net-next v2 3/6] net: add get_netmem/put_netmem support Mina Almasry
2025-01-30 21:15 ` [PATCH RFC net-next v2 4/6] net: devmem: TCP tx netlink api Mina Almasry
2025-01-31 8:29 ` Simon Horman
2025-01-30 21:15 ` [PATCH RFC net-next v2 5/6] net: devmem: Implement TX path Mina Almasry
2025-01-30 23:07 ` Stanislav Fomichev
2025-01-31 9:09 ` Simon Horman
2025-01-30 21:15 ` [PATCH RFC net-next v2 6/6] net: devmem: make dmabuf unbinding scheduled work Mina Almasry
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