Re: [PATCH RFC 2/3] selftests/bpf: add vsock to vmtest.sh

Re: [PATCH RFC 2/3] selftests/bpf: add vsock to vmtest.sh

[Stefano Garzarella]

On Wed, Jan 18, 2023 at 12:27:40PM -0800, Bobby Eshleman wrote:
>Add the ability to use vsock in the vmtest.sh script and
>the test kernel config.
>
>Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
>---
> tools/testing/selftests/bpf/config.x86_64 | 4 ++++
> tools/testing/selftests/bpf/vmtest.sh     | 1 +
> 2 files changed, 5 insertions(+)
>
>diff --git a/tools/testing/selftests/bpf/config.x86_64 b/tools/testing/selftests/bpf/config.x86_64
>index dd97d61d325ca..db5e6b9a91711 100644
>--- a/tools/testing/selftests/bpf/config.x86_64
>+++ b/tools/testing/selftests/bpf/config.x86_64
>@@ -234,7 +234,11 @@ CONFIG_VIRTIO_BLK=y
> CONFIG_VIRTIO_CONSOLE=y
> CONFIG_VIRTIO_NET=y
> CONFIG_VIRTIO_PCI=y
>+CONFIG_VIRTIO_VSOCKETS=y
>+CONFIG_VIRTIO_VSOCKETS_COMMON=y
> CONFIG_VLAN_8021Q=y
>+CONFIG_VSOCKETS=y
>+CONFIG_VSOCKETS_LOOPBACK=y
> CONFIG_X86_ACPI_CPUFREQ=y
> CONFIG_X86_CPUID=y
> CONFIG_X86_MSR=y
>diff --git a/tools/testing/selftests/bpf/vmtest.sh b/tools/testing/selftests/bpf/vmtest.sh
>index 316a56d680f25..aad27ffd4ec68 100755
>--- a/tools/testing/selftests/bpf/vmtest.sh
>+++ b/tools/testing/selftests/bpf/vmtest.sh
>@@ -250,6 +250,7 @@ EOF
> 		-enable-kvm \
> 		-m 4G \
> 		-drive file="${rootfs_img}",format=raw,index=1,media=disk,if=virtio,cache=none \
>+		-device vhost-vsock-pci,guest-cid=1234 \

I'm not sure if this will work with qemu-system-s390x and 
qemu-system-aarch64.

Maybe the "virt" machine of qemu-system-aarch64 supports PCI, but IIRC 
s390x doesn't support it and we should use the vhost-vsock-ccw device.

In addition, we are changing only config.x86_64, so maybe we should add 
the vhost-vsock-pci device only for x86_64 (maybe in the QEMU_FLAGS or a 
new VSOCK_DEV variable), and run the tests only for that architecture.

Thanks,
Stefano

> 		-kernel "${kernel_bzimage}" \
> 		-append "root=/dev/vda rw console=${QEMU_CONSOLE}"
> }
>
>-- 
>2.30.2
>

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Re: [PATCH RFC 3/3] selftests/bpf: Add a test case for vsock sockmap

[Stefano Garzarella]

On Wed, Jan 18, 2023 at 12:27:41PM -0800, Bobby Eshleman wrote:
>Add a test case testing the redirection from connectible AF_VSOCK
>sockets to connectible AF_UNIX sockets.
>
>Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
>---
> .../selftests/bpf/prog_tests/sockmap_listen.c      | 163 +++++++++++++++++++++
> 1 file changed, 163 insertions(+)
>
>diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
>index 2cf0c7a3fe232..8b5a2e09c9ede 100644
>--- a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
>+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
>@@ -18,6 +18,7 @@
> #include <string.h>
> #include <sys/select.h>
> #include <unistd.h>
>+#include <linux/vm_sockets.h>
>
> #include <bpf/bpf.h>
> #include <bpf/libbpf.h>
>@@ -249,6 +250,16 @@ static void init_addr_loopback6(struct sockaddr_storage *ss, socklen_t *len)
> 	*len = sizeof(*addr6);
> }
>
>+static void init_addr_loopback_vsock(struct sockaddr_storage *ss, socklen_t *len)
>+{
>+	struct sockaddr_vm *addr = memset(ss, 0, sizeof(*ss));
>+
>+	addr->svm_family = AF_VSOCK;
>+	addr->svm_port = VMADDR_PORT_ANY;
>+	addr->svm_cid = VMADDR_CID_LOCAL;

Wait, IIUC we only use loopback, so why do we need to attach the 
vhost-vsock-pci device to QEMU?

At that point if we add CONFIG_VSOCKETS_LOOPBACK in all configurations, 
it should also work with aarch64 and s390x.

Thanks,
Stefano

>+	*len = sizeof(*addr);
>+}
>+
> static void init_addr_loopback(int family, struct sockaddr_storage *ss,
> 			       socklen_t *len)
> {
>@@ -259,6 +270,9 @@ static void init_addr_loopback(int family, struct sockaddr_storage *ss,
> 	case AF_INET6:
> 		init_addr_loopback6(ss, len);
> 		return;
>+	case AF_VSOCK:
>+		init_addr_loopback_vsock(ss, len);
>+		return;
> 	default:
> 		FAIL("unsupported address family %d", family);
> 	}
>@@ -1434,6 +1448,8 @@ static const char *family_str(sa_family_t family)
> 		return "IPv6";
> 	case AF_UNIX:
> 		return "Unix";
>+	case AF_VSOCK:
>+		return "VSOCK";
> 	default:
> 		return "unknown";
> 	}
>@@ -1644,6 +1660,151 @@ static void test_unix_redir(struct test_sockmap_listen *skel, struct bpf_map *ma
> 	unix_skb_redir_to_connected(skel, map, sotype);
> }
>
>+/* Returns two connected loopback vsock sockets */
>+static int vsock_socketpair_connectible(int sotype, int *v0, int *v1)
>+{
>+	struct sockaddr_storage addr;
>+	socklen_t len = sizeof(addr);
>+	int s, p, c;
>+
>+	s = socket_loopback(AF_VSOCK, sotype);
>+	if (s < 0)
>+		return -1;
>+
>+	c = xsocket(AF_VSOCK, sotype | SOCK_NONBLOCK, 0);
>+	if (c == -1)
>+		goto close_srv;
>+
>+	if (getsockname(s, sockaddr(&addr), &len) < 0)
>+		goto close_cli;
>+
>+	if (connect(c, sockaddr(&addr), len) < 0 && errno != EINPROGRESS) {
>+		FAIL_ERRNO("connect");
>+		goto close_cli;
>+	}
>+
>+	len = sizeof(addr);
>+	p = accept_timeout(s, sockaddr(&addr), &len, IO_TIMEOUT_SEC);
>+	if (p < 0)
>+		goto close_cli;
>+
>+	*v0 = p;
>+	*v1 = c;
>+
>+	return 0;
>+
>+close_cli:
>+	close(c);
>+close_srv:
>+	close(s);
>+
>+	return -1;
>+}
>+
>+static void vsock_unix_redir_connectible(int sock_mapfd, int verd_mapfd,
>+					 enum redir_mode mode, int sotype)
>+{
>+	const char *log_prefix = redir_mode_str(mode);
>+	char a = 'a', b = 'b';
>+	int u0, u1, v0, v1;
>+	int sfd[2];
>+	unsigned int pass;
>+	int err, n;
>+	u32 key;
>+
>+	zero_verdict_count(verd_mapfd);
>+
>+	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0, sfd))
>+		return;
>+
>+	u0 = sfd[0];
>+	u1 = sfd[1];
>+
>+	err = vsock_socketpair_connectible(sotype, &v0, &v1);
>+	if (err) {
>+		FAIL("vsock_socketpair_connectible() failed");
>+		goto close_uds;
>+	}
>+
>+	err = add_to_sockmap(sock_mapfd, u0, v0);
>+	if (err) {
>+		FAIL("add_to_sockmap failed");
>+		goto close_vsock;
>+	}
>+
>+	n = write(v1, &a, sizeof(a));
>+	if (n < 0)
>+		FAIL_ERRNO("%s: write", log_prefix);
>+	if (n == 0)
>+		FAIL("%s: incomplete write", log_prefix);
>+	if (n < 1)
>+		goto out;
>+
>+	n = recv(mode == REDIR_INGRESS ? u0 : u1, &b, sizeof(b), MSG_DONTWAIT);
>+	if (n < 0)
>+		FAIL("%s: recv() err, errno=%d", log_prefix, errno);
>+	if (n == 0)
>+		FAIL("%s: incomplete recv", log_prefix);
>+	if (b != a)
>+		FAIL("%s: vsock socket map failed, %c != %c", log_prefix, a, b);
>+
>+	key = SK_PASS;
>+	err = xbpf_map_lookup_elem(verd_mapfd, &key, &pass);
>+	if (err)
>+		goto out;
>+	if (pass != 1)
>+		FAIL("%s: want pass count 1, have %d", log_prefix, pass);
>+out:
>+	key = 0;
>+	bpf_map_delete_elem(sock_mapfd, &key);
>+	key = 1;
>+	bpf_map_delete_elem(sock_mapfd, &key);
>+
>+close_vsock:
>+	close(v0);
>+	close(v1);
>+
>+close_uds:
>+	close(u0);
>+	close(u1);
>+}
>+
>+static void vsock_unix_skb_redir_connectible(struct test_sockmap_listen *skel,
>+					     struct bpf_map *inner_map,
>+					     int sotype)
>+{
>+	int verdict = bpf_program__fd(skel->progs.prog_skb_verdict);
>+	int verdict_map = bpf_map__fd(skel->maps.verdict_map);
>+	int sock_map = bpf_map__fd(inner_map);
>+	int err;
>+
>+	err = xbpf_prog_attach(verdict, sock_map, BPF_SK_SKB_VERDICT, 0);
>+	if (err)
>+		return;
>+
>+	skel->bss->test_ingress = false;
>+	vsock_unix_redir_connectible(sock_map, verdict_map, REDIR_EGRESS, sotype);
>+	skel->bss->test_ingress = true;
>+	vsock_unix_redir_connectible(sock_map, verdict_map, REDIR_INGRESS, sotype);
>+
>+	xbpf_prog_detach2(verdict, sock_map, BPF_SK_SKB_VERDICT);
>+}
>+
>+static void test_vsock_redir(struct test_sockmap_listen *skel, struct bpf_map *map)
>+{
>+	const char *family_name, *map_name;
>+	char s[MAX_TEST_NAME];
>+
>+	family_name = family_str(AF_VSOCK);
>+	map_name = map_type_str(map);
>+	snprintf(s, sizeof(s), "%s %s %s", map_name, family_name, __func__);
>+	if (!test__start_subtest(s))
>+		return;
>+
>+	vsock_unix_skb_redir_connectible(skel, map, SOCK_STREAM);
>+	vsock_unix_skb_redir_connectible(skel, map, SOCK_SEQPACKET);
>+}
>+
> static void test_reuseport(struct test_sockmap_listen *skel,
> 			   struct bpf_map *map, int family, int sotype)
> {
>@@ -2015,12 +2176,14 @@ void serial_test_sockmap_listen(void)
> 	run_tests(skel, skel->maps.sock_map, AF_INET6);
> 	test_unix_redir(skel, skel->maps.sock_map, SOCK_DGRAM);
> 	test_unix_redir(skel, skel->maps.sock_map, SOCK_STREAM);
>+	test_vsock_redir(skel, skel->maps.sock_map);
>
> 	skel->bss->test_sockmap = false;
> 	run_tests(skel, skel->maps.sock_hash, AF_INET);
> 	run_tests(skel, skel->maps.sock_hash, AF_INET6);
> 	test_unix_redir(skel, skel->maps.sock_hash, SOCK_DGRAM);
> 	test_unix_redir(skel, skel->maps.sock_hash, SOCK_STREAM);
>+	test_vsock_redir(skel, skel->maps.sock_hash);
>
> 	test_sockmap_listen__destroy(skel);
> }
>
>-- 
>2.30.2
>

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Re: [PATCH RFC 0/3] vsock: add support for sockmap

[Stefano Garzarella]

Hi Bobby,

On Wed, Jan 18, 2023 at 12:27:39PM -0800, Bobby Eshleman wrote:
>Add support for sockmap to vsock.
>
>We're testing usage of vsock as a way to redirect guest-local UDS requests to
>the host and this patch series greatly improves the performance of such a
>setup.
>
>Compared to copying packets via userspace, this improves throughput by 221% in
>basic testing.

Cool, nice series!

>
>Tested as follows.
>
>Setup: guest unix dgram sender -> guest vsock redirector -> host vsock server
>Threads: 1
>Payload: 64k
>No sockmap:
>- 76.3 MB/s
>- The guest vsock redirector was
>  "socat VSOCK-CONNECT:2:1234 UNIX-RECV:/path/to/sock"
>Using sockmap (this patch):
>- 168.8 MB/s (+221%)

Assuming the absolute value is correct, there is a typo here, it would 
be +121% right?

>- The guest redirector was a simple sockmap echo server,
>  redirecting unix ingress to vsock 2:1234 egress.
>- Same sender and server programs
>
>Only the virtio transport has been tested.

I think is fine for now.

>The loopback transport was used in
>writing bpf/selftests, but not thoroughly tested otherwise.

I did a quick review mainly for vsock stuff.
Hoping others can take a better look at net/vmw_vsock/vsock_bpf.c, since 
I'm not very familiar with that subsystem.

FYI I will be off the next two weeks (till Feb 7) with limited internet 
access.

Thanks,
Stefano

>
>This series requires the skb patch.
>
>To: Stefan Hajnoczi <stefanha@redhat.com>
>To: Stefano Garzarella <sgarzare@redhat.com>
>To: "Michael S. Tsirkin" <mst@redhat.com>
>To: Jason Wang <jasowang@redhat.com>
>To: "David S. Miller" <davem@davemloft.net>
>To: Eric Dumazet <edumazet@google.com>
>To: Jakub Kicinski <kuba@kernel.org>
>To: Paolo Abeni <pabeni@redhat.com>
>To: Andrii Nakryiko <andrii@kernel.org>
>To: Mykola Lysenko <mykolal@fb.com>
>To: Alexei Starovoitov <ast@kernel.org>
>To: Daniel Borkmann <daniel@iogearbox.net>
>To: Martin KaFai Lau <martin.lau@linux.dev>
>To: Song Liu <song@kernel.org>
>To: Yonghong Song <yhs@fb.com>
>To: John Fastabend <john.fastabend@gmail.com>
>To: KP Singh <kpsingh@kernel.org>
>To: Stanislav Fomichev <sdf@google.com>
>To: Hao Luo <haoluo@google.com>
>To: Jiri Olsa <jolsa@kernel.org>
>To: Shuah Khan <shuah@kernel.org>
>Cc: linux-kernel@vger.kernel.org
>Cc: kvm@vger.kernel.org
>Cc: virtualization@lists.linux-foundation.org
>Cc: netdev@vger.kernel.org
>Cc: bpf@vger.kernel.org
>Cc: linux-kselftest@vger.kernel.org
>Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
>
>---
>Bobby Eshleman (3):
>      vsock: support sockmap
>      selftests/bpf: add vsock to vmtest.sh
>      selftests/bpf: Add a test case for vsock sockmap
>
> drivers/vhost/vsock.c                              |   1 +
> include/linux/virtio_vsock.h                       |   1 +
> include/net/af_vsock.h                             |  17 ++
> net/vmw_vsock/Makefile                             |   1 +
> net/vmw_vsock/af_vsock.c                           |  59 ++++++-
> net/vmw_vsock/virtio_transport.c                   |   2 +
> net/vmw_vsock/virtio_transport_common.c            |  22 +++
> net/vmw_vsock/vsock_bpf.c                          | 180 +++++++++++++++++++++
> net/vmw_vsock/vsock_loopback.c                     |   2 +
> tools/testing/selftests/bpf/config.x86_64          |   4 +
> .../selftests/bpf/prog_tests/sockmap_listen.c      | 163 +++++++++++++++++++
> tools/testing/selftests/bpf/vmtest.sh              |   1 +
> 12 files changed, 447 insertions(+), 6 deletions(-)
>---
>base-commit: f12f4326c6a75a74e908714be6d2f0e2f0fd0d76
>change-id: 20230118-support-vsock-sockmap-connectible-2e1297d2111a
>
>Best regards,
>-- 
>Bobby Eshleman <bobby.eshleman@bytedance.com>
>

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Re: [PATCH RFC 1/3] vsock: support sockmap

[Stefano Garzarella]

On Wed, Jan 18, 2023 at 12:27:39PM -0800, Bobby Eshleman wrote:
>This patch adds sockmap support for vsock sockets. It is intended to be
>usable by all transports, but only the virtio transport is implemented.
>
>Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
>---
> drivers/vhost/vsock.c                   |   1 +
> include/linux/virtio_vsock.h            |   1 +
> include/net/af_vsock.h                  |  17 +++
> net/vmw_vsock/Makefile                  |   1 +
> net/vmw_vsock/af_vsock.c                |  59 +++++++++--
> net/vmw_vsock/virtio_transport.c        |   2 +
> net/vmw_vsock/virtio_transport_common.c |  22 ++++
> net/vmw_vsock/vsock_bpf.c               | 180 ++++++++++++++++++++++++++++++++
> net/vmw_vsock/vsock_loopback.c          |   2 +
> 9 files changed, 279 insertions(+), 6 deletions(-)

./scripts/checkpatch.pl --strict prints some simple warnings/checks that
I suggest to fix :-)

>
>diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
>index 1f3b89c885cca..3c6dc036b9044 100644
>--- a/drivers/vhost/vsock.c
>+++ b/drivers/vhost/vsock.c
>@@ -439,6 +439,7 @@ static struct virtio_transport vhost_transport = {
> 		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
> 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
>
>+		.read_skb = virtio_transport_read_skb,
> 	},
>
> 	.send_pkt = vhost_transport_send_pkt,
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index 3f9c166113063..c58453699ee98 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -245,4 +245,5 @@ u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 wanted);
> void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit);
> void virtio_transport_deliver_tap_pkt(struct sk_buff *skb);
> int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *list);
>+int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t read_actor);
> #endif /* _LINUX_VIRTIO_VSOCK_H */
>diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
>index 568a87c5e0d0f..a73f5fbd296af 100644
>--- a/include/net/af_vsock.h
>+++ b/include/net/af_vsock.h
>@@ -75,6 +75,7 @@ struct vsock_sock {
> 	void *trans;
> };
>
>+s64 vsock_connectible_has_data(struct vsock_sock *vsk);
> s64 vsock_stream_has_data(struct vsock_sock *vsk);
> s64 vsock_stream_has_space(struct vsock_sock *vsk);
> struct sock *vsock_create_connected(struct sock *parent);
>@@ -173,6 +174,9 @@ struct vsock_transport {
>
> 	/* Addressing. */
> 	u32 (*get_local_cid)(void);
>+
>+	/* Read a single skb */
>+	int (*read_skb)(struct vsock_sock *, skb_read_actor_t);
> };
>
> /**** CORE ****/
>@@ -225,5 +229,18 @@ int vsock_init_tap(void);
> int vsock_add_tap(struct vsock_tap *vt);
> int vsock_remove_tap(struct vsock_tap *vt);
> void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque);
>+int vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
>+			      int flags);
>+int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
>+			       size_t len, int flags);
>+
>+#ifdef CONFIG_BPF_SYSCALL
>+extern struct proto vsock_proto;
>+int vsock_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
>+void __init vsock_bpf_build_proto(void);
>+#else
>+static inline void __init vsock_bpf_build_proto(void)
>+{}
>+#endif
>
> #endif /* __AF_VSOCK_H__ */
>diff --git a/net/vmw_vsock/Makefile b/net/vmw_vsock/Makefile
>index 6a943ec95c4a5..5da74c4a9f1d1 100644
>--- a/net/vmw_vsock/Makefile
>+++ b/net/vmw_vsock/Makefile
>@@ -8,6 +8,7 @@ obj-$(CONFIG_HYPERV_VSOCKETS) += hv_sock.o
> obj-$(CONFIG_VSOCKETS_LOOPBACK) += vsock_loopback.o
>
> vsock-y += af_vsock.o af_vsock_tap.o vsock_addr.o
>+vsock-$(CONFIG_BPF_SYSCALL) += vsock_bpf.o
>
> vsock_diag-y += diag.o
>
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index d593d5b6d4b15..7081b3a992c1e 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -116,10 +116,13 @@ static void vsock_sk_destruct(struct sock *sk);
> static int vsock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
>
> /* Protocol family. */
>-static struct proto vsock_proto = {
>+struct proto vsock_proto = {
> 	.name = "AF_VSOCK",
> 	.owner = THIS_MODULE,
> 	.obj_size = sizeof(struct vsock_sock),
>+#ifdef CONFIG_BPF_SYSCALL
>+	.psock_update_sk_prot = vsock_bpf_update_proto,
>+#endif
> };
>
> /* The default peer timeout indicates how long we will wait for a peer response
>@@ -865,7 +868,7 @@ s64 vsock_stream_has_data(struct vsock_sock *vsk)
> }
> EXPORT_SYMBOL_GPL(vsock_stream_has_data);
>
>-static s64 vsock_connectible_has_data(struct vsock_sock *vsk)
>+s64 vsock_connectible_has_data(struct vsock_sock *vsk)
> {
> 	struct sock *sk = sk_vsock(vsk);
>
>@@ -874,6 +877,7 @@ static s64 vsock_connectible_has_data(struct vsock_sock *vsk)
> 	else
> 		return vsock_stream_has_data(vsk);
> }
>+EXPORT_SYMBOL_GPL(vsock_connectible_has_data);
>
> s64 vsock_stream_has_space(struct vsock_sock *vsk)
> {
>@@ -1131,6 +1135,19 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
> 	return mask;
> }
>
>+static int vsock_read_skb(struct sock *sk, skb_read_actor_t read_actor)
>+{
>+	struct vsock_sock *vsk = vsock_sk(sk);
>+
>+	if (!vsk->transport)
>+		return -ENODEV;
>+
>+	if (!vsk->transport->read_skb)
>+		return -EOPNOTSUPP;
>+
>+	return vsk->transport->read_skb(vsk, read_actor);
>+}
>+
> static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
> 			       size_t len)
> {
>@@ -1241,19 +1258,32 @@ static int vsock_dgram_connect(struct socket *sock,
>
> 	memcpy(&vsk->remote_addr, remote_addr, sizeof(vsk->remote_addr));
> 	sock->state = SS_CONNECTED;
>+	sk->sk_state = TCP_ESTABLISHED;

Why we need this change?
If it's a fix, we should put it in another patch.

>
> out:
> 	release_sock(sk);
> 	return err;
> }
>
>-static int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
>-			       size_t len, int flags)
>+int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
>+			size_t len, int flags)
> {
>-	struct vsock_sock *vsk = vsock_sk(sock->sk);
>+	const struct proto *prot;

We should use the guard for this statement as in
vsock_connectible_recvmsg().

>+	struct vsock_sock *vsk;
>+	struct sock *sk;
>+
>+	sk = sock->sk;
>+	vsk = vsock_sk(sk);
>+
>+#ifdef CONFIG_BPF_SYSCALL
>+	prot = READ_ONCE(sk->sk_prot);
>+	if (prot != &vsock_proto)
>+		return prot->recvmsg(sk, msg, len, flags, NULL);
>+#endif
>
> 	return vsk->transport->dgram_dequeue(vsk, msg, len, flags);
> }
>+EXPORT_SYMBOL_GPL(vsock_dgram_recvmsg);
>
> static const struct proto_ops vsock_dgram_ops = {
> 	.family = PF_VSOCK,
>@@ -1272,6 +1302,7 @@ static const struct proto_ops vsock_dgram_ops = {
> 	.recvmsg = vsock_dgram_recvmsg,
> 	.mmap = sock_no_mmap,
> 	.sendpage = sock_no_sendpage,
>+	.read_skb = vsock_read_skb,
> };
>
> static int vsock_transport_cancel_pkt(struct vsock_sock *vsk)
>@@ -2085,13 +2116,16 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
> 	return err;
> }
>
>-static int
>+int
> vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> 			  int flags)
> {
> 	struct sock *sk;
> 	struct vsock_sock *vsk;
> 	const struct vsock_transport *transport;
>+#ifdef CONFIG_BPF_SYSCALL
>+	const struct proto *prot;
>+#endif
> 	int err;
>
> 	sk = sock->sk;
>@@ -2138,6 +2172,14 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> 		goto out;
> 	}
>
>+#ifdef CONFIG_BPF_SYSCALL
>+	prot = READ_ONCE(sk->sk_prot);
>+	if (prot != &vsock_proto) {
>+		release_sock(sk);
>+		return prot->recvmsg(sk, msg, len, flags, NULL);
>+	}
>+#endif
>+
> 	if (sk->sk_type == SOCK_STREAM)
> 		err = __vsock_stream_recvmsg(sk, msg, len, flags);
> 	else
>@@ -2147,6 +2189,7 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> 	release_sock(sk);
> 	return err;
> }
>+EXPORT_SYMBOL_GPL(vsock_connectible_recvmsg);
>
> static int vsock_set_rcvlowat(struct sock *sk, int val)
> {
>@@ -2187,6 +2230,7 @@ static const struct proto_ops vsock_stream_ops = {
> 	.mmap = sock_no_mmap,
> 	.sendpage = sock_no_sendpage,
> 	.set_rcvlowat = vsock_set_rcvlowat,
>+	.read_skb = vsock_read_skb,
> };
>
> static const struct proto_ops vsock_seqpacket_ops = {
>@@ -2208,6 +2252,7 @@ static const struct proto_ops vsock_seqpacket_ops = {
> 	.recvmsg = vsock_connectible_recvmsg,
> 	.mmap = sock_no_mmap,
> 	.sendpage = sock_no_sendpage,
>+	.read_skb = vsock_read_skb,
> };
>
> static int vsock_create(struct net *net, struct socket *sock,
>@@ -2347,6 +2392,8 @@ static int __init vsock_init(void)
> 		goto err_unregister_proto;
> 	}
>
>+	vsock_bpf_build_proto();
>+
> 	return 0;
>
> err_unregister_proto:
>diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>index 28b5a8e8e0948..e95df847176b6 100644
>--- a/net/vmw_vsock/virtio_transport.c
>+++ b/net/vmw_vsock/virtio_transport.c
>@@ -457,6 +457,8 @@ static struct virtio_transport virtio_transport = {
> 		.notify_send_pre_enqueue  = 
> 		virtio_transport_notify_send_pre_enqueue,
> 		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
> 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
>+
>+		.read_skb = virtio_transport_read_skb,
> 	},
>
> 	.send_pkt = virtio_transport_send_pkt,
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index a1581c77cf84a..9a87ead5b1fc5 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -1388,6 +1388,28 @@ int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *queue)
> }
> EXPORT_SYMBOL_GPL(virtio_transport_purge_skbs);
>
>+int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_actor)
>+{
>+	struct virtio_vsock_sock *vvs = vsk->trans;
>+	struct sock *sk = sk_vsock(vsk);
>+	struct sk_buff *skb;
>+	int copied = 0;

We could avoid initializing `copied`, since it is overwritten later.

>+	int off = 0;
>+	int err;
>+
>+	spin_lock_bh(&vvs->rx_lock);
>+	skb = __skb_recv_datagram(sk, &vvs->rx_queue, MSG_DONTWAIT, &off, &err);

Will this work also for STREAM and SEQPACKET sockets?

>+	spin_unlock_bh(&vvs->rx_lock);
>+
>+	if (!skb)
>+		return err;
>+
>+	copied = recv_actor(sk, skb);
>+	kfree_skb(skb);

I would have moved these steps to vsock_read_skb() to avoid duplicating
these steps in each transport. Perhaps not all transports want to pass
skb ownership to the caller, though, so maybe we can leave it that
way for now.

>+	return copied;
>+}
>+EXPORT_SYMBOL_GPL(virtio_transport_read_skb);
>+
> MODULE_LICENSE("GPL v2");
> MODULE_AUTHOR("Asias He");
> MODULE_DESCRIPTION("common code for virtio vsock");
>diff --git a/net/vmw_vsock/vsock_bpf.c b/net/vmw_vsock/vsock_bpf.c
>new file mode 100644
>index 0000000000000..9e11282d3bc1f
>--- /dev/null
>+++ b/net/vmw_vsock/vsock_bpf.c
>@@ -0,0 +1,180 @@
>+// SPDX-License-Identifier: GPL-2.0
>+/* Copyright (c) 2022 Bobby Eshleman <bobby.eshleman@bytedance.com>
>+ *
>+ * Based off of net/unix/unix_bpf.c
>+ */
>+
>+#include <linux/bpf.h>
>+#include <linux/module.h>
>+#include <linux/skmsg.h>
>+#include <linux/socket.h>
>+#include <net/af_vsock.h>
>+#include <net/sock.h>
>+
>+#define vsock_sk_has_data(__sk, __psock)				\
>+		({	!skb_queue_empty(&__sk->sk_receive_queue) ||	\
>+			!skb_queue_empty(&__psock->ingress_skb) ||	\
>+			!list_empty(&__psock->ingress_msg);		\
>+		})
>+
>+static struct proto *vsock_dgram_prot_saved __read_mostly;
>+static DEFINE_SPINLOCK(vsock_dgram_prot_lock);
>+static struct proto vsock_dgram_bpf_prot;
>+
>+static bool vsock_has_data(struct vsock_sock *vsk, struct sk_psock *psock)
>+{
>+	struct sock *sk = sk_vsock(vsk);
>+	s64 ret;
>+
>+	ret = vsock_connectible_has_data(vsk);
>+	if (ret > 0)
>+		return true;
>+
>+	return vsock_sk_has_data(sk, psock);
>+}
>+
>+static int vsock_msg_wait_data(struct sock *sk, struct sk_psock *psock, long timeo)
>+{
>+	struct vsock_sock *vsk;
>+	int err;
>+
>+	DEFINE_WAIT(wait);
>+
>+	vsk = vsock_sk(sk);
>+	err = 0;
>+
>+	while (vsock_has_data(vsk, psock)) {
>+		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
>+
>+		if (sk->sk_err != 0 ||
>+		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
>+		    (vsk->peer_shutdown & SEND_SHUTDOWN)) {
>+			break;
>+		}
>+
>+		if (timeo == 0) {
>+			err = -EAGAIN;
>+			break;
>+		}
>+
>+		release_sock(sk);
>+		timeo = schedule_timeout(timeo);
>+		lock_sock(sk);
>+
>+		if (signal_pending(current)) {
>+			err = sock_intr_errno(timeo);
>+			break;
>+		} else if (timeo == 0) {
>+			err = -EAGAIN;
>+			break;
>+		}
>+	}
>+
>+	finish_wait(sk_sleep(sk), &wait);
>+
>+	if (err)
>+		return err;
>+
>+	return 0;
>+}
>+
>+static int vsock_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags)
>+{
>+	int err;
>+	struct socket *sock = sk->sk_socket;
>+
>+	if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)
>+		err = vsock_connectible_recvmsg(sock, msg, len, flags);
>+	else

Could it happen that it is not DGRAM and we should return an error in
this case?

Thanks,
Stefano

>+		err = vsock_dgram_recvmsg(sock, msg, len, flags);
>+
>+	return err;
>+}
>+
>+static int vsock_bpf_recvmsg(struct sock *sk, struct msghdr *msg,
>+			     size_t len, int flags, int *addr_len)
>+{
>+	int copied;
>+	struct sk_psock *psock;
>+
>+	lock_sock(sk);
>+	psock = sk_psock_get(sk);
>+	if (unlikely(!psock)) {
>+		release_sock(sk);
>+		return vsock_recvmsg(sk, msg, len, flags);
>+	}
>+
>+	if (vsock_has_data(vsock_sk(sk), psock) && sk_psock_queue_empty(psock)) {
>+		sk_psock_put(sk, psock);
>+		release_sock(sk);
>+		return vsock_recvmsg(sk, msg, len, flags);
>+	}
>+
>+msg_bytes_ready:
>+	copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
>+	if (!copied) {
>+		long timeo;
>+		int data;
>+
>+		timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
>+		data = vsock_msg_wait_data(sk, psock, timeo);
>+		if (data) {
>+			if (!sk_psock_queue_empty(psock))
>+				goto msg_bytes_ready;
>+			sk_psock_put(sk, psock);
>+			release_sock(sk);
>+			return vsock_recvmsg(sk, msg, len, flags);
>+		}
>+		copied = -EAGAIN;
>+	}
>+	sk_psock_put(sk, psock);
>+	release_sock(sk);
>+
>+	return copied;
>+}
>+
>+/* Copy of original proto with updated sock_map methods */
>+static struct proto vsock_dgram_bpf_prot = {
>+	.close = sock_map_close,
>+	.recvmsg = vsock_bpf_recvmsg,
>+	.sock_is_readable = sk_msg_is_readable,
>+	.unhash = sock_map_unhash,
>+};
>+
>+static void vsock_dgram_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
>+{
>+	*prot        = *base;
>+	prot->close  = sock_map_close;
>+	prot->recvmsg = vsock_bpf_recvmsg;
>+	prot->sock_is_readable = sk_msg_is_readable;
>+}
>+
>+static void vsock_dgram_bpf_check_needs_rebuild(struct proto *ops)
>+{
>+	if (unlikely(ops != smp_load_acquire(&vsock_dgram_prot_saved))) {
>+		spin_lock_bh(&vsock_dgram_prot_lock);
>+		if (likely(ops != vsock_dgram_prot_saved)) {
>+			vsock_dgram_bpf_rebuild_protos(&vsock_dgram_bpf_prot, ops);
>+			smp_store_release(&vsock_dgram_prot_saved, ops);
>+		}
>+		spin_unlock_bh(&vsock_dgram_prot_lock);
>+	}
>+}
>+
>+int vsock_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
>+{
>+	if (restore) {
>+		sk->sk_write_space = psock->saved_write_space;
>+		sock_replace_proto(sk, psock->sk_proto);
>+		return 0;
>+	}
>+
>+	vsock_dgram_bpf_check_needs_rebuild(psock->sk_proto);
>+	sock_replace_proto(sk, &vsock_dgram_bpf_prot);
>+	return 0;
>+}
>+
>+void __init vsock_bpf_build_proto(void)
>+{
>+	vsock_dgram_bpf_rebuild_protos(&vsock_dgram_bpf_prot, &vsock_proto);
>+}
>diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c
>index 671e03240fc52..40753b661c135 100644
>--- a/net/vmw_vsock/vsock_loopback.c
>+++ b/net/vmw_vsock/vsock_loopback.c
>@@ -94,6 +94,8 @@ static struct virtio_transport loopback_transport = {
> 		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
> 		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
> 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
>+
>+		.read_skb = virtio_transport_read_skb,
> 	},
>
> 	.send_pkt = vsock_loopback_send_pkt,
>
>-- 
>2.30.2
>

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Re: [PATCH RFC 1/3] vsock: support sockmap

[Stefano Garzarella]

On Wed, Jan 18, 2023 at 03:08:11PM +0000, Bobby Eshleman wrote:
>On Thu, Jan 19, 2023 at 11:39:36AM +0100, Stefano Garzarella wrote:
>> On Wed, Jan 18, 2023 at 12:27:39PM -0800, Bobby Eshleman wrote:
>> > This patch adds sockmap support for vsock sockets. It is intended to be
>> > usable by all transports, but only the virtio transport is implemented.
>> >
>> > Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
>> > ---
>> > drivers/vhost/vsock.c                   |   1 +
>> > include/linux/virtio_vsock.h            |   1 +
>> > include/net/af_vsock.h                  |  17 +++
>> > net/vmw_vsock/Makefile                  |   1 +
>> > net/vmw_vsock/af_vsock.c                |  59 +++++++++--
>> > net/vmw_vsock/virtio_transport.c        |   2 +
>> > net/vmw_vsock/virtio_transport_common.c |  22 ++++
>> > net/vmw_vsock/vsock_bpf.c               | 180 ++++++++++++++++++++++++++++++++
>> > net/vmw_vsock/vsock_loopback.c          |   2 +
>> > 9 files changed, 279 insertions(+), 6 deletions(-)
>>
>> ./scripts/checkpatch.pl --strict prints some simple warnings/checks that
>> I suggest to fix :-)
>>
>
>Oops, thanks. New machine, forgot my pre-commit hook. Putting in place
>now.
>
>> >
>> > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
>> > index 1f3b89c885cca..3c6dc036b9044 100644
>> > --- a/drivers/vhost/vsock.c
>> > +++ b/drivers/vhost/vsock.c
>> > @@ -439,6 +439,7 @@ static struct virtio_transport vhost_transport = {
>> > 		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
>> > 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
>> >
>> > +		.read_skb = virtio_transport_read_skb,
>> > 	},
>> >
>> > 	.send_pkt = vhost_transport_send_pkt,
>> > diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>> > index 3f9c166113063..c58453699ee98 100644
>> > --- a/include/linux/virtio_vsock.h
>> > +++ b/include/linux/virtio_vsock.h
>> > @@ -245,4 +245,5 @@ u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 wanted);
>> > void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit);
>> > void virtio_transport_deliver_tap_pkt(struct sk_buff *skb);
>> > int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *list);
>> > +int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t read_actor);
>> > #endif /* _LINUX_VIRTIO_VSOCK_H */
>> > diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
>> > index 568a87c5e0d0f..a73f5fbd296af 100644
>> > --- a/include/net/af_vsock.h
>> > +++ b/include/net/af_vsock.h
>> > @@ -75,6 +75,7 @@ struct vsock_sock {
>> > 	void *trans;
>> > };
>> >
>> > +s64 vsock_connectible_has_data(struct vsock_sock *vsk);
>> > s64 vsock_stream_has_data(struct vsock_sock *vsk);
>> > s64 vsock_stream_has_space(struct vsock_sock *vsk);
>> > struct sock *vsock_create_connected(struct sock *parent);
>> > @@ -173,6 +174,9 @@ struct vsock_transport {
>> >
>> > 	/* Addressing. */
>> > 	u32 (*get_local_cid)(void);
>> > +
>> > +	/* Read a single skb */
>> > +	int (*read_skb)(struct vsock_sock *, skb_read_actor_t);
>> > };
>> >
>> > /**** CORE ****/
>> > @@ -225,5 +229,18 @@ int vsock_init_tap(void);
>> > int vsock_add_tap(struct vsock_tap *vt);
>> > int vsock_remove_tap(struct vsock_tap *vt);
>> > void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque);
>> > +int vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
>> > +			      int flags);
>> > +int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
>> > +			       size_t len, int flags);
>> > +
>> > +#ifdef CONFIG_BPF_SYSCALL
>> > +extern struct proto vsock_proto;
>> > +int vsock_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
>> > +void __init vsock_bpf_build_proto(void);
>> > +#else
>> > +static inline void __init vsock_bpf_build_proto(void)
>> > +{}
>> > +#endif
>> >
>> > #endif /* __AF_VSOCK_H__ */
>> > diff --git a/net/vmw_vsock/Makefile b/net/vmw_vsock/Makefile
>> > index 6a943ec95c4a5..5da74c4a9f1d1 100644
>> > --- a/net/vmw_vsock/Makefile
>> > +++ b/net/vmw_vsock/Makefile
>> > @@ -8,6 +8,7 @@ obj-$(CONFIG_HYPERV_VSOCKETS) += hv_sock.o
>> > obj-$(CONFIG_VSOCKETS_LOOPBACK) += vsock_loopback.o
>> >
>> > vsock-y += af_vsock.o af_vsock_tap.o vsock_addr.o
>> > +vsock-$(CONFIG_BPF_SYSCALL) += vsock_bpf.o
>> >
>> > vsock_diag-y += diag.o
>> >
>> > diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>> > index d593d5b6d4b15..7081b3a992c1e 100644
>> > --- a/net/vmw_vsock/af_vsock.c
>> > +++ b/net/vmw_vsock/af_vsock.c
>> > @@ -116,10 +116,13 @@ static void vsock_sk_destruct(struct sock *sk);
>> > static int vsock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
>> >
>> > /* Protocol family. */
>> > -static struct proto vsock_proto = {
>> > +struct proto vsock_proto = {
>> > 	.name = "AF_VSOCK",
>> > 	.owner = THIS_MODULE,
>> > 	.obj_size = sizeof(struct vsock_sock),
>> > +#ifdef CONFIG_BPF_SYSCALL
>> > +	.psock_update_sk_prot = vsock_bpf_update_proto,
>> > +#endif
>> > };
>> >
>> > /* The default peer timeout indicates how long we will wait for a peer response
>> > @@ -865,7 +868,7 @@ s64 vsock_stream_has_data(struct vsock_sock *vsk)
>> > }
>> > EXPORT_SYMBOL_GPL(vsock_stream_has_data);
>> >
>> > -static s64 vsock_connectible_has_data(struct vsock_sock *vsk)
>> > +s64 vsock_connectible_has_data(struct vsock_sock *vsk)
>> > {
>> > 	struct sock *sk = sk_vsock(vsk);
>> >
>> > @@ -874,6 +877,7 @@ static s64 vsock_connectible_has_data(struct vsock_sock *vsk)
>> > 	else
>> > 		return vsock_stream_has_data(vsk);
>> > }
>> > +EXPORT_SYMBOL_GPL(vsock_connectible_has_data);
>> >
>> > s64 vsock_stream_has_space(struct vsock_sock *vsk)
>> > {
>> > @@ -1131,6 +1135,19 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
>> > 	return mask;
>> > }
>> >
>> > +static int vsock_read_skb(struct sock *sk, skb_read_actor_t read_actor)
>> > +{
>> > +	struct vsock_sock *vsk = vsock_sk(sk);
>> > +
>> > +	if (!vsk->transport)
>> > +		return -ENODEV;
>> > +
>> > +	if (!vsk->transport->read_skb)
>> > +		return -EOPNOTSUPP;
>> > +
>> > +	return vsk->transport->read_skb(vsk, read_actor);
>> > +}
>> > +
>> > static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
>> > 			       size_t len)
>> > {
>> > @@ -1241,19 +1258,32 @@ static int vsock_dgram_connect(struct socket *sock,
>> >
>> > 	memcpy(&vsk->remote_addr, remote_addr, sizeof(vsk->remote_addr));
>> > 	sock->state = SS_CONNECTED;
>> > +	sk->sk_state = TCP_ESTABLISHED;
>>
>> Why we need this change?
>> If it's a fix, we should put it in another patch.
>>
>
>This is just required by sockmap's function that determines if a socket
>is a valid one to add to a map. It will refuse to add any socket that is
>not TCP_ESTABLISHED to a sockmap.
>
>This was the approach that unix dgrams took, so I followed here.

Okay, make sense to me.
Maybe mention that in the commit message.

>
>> >
>> > out:
>> > 	release_sock(sk);
>> > 	return err;
>> > }
>> >
>> > -static int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
>> > -			       size_t len, int flags)
>> > +int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
>> > +			size_t len, int flags)
>> > {
>> > -	struct vsock_sock *vsk = vsock_sk(sock->sk);
>> > +	const struct proto *prot;
>>
>> We should use the guard for this statement as in
>> vsock_connectible_recvmsg().
>>
>
>Got it.
>
>> > +	struct vsock_sock *vsk;
>> > +	struct sock *sk;
>> > +
>> > +	sk = sock->sk;
>> > +	vsk = vsock_sk(sk);
>> > +
>> > +#ifdef CONFIG_BPF_SYSCALL
>> > +	prot = READ_ONCE(sk->sk_prot);
>> > +	if (prot != &vsock_proto)
>> > +		return prot->recvmsg(sk, msg, len, flags, NULL);
>> > +#endif
>> >
>> > 	return vsk->transport->dgram_dequeue(vsk, msg, len, flags);
>> > }
>> > +EXPORT_SYMBOL_GPL(vsock_dgram_recvmsg);
>> >
>> > static const struct proto_ops vsock_dgram_ops = {
>> > 	.family = PF_VSOCK,
>> > @@ -1272,6 +1302,7 @@ static const struct proto_ops vsock_dgram_ops = {
>> > 	.recvmsg = vsock_dgram_recvmsg,
>> > 	.mmap = sock_no_mmap,
>> > 	.sendpage = sock_no_sendpage,
>> > +	.read_skb = vsock_read_skb,
>> > };
>> >
>> > static int vsock_transport_cancel_pkt(struct vsock_sock *vsk)
>> > @@ -2085,13 +2116,16 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
>> > 	return err;
>> > }
>> >
>> > -static int
>> > +int
>> > vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
>> > 			  int flags)
>> > {
>> > 	struct sock *sk;
>> > 	struct vsock_sock *vsk;
>> > 	const struct vsock_transport *transport;
>> > +#ifdef CONFIG_BPF_SYSCALL
>> > +	const struct proto *prot;
>> > +#endif
>> > 	int err;
>> >
>> > 	sk = sock->sk;
>> > @@ -2138,6 +2172,14 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
>> > 		goto out;
>> > 	}
>> >
>> > +#ifdef CONFIG_BPF_SYSCALL
>> > +	prot = READ_ONCE(sk->sk_prot);
>> > +	if (prot != &vsock_proto) {
>> > +		release_sock(sk);
>> > +		return prot->recvmsg(sk, msg, len, flags, NULL);
>> > +	}
>> > +#endif
>> > +
>> > 	if (sk->sk_type == SOCK_STREAM)
>> > 		err = __vsock_stream_recvmsg(sk, msg, len, flags);
>> > 	else
>> > @@ -2147,6 +2189,7 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
>> > 	release_sock(sk);
>> > 	return err;
>> > }
>> > +EXPORT_SYMBOL_GPL(vsock_connectible_recvmsg);
>> >
>> > static int vsock_set_rcvlowat(struct sock *sk, int val)
>> > {
>> > @@ -2187,6 +2230,7 @@ static const struct proto_ops vsock_stream_ops = {
>> > 	.mmap = sock_no_mmap,
>> > 	.sendpage = sock_no_sendpage,
>> > 	.set_rcvlowat = vsock_set_rcvlowat,
>> > +	.read_skb = vsock_read_skb,
>> > };
>> >
>> > static const struct proto_ops vsock_seqpacket_ops = {
>> > @@ -2208,6 +2252,7 @@ static const struct proto_ops vsock_seqpacket_ops = {
>> > 	.recvmsg = vsock_connectible_recvmsg,
>> > 	.mmap = sock_no_mmap,
>> > 	.sendpage = sock_no_sendpage,
>> > +	.read_skb = vsock_read_skb,
>> > };
>> >
>> > static int vsock_create(struct net *net, struct socket *sock,
>> > @@ -2347,6 +2392,8 @@ static int __init vsock_init(void)
>> > 		goto err_unregister_proto;
>> > 	}
>> >
>> > +	vsock_bpf_build_proto();
>> > +
>> > 	return 0;
>> >
>> > err_unregister_proto:
>> > diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>> > index 28b5a8e8e0948..e95df847176b6 100644
>> > --- a/net/vmw_vsock/virtio_transport.c
>> > +++ b/net/vmw_vsock/virtio_transport.c
>> > @@ -457,6 +457,8 @@ static struct virtio_transport virtio_transport = {
>> > 		.notify_send_pre_enqueue  =
>> > 		virtio_transport_notify_send_pre_enqueue,
>> > 		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
>> > 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
>> > +
>> > +		.read_skb = virtio_transport_read_skb,
>> > 	},
>> >
>> > 	.send_pkt = virtio_transport_send_pkt,
>> > diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>> > index a1581c77cf84a..9a87ead5b1fc5 100644
>> > --- a/net/vmw_vsock/virtio_transport_common.c
>> > +++ b/net/vmw_vsock/virtio_transport_common.c
>> > @@ -1388,6 +1388,28 @@ int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *queue)
>> > }
>> > EXPORT_SYMBOL_GPL(virtio_transport_purge_skbs);
>> >
>> > +int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_actor)
>> > +{
>> > +	struct virtio_vsock_sock *vvs = vsk->trans;
>> > +	struct sock *sk = sk_vsock(vsk);
>> > +	struct sk_buff *skb;
>> > +	int copied = 0;
>>
>> We could avoid initializing `copied`, since it is overwritten later.
>>
>
>Got it.
>
>> > +	int off = 0;
>> > +	int err;
>> > +
>> > +	spin_lock_bh(&vvs->rx_lock);
>> > +	skb = __skb_recv_datagram(sk, &vvs->rx_queue, MSG_DONTWAIT, &off, &err);
>>
>> Will this work also for STREAM and SEQPACKET sockets?
>>
>
>Yep, it is used for non-datagram sockets as well because it is free of race
>conditions, and handles waits/errors sensibly. For example, in
>unix_accept():
>
>https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/unix/af_unix.c#n1696

Good to know :-)
I'd add a comment, just because the function name suggests something 
else.

>
>> > +	spin_unlock_bh(&vvs->rx_lock);
>> > +
>> > +	if (!skb)
>> > +		return err;
>> > +
>> > +	copied = recv_actor(sk, skb);
>> > +	kfree_skb(skb);
>>
>> I would have moved these steps to vsock_read_skb() to avoid duplicating
>> these steps in each transport. Perhaps not all transports want to pass
>> skb ownership to the caller, though, so maybe we can leave it that
>> way for now.
>>
>
>That is a good point though. I bet your initial hunch is the right one.
>If even one other transport duplicates this, then I'd say it is worth
>pulling up into vsock_read_skb().

Make sense to me :-)

>
>> > +	return copied;
>> > +}
>> > +EXPORT_SYMBOL_GPL(virtio_transport_read_skb);
>> > +
>> > MODULE_LICENSE("GPL v2");
>> > MODULE_AUTHOR("Asias He");
>> > MODULE_DESCRIPTION("common code for virtio vsock");
>> > diff --git a/net/vmw_vsock/vsock_bpf.c b/net/vmw_vsock/vsock_bpf.c
>> > new file mode 100644
>> > index 0000000000000..9e11282d3bc1f
>> > --- /dev/null
>> > +++ b/net/vmw_vsock/vsock_bpf.c
>> > @@ -0,0 +1,180 @@
>> > +// SPDX-License-Identifier: GPL-2.0
>> > +/* Copyright (c) 2022 Bobby Eshleman <bobby.eshleman@bytedance.com>
>> > + *
>> > + * Based off of net/unix/unix_bpf.c
>> > + */
>> > +
>> > +#include <linux/bpf.h>
>> > +#include <linux/module.h>
>> > +#include <linux/skmsg.h>
>> > +#include <linux/socket.h>
>> > +#include <net/af_vsock.h>
>> > +#include <net/sock.h>
>> > +
>> > +#define vsock_sk_has_data(__sk, __psock)				\
>> > +		({	!skb_queue_empty(&__sk->sk_receive_queue) ||	\
>> > +			!skb_queue_empty(&__psock->ingress_skb) ||	\
>> > +			!list_empty(&__psock->ingress_msg);		\
>> > +		})
>> > +
>> > +static struct proto *vsock_dgram_prot_saved __read_mostly;
>> > +static DEFINE_SPINLOCK(vsock_dgram_prot_lock);
>> > +static struct proto vsock_dgram_bpf_prot;
>> > +
>> > +static bool vsock_has_data(struct vsock_sock *vsk, struct sk_psock *psock)
>> > +{
>> > +	struct sock *sk = sk_vsock(vsk);
>> > +	s64 ret;
>> > +
>> > +	ret = vsock_connectible_has_data(vsk);
>> > +	if (ret > 0)
>> > +		return true;
>> > +
>> > +	return vsock_sk_has_data(sk, psock);
>> > +}
>> > +
>> > +static int vsock_msg_wait_data(struct sock *sk, struct sk_psock *psock, long timeo)
>> > +{
>> > +	struct vsock_sock *vsk;
>> > +	int err;
>> > +
>> > +	DEFINE_WAIT(wait);
>> > +
>> > +	vsk = vsock_sk(sk);
>> > +	err = 0;
>> > +
>> > +	while (vsock_has_data(vsk, psock)) {
>> > +		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
>> > +
>> > +		if (sk->sk_err != 0 ||
>> > +		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
>> > +		    (vsk->peer_shutdown & SEND_SHUTDOWN)) {
>> > +			break;
>> > +		}
>> > +
>> > +		if (timeo == 0) {
>> > +			err = -EAGAIN;
>> > +			break;
>> > +		}
>> > +
>> > +		release_sock(sk);
>> > +		timeo = schedule_timeout(timeo);
>> > +		lock_sock(sk);
>> > +
>> > +		if (signal_pending(current)) {
>> > +			err = sock_intr_errno(timeo);
>> > +			break;
>> > +		} else if (timeo == 0) {
>> > +			err = -EAGAIN;
>> > +			break;
>> > +		}
>> > +	}
>> > +
>> > +	finish_wait(sk_sleep(sk), &wait);
>> > +
>> > +	if (err)
>> > +		return err;
>> > +
>> > +	return 0;
>> > +}
>> > +
>> > +static int vsock_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags)
>> > +{
>> > +	int err;
>> > +	struct socket *sock = sk->sk_socket;
>> > +
>> > +	if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)
>> > +		err = vsock_connectible_recvmsg(sock, msg, len, flags);
>> > +	else
>>
>> Could it happen that it is not DGRAM and we should return an error in
>> this case?
>>
>
>I'm not sure but for the sake of safety, I'll add that.

Yep, I agree.

Thanks,
Stefano

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Re: [PATCH RFC 1/3] vsock: support sockmap

[Cong Wang]

On Wed, Jan 18, 2023 at 12:27:39PM -0800, Bobby Eshleman wrote:
> +static int vsock_read_skb(struct sock *sk, skb_read_actor_t read_actor)
> +{
> +	struct vsock_sock *vsk = vsock_sk(sk);
> +
> +	if (!vsk->transport)
> +		return -ENODEV;
> +
> +	if (!vsk->transport->read_skb)
> +		return -EOPNOTSUPP;

Can we move these two checks to sockmap update path? It would make
vsock_read_skb() faster.

> +
> +	return vsk->transport->read_skb(vsk, read_actor);
> +}

Essentially can be just this one line.

Thanks.
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