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[RFC 2/3] virtio-net: add support for offloading XDP program
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From: |
Prashant Bhole |
|
Subject: |
[RFC 2/3] virtio-net: add support for offloading XDP program |
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Date: |
Tue, 26 Nov 2019 19:09:13 +0900 |
From: Jason Wang <address@hidden>
This feature involves offloading of XDP program and ebpf map from
the guest to the host. This patch takes care of offloadin of program.
A handler for VIRTIO_NET_CTRL_EBPF command is added in virtio-net.
The control buffer consist of struct virtio_net_ctrl_ebpf_prog and
followed by an ebpf program instructions. An array of bpf_insn is
prepared and passed to libbpf API bpf_load_program. The program fd is
retuned by the API is then attached to tap fd using TUNSETOFFLOADEDXDP
ioctl command.
Signed-off-by: Jason Wang <address@hidden>
Co-developed-by: Prashant Bhole <address@hidden>
Signed-off-by: Prashant Bhole <address@hidden>
---
hw/net/virtio-net.c | 69 +++++++++++++++++++++
include/net/tap.h | 2 +
include/standard-headers/linux/virtio_net.h | 27 ++++++++
net/Makefile.objs | 1 +
net/tap-bsd.c | 5 ++
net/tap-linux.c | 48 ++++++++++++++
net/tap-linux.h | 1 +
net/tap-solaris.c | 5 ++
net/tap-stub.c | 5 ++
net/tap.c | 7 +++
net/tap_int.h | 1 +
11 files changed, 171 insertions(+)
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 97a5113f7e..7cc1bd1654 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -43,6 +43,11 @@
#include "monitor/qdev.h"
#include "hw/pci/pci.h"
+#ifdef CONFIG_LIBBPF
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+#endif
+
#define VIRTIO_NET_VM_VERSION 11
#define MAC_TABLE_ENTRIES 64
@@ -628,6 +633,21 @@ static int peer_attach(VirtIONet *n, int index)
return tap_enable(nc->peer);
}
+static int peer_attach_ebpf(VirtIONet *n, int len, void *insns, uint8_t gpl)
+{
+ NetClientState *nc = qemu_get_subqueue(n->nic, 0);
+
+ if (!nc->peer) {
+ return 0;
+ }
+
+ if (nc->peer->info->type != NET_CLIENT_DRIVER_TAP) {
+ return 0;
+ }
+
+ return tap_attach_ebpf(nc->peer, len, insns, gpl);
+}
+
static int peer_detach(VirtIONet *n, int index)
{
NetClientState *nc = qemu_get_subqueue(n->nic, index);
@@ -991,6 +1011,53 @@ static int virtio_net_handle_offloads(VirtIONet *n,
uint8_t cmd,
}
}
+static int virtio_net_handle_ebpf_prog(VirtIONet *n, struct iovec *iov,
+ unsigned int iov_cnt)
+{
+#ifdef CONFIG_LIBBPF
+ struct bpf_insn prog[4096];
+ struct virtio_net_ctrl_ebpf_prog ctrl;
+ size_t s;
+ int err = VIRTIO_NET_ERR;
+
+ s = iov_to_buf(iov, iov_cnt, 0, &ctrl, sizeof(ctrl));
+ if (s != sizeof(ctrl)) {
+ error_report("Invalid ebpf prog control buffer");
+ goto err;
+ }
+
+ if (ctrl.cmd == VIRTIO_NET_BPF_CMD_SET_OFFLOAD) {
+ s = iov_to_buf(iov, iov_cnt, sizeof(ctrl), prog, sizeof(prog));
+ if (s != ctrl.len) {
+ error_report("Invalid ebpf prog control buffer");
+ goto err;
+ }
+
+ err = peer_attach_ebpf(n, s, prog, ctrl.gpl_compatible);
+ if (err) {
+ error_report("Failed to attach XDP program");
+ goto err;
+ }
+ } else if (ctrl.cmd == VIRTIO_NET_BPF_CMD_UNSET_OFFLOAD) {
+ err = peer_attach_ebpf(n, 0, NULL, 0);
+ }
+err:
+ return err ? VIRTIO_NET_ERR : VIRTIO_NET_OK;
+#else
+ return VIRTIO_NET_ERR;
+#endif
+}
+
+static int virtio_net_handle_ebpf(VirtIONet *n, uint8_t cmd,
+ struct iovec *iov, unsigned int iov_cnt)
+{
+ if (cmd == VIRTIO_NET_CTRL_EBPF_PROG) {
+ return virtio_net_handle_ebpf_prog(n, iov, iov_cnt);
+ }
+
+ return VIRTIO_NET_ERR;
+}
+
static int virtio_net_handle_mac(VirtIONet *n, uint8_t cmd,
struct iovec *iov, unsigned int iov_cnt)
{
@@ -1208,6 +1275,8 @@ static void virtio_net_handle_ctrl(VirtIODevice *vdev,
VirtQueue *vq)
status = virtio_net_handle_mq(n, ctrl.cmd, iov, iov_cnt);
} else if (ctrl.class == VIRTIO_NET_CTRL_GUEST_OFFLOADS) {
status = virtio_net_handle_offloads(n, ctrl.cmd, iov, iov_cnt);
+ } else if (ctrl.class == VIRTIO_NET_CTRL_EBPF) {
+ status = virtio_net_handle_ebpf(n, ctrl.cmd, iov, iov_cnt);
}
s = iov_from_buf(elem->in_sg, elem->in_num, 0, &status,
sizeof(status));
diff --git a/include/net/tap.h b/include/net/tap.h
index 5d585515f9..19c507a1c2 100644
--- a/include/net/tap.h
+++ b/include/net/tap.h
@@ -33,6 +33,8 @@ int tap_disable(NetClientState *nc);
int tap_get_fd(NetClientState *nc);
+int tap_attach_ebpf(NetClientState *nc, int len, void *insns, uint8_t gpl);
+
struct vhost_net;
struct vhost_net *tap_get_vhost_net(NetClientState *nc);
diff --git a/include/standard-headers/linux/virtio_net.h
b/include/standard-headers/linux/virtio_net.h
index 260c3681d7..83292c81bc 100644
--- a/include/standard-headers/linux/virtio_net.h
+++ b/include/standard-headers/linux/virtio_net.h
@@ -261,4 +261,31 @@ struct virtio_net_ctrl_mq {
#define VIRTIO_NET_CTRL_GUEST_OFFLOADS 5
#define VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET 0
+/*
+ * Control XDP offloads offloads
+ *
+ * When guest wants to offload XDP program to tap device, it calls
+ * VIRTIO_NET_CTRL_EBPF_PROG along with VIRTIO_NET_BPF_CMD_SET_OFFLOAD
+ * subcommands. When offloading is successful, the tap device run offloaded
+ * XDP program for each packet before sending it to the guest.
+ *
+ * VIRTIO_NET_BPF_CMD_UNSET_OFFLOAD removes the the offloaded program from
+ * the tap device, if exists.
+ */
+
+struct virtio_net_ctrl_ebpf_prog {
+ /* program length in bytes */
+ __virtio32 len;
+ __virtio16 cmd;
+ __virtio16 gpl_compatible;
+ uint8_t insns[0];
+};
+
+#define VIRTIO_NET_CTRL_EBPF 6
+ #define VIRTIO_NET_CTRL_EBPF_PROG 1
+
+/* Commands for VIRTIO_NET_CTRL_EBPF_PROG */
+#define VIRTIO_NET_BPF_CMD_SET_OFFLOAD 1
+#define VIRTIO_NET_BPF_CMD_UNSET_OFFLOAD 2
+
#endif /* _LINUX_VIRTIO_NET_H */
diff --git a/net/Makefile.objs b/net/Makefile.objs
index c5d076d19c..e7645225be 100644
--- a/net/Makefile.objs
+++ b/net/Makefile.objs
@@ -28,5 +28,6 @@ common-obj-$(CONFIG_POSIX) += tap.o $(tap-obj-y)
common-obj-$(CONFIG_WIN32) += tap-win32.o
vde.o-libs = $(VDE_LIBS)
+tap-linux.o-libs = $(LIBBPF_LIBS)
common-obj-$(CONFIG_CAN_BUS) += can/
diff --git a/net/tap-bsd.c b/net/tap-bsd.c
index a5c3707f80..e4e2a5c799 100644
--- a/net/tap-bsd.c
+++ b/net/tap-bsd.c
@@ -259,3 +259,8 @@ int tap_fd_get_ifname(int fd, char *ifname)
{
return -1;
}
+
+int tap_fd_attach_ebpf(int fd, int len, void *insns, uint8_t gpl)
+{
+ return -EINVAL;
+}
diff --git a/net/tap-linux.c b/net/tap-linux.c
index e0dd442ee3..3ff806bf4f 100644
--- a/net/tap-linux.c
+++ b/net/tap-linux.c
@@ -31,6 +31,8 @@
#include <net/if.h>
#include <sys/ioctl.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
#include "qapi/error.h"
#include "qemu/error-report.h"
@@ -314,3 +316,49 @@ int tap_fd_get_ifname(int fd, char *ifname)
pstrcpy(ifname, sizeof(ifr.ifr_name), ifr.ifr_name);
return 0;
}
+
+int tap_fd_attach_ebpf(int fd, int len, void *insns, uint8_t gpl)
+{
+#ifdef CONFIG_LIBBPF
+ struct bpf_insn *prog = (struct bpf_insn *)insns;
+ static char log_buf[65536];
+ char license[16] = {0};
+ int num_insn;
+ int bpf_fd;
+ int ret;
+
+ if (!prog) {
+ bpf_fd = -1;
+ ret = ioctl(fd, TUNSETOFFLOADEDXDP, &bpf_fd);
+ if (ret) {
+ error_report("Failed to remove offloaded XDP: %s",
strerror(errno));
+ return -EFAULT;
+ }
+ return ret;
+ }
+
+ num_insn = len / sizeof(prog[0]);
+ if (gpl) {
+ strncpy(license, "GPL", sizeof(license));
+ }
+
+ bpf_fd = bpf_load_program(BPF_PROG_TYPE_XDP, prog, num_insn, license,
+ 0, log_buf, sizeof(log_buf));
+ if (bpf_fd < 0) {
+ error_report("Failed to load XDP program: %s", strerror(errno));
+ error_report("ebpf verifier log: %s", log_buf);
+ return -EFAULT;
+ }
+
+ ret = ioctl(fd, TUNSETOFFLOADEDXDP, &bpf_fd);
+ if (ret) {
+ error_report("Failed to set offloaded XDP: %s", strerror(errno));
+ return -EFAULT;
+ }
+ close(bpf_fd);
+
+ return ret;
+#else
+ return -EINVAL;
+#endif
+}
diff --git a/net/tap-linux.h b/net/tap-linux.h
index 2f36d100fc..791aeaebc4 100644
--- a/net/tap-linux.h
+++ b/net/tap-linux.h
@@ -31,6 +31,7 @@
#define TUNSETQUEUE _IOW('T', 217, int)
#define TUNSETVNETLE _IOW('T', 220, int)
#define TUNSETVNETBE _IOW('T', 222, int)
+#define TUNSETOFFLOADEDXDP _IOW('T', 228, int)
#endif
diff --git a/net/tap-solaris.c b/net/tap-solaris.c
index 4725d2314e..38b9136b5f 100644
--- a/net/tap-solaris.c
+++ b/net/tap-solaris.c
@@ -254,3 +254,8 @@ int tap_fd_get_ifname(int fd, char *ifname)
{
return -1;
}
+
+int tap_fd_attach_ebpf(int fd, int len, void *insns, uint8_t gpl)
+{
+ return -EINVAL;
+}
diff --git a/net/tap-stub.c b/net/tap-stub.c
index a9ab8f8293..5f4161b390 100644
--- a/net/tap-stub.c
+++ b/net/tap-stub.c
@@ -85,3 +85,8 @@ int tap_fd_get_ifname(int fd, char *ifname)
{
return -1;
}
+
+int tap_fd_attach_ebpf(int fd, int len, void *insns, uint8_t gpl)
+{
+ return -EINVAL;
+}
diff --git a/net/tap.c b/net/tap.c
index 6207f61f84..3dba8eacb1 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -971,6 +971,13 @@ int tap_enable(NetClientState *nc)
}
}
+int tap_attach_ebpf(NetClientState *nc, int len, void *insns, uint8_t gpl)
+{
+ TAPState *s = DO_UPCAST(TAPState, nc, nc);
+
+ return tap_fd_attach_ebpf(s->fd, len, insns, gpl);
+}
+
int tap_disable(NetClientState *nc)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
diff --git a/net/tap_int.h b/net/tap_int.h
index e3194b23f4..af641607e2 100644
--- a/net/tap_int.h
+++ b/net/tap_int.h
@@ -44,5 +44,6 @@ int tap_fd_set_vnet_be(int fd, int vnet_is_be);
int tap_fd_enable(int fd);
int tap_fd_disable(int fd);
int tap_fd_get_ifname(int fd, char *ifname);
+int tap_fd_attach_ebpf(int fd, int len, void *insns, uint8_t gpl);
#endif /* NET_TAP_INT_H */
--
2.20.1