vhost-user: introduce vhost-user API

Add vhost_user.c and vhost_user.h that define the functions needed
to implement vhost-user backend.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Makefile

@@ -47,7 +47,7 @@ FLAGS += -DDUAL_STACK_SOCKETS=$(DUAL_STACK_SOCKETS)
 PASST_SRCS = arch.c arp.c checksum.c conf.c dhcp.c dhcpv6.c flow.c fwd.c \
 	icmp.c igmp.c inany.c iov.c ip.c isolation.c lineread.c log.c mld.c \
 	ndp.c netlink.c packet.c passt.c pasta.c pcap.c pif.c tap.c tcp.c \
-	tcp_buf.c tcp_splice.c udp.c util.c virtio.c
+	tcp_buf.c tcp_splice.c udp.c util.c vhost_user.c virtio.c
 QRAP_SRCS = qrap.c
 SRCS = $(PASST_SRCS) $(QRAP_SRCS)
 
@@ -56,7 +56,8 @@ MANPAGES = passt.1 pasta.1 qrap.1
 PASST_HEADERS = arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h flow.h fwd.h \
 	flow_table.h icmp.h inany.h iov.h ip.h isolation.h lineread.h log.h \
 	ndp.h netlink.h packet.h passt.h pasta.h pcap.h pif.h siphash.h tap.h \
-	tcp.h tcp_buf.h tcp_conn.h tcp_splice.h udp.h util.h virtio.h
+	tcp.h tcp_buf.h tcp_conn.h tcp_splice.h udp.h util.h vhost_user.h \
+	virtio.h
 HEADERS = $(PASST_HEADERS) seccomp.h
 
 C := \#include <linux/tcp.h>\nstruct tcp_info x = { .tcpi_snd_wnd = 0 };

passt.c

@@ -73,6 +73,8 @@ char *epoll_type_str[] = {
 	[EPOLL_TYPE_TAP_PASTA]		= "/dev/net/tun device",
 	[EPOLL_TYPE_TAP_PASST]		= "connected qemu socket",
 	[EPOLL_TYPE_TAP_LISTEN]		= "listening qemu socket",
+	[EPOLL_TYPE_VHOST_CMD]		= "vhost-user command socket",
+	[EPOLL_TYPE_VHOST_KICK]		= "vhost-user kick socket",
 };
 static_assert(ARRAY_SIZE(epoll_type_str) == EPOLL_NUM_TYPES,
 	      "epoll_type_str[] doesn't match enum epoll_type");

passt.h

@@ -42,6 +42,7 @@ union epoll_ref;
 #include "fwd.h"
 #include "tcp.h"
 #include "udp.h"
+#include "vhost_user.h"
 
 /**
  * enum epoll_type - Different types of fds we poll over
@@ -73,6 +74,10 @@ enum epoll_type {
 	EPOLL_TYPE_TAP_PASST,
 	/* socket listening for qemu socket connections */
 	EPOLL_TYPE_TAP_LISTEN,
+	/* vhost-user command socket */
+	EPOLL_TYPE_VHOST_CMD,
+	/* vhost-user kick event socket */
+	EPOLL_TYPE_VHOST_KICK,
 
 	EPOLL_NUM_TYPES,
 };
@@ -307,6 +312,9 @@ struct ctx {
 
 	int low_wmem;
 	int low_rmem;
+
+	/* vhost-user */
+	struct VuDev vdev;
 };
 
 void proto_update_l2_buf(const unsigned char *eth_d,

tap.c

@@ -1054,7 +1054,7 @@ void packet_add_all_do(struct ctx *c, ssize_t len, char *p,
  * tap_sock_reset() - Handle closing or failure of connect AF_UNIX socket
  * @c:		Execution context
  */
-static void tap_sock_reset(struct ctx *c)
+void tap_sock_reset(struct ctx *c)
 {
 	if (c->one_off) {
 		info("Client closed connection, exiting");

tap.h

@@ -97,12 +97,15 @@ void tap_handler_pasta(struct ctx *c, uint32_t events,
 		       const struct timespec *now);
 void tap_handler_passt(struct ctx *c, uint32_t events,
 		       const struct timespec *now);
+void tap_sock_reset(struct ctx *c);
 void tap_sock_init(struct ctx *c);
 void pool_flush_all(void);
 void tap_handler_all(struct ctx *c, const struct timespec *now);
 
 void packet_add_do(struct pool *p, size_t len, const char *start,
 		   const char *func, int line);
+void packet_add_all_do(struct ctx *c, ssize_t len, char *p,
+		       const char *func, int line);
 #define packet_add_all(p, len, start)					\
 	packet_add_all_do(p, len, start, __func__, __LINE__)
 

vhost_user.h

@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/* some parts from subprojects/libvhost-user/libvhost-user.h */
+
+#ifndef VHOST_USER_H
+#define VHOST_USER_H
+
+#include "virtio.h"
+#include "iov.h"
+
+#define VHOST_USER_F_PROTOCOL_FEATURES 30
+
+#define VHOST_MEMORY_BASELINE_NREGIONS 8
+
+enum vhost_user_protocol_feature {
+	VHOST_USER_PROTOCOL_F_MQ = 0,
+	VHOST_USER_PROTOCOL_F_LOG_SHMFD = 1,
+	VHOST_USER_PROTOCOL_F_RARP = 2,
+	VHOST_USER_PROTOCOL_F_REPLY_ACK = 3,
+	VHOST_USER_PROTOCOL_F_NET_MTU = 4,
+	VHOST_USER_PROTOCOL_F_BACKEND_REQ = 5,
+	VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6,
+	VHOST_USER_PROTOCOL_F_CRYPTO_SESSION = 7,
+	VHOST_USER_PROTOCOL_F_PAGEFAULT = 8,
+	VHOST_USER_PROTOCOL_F_CONFIG = 9,
+	VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD = 10,
+	VHOST_USER_PROTOCOL_F_HOST_NOTIFIER = 11,
+	VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD = 12,
+	VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14,
+	VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15,
+
+	VHOST_USER_PROTOCOL_F_MAX
+};
+
+enum vhost_user_request {
+	VHOST_USER_NONE = 0,
+	VHOST_USER_GET_FEATURES = 1,
+	VHOST_USER_SET_FEATURES = 2,
+	VHOST_USER_SET_OWNER = 3,
+	VHOST_USER_RESET_OWNER = 4,
+	VHOST_USER_SET_MEM_TABLE = 5,
+	VHOST_USER_SET_LOG_BASE = 6,
+	VHOST_USER_SET_LOG_FD = 7,
+	VHOST_USER_SET_VRING_NUM = 8,
+	VHOST_USER_SET_VRING_ADDR = 9,
+	VHOST_USER_SET_VRING_BASE = 10,
+	VHOST_USER_GET_VRING_BASE = 11,
+	VHOST_USER_SET_VRING_KICK = 12,
+	VHOST_USER_SET_VRING_CALL = 13,
+	VHOST_USER_SET_VRING_ERR = 14,
+	VHOST_USER_GET_PROTOCOL_FEATURES = 15,
+	VHOST_USER_SET_PROTOCOL_FEATURES = 16,
+	VHOST_USER_GET_QUEUE_NUM = 17,
+	VHOST_USER_SET_VRING_ENABLE = 18,
+	VHOST_USER_SEND_RARP = 19,
+	VHOST_USER_NET_SET_MTU = 20,
+	VHOST_USER_SET_BACKEND_REQ_FD = 21,
+	VHOST_USER_IOTLB_MSG = 22,
+	VHOST_USER_SET_VRING_ENDIAN = 23,
+	VHOST_USER_GET_CONFIG = 24,
+	VHOST_USER_SET_CONFIG = 25,
+	VHOST_USER_CREATE_CRYPTO_SESSION = 26,
+	VHOST_USER_CLOSE_CRYPTO_SESSION = 27,
+	VHOST_USER_POSTCOPY_ADVISE  = 28,
+	VHOST_USER_POSTCOPY_LISTEN  = 29,
+	VHOST_USER_POSTCOPY_END     = 30,
+	VHOST_USER_GET_INFLIGHT_FD = 31,
+	VHOST_USER_SET_INFLIGHT_FD = 32,
+	VHOST_USER_GPU_SET_SOCKET = 33,
+	VHOST_USER_VRING_KICK = 35,
+	VHOST_USER_GET_MAX_MEM_SLOTS = 36,
+	VHOST_USER_ADD_MEM_REG = 37,
+	VHOST_USER_REM_MEM_REG = 38,
+	VHOST_USER_MAX
+};
+
+typedef struct {
+	enum vhost_user_request request;
+
+#define VHOST_USER_VERSION_MASK     0x3
+#define VHOST_USER_REPLY_MASK       (0x1 << 2)
+#define VHOST_USER_NEED_REPLY_MASK  (0x1 << 3)
+	uint32_t flags;
+	uint32_t size; /* the following payload size */
+} __attribute__ ((__packed__)) vhost_user_header;
+
+typedef struct VhostUserMemory_region {
+	uint64_t guest_phys_addr;
+	uint64_t memory_size;
+	uint64_t userspace_addr;
+	uint64_t mmap_offset;
+} VhostUserMemory_region;
+
+struct VhostUserMemory {
+	uint32_t nregions;
+	uint32_t padding;
+	struct VhostUserMemory_region regions[VHOST_MEMORY_BASELINE_NREGIONS];
+};
+
+typedef union {
+#define VHOST_USER_VRING_IDX_MASK   0xff
+#define VHOST_USER_VRING_NOFD_MASK  (0x1 << 8)
+	uint64_t u64;
+	struct vhost_vring_state state;
+	struct vhost_vring_addr addr;
+	struct VhostUserMemory memory;
+} vhost_user_payload;
+
+typedef struct VhostUserMsg {
+	vhost_user_header hdr;
+	vhost_user_payload payload;
+
+	int fds[VHOST_MEMORY_BASELINE_NREGIONS];
+	int fd_num;
+	uint8_t *data;
+} __attribute__ ((__packed__)) VhostUserMsg;
+#define VHOST_USER_HDR_SIZE sizeof(vhost_user_header)
+
+#define VHOST_USER_RX_QUEUE 0
+#define VHOST_USER_TX_QUEUE 1
+
+static inline bool vu_queue_enabled(VuVirtq *vq)
+{
+	return vq->enable;
+}
+
+static inline bool vu_queue_started(const VuVirtq *vq)
+{
+	return vq->started;
+}
+
+size_t tap_send_frames_vu(const struct ctx *c, const struct iovec *iov,
+			  size_t n);
+int vu_send(const struct ctx *c, const void *data, size_t len);
+void vu_print_capabilities(void);
+void vu_init(struct ctx *c);
+void vu_kick_cb(struct ctx *c, union epoll_ref ref);
+void tap_handler_vu(struct ctx *c, uint32_t events);
+#endif /* VHOST_USER_H */