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linux-sg2042/drivers/xen/pvcalls-front.h

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xen/pvcalls: implement socket command and handle events Send a PVCALLS_SOCKET command to the backend, use the masked req_prod_pvt as req_id. This way, req_id is guaranteed to be between 0 and PVCALLS_NR_REQ_PER_RING. We already have a slot in the rsp array ready for the response, and there cannot be two outstanding responses with the same req_id. Wait for the response by waiting on the inflight_req waitqueue and check for the req_id field in rsp[req_id]. Use atomic accesses and barriers to read the field. Note that the barriers are simple smp barriers (as opposed to virt barriers) because they are for internal frontend synchronization, not frontend<->backend communication. Once a response is received, clear the corresponding rsp slot by setting req_id to PVCALLS_INVALID_ID. Note that PVCALLS_INVALID_ID is invalid only from the frontend point of view. It is not part of the PVCalls protocol. pvcalls_front_event_handler is in charge of copying responses from the ring to the appropriate rsp slot. It is done by copying the body of the response first, then by copying req_id atomically. After the copies, wake up anybody waiting on waitqueue. socket_lock protects accesses to the ring. Convert the pointer to sock_mapping into an uintptr_t and use it as id for the new socket to pass to the backend. The struct will be fully initialized later on connect or bind. sock->sk->sk_send_head is not used for ip sockets: reuse the field to store a pointer to the struct sock_mapping corresponding to the socket. This way, we can easily get the struct sock_mapping from the struct socket. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:54 +08:00
#ifndef __PVCALLS_FRONT_H__
#define __PVCALLS_FRONT_H__
#include <linux/net.h>
int pvcalls_front_socket(struct socket *sock);
xen/pvcalls: implement connect command Send PVCALLS_CONNECT to the backend. Allocate a new ring and evtchn for the active socket. Introduce fields in struct sock_mapping to keep track of active sockets. Introduce a waitqueue to allow the frontend to wait on data coming from the backend on the active socket (recvmsg command). Two mutexes (one of reads and one for writes) will be used to protect the active socket in and out rings from concurrent accesses. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:55 +08:00
int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
int addr_len, int flags);
xen/pvcalls: implement bind command Send PVCALLS_BIND to the backend. Introduce a new structure, part of struct sock_mapping, to store information specific to passive sockets. Introduce a status field to keep track of the status of the passive socket. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:56 +08:00
int pvcalls_front_bind(struct socket *sock,
struct sockaddr *addr,
int addr_len);
xen/pvcalls: implement listen command Send PVCALLS_LISTEN to the backend. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:57 +08:00
int pvcalls_front_listen(struct socket *sock, int backlog);
xen/pvcalls: implement accept command Introduce a waitqueue to allow only one outstanding accept command at any given time and to implement polling on the passive socket. Introduce a flags field to keep track of in-flight accept and poll commands. Send PVCALLS_ACCEPT to the backend. Allocate a new active socket. Make sure that only one accept command is executed at any given time by setting PVCALLS_FLAG_ACCEPT_INFLIGHT and waiting on the inflight_accept_req waitqueue. Convert the new struct sock_mapping pointer into an uintptr_t and use it as id for the new socket to pass to the backend. Check if the accept call is non-blocking: in that case after sending the ACCEPT command to the backend store the sock_mapping pointer of the new struct and the inflight req_id then return -EAGAIN (which will respond only when there is something to accept). Next time accept is called, we'll check if the ACCEPT command has been answered, if so we'll pick up where we left off, otherwise we return -EAGAIN again. Note that, differently from the other commands, we can use wait_event_interruptible (instead of wait_event) in the case of accept as we are able to track the req_id of the ACCEPT response that we are waiting. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:58 +08:00
int pvcalls_front_accept(struct socket *sock,
struct socket *newsock,
int flags);
xen/pvcalls: implement sendmsg Send data to an active socket by copying data to the "out" ring. Take the active socket out_mutex so that only one function can access the ring at any given time. If not enough room is available on the ring, rather than returning immediately or sleep-waiting, spin for up to 5000 cycles. This small optimization turns out to improve performance significantly. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:59 +08:00
int pvcalls_front_sendmsg(struct socket *sock,
struct msghdr *msg,
size_t len);
xen/pvcalls: implement socket command and handle events Send a PVCALLS_SOCKET command to the backend, use the masked req_prod_pvt as req_id. This way, req_id is guaranteed to be between 0 and PVCALLS_NR_REQ_PER_RING. We already have a slot in the rsp array ready for the response, and there cannot be two outstanding responses with the same req_id. Wait for the response by waiting on the inflight_req waitqueue and check for the req_id field in rsp[req_id]. Use atomic accesses and barriers to read the field. Note that the barriers are simple smp barriers (as opposed to virt barriers) because they are for internal frontend synchronization, not frontend<->backend communication. Once a response is received, clear the corresponding rsp slot by setting req_id to PVCALLS_INVALID_ID. Note that PVCALLS_INVALID_ID is invalid only from the frontend point of view. It is not part of the PVCalls protocol. pvcalls_front_event_handler is in charge of copying responses from the ring to the appropriate rsp slot. It is done by copying the body of the response first, then by copying req_id atomically. After the copies, wake up anybody waiting on waitqueue. socket_lock protects accesses to the ring. Convert the pointer to sock_mapping into an uintptr_t and use it as id for the new socket to pass to the backend. The struct will be fully initialized later on connect or bind. sock->sk->sk_send_head is not used for ip sockets: reuse the field to store a pointer to the struct sock_mapping corresponding to the socket. This way, we can easily get the struct sock_mapping from the struct socket. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-10-31 06:40:54 +08:00
#endif