| Message ID | 1501017730-12797-4-git-send-email-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 7/25/2017 5:22 PM, Stefano Stabellini wrote: > Send PVCALLS_CONNECT to the backend. Allocate a new ring and evtchn for > the active socket. > > Introduce a data structure to keep track of 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. > > 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. This needs to be documented in the code, not (just) in commit message. > > Convert the struct socket pointer into an uint64_t and use it as id for > the new socket to pass to the backend. > > Signed-off-by: Stefano Stabellini <stefano@aporeto.com> > CC: boris.ostrovsky@oracle.com > CC: jgross@suse.com > --- > drivers/xen/pvcalls-front.c | 177 +++++++++++++++++++++++++++++++++++++++++--- > drivers/xen/pvcalls-front.h | 2 + > 2 files changed, 168 insertions(+), 11 deletions(-) > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > index d1dbcf1..d0f5f42 100644 > --- a/drivers/xen/pvcalls-front.c > +++ b/drivers/xen/pvcalls-front.c > @@ -13,6 +13,10 @@ > */ > > #include <linux/module.h> > +#include <linux/net.h> > +#include <linux/socket.h> > + > +#include <net/sock.h> > > #include <xen/events.h> > #include <xen/grant_table.h> > @@ -40,6 +44,24 @@ struct pvcalls_bedata { > }; > struct xenbus_device *pvcalls_front_dev; > > +struct sock_mapping { > + bool active_socket; > + struct list_head list; > + struct socket *sock; > + union { > + struct { > + int irq; > + grant_ref_t ref; > + struct pvcalls_data_intf *ring; > + struct pvcalls_data data; > + struct mutex in_mutex; > + struct mutex out_mutex; > + > + wait_queue_head_t inflight_conn_req; > + } active; > + }; > +}; > + > static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) > { > struct xenbus_device *dev = dev_id; > @@ -84,6 +106,18 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) > return IRQ_HANDLED; > } > > +static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map) > +{ > + struct sock_mapping *map = sock_map; > + > + if (map == NULL) > + return IRQ_HANDLED; > + > + wake_up_interruptible(&map->active.inflight_conn_req); > + > + return IRQ_HANDLED; > +} > + > int pvcalls_front_socket(struct socket *sock) > { > struct pvcalls_bedata *bedata; > @@ -137,6 +171,127 @@ int pvcalls_front_socket(struct socket *sock) > return ret; > } > > +static struct sock_mapping *create_active(int *evtchn) > +{ > + struct sock_mapping *map = NULL; > + void *bytes; > + int ret, irq = -1, i; > + > + map = kzalloc(sizeof(*map), GFP_KERNEL); > + if (map == NULL) > + return NULL; > + > + init_waitqueue_head(&map->active.inflight_conn_req); > + > + map->active.ring = (struct pvcalls_data_intf *) > + __get_free_page(GFP_KERNEL | __GFP_ZERO); > + if (map->active.ring == NULL) > + goto out_error; > + memset(map->active.ring, 0, XEN_PAGE_SIZE); > + map->active.ring->ring_order = RING_ORDER; > + bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, > + map->active.ring->ring_order); > + if (bytes == NULL) > + goto out_error; > + for (i = 0; i < (1 << map->active.ring->ring_order); i++) > + map->active.ring->ref[i] = gnttab_grant_foreign_access( > + pvcalls_front_dev->otherend_id, > + pfn_to_gfn(virt_to_pfn(bytes) + i), 0); > + > + map->active.ref = gnttab_grant_foreign_access( > + pvcalls_front_dev->otherend_id, > + pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0); > + > + map->active.data.in = bytes; > + map->active.data.out = bytes + > + XEN_FLEX_RING_SIZE(map->active.ring->ring_order); > + > + ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn); > + if (ret) > + goto out_error; > + irq = bind_evtchn_to_irqhandler(*evtchn, pvcalls_front_conn_handler, > + 0, "pvcalls-frontend", map); > + if (irq < 0) > + goto out_error; > + > + map->active.irq = irq; > + map->active_socket = true; > + mutex_init(&map->active.in_mutex); > + mutex_init(&map->active.out_mutex); > + > + return map; > + > +out_error: > + if (irq >= 0) > + unbind_from_irqhandler(irq, map); > + else if (*evtchn >= 0) > + xenbus_free_evtchn(pvcalls_front_dev, *evtchn); > + kfree(map->active.data.in); > + kfree(map->active.ring); > + kfree(map); > + return NULL; > +} > + > +int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, > + int addr_len, int flags) > +{ > + struct pvcalls_bedata *bedata; > + struct sock_mapping *map = NULL; > + struct xen_pvcalls_request *req; > + int notify, req_id, ret, evtchn; > + > + if (!pvcalls_front_dev) > + return -ENETUNREACH; > + if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM) > + return -ENOTSUPP; > + > + bedata = dev_get_drvdata(&pvcalls_front_dev->dev); > + > + spin_lock(&bedata->pvcallss_lock); > + req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1); > + if (RING_FULL(&bedata->ring) || > + READ_ONCE(bedata->rsp[req_id].req_id) != PVCALLS_INVALID_ID) { > + spin_unlock(&bedata->pvcallss_lock); > + return -EAGAIN; > + } > + > + map = create_active(&evtchn); > + if (!map) { > + spin_unlock(&bedata->pvcallss_lock); > + return -ENOMEM; > + } > + > + req = RING_GET_REQUEST(&bedata->ring, req_id); > + req->req_id = req_id; > + req->cmd = PVCALLS_CONNECT; > + req->u.connect.id = (uint64_t)sock; > + memcpy(req->u.connect.addr, addr, sizeof(*addr)); > + req->u.connect.len = addr_len; > + req->u.connect.flags = flags; > + req->u.connect.ref = map->active.ref; > + req->u.connect.evtchn = evtchn; > + > + list_add_tail(&map->list, &bedata->socket_mappings); > + map->sock = sock; > + WRITE_ONCE(sock->sk->sk_send_head, (void *)map); > + > + bedata->ring.req_prod_pvt++; > + RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); > + spin_unlock(&bedata->pvcallss_lock); > + > + if (notify) > + notify_remote_via_irq(bedata->irq); > + > + wait_event(bedata->inflight_req, > + READ_ONCE(bedata->rsp[req_id].req_id) == req_id); > + > + ret = bedata->rsp[req_id].ret; > + /* read ret, then set this rsp slot to be reused */ > + smp_mb(); > + WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID); > + return ret; > +} > + > static const struct xenbus_device_id pvcalls_front_ids[] = { > { "pvcalls" }, > { "" } > @@ -150,7 +305,7 @@ static int pvcalls_front_remove(struct xenbus_device *dev) > static int pvcalls_front_probe(struct xenbus_device *dev, > const struct xenbus_device_id *id) > { > - int ret = -EFAULT, evtchn, ref = -1, i; > + int ret = -ENOMEM, evtchn, ref = -1, i; > unsigned int max_page_order, function_calls, len; > char *versions; > grant_ref_t gref_head = 0; > @@ -171,15 +326,13 @@ static int pvcalls_front_probe(struct xenbus_device *dev, > return -EINVAL; > } > kfree(versions); > - ret = xenbus_scanf(XBT_NIL, dev->otherend, > - "max-page-order", "%u", &max_page_order); > - if (ret <= 0) > - return -ENODEV; > + max_page_order = xenbus_read_unsigned(dev->otherend, > + "max-page-order", 0); > if (max_page_order < RING_ORDER) > return -ENODEV; > - ret = xenbus_scanf(XBT_NIL, dev->otherend, > - "function-calls", "%u", &function_calls); > - if (ret <= 0 || function_calls != 1) > + function_calls = xenbus_read_unsigned(dev->otherend, > + "function-calls", 0); > + if (function_calls != 1) > return -ENODEV; > pr_info("%s max-page-order is %u\n", __func__, max_page_order); > > @@ -187,6 +340,8 @@ static int pvcalls_front_probe(struct xenbus_device *dev, > if (!bedata) > return -ENOMEM; > > + dev_set_drvdata(&dev->dev, bedata); > + pvcalls_front_dev = dev; > init_waitqueue_head(&bedata->inflight_req); > for (i = 0; i < PVCALLS_NR_REQ_PER_RING; i++) > bedata->rsp[i].req_id = PVCALLS_INVALID_ID; > @@ -214,8 +369,10 @@ static int pvcalls_front_probe(struct xenbus_device *dev, > if (ret < 0) > goto error; > bedata->ref = ref = gnttab_claim_grant_reference(&gref_head); > - if (ref < 0) > + if (ref < 0) { > + ret = ref; > goto error; > + } > gnttab_grant_foreign_access_ref(ref, dev->otherend_id, > virt_to_gfn((void *)sring), 0); > > @@ -246,8 +403,6 @@ static int pvcalls_front_probe(struct xenbus_device *dev, > INIT_LIST_HEAD(&bedata->socket_mappings); > INIT_LIST_HEAD(&bedata->socketpass_mappings); > spin_lock_init(&bedata->pvcallss_lock); > - dev_set_drvdata(&dev->dev, bedata); > - pvcalls_front_dev = dev; > xenbus_switch_state(dev, XenbusStateInitialised); Why are these changes made here and not in the original patch? -boris > > return 0; > diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h > index b7dabed..63b0417 100644 > --- a/drivers/xen/pvcalls-front.h > +++ b/drivers/xen/pvcalls-front.h > @@ -4,5 +4,7 @@ > #include <linux/net.h> > > int pvcalls_front_socket(struct socket *sock); > +int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, > + int addr_len, int flags); > > #endif
On Wed, 26 Jul 2017, Boris Ostrovsky wrote: > On 7/25/2017 5:22 PM, Stefano Stabellini wrote: > > Send PVCALLS_CONNECT to the backend. Allocate a new ring and evtchn for > > the active socket. > > > > Introduce a data structure to keep track of 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. > > > > 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. > > This needs to be documented in the code, not (just) in commit message. I'll add an in-code comment > > > > Convert the struct socket pointer into an uint64_t and use it as id for > > the new socket to pass to the backend. > > > > Signed-off-by: Stefano Stabellini <stefano@aporeto.com> > > CC: boris.ostrovsky@oracle.com > > CC: jgross@suse.com > > --- > > drivers/xen/pvcalls-front.c | 177 > > +++++++++++++++++++++++++++++++++++++++++--- > > drivers/xen/pvcalls-front.h | 2 + > > 2 files changed, 168 insertions(+), 11 deletions(-) > > > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > > index d1dbcf1..d0f5f42 100644 > > --- a/drivers/xen/pvcalls-front.c > > +++ b/drivers/xen/pvcalls-front.c > > @@ -13,6 +13,10 @@ > > */ > > #include <linux/module.h> > > +#include <linux/net.h> > > +#include <linux/socket.h> > > + > > +#include <net/sock.h> > > #include <xen/events.h> > > #include <xen/grant_table.h> > > @@ -40,6 +44,24 @@ struct pvcalls_bedata { > > }; > > struct xenbus_device *pvcalls_front_dev; > > +struct sock_mapping { > > + bool active_socket; > > + struct list_head list; > > + struct socket *sock; > > + union { > > + struct { > > + int irq; > > + grant_ref_t ref; > > + struct pvcalls_data_intf *ring; > > + struct pvcalls_data data; > > + struct mutex in_mutex; > > + struct mutex out_mutex; > > + > > + wait_queue_head_t inflight_conn_req; > > + } active; > > + }; > > +}; > > + > > static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) > > { > > struct xenbus_device *dev = dev_id; > > @@ -84,6 +106,18 @@ static irqreturn_t pvcalls_front_event_handler(int irq, > > void *dev_id) > > return IRQ_HANDLED; > > } > > +static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map) > > +{ > > + struct sock_mapping *map = sock_map; > > + > > + if (map == NULL) > > + return IRQ_HANDLED; > > + > > + wake_up_interruptible(&map->active.inflight_conn_req); > > + > > + return IRQ_HANDLED; > > +} > > + > > int pvcalls_front_socket(struct socket *sock) > > { > > struct pvcalls_bedata *bedata; > > @@ -137,6 +171,127 @@ int pvcalls_front_socket(struct socket *sock) > > return ret; > > } > > +static struct sock_mapping *create_active(int *evtchn) > > +{ > > + struct sock_mapping *map = NULL; > > + void *bytes; > > + int ret, irq = -1, i; > > + > > + map = kzalloc(sizeof(*map), GFP_KERNEL); > > + if (map == NULL) > > + return NULL; > > + > > + init_waitqueue_head(&map->active.inflight_conn_req); > > + > > + map->active.ring = (struct pvcalls_data_intf *) > > + __get_free_page(GFP_KERNEL | __GFP_ZERO); > > + if (map->active.ring == NULL) > > + goto out_error; > > + memset(map->active.ring, 0, XEN_PAGE_SIZE); > > + map->active.ring->ring_order = RING_ORDER; > > + bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, > > + map->active.ring->ring_order); > > + if (bytes == NULL) > > + goto out_error; > > + for (i = 0; i < (1 << map->active.ring->ring_order); i++) > > + map->active.ring->ref[i] = gnttab_grant_foreign_access( > > + pvcalls_front_dev->otherend_id, > > + pfn_to_gfn(virt_to_pfn(bytes) + i), 0); > > + > > + map->active.ref = gnttab_grant_foreign_access( > > + pvcalls_front_dev->otherend_id, > > + pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0); > > + > > + map->active.data.in = bytes; > > + map->active.data.out = bytes + > > + XEN_FLEX_RING_SIZE(map->active.ring->ring_order); > > + > > + ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn); > > + if (ret) > > + goto out_error; > > + irq = bind_evtchn_to_irqhandler(*evtchn, pvcalls_front_conn_handler, > > + 0, "pvcalls-frontend", map); > > + if (irq < 0) > > + goto out_error; > > + > > + map->active.irq = irq; > > + map->active_socket = true; > > + mutex_init(&map->active.in_mutex); > > + mutex_init(&map->active.out_mutex); > > + > > + return map; > > + > > +out_error: > > + if (irq >= 0) > > + unbind_from_irqhandler(irq, map); > > + else if (*evtchn >= 0) > > + xenbus_free_evtchn(pvcalls_front_dev, *evtchn); > > + kfree(map->active.data.in); > > + kfree(map->active.ring); > > + kfree(map); > > + return NULL; > > +} > > + > > +int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, > > + int addr_len, int flags) > > +{ > > + struct pvcalls_bedata *bedata; > > + struct sock_mapping *map = NULL; > > + struct xen_pvcalls_request *req; > > + int notify, req_id, ret, evtchn; > > + > > + if (!pvcalls_front_dev) > > + return -ENETUNREACH; > > + if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM) > > + return -ENOTSUPP; > > + > > + bedata = dev_get_drvdata(&pvcalls_front_dev->dev); > > + > > + spin_lock(&bedata->pvcallss_lock); > > + req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1); > > + if (RING_FULL(&bedata->ring) || > > + READ_ONCE(bedata->rsp[req_id].req_id) != PVCALLS_INVALID_ID) { > > + spin_unlock(&bedata->pvcallss_lock); > > + return -EAGAIN; > > + } > > + > > + map = create_active(&evtchn); > > + if (!map) { > > + spin_unlock(&bedata->pvcallss_lock); > > + return -ENOMEM; > > + } > > + > > + req = RING_GET_REQUEST(&bedata->ring, req_id); > > + req->req_id = req_id; > > + req->cmd = PVCALLS_CONNECT; > > + req->u.connect.id = (uint64_t)sock; > > + memcpy(req->u.connect.addr, addr, sizeof(*addr)); > > + req->u.connect.len = addr_len; > > + req->u.connect.flags = flags; > > + req->u.connect.ref = map->active.ref; > > + req->u.connect.evtchn = evtchn; > > + > > + list_add_tail(&map->list, &bedata->socket_mappings); > > + map->sock = sock; > > + WRITE_ONCE(sock->sk->sk_send_head, (void *)map); > > + > > + bedata->ring.req_prod_pvt++; > > + RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); > > + spin_unlock(&bedata->pvcallss_lock); > > + > > + if (notify) > > + notify_remote_via_irq(bedata->irq); > > + > > + wait_event(bedata->inflight_req, > > + READ_ONCE(bedata->rsp[req_id].req_id) == req_id); > > + > > + ret = bedata->rsp[req_id].ret; > > + /* read ret, then set this rsp slot to be reused */ > > + smp_mb(); > > + WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID); > > + return ret; > > +} > > + > > static const struct xenbus_device_id pvcalls_front_ids[] = { > > { "pvcalls" }, > > { "" } > > @@ -150,7 +305,7 @@ static int pvcalls_front_remove(struct xenbus_device > > *dev) > > static int pvcalls_front_probe(struct xenbus_device *dev, > > const struct xenbus_device_id *id) > > { > > - int ret = -EFAULT, evtchn, ref = -1, i; > > + int ret = -ENOMEM, evtchn, ref = -1, i; > > unsigned int max_page_order, function_calls, len; > > char *versions; > > grant_ref_t gref_head = 0; > > @@ -171,15 +326,13 @@ static int pvcalls_front_probe(struct xenbus_device > > *dev, > > return -EINVAL; > > } > > kfree(versions); > > - ret = xenbus_scanf(XBT_NIL, dev->otherend, > > - "max-page-order", "%u", &max_page_order); > > - if (ret <= 0) > > - return -ENODEV; > > + max_page_order = xenbus_read_unsigned(dev->otherend, > > + "max-page-order", 0); > > if (max_page_order < RING_ORDER) > > return -ENODEV; > > - ret = xenbus_scanf(XBT_NIL, dev->otherend, > > - "function-calls", "%u", &function_calls); > > - if (ret <= 0 || function_calls != 1) > > + function_calls = xenbus_read_unsigned(dev->otherend, > > + "function-calls", 0); > > + if (function_calls != 1) > > return -ENODEV; > > pr_info("%s max-page-order is %u\n", __func__, max_page_order); > > @@ -187,6 +340,8 @@ static int pvcalls_front_probe(struct xenbus_device > > *dev, > > if (!bedata) > > return -ENOMEM; > > + dev_set_drvdata(&dev->dev, bedata); > > + pvcalls_front_dev = dev; > > init_waitqueue_head(&bedata->inflight_req); > > for (i = 0; i < PVCALLS_NR_REQ_PER_RING; i++) > > bedata->rsp[i].req_id = PVCALLS_INVALID_ID; > > @@ -214,8 +369,10 @@ static int pvcalls_front_probe(struct xenbus_device > > *dev, > > if (ret < 0) > > goto error; > > bedata->ref = ref = gnttab_claim_grant_reference(&gref_head); > > - if (ref < 0) > > + if (ref < 0) { > > + ret = ref; > > goto error; > > + } > > gnttab_grant_foreign_access_ref(ref, dev->otherend_id, > > virt_to_gfn((void *)sring), 0); > > @@ -246,8 +403,6 @@ static int pvcalls_front_probe(struct xenbus_device > > *dev, > > INIT_LIST_HEAD(&bedata->socket_mappings); > > INIT_LIST_HEAD(&bedata->socketpass_mappings); > > spin_lock_init(&bedata->pvcallss_lock); > > - dev_set_drvdata(&dev->dev, bedata); > > - pvcalls_front_dev = dev; > > xenbus_switch_state(dev, XenbusStateInitialised); > > Why are these changes made here and not in the original patch? I made a mistake in updating the patches for v2 :-( I'll fix it. > > return 0; > > diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h > > index b7dabed..63b0417 100644 > > --- a/drivers/xen/pvcalls-front.h > > +++ b/drivers/xen/pvcalls-front.h > > @@ -4,5 +4,7 @@ > > #include <linux/net.h> > > int pvcalls_front_socket(struct socket *sock); > > +int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, > > + int addr_len, int flags); > > #endif >
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index d1dbcf1..d0f5f42 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -13,6 +13,10 @@ */ #include <linux/module.h> +#include <linux/net.h> +#include <linux/socket.h> + +#include <net/sock.h> #include <xen/events.h> #include <xen/grant_table.h> @@ -40,6 +44,24 @@ struct pvcalls_bedata { }; struct xenbus_device *pvcalls_front_dev; +struct sock_mapping { + bool active_socket; + struct list_head list; + struct socket *sock; + union { + struct { + int irq; + grant_ref_t ref; + struct pvcalls_data_intf *ring; + struct pvcalls_data data; + struct mutex in_mutex; + struct mutex out_mutex; + + wait_queue_head_t inflight_conn_req; + } active; + }; +}; + static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) { struct xenbus_device *dev = dev_id; @@ -84,6 +106,18 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) return IRQ_HANDLED; } +static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map) +{ + struct sock_mapping *map = sock_map; + + if (map == NULL) + return IRQ_HANDLED; + + wake_up_interruptible(&map->active.inflight_conn_req); + + return IRQ_HANDLED; +} + int pvcalls_front_socket(struct socket *sock) { struct pvcalls_bedata *bedata; @@ -137,6 +171,127 @@ int pvcalls_front_socket(struct socket *sock) return ret; } +static struct sock_mapping *create_active(int *evtchn) +{ + struct sock_mapping *map = NULL; + void *bytes; + int ret, irq = -1, i; + + map = kzalloc(sizeof(*map), GFP_KERNEL); + if (map == NULL) + return NULL; + + init_waitqueue_head(&map->active.inflight_conn_req); + + map->active.ring = (struct pvcalls_data_intf *) + __get_free_page(GFP_KERNEL | __GFP_ZERO); + if (map->active.ring == NULL) + goto out_error; + memset(map->active.ring, 0, XEN_PAGE_SIZE); + map->active.ring->ring_order = RING_ORDER; + bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, + map->active.ring->ring_order); + if (bytes == NULL) + goto out_error; + for (i = 0; i < (1 << map->active.ring->ring_order); i++) + map->active.ring->ref[i] = gnttab_grant_foreign_access( + pvcalls_front_dev->otherend_id, + pfn_to_gfn(virt_to_pfn(bytes) + i), 0); + + map->active.ref = gnttab_grant_foreign_access( + pvcalls_front_dev->otherend_id, + pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0); + + map->active.data.in = bytes; + map->active.data.out = bytes + + XEN_FLEX_RING_SIZE(map->active.ring->ring_order); + + ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn); + if (ret) + goto out_error; + irq = bind_evtchn_to_irqhandler(*evtchn, pvcalls_front_conn_handler, + 0, "pvcalls-frontend", map); + if (irq < 0) + goto out_error; + + map->active.irq = irq; + map->active_socket = true; + mutex_init(&map->active.in_mutex); + mutex_init(&map->active.out_mutex); + + return map; + +out_error: + if (irq >= 0) + unbind_from_irqhandler(irq, map); + else if (*evtchn >= 0) + xenbus_free_evtchn(pvcalls_front_dev, *evtchn); + kfree(map->active.data.in); + kfree(map->active.ring); + kfree(map); + return NULL; +} + +int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, + int addr_len, int flags) +{ + struct pvcalls_bedata *bedata; + struct sock_mapping *map = NULL; + struct xen_pvcalls_request *req; + int notify, req_id, ret, evtchn; + + if (!pvcalls_front_dev) + return -ENETUNREACH; + if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM) + return -ENOTSUPP; + + bedata = dev_get_drvdata(&pvcalls_front_dev->dev); + + spin_lock(&bedata->pvcallss_lock); + req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1); + if (RING_FULL(&bedata->ring) || + READ_ONCE(bedata->rsp[req_id].req_id) != PVCALLS_INVALID_ID) { + spin_unlock(&bedata->pvcallss_lock); + return -EAGAIN; + } + + map = create_active(&evtchn); + if (!map) { + spin_unlock(&bedata->pvcallss_lock); + return -ENOMEM; + } + + req = RING_GET_REQUEST(&bedata->ring, req_id); + req->req_id = req_id; + req->cmd = PVCALLS_CONNECT; + req->u.connect.id = (uint64_t)sock; + memcpy(req->u.connect.addr, addr, sizeof(*addr)); + req->u.connect.len = addr_len; + req->u.connect.flags = flags; + req->u.connect.ref = map->active.ref; + req->u.connect.evtchn = evtchn; + + list_add_tail(&map->list, &bedata->socket_mappings); + map->sock = sock; + WRITE_ONCE(sock->sk->sk_send_head, (void *)map); + + bedata->ring.req_prod_pvt++; + RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); + spin_unlock(&bedata->pvcallss_lock); + + if (notify) + notify_remote_via_irq(bedata->irq); + + wait_event(bedata->inflight_req, + READ_ONCE(bedata->rsp[req_id].req_id) == req_id); + + ret = bedata->rsp[req_id].ret; + /* read ret, then set this rsp slot to be reused */ + smp_mb(); + WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID); + return ret; +} + static const struct xenbus_device_id pvcalls_front_ids[] = { { "pvcalls" }, { "" } @@ -150,7 +305,7 @@ static int pvcalls_front_remove(struct xenbus_device *dev) static int pvcalls_front_probe(struct xenbus_device *dev, const struct xenbus_device_id *id) { - int ret = -EFAULT, evtchn, ref = -1, i; + int ret = -ENOMEM, evtchn, ref = -1, i; unsigned int max_page_order, function_calls, len; char *versions; grant_ref_t gref_head = 0; @@ -171,15 +326,13 @@ static int pvcalls_front_probe(struct xenbus_device *dev, return -EINVAL; } kfree(versions); - ret = xenbus_scanf(XBT_NIL, dev->otherend, - "max-page-order", "%u", &max_page_order); - if (ret <= 0) - return -ENODEV; + max_page_order = xenbus_read_unsigned(dev->otherend, + "max-page-order", 0); if (max_page_order < RING_ORDER) return -ENODEV; - ret = xenbus_scanf(XBT_NIL, dev->otherend, - "function-calls", "%u", &function_calls); - if (ret <= 0 || function_calls != 1) + function_calls = xenbus_read_unsigned(dev->otherend, + "function-calls", 0); + if (function_calls != 1) return -ENODEV; pr_info("%s max-page-order is %u\n", __func__, max_page_order); @@ -187,6 +340,8 @@ static int pvcalls_front_probe(struct xenbus_device *dev, if (!bedata) return -ENOMEM; + dev_set_drvdata(&dev->dev, bedata); + pvcalls_front_dev = dev; init_waitqueue_head(&bedata->inflight_req); for (i = 0; i < PVCALLS_NR_REQ_PER_RING; i++) bedata->rsp[i].req_id = PVCALLS_INVALID_ID; @@ -214,8 +369,10 @@ static int pvcalls_front_probe(struct xenbus_device *dev, if (ret < 0) goto error; bedata->ref = ref = gnttab_claim_grant_reference(&gref_head); - if (ref < 0) + if (ref < 0) { + ret = ref; goto error; + } gnttab_grant_foreign_access_ref(ref, dev->otherend_id, virt_to_gfn((void *)sring), 0); @@ -246,8 +403,6 @@ static int pvcalls_front_probe(struct xenbus_device *dev, INIT_LIST_HEAD(&bedata->socket_mappings); INIT_LIST_HEAD(&bedata->socketpass_mappings); spin_lock_init(&bedata->pvcallss_lock); - dev_set_drvdata(&dev->dev, bedata); - pvcalls_front_dev = dev; xenbus_switch_state(dev, XenbusStateInitialised); return 0; diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h index b7dabed..63b0417 100644 --- a/drivers/xen/pvcalls-front.h +++ b/drivers/xen/pvcalls-front.h @@ -4,5 +4,7 @@ #include <linux/net.h> int pvcalls_front_socket(struct socket *sock); +int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, + int addr_len, int flags); #endif
Send PVCALLS_CONNECT to the backend. Allocate a new ring and evtchn for the active socket. Introduce a data structure to keep track of 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. 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. Convert the struct socket pointer into an uint64_t and use it as id for the new socket to pass to the backend. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com --- drivers/xen/pvcalls-front.c | 177 +++++++++++++++++++++++++++++++++++++++++--- drivers/xen/pvcalls-front.h | 2 + 2 files changed, 168 insertions(+), 11 deletions(-)