* [PATCH v6 02/13] xen/pvcalls: implement frontend disconnect
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-25 13:49 ` Boris Ostrovsky
2017-10-24 17:33 ` [PATCH v6 03/13] xen/pvcalls: connect to the backend Stefano Stabellini
` (10 subsequent siblings)
11 siblings, 1 reply; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
Introduce a data structure named pvcalls_bedata. It contains pointers to
the command ring, the event channel, a list of active sockets and a list
of passive sockets. Lists accesses are protected by a spin_lock.
Introduce a waitqueue to allow waiting for a response on commands sent
to the backend.
Introduce an array of struct xen_pvcalls_response to store commands
responses.
pvcalls_refcount is used to keep count of the outstanding pvcalls users.
Only remove connections once the refcount is zero.
Implement pvcalls frontend removal function. Go through the list of
active and passive sockets and free them all, one at a time.
Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
---
drivers/xen/pvcalls-front.c | 65 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index a8d38c2..4babacf 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -20,6 +20,45 @@
#include <xen/xenbus.h>
#include <xen/interface/io/pvcalls.h>
+#define PVCALLS_INVALID_ID UINT_MAX
+#define PVCALLS_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
+#define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE)
+
+struct pvcalls_bedata {
+ struct xen_pvcalls_front_ring ring;
+ grant_ref_t ref;
+ int irq;
+
+ struct list_head socket_mappings;
+ spinlock_t socket_lock;
+
+ wait_queue_head_t inflight_req;
+ struct xen_pvcalls_response rsp[PVCALLS_NR_RSP_PER_RING];
+};
+/* Only one front/back connection supported. */
+static struct xenbus_device *pvcalls_front_dev;
+static atomic_t pvcalls_refcount;
+
+/* first increment refcount, then proceed */
+#define pvcalls_enter() { \
+ atomic_inc(&pvcalls_refcount); \
+}
+
+/* first complete other operations, then decrement refcount */
+#define pvcalls_exit() { \
+ atomic_dec(&pvcalls_refcount); \
+}
+
+static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
+{
+ return IRQ_HANDLED;
+}
+
+static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
+ struct sock_mapping *map, bool locked)
+{
+}
+
static const struct xenbus_device_id pvcalls_front_ids[] = {
{ "pvcalls" },
{ "" }
@@ -27,6 +66,32 @@
static int pvcalls_front_remove(struct xenbus_device *dev)
{
+ struct pvcalls_bedata *bedata;
+ struct sock_mapping *map = NULL, *n;
+
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+ dev_set_drvdata(&dev->dev, NULL);
+ pvcalls_front_dev = NULL;
+ if (bedata->irq >= 0)
+ unbind_from_irqhandler(bedata->irq, dev);
+
+ smp_mb();
+ while (atomic_read(&pvcalls_refcount) > 0)
+ cpu_relax();
+ list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) {
+ if (map->active_socket) {
+ /* No need to lock, refcount is 0 */
+ pvcalls_front_free_map(bedata, map, true);
+ } else {
+ list_del(&map->list);
+ kfree(map);
+ }
+ }
+ if (bedata->ref >= 0)
+ gnttab_end_foreign_access(bedata->ref, 0, 0);
+ kfree(bedata->ring.sring);
+ kfree(bedata);
+ xenbus_switch_state(dev, XenbusStateClosed);
return 0;
}
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH v6 02/13] xen/pvcalls: implement frontend disconnect
2017-10-24 17:33 ` [PATCH v6 02/13] xen/pvcalls: implement frontend disconnect Stefano Stabellini
@ 2017-10-25 13:49 ` Boris Ostrovsky
2017-10-25 23:22 ` Stefano Stabellini
0 siblings, 1 reply; 22+ messages in thread
From: Boris Ostrovsky @ 2017-10-25 13:49 UTC (permalink / raw)
To: Stefano Stabellini, xen-devel; +Cc: linux-kernel, jgross, Stefano Stabellini
On 10/24/2017 01:33 PM, Stefano Stabellini wrote:
> +static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
> + struct sock_mapping *map, bool locked)
> +{
> +}
> +
> static const struct xenbus_device_id pvcalls_front_ids[] = {
> { "pvcalls" },
> { "" }
> @@ -27,6 +66,32 @@
>
> static int pvcalls_front_remove(struct xenbus_device *dev)
> {
> + struct pvcalls_bedata *bedata;
> + struct sock_mapping *map = NULL, *n;
Your last comment made me look again at sock_mapping definition. And
then I noticed that it is not defined until patch 4 ;-(
-boris
> +
> + bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
> + dev_set_drvdata(&dev->dev, NULL);
> + pvcalls_front_dev = NULL;
> + if (bedata->irq >= 0)
> + unbind_from_irqhandler(bedata->irq, dev);
> +
> + smp_mb();
> + while (atomic_read(&pvcalls_refcount) > 0)
> + cpu_relax();
> + list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) {
> + if (map->active_socket) {
> + /* No need to lock, refcount is 0 */
> + pvcalls_front_free_map(bedata, map, true);
> + } else {
> + list_del(&map->list);
> + kfree(map);
> + }
> + }
> + if (bedata->ref >= 0)
> + gnttab_end_foreign_access(bedata->ref, 0, 0);
> + kfree(bedata->ring.sring);
> + kfree(bedata);
> + xenbus_switch_state(dev, XenbusStateClosed);
> return 0;
> }
>
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH v6 02/13] xen/pvcalls: implement frontend disconnect
2017-10-25 13:49 ` Boris Ostrovsky
@ 2017-10-25 23:22 ` Stefano Stabellini
0 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-25 23:22 UTC (permalink / raw)
To: Boris Ostrovsky
Cc: Stefano Stabellini, xen-devel, linux-kernel, jgross, Stefano Stabellini
On Wed, 25 Oct 2017, Boris Ostrovsky wrote:
> On 10/24/2017 01:33 PM, Stefano Stabellini wrote:
> > +static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
> > + struct sock_mapping *map, bool locked)
> > +{
> > +}
> > +
> > static const struct xenbus_device_id pvcalls_front_ids[] = {
> > { "pvcalls" },
> > { "" }
> > @@ -27,6 +66,32 @@
> >
> > static int pvcalls_front_remove(struct xenbus_device *dev)
> > {
> > + struct pvcalls_bedata *bedata;
> > + struct sock_mapping *map = NULL, *n;
>
> Your last comment made me look again at sock_mapping definition. And
> then I noticed that it is not defined until patch 4 ;-(
I moved the definition of struct sock_mapping to this patch. Then, I
tested the build patch by patch. I also had to move a few #includes from
patch #5 to #4, but everything builds fine now.
> > +
> > + bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
> > + dev_set_drvdata(&dev->dev, NULL);
> > + pvcalls_front_dev = NULL;
> > + if (bedata->irq >= 0)
> > + unbind_from_irqhandler(bedata->irq, dev);
> > +
> > + smp_mb();
> > + while (atomic_read(&pvcalls_refcount) > 0)
> > + cpu_relax();
> > + list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) {
> > + if (map->active_socket) {
> > + /* No need to lock, refcount is 0 */
> > + pvcalls_front_free_map(bedata, map, true);
> > + } else {
> > + list_del(&map->list);
> > + kfree(map);
> > + }
> > + }
> > + if (bedata->ref >= 0)
> > + gnttab_end_foreign_access(bedata->ref, 0, 0);
> > + kfree(bedata->ring.sring);
> > + kfree(bedata);
> > + xenbus_switch_state(dev, XenbusStateClosed);
> > return 0;
> > }
> >
>
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH v6 03/13] xen/pvcalls: connect to the backend
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 02/13] xen/pvcalls: implement frontend disconnect Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 04/13] xen/pvcalls: implement socket command and handle events Stefano Stabellini
` (9 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
Implement the probe function for the pvcalls frontend. Read the
supported versions, max-page-order and function-calls nodes from
xenstore.
Only one frontend<->backend connection is supported at any given time
for a guest. Store the active frontend device to a static pointer.
Introduce a stub functions for the event handler.
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
---
drivers/xen/pvcalls-front.c | 132 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 132 insertions(+)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 4babacf..530ef05 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -98,12 +98,144 @@ 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 = -ENOMEM, evtchn, i;
+ unsigned int max_page_order, function_calls, len;
+ char *versions;
+ grant_ref_t gref_head = 0;
+ struct xenbus_transaction xbt;
+ struct pvcalls_bedata *bedata = NULL;
+ struct xen_pvcalls_sring *sring;
+
+ if (pvcalls_front_dev != NULL) {
+ dev_err(&dev->dev, "only one PV Calls connection supported\n");
+ return -EINVAL;
+ }
+
+ versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len);
+ if (!len)
+ return -EINVAL;
+ if (strcmp(versions, "1")) {
+ kfree(versions);
+ return -EINVAL;
+ }
+ kfree(versions);
+ max_page_order = xenbus_read_unsigned(dev->otherend,
+ "max-page-order", 0);
+ if (max_page_order < PVCALLS_RING_ORDER)
+ return -ENODEV;
+ function_calls = xenbus_read_unsigned(dev->otherend,
+ "function-calls", 0);
+ /* See XENBUS_FUNCTIONS_CALLS in pvcalls.h */
+ if (function_calls != 1)
+ return -ENODEV;
+ pr_info("%s max-page-order is %u\n", __func__, max_page_order);
+
+ bedata = kzalloc(sizeof(struct pvcalls_bedata), GFP_KERNEL);
+ if (!bedata)
+ return -ENOMEM;
+
+ dev_set_drvdata(&dev->dev, bedata);
+ pvcalls_front_dev = dev;
+ init_waitqueue_head(&bedata->inflight_req);
+ INIT_LIST_HEAD(&bedata->socket_mappings);
+ spin_lock_init(&bedata->socket_lock);
+ bedata->irq = -1;
+ bedata->ref = -1;
+
+ for (i = 0; i < PVCALLS_NR_RSP_PER_RING; i++)
+ bedata->rsp[i].req_id = PVCALLS_INVALID_ID;
+
+ sring = (struct xen_pvcalls_sring *) __get_free_page(GFP_KERNEL |
+ __GFP_ZERO);
+ if (!sring)
+ goto error;
+ SHARED_RING_INIT(sring);
+ FRONT_RING_INIT(&bedata->ring, sring, XEN_PAGE_SIZE);
+
+ ret = xenbus_alloc_evtchn(dev, &evtchn);
+ if (ret)
+ goto error;
+
+ bedata->irq = bind_evtchn_to_irqhandler(evtchn,
+ pvcalls_front_event_handler,
+ 0, "pvcalls-frontend", dev);
+ if (bedata->irq < 0) {
+ ret = bedata->irq;
+ goto error;
+ }
+
+ ret = gnttab_alloc_grant_references(1, &gref_head);
+ if (ret < 0)
+ goto error;
+ bedata->ref = gnttab_claim_grant_reference(&gref_head);
+ if (bedata->ref < 0) {
+ ret = bedata->ref;
+ goto error;
+ }
+ gnttab_grant_foreign_access_ref(bedata->ref, dev->otherend_id,
+ virt_to_gfn((void *)sring), 0);
+
+ again:
+ ret = xenbus_transaction_start(&xbt);
+ if (ret) {
+ xenbus_dev_fatal(dev, ret, "starting transaction");
+ goto error;
+ }
+ ret = xenbus_printf(xbt, dev->nodename, "version", "%u", 1);
+ if (ret)
+ goto error_xenbus;
+ ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", bedata->ref);
+ if (ret)
+ goto error_xenbus;
+ ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
+ evtchn);
+ if (ret)
+ goto error_xenbus;
+ ret = xenbus_transaction_end(xbt, 0);
+ if (ret) {
+ if (ret == -EAGAIN)
+ goto again;
+ xenbus_dev_fatal(dev, ret, "completing transaction");
+ goto error;
+ }
+ xenbus_switch_state(dev, XenbusStateInitialised);
+
return 0;
+
+ error_xenbus:
+ xenbus_transaction_end(xbt, 1);
+ xenbus_dev_fatal(dev, ret, "writing xenstore");
+ error:
+ pvcalls_front_remove(dev);
+ return ret;
}
static void pvcalls_front_changed(struct xenbus_device *dev,
enum xenbus_state backend_state)
{
+ switch (backend_state) {
+ case XenbusStateReconfiguring:
+ case XenbusStateReconfigured:
+ case XenbusStateInitialising:
+ case XenbusStateInitialised:
+ case XenbusStateUnknown:
+ break;
+
+ case XenbusStateInitWait:
+ break;
+
+ case XenbusStateConnected:
+ xenbus_switch_state(dev, XenbusStateConnected);
+ break;
+
+ case XenbusStateClosed:
+ if (dev->state == XenbusStateClosed)
+ break;
+ /* Missed the backend's CLOSING state -- fallthrough */
+ case XenbusStateClosing:
+ xenbus_frontend_closed(dev);
+ break;
+ }
}
static struct xenbus_driver pvcalls_front_driver = {
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* [PATCH v6 04/13] xen/pvcalls: implement socket command and handle events
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 02/13] xen/pvcalls: implement frontend disconnect Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 03/13] xen/pvcalls: connect to the backend Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 05/13] xen/pvcalls: implement connect command Stefano Stabellini
` (8 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
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.
Create a new struct sock_mapping and convert the pointer into an
uint64_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. In this patch
the struct sock_mapping is empty, the fields will be added by the next
patch.
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
---
drivers/xen/pvcalls-front.c | 133 ++++++++++++++++++++++++++++++++++++++++++++
drivers/xen/pvcalls-front.h | 8 +++
2 files changed, 141 insertions(+)
create mode 100644 drivers/xen/pvcalls-front.h
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 530ef05..8b39be5 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -20,6 +20,8 @@
#include <xen/xenbus.h>
#include <xen/interface/io/pvcalls.h>
+#include "pvcalls-front.h"
+
#define PVCALLS_INVALID_ID UINT_MAX
#define PVCALLS_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
#define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE)
@@ -49,8 +51,64 @@ struct pvcalls_bedata {
atomic_dec(&pvcalls_refcount); \
}
+struct sock_mapping {
+ bool active_socket;
+ struct list_head list;
+ struct socket *sock;
+};
+
+static inline int get_request(struct pvcalls_bedata *bedata, int *req_id)
+{
+ *req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1);
+ if (RING_FULL(&bedata->ring) ||
+ bedata->rsp[*req_id].req_id != PVCALLS_INVALID_ID)
+ return -EAGAIN;
+ return 0;
+}
+
static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
{
+ struct xenbus_device *dev = dev_id;
+ struct pvcalls_bedata *bedata;
+ struct xen_pvcalls_response *rsp;
+ uint8_t *src, *dst;
+ int req_id = 0, more = 0, done = 0;
+
+ if (dev == NULL)
+ return IRQ_HANDLED;
+
+ pvcalls_enter();
+ bedata = dev_get_drvdata(&dev->dev);
+ if (bedata == NULL) {
+ pvcalls_exit();
+ return IRQ_HANDLED;
+ }
+
+again:
+ while (RING_HAS_UNCONSUMED_RESPONSES(&bedata->ring)) {
+ rsp = RING_GET_RESPONSE(&bedata->ring, bedata->ring.rsp_cons);
+
+ req_id = rsp->req_id;
+ dst = (uint8_t *)&bedata->rsp[req_id] + sizeof(rsp->req_id);
+ src = (uint8_t *)rsp + sizeof(rsp->req_id);
+ memcpy(dst, src, sizeof(*rsp) - sizeof(rsp->req_id));
+ /*
+ * First copy the rest of the data, then req_id. It is
+ * paired with the barrier when accessing bedata->rsp.
+ */
+ smp_wmb();
+ bedata->rsp[req_id].req_id = rsp->req_id;
+
+ done = 1;
+ bedata->ring.rsp_cons++;
+ }
+
+ RING_FINAL_CHECK_FOR_RESPONSES(&bedata->ring, more);
+ if (more)
+ goto again;
+ if (done)
+ wake_up(&bedata->inflight_req);
+ pvcalls_exit();
return IRQ_HANDLED;
}
@@ -59,6 +117,81 @@ static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
{
}
+int pvcalls_front_socket(struct socket *sock)
+{
+ struct pvcalls_bedata *bedata;
+ struct sock_mapping *map = NULL;
+ struct xen_pvcalls_request *req;
+ int notify, req_id, ret;
+
+ /*
+ * PVCalls only supports domain AF_INET,
+ * type SOCK_STREAM and protocol 0 sockets for now.
+ *
+ * Check socket type here, AF_INET and protocol checks are done
+ * by the caller.
+ */
+ if (sock->type != SOCK_STREAM)
+ return -EOPNOTSUPP;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return -EACCES;
+ }
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = kzalloc(sizeof(*map), GFP_KERNEL);
+ if (map == NULL) {
+ pvcalls_exit();
+ return -ENOMEM;
+ }
+
+ spin_lock(&bedata->socket_lock);
+
+ ret = get_request(bedata, &req_id);
+ if (ret < 0) {
+ kfree(map);
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return ret;
+ }
+
+ /*
+ * 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.
+ */
+ sock->sk->sk_send_head = (void *)map;
+ list_add_tail(&map->list, &bedata->socket_mappings);
+
+ req = RING_GET_REQUEST(&bedata->ring, req_id);
+ req->req_id = req_id;
+ req->cmd = PVCALLS_SOCKET;
+ req->u.socket.id = (uint64_t) map;
+ req->u.socket.domain = AF_INET;
+ req->u.socket.type = SOCK_STREAM;
+ req->u.socket.protocol = IPPROTO_IP;
+
+ bedata->ring.req_prod_pvt++;
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
+ spin_unlock(&bedata->socket_lock);
+ if (notify)
+ notify_remote_via_irq(bedata->irq);
+
+ wait_event(bedata->inflight_req,
+ READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
+
+ /* read req_id, then the content */
+ smp_rmb();
+ ret = bedata->rsp[req_id].ret;
+ bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
+
+ pvcalls_exit();
+ return ret;
+}
+
static const struct xenbus_device_id pvcalls_front_ids[] = {
{ "pvcalls" },
{ "" }
diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h
new file mode 100644
index 0000000..b7dabed
--- /dev/null
+++ b/drivers/xen/pvcalls-front.h
@@ -0,0 +1,8 @@
+#ifndef __PVCALLS_FRONT_H__
+#define __PVCALLS_FRONT_H__
+
+#include <linux/net.h>
+
+int pvcalls_front_socket(struct socket *sock);
+
+#endif
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* [PATCH v6 05/13] xen/pvcalls: implement connect command
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
` (2 preceding siblings ...)
2017-10-24 17:33 ` [PATCH v6 04/13] xen/pvcalls: implement socket command and handle events Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 06/13] xen/pvcalls: implement bind command Stefano Stabellini
` (7 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
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
---
drivers/xen/pvcalls-front.c | 162 ++++++++++++++++++++++++++++++++++++++++++++
drivers/xen/pvcalls-front.h | 2 +
2 files changed, 164 insertions(+)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 8b39be5..c426d41 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>
@@ -55,6 +59,18 @@ 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 inline int get_request(struct pvcalls_bedata *bedata, int *req_id)
@@ -117,6 +133,18 @@ static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
{
}
+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;
@@ -192,6 +220,132 @@ int pvcalls_front_socket(struct socket *sock)
return ret;
}
+static int create_active(struct sock_mapping *map, int *evtchn)
+{
+ void *bytes;
+ int ret = -ENOMEM, irq = -1, i;
+
+ *evtchn = -1;
+ 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;
+ map->active.ring->ring_order = PVCALLS_RING_ORDER;
+ bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+ PVCALLS_RING_ORDER);
+ if (bytes == NULL)
+ goto out_error;
+ for (i = 0; i < (1 << PVCALLS_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(PVCALLS_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) {
+ ret = irq;
+ goto out_error;
+ }
+
+ map->active.irq = irq;
+ map->active_socket = true;
+ mutex_init(&map->active.in_mutex);
+ mutex_init(&map->active.out_mutex);
+
+ return 0;
+
+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);
+ return ret;
+}
+
+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 (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
+ return -EOPNOTSUPP;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return -ENOTCONN;
+ }
+
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = (struct sock_mapping *)sock->sk->sk_send_head;
+ if (!map) {
+ pvcalls_exit();
+ return -ENOTSOCK;
+ }
+
+ spin_lock(&bedata->socket_lock);
+ ret = get_request(bedata, &req_id);
+ if (ret < 0) {
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return ret;
+ }
+ ret = create_active(map, &evtchn);
+ if (ret < 0) {
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return ret;
+ }
+
+ req = RING_GET_REQUEST(&bedata->ring, req_id);
+ req->req_id = req_id;
+ req->cmd = PVCALLS_CONNECT;
+ req->u.connect.id = (uint64_t)map;
+ req->u.connect.len = addr_len;
+ req->u.connect.flags = flags;
+ req->u.connect.ref = map->active.ref;
+ req->u.connect.evtchn = evtchn;
+ memcpy(req->u.connect.addr, addr, sizeof(*addr));
+
+ map->sock = sock;
+
+ bedata->ring.req_prod_pvt++;
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
+ spin_unlock(&bedata->socket_lock);
+
+ if (notify)
+ notify_remote_via_irq(bedata->irq);
+
+ wait_event(bedata->inflight_req,
+ READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
+
+ /* read req_id, then the content */
+ smp_rmb();
+ ret = bedata->rsp[req_id].ret;
+ bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
+ pvcalls_exit();
+ return ret;
+}
+
static const struct xenbus_device_id pvcalls_front_ids[] = {
{ "pvcalls" },
{ "" }
@@ -208,6 +362,14 @@ static int pvcalls_front_remove(struct xenbus_device *dev)
if (bedata->irq >= 0)
unbind_from_irqhandler(bedata->irq, dev);
+ list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) {
+ map->sock->sk->sk_send_head = NULL;
+ if (map->active_socket) {
+ map->active.ring->in_error = -EBADF;
+ wake_up_interruptible(&map->active.inflight_conn_req);
+ }
+ }
+
smp_mb();
while (atomic_read(&pvcalls_refcount) > 0)
cpu_relax();
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
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* [PATCH v6 06/13] xen/pvcalls: implement bind command
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
` (3 preceding siblings ...)
2017-10-24 17:33 ` [PATCH v6 05/13] xen/pvcalls: implement connect command Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 07/13] xen/pvcalls: implement listen command Stefano Stabellini
` (6 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
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
---
drivers/xen/pvcalls-front.c | 66 +++++++++++++++++++++++++++++++++++++++++++++
drivers/xen/pvcalls-front.h | 3 +++
2 files changed, 69 insertions(+)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index c426d41..81baebd 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -70,6 +70,13 @@ struct sock_mapping {
wait_queue_head_t inflight_conn_req;
} active;
+ struct {
+ /* Socket status */
+#define PVCALLS_STATUS_UNINITALIZED 0
+#define PVCALLS_STATUS_BIND 1
+#define PVCALLS_STATUS_LISTEN 2
+ uint8_t status;
+ } passive;
};
};
@@ -346,6 +353,65 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
return ret;
}
+int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
+{
+ struct pvcalls_bedata *bedata;
+ struct sock_mapping *map = NULL;
+ struct xen_pvcalls_request *req;
+ int notify, req_id, ret;
+
+ if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
+ return -EOPNOTSUPP;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return -ENOTCONN;
+ }
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = (struct sock_mapping *) sock->sk->sk_send_head;
+ if (map == NULL) {
+ pvcalls_exit();
+ return -ENOTSOCK;
+ }
+
+ spin_lock(&bedata->socket_lock);
+ ret = get_request(bedata, &req_id);
+ if (ret < 0) {
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return ret;
+ }
+ req = RING_GET_REQUEST(&bedata->ring, req_id);
+ req->req_id = req_id;
+ map->sock = sock;
+ req->cmd = PVCALLS_BIND;
+ req->u.bind.id = (uint64_t)map;
+ memcpy(req->u.bind.addr, addr, sizeof(*addr));
+ req->u.bind.len = addr_len;
+
+ map->active_socket = false;
+
+ bedata->ring.req_prod_pvt++;
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
+ spin_unlock(&bedata->socket_lock);
+ if (notify)
+ notify_remote_via_irq(bedata->irq);
+
+ wait_event(bedata->inflight_req,
+ READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
+
+ /* read req_id, then the content */
+ smp_rmb();
+ ret = bedata->rsp[req_id].ret;
+ bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
+
+ map->passive.status = PVCALLS_STATUS_BIND;
+ pvcalls_exit();
+ return 0;
+}
+
static const struct xenbus_device_id pvcalls_front_ids[] = {
{ "pvcalls" },
{ "" }
diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h
index 63b0417..8b0a274 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -6,5 +6,8 @@
int pvcalls_front_socket(struct socket *sock);
int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
int addr_len, int flags);
+int pvcalls_front_bind(struct socket *sock,
+ struct sockaddr *addr,
+ int addr_len);
#endif
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* [PATCH v6 07/13] xen/pvcalls: implement listen command
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
` (4 preceding siblings ...)
2017-10-24 17:33 ` [PATCH v6 06/13] xen/pvcalls: implement bind command Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 08/13] xen/pvcalls: implement accept command Stefano Stabellini
` (5 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
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
---
drivers/xen/pvcalls-front.c | 57 +++++++++++++++++++++++++++++++++++++++++++++
drivers/xen/pvcalls-front.h | 1 +
2 files changed, 58 insertions(+)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 81baebd..f616378 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -412,6 +412,63 @@ int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
return 0;
}
+int pvcalls_front_listen(struct socket *sock, int backlog)
+{
+ struct pvcalls_bedata *bedata;
+ struct sock_mapping *map;
+ struct xen_pvcalls_request *req;
+ int notify, req_id, ret;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return -ENOTCONN;
+ }
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = (struct sock_mapping *) sock->sk->sk_send_head;
+ if (!map) {
+ pvcalls_exit();
+ return -ENOTSOCK;
+ }
+
+ if (map->passive.status != PVCALLS_STATUS_BIND) {
+ pvcalls_exit();
+ return -EOPNOTSUPP;
+ }
+
+ spin_lock(&bedata->socket_lock);
+ ret = get_request(bedata, &req_id);
+ if (ret < 0) {
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return ret;
+ }
+ req = RING_GET_REQUEST(&bedata->ring, req_id);
+ req->req_id = req_id;
+ req->cmd = PVCALLS_LISTEN;
+ req->u.listen.id = (uint64_t) map;
+ req->u.listen.backlog = backlog;
+
+ bedata->ring.req_prod_pvt++;
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
+ spin_unlock(&bedata->socket_lock);
+ if (notify)
+ notify_remote_via_irq(bedata->irq);
+
+ wait_event(bedata->inflight_req,
+ READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
+
+ /* read req_id, then the content */
+ smp_rmb();
+ ret = bedata->rsp[req_id].ret;
+ bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
+
+ map->passive.status = PVCALLS_STATUS_LISTEN;
+ pvcalls_exit();
+ return ret;
+}
+
static const struct xenbus_device_id pvcalls_front_ids[] = {
{ "pvcalls" },
{ "" }
diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h
index 8b0a274..aa8fe10 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -9,5 +9,6 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
int pvcalls_front_bind(struct socket *sock,
struct sockaddr *addr,
int addr_len);
+int pvcalls_front_listen(struct socket *sock, int backlog);
#endif
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* [PATCH v6 08/13] xen/pvcalls: implement accept command
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
` (5 preceding siblings ...)
2017-10-24 17:33 ` [PATCH v6 07/13] xen/pvcalls: implement listen command Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 09/13] xen/pvcalls: implement sendmsg Stefano Stabellini
` (4 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
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 uint64_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
---
drivers/xen/pvcalls-front.c | 145 ++++++++++++++++++++++++++++++++++++++++++++
drivers/xen/pvcalls-front.h | 3 +
2 files changed, 148 insertions(+)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index f616378..507c6a8 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -76,6 +76,16 @@ struct sock_mapping {
#define PVCALLS_STATUS_BIND 1
#define PVCALLS_STATUS_LISTEN 2
uint8_t status;
+ /*
+ * Internal state-machine flags.
+ * Only one accept operation can be inflight for a socket.
+ * Only one poll operation can be inflight for a given socket.
+ */
+#define PVCALLS_FLAG_ACCEPT_INFLIGHT 0
+ uint8_t flags;
+ uint32_t inflight_req_id;
+ struct sock_mapping *accept_map;
+ wait_queue_head_t inflight_accept_req;
} passive;
};
};
@@ -391,6 +401,8 @@ int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
memcpy(req->u.bind.addr, addr, sizeof(*addr));
req->u.bind.len = addr_len;
+ init_waitqueue_head(&map->passive.inflight_accept_req);
+
map->active_socket = false;
bedata->ring.req_prod_pvt++;
@@ -469,6 +481,139 @@ int pvcalls_front_listen(struct socket *sock, int backlog)
return ret;
}
+int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
+{
+ struct pvcalls_bedata *bedata;
+ struct sock_mapping *map;
+ struct sock_mapping *map2 = NULL;
+ struct xen_pvcalls_request *req;
+ int notify, req_id, ret, evtchn, nonblock;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return -ENOTCONN;
+ }
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = (struct sock_mapping *) sock->sk->sk_send_head;
+ if (!map) {
+ pvcalls_exit();
+ return -ENOTSOCK;
+ }
+
+ if (map->passive.status != PVCALLS_STATUS_LISTEN) {
+ pvcalls_exit();
+ return -EINVAL;
+ }
+
+ nonblock = flags & SOCK_NONBLOCK;
+ /*
+ * Backend only supports 1 inflight accept request, will return
+ * errors for the others
+ */
+ if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+ (void *)&map->passive.flags)) {
+ req_id = READ_ONCE(map->passive.inflight_req_id);
+ if (req_id != PVCALLS_INVALID_ID &&
+ READ_ONCE(bedata->rsp[req_id].req_id) == req_id) {
+ map2 = map->passive.accept_map;
+ goto received;
+ }
+ if (nonblock) {
+ pvcalls_exit();
+ return -EAGAIN;
+ }
+ if (wait_event_interruptible(map->passive.inflight_accept_req,
+ !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+ (void *)&map->passive.flags))) {
+ pvcalls_exit();
+ return -EINTR;
+ }
+ }
+
+ spin_lock(&bedata->socket_lock);
+ ret = get_request(bedata, &req_id);
+ if (ret < 0) {
+ clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+ (void *)&map->passive.flags);
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return ret;
+ }
+ map2 = kzalloc(sizeof(*map2), GFP_KERNEL);
+ if (map2 == NULL) {
+ clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+ (void *)&map->passive.flags);
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return -ENOMEM;
+ }
+ ret = create_active(map2, &evtchn);
+ if (ret < 0) {
+ kfree(map2);
+ clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+ (void *)&map->passive.flags);
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return ret;
+ }
+ list_add_tail(&map2->list, &bedata->socket_mappings);
+
+ req = RING_GET_REQUEST(&bedata->ring, req_id);
+ req->req_id = req_id;
+ req->cmd = PVCALLS_ACCEPT;
+ req->u.accept.id = (uint64_t) map;
+ req->u.accept.ref = map2->active.ref;
+ req->u.accept.id_new = (uint64_t) map2;
+ req->u.accept.evtchn = evtchn;
+ map->passive.accept_map = map2;
+
+ bedata->ring.req_prod_pvt++;
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
+ spin_unlock(&bedata->socket_lock);
+ if (notify)
+ notify_remote_via_irq(bedata->irq);
+ /* We could check if we have received a response before returning. */
+ if (nonblock) {
+ WRITE_ONCE(map->passive.inflight_req_id, req_id);
+ pvcalls_exit();
+ return -EAGAIN;
+ }
+
+ if (wait_event_interruptible(bedata->inflight_req,
+ READ_ONCE(bedata->rsp[req_id].req_id) == req_id)) {
+ pvcalls_exit();
+ return -EINTR;
+ }
+ /* read req_id, then the content */
+ smp_rmb();
+
+received:
+ map2->sock = newsock;
+ newsock->sk = kzalloc(sizeof(*newsock->sk), GFP_KERNEL);
+ if (!newsock->sk) {
+ bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
+ map->passive.inflight_req_id = PVCALLS_INVALID_ID;
+ clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+ (void *)&map->passive.flags);
+ pvcalls_front_free_map(bedata, map2, false);
+ pvcalls_exit();
+ return -ENOMEM;
+ }
+ newsock->sk->sk_send_head = (void *)map2;
+
+ ret = bedata->rsp[req_id].ret;
+ bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
+ map->passive.inflight_req_id = PVCALLS_INVALID_ID;
+
+ clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags);
+ wake_up(&map->passive.inflight_accept_req);
+
+ pvcalls_exit();
+ return ret;
+}
+
static const struct xenbus_device_id pvcalls_front_ids[] = {
{ "pvcalls" },
{ "" }
diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h
index aa8fe10..ab4f1da 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -10,5 +10,8 @@ int pvcalls_front_bind(struct socket *sock,
struct sockaddr *addr,
int addr_len);
int pvcalls_front_listen(struct socket *sock, int backlog);
+int pvcalls_front_accept(struct socket *sock,
+ struct socket *newsock,
+ int flags);
#endif
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* [PATCH v6 09/13] xen/pvcalls: implement sendmsg
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
` (6 preceding siblings ...)
2017-10-24 17:33 ` [PATCH v6 08/13] xen/pvcalls: implement accept command Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 10/13] xen/pvcalls: implement recvmsg Stefano Stabellini
` (3 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
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
---
drivers/xen/pvcalls-front.c | 118 ++++++++++++++++++++++++++++++++++++++++++++
drivers/xen/pvcalls-front.h | 3 ++
2 files changed, 121 insertions(+)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 507c6a8..27b7970 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -29,6 +29,7 @@
#define PVCALLS_INVALID_ID UINT_MAX
#define PVCALLS_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
#define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE)
+#define PVCALLS_FRONT_MAX_SPIN 5000
struct pvcalls_bedata {
struct xen_pvcalls_front_ring ring;
@@ -99,6 +100,23 @@ static inline int get_request(struct pvcalls_bedata *bedata, int *req_id)
return 0;
}
+static bool pvcalls_front_write_todo(struct sock_mapping *map)
+{
+ struct pvcalls_data_intf *intf = map->active.ring;
+ RING_IDX cons, prod, size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
+ int32_t error;
+
+ error = intf->out_error;
+ if (error == -ENOTCONN)
+ return false;
+ if (error != 0)
+ return true;
+
+ cons = intf->out_cons;
+ prod = intf->out_prod;
+ return !!(size - pvcalls_queued(prod, cons, size));
+}
+
static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
{
struct xenbus_device *dev = dev_id;
@@ -363,6 +381,106 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
return ret;
}
+static int __write_ring(struct pvcalls_data_intf *intf,
+ struct pvcalls_data *data,
+ struct iov_iter *msg_iter,
+ int len)
+{
+ RING_IDX cons, prod, size, masked_prod, masked_cons;
+ RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
+ int32_t error;
+
+ error = intf->out_error;
+ if (error < 0)
+ return error;
+ cons = intf->out_cons;
+ prod = intf->out_prod;
+ /* read indexes before continuing */
+ virt_mb();
+
+ size = pvcalls_queued(prod, cons, array_size);
+ if (size >= array_size)
+ return -EINVAL;
+ if (len > array_size - size)
+ len = array_size - size;
+
+ masked_prod = pvcalls_mask(prod, array_size);
+ masked_cons = pvcalls_mask(cons, array_size);
+
+ if (masked_prod < masked_cons) {
+ copy_from_iter(data->out + masked_prod, len, msg_iter);
+ } else {
+ if (len > array_size - masked_prod) {
+ copy_from_iter(data->out + masked_prod,
+ array_size - masked_prod, msg_iter);
+ copy_from_iter(data->out,
+ len - (array_size - masked_prod),
+ msg_iter);
+ } else {
+ copy_from_iter(data->out + masked_prod, len, msg_iter);
+ }
+ }
+ /* write to ring before updating pointer */
+ virt_wmb();
+ intf->out_prod += len;
+
+ return len;
+}
+
+int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg,
+ size_t len)
+{
+ struct pvcalls_bedata *bedata;
+ struct sock_mapping *map;
+ int sent, tot_sent = 0;
+ int count = 0, flags;
+
+ flags = msg->msg_flags;
+ if (flags & (MSG_CONFIRM|MSG_DONTROUTE|MSG_EOR|MSG_OOB))
+ return -EOPNOTSUPP;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return -ENOTCONN;
+ }
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = (struct sock_mapping *) sock->sk->sk_send_head;
+ if (!map) {
+ pvcalls_exit();
+ return -ENOTSOCK;
+ }
+
+ mutex_lock(&map->active.out_mutex);
+ if ((flags & MSG_DONTWAIT) && !pvcalls_front_write_todo(map)) {
+ mutex_unlock(&map->active.out_mutex);
+ pvcalls_exit();
+ return -EAGAIN;
+ }
+ if (len > INT_MAX)
+ len = INT_MAX;
+
+again:
+ count++;
+ sent = __write_ring(map->active.ring,
+ &map->active.data, &msg->msg_iter,
+ len);
+ if (sent > 0) {
+ len -= sent;
+ tot_sent += sent;
+ notify_remote_via_irq(map->active.irq);
+ }
+ if (sent >= 0 && len > 0 && count < PVCALLS_FRONT_MAX_SPIN)
+ goto again;
+ if (sent < 0)
+ tot_sent = sent;
+
+ mutex_unlock(&map->active.out_mutex);
+ pvcalls_exit();
+ return tot_sent;
+}
+
int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
{
struct pvcalls_bedata *bedata;
diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h
index ab4f1da..d937c24 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -13,5 +13,8 @@ int pvcalls_front_bind(struct socket *sock,
int pvcalls_front_accept(struct socket *sock,
struct socket *newsock,
int flags);
+int pvcalls_front_sendmsg(struct socket *sock,
+ struct msghdr *msg,
+ size_t len);
#endif
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* [PATCH v6 10/13] xen/pvcalls: implement recvmsg
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
` (7 preceding siblings ...)
2017-10-24 17:33 ` [PATCH v6 09/13] xen/pvcalls: implement sendmsg Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 11/13] xen/pvcalls: implement poll command Stefano Stabellini
` (2 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
Implement recvmsg by copying data from the "in" ring. If not enough data
is available and the recvmsg call is blocking, then wait on the
inflight_conn_req waitqueue. Take the active socket in_mutex so that
only one function can access the ring at any given time.
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
---
drivers/xen/pvcalls-front.c | 108 ++++++++++++++++++++++++++++++++++++++++++++
drivers/xen/pvcalls-front.h | 4 ++
2 files changed, 112 insertions(+)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 27b7970..a07be6a 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -117,6 +117,20 @@ static bool pvcalls_front_write_todo(struct sock_mapping *map)
return !!(size - pvcalls_queued(prod, cons, size));
}
+static bool pvcalls_front_read_todo(struct sock_mapping *map)
+{
+ struct pvcalls_data_intf *intf = map->active.ring;
+ RING_IDX cons, prod;
+ int32_t error;
+
+ cons = intf->in_cons;
+ prod = intf->in_prod;
+ error = intf->in_error;
+ return (error != 0 ||
+ pvcalls_queued(prod, cons,
+ XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER)) != 0);
+}
+
static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
{
struct xenbus_device *dev = dev_id;
@@ -481,6 +495,100 @@ int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg,
return tot_sent;
}
+static int __read_ring(struct pvcalls_data_intf *intf,
+ struct pvcalls_data *data,
+ struct iov_iter *msg_iter,
+ size_t len, int flags)
+{
+ RING_IDX cons, prod, size, masked_prod, masked_cons;
+ RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
+ int32_t error;
+
+ cons = intf->in_cons;
+ prod = intf->in_prod;
+ error = intf->in_error;
+ /* get pointers before reading from the ring */
+ virt_rmb();
+ if (error < 0)
+ return error;
+
+ size = pvcalls_queued(prod, cons, array_size);
+ masked_prod = pvcalls_mask(prod, array_size);
+ masked_cons = pvcalls_mask(cons, array_size);
+
+ if (size == 0)
+ return 0;
+
+ if (len > size)
+ len = size;
+
+ if (masked_prod > masked_cons) {
+ copy_to_iter(data->in + masked_cons, len, msg_iter);
+ } else {
+ if (len > (array_size - masked_cons)) {
+ copy_to_iter(data->in + masked_cons,
+ array_size - masked_cons, msg_iter);
+ copy_to_iter(data->in,
+ len - (array_size - masked_cons),
+ msg_iter);
+ } else {
+ copy_to_iter(data->in + masked_cons, len, msg_iter);
+ }
+ }
+ /* read data from the ring before increasing the index */
+ virt_mb();
+ if (!(flags & MSG_PEEK))
+ intf->in_cons += len;
+
+ return len;
+}
+
+int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
+ int flags)
+{
+ struct pvcalls_bedata *bedata;
+ int ret;
+ struct sock_mapping *map;
+
+ if (flags & (MSG_CMSG_CLOEXEC|MSG_ERRQUEUE|MSG_OOB|MSG_TRUNC))
+ return -EOPNOTSUPP;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return -ENOTCONN;
+ }
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = (struct sock_mapping *) sock->sk->sk_send_head;
+ if (!map) {
+ pvcalls_exit();
+ return -ENOTSOCK;
+ }
+
+ mutex_lock(&map->active.in_mutex);
+ if (len > XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER))
+ len = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
+
+ while (!(flags & MSG_DONTWAIT) && !pvcalls_front_read_todo(map)) {
+ wait_event_interruptible(map->active.inflight_conn_req,
+ pvcalls_front_read_todo(map));
+ }
+ ret = __read_ring(map->active.ring, &map->active.data,
+ &msg->msg_iter, len, flags);
+
+ if (ret > 0)
+ notify_remote_via_irq(map->active.irq);
+ if (ret == 0)
+ ret = (flags & MSG_DONTWAIT) ? -EAGAIN : 0;
+ if (ret == -ENOTCONN)
+ ret = 0;
+
+ mutex_unlock(&map->active.in_mutex);
+ pvcalls_exit();
+ return ret;
+}
+
int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
{
struct pvcalls_bedata *bedata;
diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h
index d937c24..de24041 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -16,5 +16,9 @@ int pvcalls_front_accept(struct socket *sock,
int pvcalls_front_sendmsg(struct socket *sock,
struct msghdr *msg,
size_t len);
+int pvcalls_front_recvmsg(struct socket *sock,
+ struct msghdr *msg,
+ size_t len,
+ int flags);
#endif
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* [PATCH v6 11/13] xen/pvcalls: implement poll command
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
` (8 preceding siblings ...)
2017-10-24 17:33 ` [PATCH v6 10/13] xen/pvcalls: implement recvmsg Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 12/13] xen/pvcalls: implement release command Stefano Stabellini
2017-10-24 17:33 ` [PATCH v6 13/13] xen: introduce a Kconfig option to enable the pvcalls frontend Stefano Stabellini
11 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
For active sockets, check the indexes and use the inflight_conn_req
waitqueue to wait.
For passive sockets if an accept is outstanding
(PVCALLS_FLAG_ACCEPT_INFLIGHT), check if it has been answered by looking
at bedata->rsp[req_id]. If so, return POLLIN. Otherwise use the
inflight_accept_req waitqueue.
If no accepts are inflight, send PVCALLS_POLL to the backend. If we have
outstanding POLL requests awaiting for a response use the inflight_req
waitqueue: inflight_req is awaken when a new response is received; on
wakeup we check whether the POLL response is arrived by looking at the
PVCALLS_FLAG_POLL_RET flag. We set the flag from
pvcalls_front_event_handler, if the response was for a POLL command.
In pvcalls_front_event_handler, get the struct sock_mapping from the
poll id (we previously converted struct sock_mapping* to uint64_t and
used it as id).
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
---
drivers/xen/pvcalls-front.c | 144 +++++++++++++++++++++++++++++++++++++++++---
drivers/xen/pvcalls-front.h | 3 +
2 files changed, 138 insertions(+), 9 deletions(-)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index a07be6a..4a413ff 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -83,6 +83,8 @@ struct sock_mapping {
* Only one poll operation can be inflight for a given socket.
*/
#define PVCALLS_FLAG_ACCEPT_INFLIGHT 0
+#define PVCALLS_FLAG_POLL_INFLIGHT 1
+#define PVCALLS_FLAG_POLL_RET 2
uint8_t flags;
uint32_t inflight_req_id;
struct sock_mapping *accept_map;
@@ -154,15 +156,32 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
rsp = RING_GET_RESPONSE(&bedata->ring, bedata->ring.rsp_cons);
req_id = rsp->req_id;
- dst = (uint8_t *)&bedata->rsp[req_id] + sizeof(rsp->req_id);
- src = (uint8_t *)rsp + sizeof(rsp->req_id);
- memcpy(dst, src, sizeof(*rsp) - sizeof(rsp->req_id));
- /*
- * First copy the rest of the data, then req_id. It is
- * paired with the barrier when accessing bedata->rsp.
- */
- smp_wmb();
- bedata->rsp[req_id].req_id = rsp->req_id;
+ if (rsp->cmd == PVCALLS_POLL) {
+ struct sock_mapping *map = (struct sock_mapping *)
+ rsp->u.poll.id;
+
+ clear_bit(PVCALLS_FLAG_POLL_INFLIGHT,
+ (void *)&map->passive.flags);
+ /*
+ * clear INFLIGHT, then set RET. It pairs with
+ * the checks at the beginning of
+ * pvcalls_front_poll_passive.
+ */
+ smp_wmb();
+ set_bit(PVCALLS_FLAG_POLL_RET,
+ (void *)&map->passive.flags);
+ } else {
+ dst = (uint8_t *)&bedata->rsp[req_id] +
+ sizeof(rsp->req_id);
+ src = (uint8_t *)rsp + sizeof(rsp->req_id);
+ memcpy(dst, src, sizeof(*rsp) - sizeof(rsp->req_id));
+ /*
+ * First copy the rest of the data, then req_id. It is
+ * paired with the barrier when accessing bedata->rsp.
+ */
+ smp_wmb();
+ bedata->rsp[req_id].req_id = req_id;
+ }
done = 1;
bedata->ring.rsp_cons++;
@@ -840,6 +859,113 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
return ret;
}
+static unsigned int pvcalls_front_poll_passive(struct file *file,
+ struct pvcalls_bedata *bedata,
+ struct sock_mapping *map,
+ poll_table *wait)
+{
+ int notify, req_id, ret;
+ struct xen_pvcalls_request *req;
+
+ if (test_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
+ (void *)&map->passive.flags)) {
+ uint32_t req_id = READ_ONCE(map->passive.inflight_req_id);
+
+ if (req_id != PVCALLS_INVALID_ID &&
+ READ_ONCE(bedata->rsp[req_id].req_id) == req_id)
+ return POLLIN | POLLRDNORM;
+
+ poll_wait(file, &map->passive.inflight_accept_req, wait);
+ return 0;
+ }
+
+ if (test_and_clear_bit(PVCALLS_FLAG_POLL_RET,
+ (void *)&map->passive.flags))
+ return POLLIN | POLLRDNORM;
+
+ /*
+ * First check RET, then INFLIGHT. No barriers necessary to
+ * ensure execution ordering because of the conditional
+ * instructions creating control dependencies.
+ */
+
+ if (test_and_set_bit(PVCALLS_FLAG_POLL_INFLIGHT,
+ (void *)&map->passive.flags)) {
+ poll_wait(file, &bedata->inflight_req, wait);
+ return 0;
+ }
+
+ spin_lock(&bedata->socket_lock);
+ ret = get_request(bedata, &req_id);
+ if (ret < 0) {
+ spin_unlock(&bedata->socket_lock);
+ return ret;
+ }
+ req = RING_GET_REQUEST(&bedata->ring, req_id);
+ req->req_id = req_id;
+ req->cmd = PVCALLS_POLL;
+ req->u.poll.id = (uint64_t) map;
+
+ bedata->ring.req_prod_pvt++;
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
+ spin_unlock(&bedata->socket_lock);
+ if (notify)
+ notify_remote_via_irq(bedata->irq);
+
+ poll_wait(file, &bedata->inflight_req, wait);
+ return 0;
+}
+
+static unsigned int pvcalls_front_poll_active(struct file *file,
+ struct pvcalls_bedata *bedata,
+ struct sock_mapping *map,
+ poll_table *wait)
+{
+ unsigned int mask = 0;
+ int32_t in_error, out_error;
+ struct pvcalls_data_intf *intf = map->active.ring;
+
+ out_error = intf->out_error;
+ in_error = intf->in_error;
+
+ poll_wait(file, &map->active.inflight_conn_req, wait);
+ if (pvcalls_front_write_todo(map))
+ mask |= POLLOUT | POLLWRNORM;
+ if (pvcalls_front_read_todo(map))
+ mask |= POLLIN | POLLRDNORM;
+ if (in_error != 0 || out_error != 0)
+ mask |= POLLERR;
+
+ return mask;
+}
+
+unsigned int pvcalls_front_poll(struct file *file, struct socket *sock,
+ poll_table *wait)
+{
+ struct pvcalls_bedata *bedata;
+ struct sock_mapping *map;
+ int ret;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return POLLNVAL;
+ }
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = (struct sock_mapping *) sock->sk->sk_send_head;
+ if (!map) {
+ pvcalls_exit();
+ return POLLNVAL;
+ }
+ if (map->active_socket)
+ ret = pvcalls_front_poll_active(file, bedata, map, wait);
+ else
+ ret = pvcalls_front_poll_passive(file, bedata, map, wait);
+ pvcalls_exit();
+ return ret;
+}
+
static const struct xenbus_device_id pvcalls_front_ids[] = {
{ "pvcalls" },
{ "" }
diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h
index de24041..25e05b8 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -20,5 +20,8 @@ int pvcalls_front_recvmsg(struct socket *sock,
struct msghdr *msg,
size_t len,
int flags);
+unsigned int pvcalls_front_poll(struct file *file,
+ struct socket *sock,
+ poll_table *wait);
#endif
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* [PATCH v6 12/13] xen/pvcalls: implement release command
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
` (9 preceding siblings ...)
2017-10-24 17:33 ` [PATCH v6 11/13] xen/pvcalls: implement poll command Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-25 14:32 ` Boris Ostrovsky
2017-10-24 17:33 ` [PATCH v6 13/13] xen: introduce a Kconfig option to enable the pvcalls frontend Stefano Stabellini
11 siblings, 1 reply; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
Send PVCALLS_RELEASE to the backend and wait for a reply. Take both
in_mutex and out_mutex to avoid concurrent accesses. Then, free the
socket.
For passive sockets, check whether we have already pre-allocated an
active socket for the purpose of being accepted. If so, free that as
well.
Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
---
drivers/xen/pvcalls-front.c | 100 ++++++++++++++++++++++++++++++++++++++++++++
drivers/xen/pvcalls-front.h | 1 +
2 files changed, 101 insertions(+)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 4a413ff..7abc039 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -199,6 +199,23 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
struct sock_mapping *map, bool locked)
{
+ int i;
+
+ unbind_from_irqhandler(map->active.irq, map);
+
+ if (!locked)
+ spin_lock(&bedata->socket_lock);
+ if (!list_empty(&map->list))
+ list_del_init(&map->list);
+ if (!locked)
+ spin_unlock(&bedata->socket_lock);
+
+ for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
+ gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0);
+ gnttab_end_foreign_access(map->active.ref, 0, 0);
+ free_page((unsigned long)map->active.ring);
+
+ kfree(map);
}
static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map)
@@ -966,6 +983,89 @@ unsigned int pvcalls_front_poll(struct file *file, struct socket *sock,
return ret;
}
+int pvcalls_front_release(struct socket *sock)
+{
+ struct pvcalls_bedata *bedata;
+ struct sock_mapping *map;
+ int req_id, notify, ret;
+ struct xen_pvcalls_request *req;
+
+ if (sock->sk == NULL)
+ return 0;
+
+ pvcalls_enter();
+ if (!pvcalls_front_dev) {
+ pvcalls_exit();
+ return -EIO;
+ }
+
+ bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
+
+ map = (struct sock_mapping *) sock->sk->sk_send_head;
+ if (map == NULL) {
+ pvcalls_exit();
+ return 0;
+ }
+
+ spin_lock(&bedata->socket_lock);
+ ret = get_request(bedata, &req_id);
+ if (ret < 0) {
+ spin_unlock(&bedata->socket_lock);
+ pvcalls_exit();
+ return ret;
+ }
+ sock->sk->sk_send_head = NULL;
+
+ req = RING_GET_REQUEST(&bedata->ring, req_id);
+ req->req_id = req_id;
+ req->cmd = PVCALLS_RELEASE;
+ req->u.release.id = (uint64_t)map;
+
+ bedata->ring.req_prod_pvt++;
+ RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
+ spin_unlock(&bedata->socket_lock);
+ if (notify)
+ notify_remote_via_irq(bedata->irq);
+
+ wait_event(bedata->inflight_req,
+ READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
+
+ if (map->active_socket) {
+ /*
+ * Set in_error and wake up inflight_conn_req to force
+ * recvmsg waiters to exit.
+ */
+ map->active.ring->in_error = -EBADF;
+ wake_up_interruptible(&map->active.inflight_conn_req);
+
+ /*
+ * Wait until there are no more waiters on the mutexes.
+ * We know that no new waiters can be added because sk_send_head
+ * is set to NULL -- we only need to wait for the existing
+ * waiters to return.
+ */
+ while (!mutex_trylock(&map->active.in_mutex) ||
+ !mutex_trylock(&map->active.out_mutex))
+ cpu_relax();
+
+ pvcalls_front_free_map(bedata, map, false);
+ } else {
+ spin_lock(&bedata->socket_lock);
+ if (READ_ONCE(map->passive.inflight_req_id) !=
+ PVCALLS_INVALID_ID) {
+ pvcalls_front_free_map(bedata,
+ map->passive.accept_map, true);
+ }
+ list_del(&map->list);
+ kfree(map);
+ spin_unlock(&bedata->socket_lock);
+ }
+ WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID);
+
+ pvcalls_exit();
+ return 0;
+}
+
static const struct xenbus_device_id pvcalls_front_ids[] = {
{ "pvcalls" },
{ "" }
diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h
index 25e05b8..3332978 100644
--- a/drivers/xen/pvcalls-front.h
+++ b/drivers/xen/pvcalls-front.h
@@ -23,5 +23,6 @@ int pvcalls_front_recvmsg(struct socket *sock,
unsigned int pvcalls_front_poll(struct file *file,
struct socket *sock,
poll_table *wait);
+int pvcalls_front_release(struct socket *sock);
#endif
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH v6 12/13] xen/pvcalls: implement release command
2017-10-24 17:33 ` [PATCH v6 12/13] xen/pvcalls: implement release command Stefano Stabellini
@ 2017-10-25 14:32 ` Boris Ostrovsky
2017-10-25 23:00 ` Stefano Stabellini
0 siblings, 1 reply; 22+ messages in thread
From: Boris Ostrovsky @ 2017-10-25 14:32 UTC (permalink / raw)
To: Stefano Stabellini, xen-devel; +Cc: linux-kernel, jgross, Stefano Stabellini
On 10/24/2017 01:33 PM, Stefano Stabellini wrote:
> Send PVCALLS_RELEASE to the backend and wait for a reply. Take both
> in_mutex and out_mutex to avoid concurrent accesses. Then, free the
> socket.
>
> For passive sockets, check whether we have already pre-allocated an
> active socket for the purpose of being accepted. If so, free that as
> well.
>
> Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
> CC: boris.ostrovsky@oracle.com
> CC: jgross@suse.com
> ---
> drivers/xen/pvcalls-front.c | 100 ++++++++++++++++++++++++++++++++++++++++++++
> drivers/xen/pvcalls-front.h | 1 +
> 2 files changed, 101 insertions(+)
>
> diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
> index 4a413ff..7abc039 100644
> --- a/drivers/xen/pvcalls-front.c
> +++ b/drivers/xen/pvcalls-front.c
> @@ -199,6 +199,23 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
> static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
> struct sock_mapping *map, bool locked)
> {
> + int i;
> +
> + unbind_from_irqhandler(map->active.irq, map);
> +
> + if (!locked)
> + spin_lock(&bedata->socket_lock);
> + if (!list_empty(&map->list))
> + list_del_init(&map->list);
> + if (!locked)
> + spin_unlock(&bedata->socket_lock);
> +
> + for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
> + gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0);
> + gnttab_end_foreign_access(map->active.ref, 0, 0);
> + free_page((unsigned long)map->active.ring);
> +
> + kfree(map);
> }
>
> static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map)
> @@ -966,6 +983,89 @@ unsigned int pvcalls_front_poll(struct file *file, struct socket *sock,
> return ret;
> }
>
> +int pvcalls_front_release(struct socket *sock)
> +{
> + struct pvcalls_bedata *bedata;
> + struct sock_mapping *map;
> + int req_id, notify, ret;
> + struct xen_pvcalls_request *req;
> +
..
> +
> + if (map->active_socket) {
> + /*
> + * Set in_error and wake up inflight_conn_req to force
> + * recvmsg waiters to exit.
> + */
> + map->active.ring->in_error = -EBADF;
> + wake_up_interruptible(&map->active.inflight_conn_req);
> +
> + /*
> + * Wait until there are no more waiters on the mutexes.
> + * We know that no new waiters can be added because sk_send_head
> + * is set to NULL -- we only need to wait for the existing
> + * waiters to return.
> + */
> + while (!mutex_trylock(&map->active.in_mutex) ||
> + !mutex_trylock(&map->active.out_mutex))
> + cpu_relax();
> +
> + pvcalls_front_free_map(bedata, map, false);
> + } else {
> + spin_lock(&bedata->socket_lock);
> + if (READ_ONCE(map->passive.inflight_req_id) !=
> + PVCALLS_INVALID_ID) {
> + pvcalls_front_free_map(bedata,
> + map->passive.accept_map, true);
> + }
> + list_del(&map->list);
> + kfree(map);
> + spin_unlock(&bedata->socket_lock);
We have different locking rules in pvcalls_front_free_map() for each of
those clauses in that in the first case we are doing grant table
operations and free_page() without the lock and in the second case we
are holding it. Is it possible to restructure this so that we prune the
lists under the lock (possibly in this routine) and call
pvcalls_front_free_map() lock-less?
-boris
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH v6 12/13] xen/pvcalls: implement release command
2017-10-25 14:32 ` Boris Ostrovsky
@ 2017-10-25 23:00 ` Stefano Stabellini
2017-10-26 14:11 ` Boris Ostrovsky
0 siblings, 1 reply; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-25 23:00 UTC (permalink / raw)
To: Boris Ostrovsky
Cc: Stefano Stabellini, xen-devel, linux-kernel, jgross, Stefano Stabellini
On Wed, 25 Oct 2017, Boris Ostrovsky wrote:
> On 10/24/2017 01:33 PM, Stefano Stabellini wrote:
> > Send PVCALLS_RELEASE to the backend and wait for a reply. Take both
> > in_mutex and out_mutex to avoid concurrent accesses. Then, free the
> > socket.
> >
> > For passive sockets, check whether we have already pre-allocated an
> > active socket for the purpose of being accepted. If so, free that as
> > well.
> >
> > Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
> > CC: boris.ostrovsky@oracle.com
> > CC: jgross@suse.com
> > ---
> > drivers/xen/pvcalls-front.c | 100 ++++++++++++++++++++++++++++++++++++++++++++
> > drivers/xen/pvcalls-front.h | 1 +
> > 2 files changed, 101 insertions(+)
> >
> > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
> > index 4a413ff..7abc039 100644
> > --- a/drivers/xen/pvcalls-front.c
> > +++ b/drivers/xen/pvcalls-front.c
> > @@ -199,6 +199,23 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
> > static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
> > struct sock_mapping *map, bool locked)
> > {
> > + int i;
> > +
> > + unbind_from_irqhandler(map->active.irq, map);
> > +
> > + if (!locked)
> > + spin_lock(&bedata->socket_lock);
> > + if (!list_empty(&map->list))
> > + list_del_init(&map->list);
> > + if (!locked)
> > + spin_unlock(&bedata->socket_lock);
> > +
> > + for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
> > + gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0);
> > + gnttab_end_foreign_access(map->active.ref, 0, 0);
> > + free_page((unsigned long)map->active.ring);
> > +
> > + kfree(map);
> > }
> >
> > static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map)
> > @@ -966,6 +983,89 @@ unsigned int pvcalls_front_poll(struct file *file, struct socket *sock,
> > return ret;
> > }
> >
> > +int pvcalls_front_release(struct socket *sock)
> > +{
> > + struct pvcalls_bedata *bedata;
> > + struct sock_mapping *map;
> > + int req_id, notify, ret;
> > + struct xen_pvcalls_request *req;
> > +
>
> ..
>
> > +
> > + if (map->active_socket) {
> > + /*
> > + * Set in_error and wake up inflight_conn_req to force
> > + * recvmsg waiters to exit.
> > + */
> > + map->active.ring->in_error = -EBADF;
> > + wake_up_interruptible(&map->active.inflight_conn_req);
> > +
> > + /*
> > + * Wait until there are no more waiters on the mutexes.
> > + * We know that no new waiters can be added because sk_send_head
> > + * is set to NULL -- we only need to wait for the existing
> > + * waiters to return.
> > + */
> > + while (!mutex_trylock(&map->active.in_mutex) ||
> > + !mutex_trylock(&map->active.out_mutex))
> > + cpu_relax();
> > +
> > + pvcalls_front_free_map(bedata, map, false);
> > + } else {
> > + spin_lock(&bedata->socket_lock);
> > + if (READ_ONCE(map->passive.inflight_req_id) !=
> > + PVCALLS_INVALID_ID) {
> > + pvcalls_front_free_map(bedata,
> > + map->passive.accept_map, true);
> > + }
> > + list_del(&map->list);
> > + kfree(map);
> > + spin_unlock(&bedata->socket_lock);
>
> We have different locking rules in pvcalls_front_free_map() for each of
> those clauses in that in the first case we are doing grant table
> operations and free_page() without the lock and in the second case we
> are holding it. Is it possible to restructure this so that we prune the
> lists under the lock (possibly in this routine) and call
> pvcalls_front_free_map() lock-less?
Yes, it is possible. However, pvcalls_front_free_map is called from a
couple of other places (pvcalls_front_accept and pvcalls_front_remove)
and we would have to add the code to remove the map from the list there
as well. I am not sure it is worth it.
I don't have a strong opinion on this. Let me know which way you prefer.
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH v6 12/13] xen/pvcalls: implement release command
2017-10-25 23:00 ` Stefano Stabellini
@ 2017-10-26 14:11 ` Boris Ostrovsky
2017-10-26 18:21 ` Stefano Stabellini
0 siblings, 1 reply; 22+ messages in thread
From: Boris Ostrovsky @ 2017-10-26 14:11 UTC (permalink / raw)
To: Stefano Stabellini; +Cc: xen-devel, linux-kernel, jgross, Stefano Stabellini
On 10/25/2017 07:00 PM, Stefano Stabellini wrote:
> On Wed, 25 Oct 2017, Boris Ostrovsky wrote:
>> On 10/24/2017 01:33 PM, Stefano Stabellini wrote:
>>> Send PVCALLS_RELEASE to the backend and wait for a reply. Take both
>>> in_mutex and out_mutex to avoid concurrent accesses. Then, free the
>>> socket.
>>>
>>> For passive sockets, check whether we have already pre-allocated an
>>> active socket for the purpose of being accepted. If so, free that as
>>> well.
>>>
>>> Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
>>> CC: boris.ostrovsky@oracle.com
>>> CC: jgross@suse.com
>>> ---
>>> drivers/xen/pvcalls-front.c | 100 ++++++++++++++++++++++++++++++++++++++++++++
>>> drivers/xen/pvcalls-front.h | 1 +
>>> 2 files changed, 101 insertions(+)
>>>
>>> diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
>>> index 4a413ff..7abc039 100644
>>> --- a/drivers/xen/pvcalls-front.c
>>> +++ b/drivers/xen/pvcalls-front.c
>>> @@ -199,6 +199,23 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
>>> static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
>>> struct sock_mapping *map, bool locked)
>>> {
>>> + int i;
>>> +
>>> + unbind_from_irqhandler(map->active.irq, map);
>>> +
>>> + if (!locked)
>>> + spin_lock(&bedata->socket_lock);
>>> + if (!list_empty(&map->list))
>>> + list_del_init(&map->list);
>>> + if (!locked)
>>> + spin_unlock(&bedata->socket_lock);
>>> +
>>> + for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
>>> + gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0);
>>> + gnttab_end_foreign_access(map->active.ref, 0, 0);
>>> + free_page((unsigned long)map->active.ring);
>>> +
>>> + kfree(map);
>>> }
>>>
>>> static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map)
>>> @@ -966,6 +983,89 @@ unsigned int pvcalls_front_poll(struct file *file, struct socket *sock,
>>> return ret;
>>> }
>>>
>>> +int pvcalls_front_release(struct socket *sock)
>>> +{
>>> + struct pvcalls_bedata *bedata;
>>> + struct sock_mapping *map;
>>> + int req_id, notify, ret;
>>> + struct xen_pvcalls_request *req;
>>> +
>> ..
>>
>>> +
>>> + if (map->active_socket) {
>>> + /*
>>> + * Set in_error and wake up inflight_conn_req to force
>>> + * recvmsg waiters to exit.
>>> + */
>>> + map->active.ring->in_error = -EBADF;
>>> + wake_up_interruptible(&map->active.inflight_conn_req);
>>> +
>>> + /*
>>> + * Wait until there are no more waiters on the mutexes.
>>> + * We know that no new waiters can be added because sk_send_head
>>> + * is set to NULL -- we only need to wait for the existing
>>> + * waiters to return.
>>> + */
>>> + while (!mutex_trylock(&map->active.in_mutex) ||
>>> + !mutex_trylock(&map->active.out_mutex))
>>> + cpu_relax();
>>> +
>>> + pvcalls_front_free_map(bedata, map, false);
>>> + } else {
>>> + spin_lock(&bedata->socket_lock);
>>> + if (READ_ONCE(map->passive.inflight_req_id) !=
>>> + PVCALLS_INVALID_ID) {
>>> + pvcalls_front_free_map(bedata,
>>> + map->passive.accept_map, true);
>>> + }
>>> + list_del(&map->list);
>>> + kfree(map);
>>> + spin_unlock(&bedata->socket_lock);
>> We have different locking rules in pvcalls_front_free_map() for each of
>> those clauses in that in the first case we are doing grant table
>> operations and free_page() without the lock and in the second case we
>> are holding it. Is it possible to restructure this so that we prune the
>> lists under the lock (possibly in this routine) and call
>> pvcalls_front_free_map() lock-less?
> Yes, it is possible. However, pvcalls_front_free_map is called from a
> couple of other places (pvcalls_front_accept and pvcalls_front_remove)
> and we would have to add the code to remove the map from the list there
> as well. I am not sure it is worth it.
>
> I don't have a strong opinion on this. Let me know which way you prefer.
I didn't realize this is called from multiple places.
How about
spin_lock(&bedata->socket_lock);
if (READ_ONCE(map->passive.inflight_req_id) !=
PVCALLS_INVALID_ID) {
if (!list_empty(&map->passive.accept_map->list))
list_del(&map->passive.accept_map->list);
}
list_del(&map->list);
spin_unlock(&bedata->socket_lock);
pvcalls_front_free_map(bedata, map->passive.accept_map, true);
kfree(map);
(I may have messed up list pointers here)
This would be slightly inefficient in that you drop the lock and then grab it again (only to find that the list is empty, presumably) but it makes pvcalls_front_free_map()'s behavior more consistent wrt locking. (Or maybe you will need to pass a bool to pvcalls_front_free_map() to indicate whether the map needs to be removed from the list for other call sites, in which case it will replace the 'locked' argument)
-boris
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH v6 12/13] xen/pvcalls: implement release command
2017-10-26 14:11 ` Boris Ostrovsky
@ 2017-10-26 18:21 ` Stefano Stabellini
0 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-26 18:21 UTC (permalink / raw)
To: Boris Ostrovsky
Cc: Stefano Stabellini, xen-devel, linux-kernel, jgross, Stefano Stabellini
On Thu, 26 Oct 2017, Boris Ostrovsky wrote:
> On 10/25/2017 07:00 PM, Stefano Stabellini wrote:
> > On Wed, 25 Oct 2017, Boris Ostrovsky wrote:
> >> On 10/24/2017 01:33 PM, Stefano Stabellini wrote:
> >>> Send PVCALLS_RELEASE to the backend and wait for a reply. Take both
> >>> in_mutex and out_mutex to avoid concurrent accesses. Then, free the
> >>> socket.
> >>>
> >>> For passive sockets, check whether we have already pre-allocated an
> >>> active socket for the purpose of being accepted. If so, free that as
> >>> well.
> >>>
> >>> Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
> >>> CC: boris.ostrovsky@oracle.com
> >>> CC: jgross@suse.com
> >>> ---
> >>> drivers/xen/pvcalls-front.c | 100 ++++++++++++++++++++++++++++++++++++++++++++
> >>> drivers/xen/pvcalls-front.h | 1 +
> >>> 2 files changed, 101 insertions(+)
> >>>
> >>> diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
> >>> index 4a413ff..7abc039 100644
> >>> --- a/drivers/xen/pvcalls-front.c
> >>> +++ b/drivers/xen/pvcalls-front.c
> >>> @@ -199,6 +199,23 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
> >>> static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
> >>> struct sock_mapping *map, bool locked)
> >>> {
> >>> + int i;
> >>> +
> >>> + unbind_from_irqhandler(map->active.irq, map);
> >>> +
> >>> + if (!locked)
> >>> + spin_lock(&bedata->socket_lock);
> >>> + if (!list_empty(&map->list))
> >>> + list_del_init(&map->list);
> >>> + if (!locked)
> >>> + spin_unlock(&bedata->socket_lock);
> >>> +
> >>> + for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
> >>> + gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0);
> >>> + gnttab_end_foreign_access(map->active.ref, 0, 0);
> >>> + free_page((unsigned long)map->active.ring);
> >>> +
> >>> + kfree(map);
> >>> }
> >>>
> >>> static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map)
> >>> @@ -966,6 +983,89 @@ unsigned int pvcalls_front_poll(struct file *file, struct socket *sock,
> >>> return ret;
> >>> }
> >>>
> >>> +int pvcalls_front_release(struct socket *sock)
> >>> +{
> >>> + struct pvcalls_bedata *bedata;
> >>> + struct sock_mapping *map;
> >>> + int req_id, notify, ret;
> >>> + struct xen_pvcalls_request *req;
> >>> +
> >> ..
> >>
> >>> +
> >>> + if (map->active_socket) {
> >>> + /*
> >>> + * Set in_error and wake up inflight_conn_req to force
> >>> + * recvmsg waiters to exit.
> >>> + */
> >>> + map->active.ring->in_error = -EBADF;
> >>> + wake_up_interruptible(&map->active.inflight_conn_req);
> >>> +
> >>> + /*
> >>> + * Wait until there are no more waiters on the mutexes.
> >>> + * We know that no new waiters can be added because sk_send_head
> >>> + * is set to NULL -- we only need to wait for the existing
> >>> + * waiters to return.
> >>> + */
> >>> + while (!mutex_trylock(&map->active.in_mutex) ||
> >>> + !mutex_trylock(&map->active.out_mutex))
> >>> + cpu_relax();
> >>> +
> >>> + pvcalls_front_free_map(bedata, map, false);
> >>> + } else {
> >>> + spin_lock(&bedata->socket_lock);
> >>> + if (READ_ONCE(map->passive.inflight_req_id) !=
> >>> + PVCALLS_INVALID_ID) {
> >>> + pvcalls_front_free_map(bedata,
> >>> + map->passive.accept_map, true);
> >>> + }
> >>> + list_del(&map->list);
> >>> + kfree(map);
> >>> + spin_unlock(&bedata->socket_lock);
> >> We have different locking rules in pvcalls_front_free_map() for each of
> >> those clauses in that in the first case we are doing grant table
> >> operations and free_page() without the lock and in the second case we
> >> are holding it. Is it possible to restructure this so that we prune the
> >> lists under the lock (possibly in this routine) and call
> >> pvcalls_front_free_map() lock-less?
> > Yes, it is possible. However, pvcalls_front_free_map is called from a
> > couple of other places (pvcalls_front_accept and pvcalls_front_remove)
> > and we would have to add the code to remove the map from the list there
> > as well. I am not sure it is worth it.
> >
> > I don't have a strong opinion on this. Let me know which way you prefer.
>
>
> I didn't realize this is called from multiple places.
>
> How about
>
> spin_lock(&bedata->socket_lock);
> if (READ_ONCE(map->passive.inflight_req_id) !=
> PVCALLS_INVALID_ID) {
> if (!list_empty(&map->passive.accept_map->list))
> list_del(&map->passive.accept_map->list);
> }
> list_del(&map->list);
> spin_unlock(&bedata->socket_lock);
>
> pvcalls_front_free_map(bedata, map->passive.accept_map, true);
> kfree(map);
>
>
> (I may have messed up list pointers here)
>
> This would be slightly inefficient in that you drop the lock and then grab it again (only to find that the list is empty, presumably) but it makes pvcalls_front_free_map()'s behavior more consistent wrt locking. (Or maybe you will need to pass a bool to pvcalls_front_free_map() to indicate whether the map needs to be removed from the list for other call sites, in which case it will replace the 'locked' argument)
Reading the code again, I realized that we don't even need to call
pvcalls_front_free_map on accept_map with the lock held because with
"sock->sk->sk_send_head = NULL;" at the beginning of the function there
are no risks of concurrent manipulation of accept_map.
We can safely do:
spin_lock(&bedata->socket_lock);
list_del(&map->list);
spin_unlock(&bedata->socket_lock);
if (READ_ONCE(map->passive.inflight_req_id) !=
PVCALLS_INVALID_ID) {
pvcalls_front_free_map(bedata, map->passive.accept_map);
}
kfree(map);
and get rid of the ugly bool lock parameter of pvcalls_front_free_map.
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH v6 13/13] xen: introduce a Kconfig option to enable the pvcalls frontend
2017-10-24 17:33 ` [PATCH v6 01/13] xen/pvcalls: introduce the pvcalls xenbus frontend Stefano Stabellini
` (10 preceding siblings ...)
2017-10-24 17:33 ` [PATCH v6 12/13] xen/pvcalls: implement release command Stefano Stabellini
@ 2017-10-24 17:33 ` Stefano Stabellini
2017-10-25 14:39 ` Boris Ostrovsky
11 siblings, 1 reply; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-24 17:33 UTC (permalink / raw)
To: xen-devel
Cc: linux-kernel, sstabellini, jgross, boris.ostrovsky, Stefano Stabellini
Also add pvcalls-front to the Makefile.
Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
---
drivers/xen/Kconfig | 9 +++++++++
drivers/xen/Makefile | 1 +
2 files changed, 10 insertions(+)
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 4545561..0b2c828 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -196,6 +196,15 @@ config XEN_PCIDEV_BACKEND
If in doubt, say m.
+config XEN_PVCALLS_FRONTEND
+ tristate "XEN PV Calls frontend driver"
+ depends on INET && XEN
+ help
+ Experimental frontend for the Xen PV Calls protocol
+ (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
+ sends a small set of POSIX calls to the backend, which
+ implements them.
+
config XEN_PVCALLS_BACKEND
bool "XEN PV Calls backend driver"
depends on INET && XEN && XEN_BACKEND
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 480b928..afb9e03 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_XEN_EFI) += efi.o
obj-$(CONFIG_XEN_SCSI_BACKEND) += xen-scsiback.o
obj-$(CONFIG_XEN_AUTO_XLATE) += xlate_mmu.o
obj-$(CONFIG_XEN_PVCALLS_BACKEND) += pvcalls-back.o
+obj-$(CONFIG_XEN_PVCALLS_FRONTEND) += pvcalls-front.o
xen-evtchn-y := evtchn.o
xen-gntdev-y := gntdev.o
xen-gntalloc-y := gntalloc.o
--
1.9.1
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH v6 13/13] xen: introduce a Kconfig option to enable the pvcalls frontend
2017-10-24 17:33 ` [PATCH v6 13/13] xen: introduce a Kconfig option to enable the pvcalls frontend Stefano Stabellini
@ 2017-10-25 14:39 ` Boris Ostrovsky
2017-10-25 22:56 ` Stefano Stabellini
0 siblings, 1 reply; 22+ messages in thread
From: Boris Ostrovsky @ 2017-10-25 14:39 UTC (permalink / raw)
To: Stefano Stabellini, xen-devel; +Cc: linux-kernel, jgross, Stefano Stabellini
On 10/24/2017 01:33 PM, Stefano Stabellini wrote:
> Also add pvcalls-front to the Makefile.
>
> Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
> CC: boris.ostrovsky@oracle.com
> CC: jgross@suse.com
> ---
> drivers/xen/Kconfig | 9 +++++++++
> drivers/xen/Makefile | 1 +
> 2 files changed, 10 insertions(+)
>
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index 4545561..0b2c828 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -196,6 +196,15 @@ config XEN_PCIDEV_BACKEND
>
> If in doubt, say m.
>
> +config XEN_PVCALLS_FRONTEND
> + tristate "XEN PV Calls frontend driver"
> + depends on INET && XEN
> + help
> + Experimental frontend for the Xen PV Calls protocol
> + (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
> + sends a small set of POSIX calls to the backend, which
> + implements them.
default n ?
(and maybe select XEN_XENBUS_FRONTEND)
-boris
> +
> config XEN_PVCALLS_BACKEND
> bool "XEN PV Calls backend driver"
> depends on INET && XEN && XEN_BACKEND
> diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> index 480b928..afb9e03 100644
> --- a/drivers/xen/Makefile
> +++ b/drivers/xen/Makefile
> @@ -39,6 +39,7 @@ obj-$(CONFIG_XEN_EFI) += efi.o
> obj-$(CONFIG_XEN_SCSI_BACKEND) += xen-scsiback.o
> obj-$(CONFIG_XEN_AUTO_XLATE) += xlate_mmu.o
> obj-$(CONFIG_XEN_PVCALLS_BACKEND) += pvcalls-back.o
> +obj-$(CONFIG_XEN_PVCALLS_FRONTEND) += pvcalls-front.o
> xen-evtchn-y := evtchn.o
> xen-gntdev-y := gntdev.o
> xen-gntalloc-y := gntalloc.o
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v6 13/13] xen: introduce a Kconfig option to enable the pvcalls frontend
2017-10-25 14:39 ` Boris Ostrovsky
@ 2017-10-25 22:56 ` Stefano Stabellini
0 siblings, 0 replies; 22+ messages in thread
From: Stefano Stabellini @ 2017-10-25 22:56 UTC (permalink / raw)
To: Boris Ostrovsky
Cc: Stefano Stabellini, xen-devel, linux-kernel, jgross, Stefano Stabellini
On Wed, 25 Oct 2017, Boris Ostrovsky wrote:
> On 10/24/2017 01:33 PM, Stefano Stabellini wrote:
> > Also add pvcalls-front to the Makefile.
> >
> > Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
> > CC: boris.ostrovsky@oracle.com
> > CC: jgross@suse.com
> > ---
> > drivers/xen/Kconfig | 9 +++++++++
> > drivers/xen/Makefile | 1 +
> > 2 files changed, 10 insertions(+)
> >
> > diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> > index 4545561..0b2c828 100644
> > --- a/drivers/xen/Kconfig
> > +++ b/drivers/xen/Kconfig
> > @@ -196,6 +196,15 @@ config XEN_PCIDEV_BACKEND
> >
> > If in doubt, say m.
> >
> > +config XEN_PVCALLS_FRONTEND
> > + tristate "XEN PV Calls frontend driver"
> > + depends on INET && XEN
> > + help
> > + Experimental frontend for the Xen PV Calls protocol
> > + (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
> > + sends a small set of POSIX calls to the backend, which
> > + implements them.
>
> default n ?
>
> (and maybe select XEN_XENBUS_FRONTEND)
Yes, good ideas, I'll add
> > +
> > config XEN_PVCALLS_BACKEND
> > bool "XEN PV Calls backend driver"
> > depends on INET && XEN && XEN_BACKEND
> > diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> > index 480b928..afb9e03 100644
> > --- a/drivers/xen/Makefile
> > +++ b/drivers/xen/Makefile
> > @@ -39,6 +39,7 @@ obj-$(CONFIG_XEN_EFI) += efi.o
> > obj-$(CONFIG_XEN_SCSI_BACKEND) += xen-scsiback.o
> > obj-$(CONFIG_XEN_AUTO_XLATE) += xlate_mmu.o
> > obj-$(CONFIG_XEN_PVCALLS_BACKEND) += pvcalls-back.o
> > +obj-$(CONFIG_XEN_PVCALLS_FRONTEND) += pvcalls-front.o
> > xen-evtchn-y := evtchn.o
> > xen-gntdev-y := gntdev.o
> > xen-gntalloc-y := gntalloc.o
>
^ permalink raw reply [flat|nested] 22+ messages in thread