| Message ID | 1501017730-12797-2-git-send-email-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 7/25/2017 5:21 PM, Stefano Stabellini wrote: > Implement the probe function for the pvcalls frontend. Read the > supported versions, max-page-order and function-calls nodes from > xenstore. > > 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. > > 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> > CC: boris.ostrovsky@oracle.com > CC: jgross@suse.com > --- > drivers/xen/pvcalls-front.c | 153 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 153 insertions(+) > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > index a8d38c2..5e0b265 100644 > --- a/drivers/xen/pvcalls-front.c > +++ b/drivers/xen/pvcalls-front.c > @@ -20,6 +20,29 @@ > #include <xen/xenbus.h> > #include <xen/interface/io/pvcalls.h> > > +#define PVCALLS_INVALID_ID (UINT_MAX) Unnecessary parentheses > +#define RING_ORDER XENBUS_MAX_RING_GRANT_ORDER PVCALLS_RING_ORDER? > +#define PVCALLS_NR_REQ_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; > + struct list_head socketpass_mappings; > + spinlock_t pvcallss_lock; > + > + wait_queue_head_t inflight_req; > + struct xen_pvcalls_response rsp[PVCALLS_NR_REQ_PER_RING]; > +}; > +struct xenbus_device *pvcalls_front_dev; static > + > +static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) > +{ > + return IRQ_HANDLED; > +} > + > static const struct xenbus_device_id pvcalls_front_ids[] = { > { "pvcalls" }, > { "" } > @@ -33,12 +56,142 @@ 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; > + 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); > + ret = xenbus_scanf(XBT_NIL, dev->otherend, > + "max-page-order", "%u", &max_page_order); > + if (ret <= 0) > + return -ENODEV; > + 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) > + 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; > + > + init_waitqueue_head(&bedata->inflight_req); > + for (i = 0; i < PVCALLS_NR_REQ_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 = ref = gnttab_claim_grant_reference(&gref_head); Is ref really needed? > + if (ref < 0) > + goto error; > + gnttab_grant_foreign_access_ref(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", 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; > + } > + > + 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; > + > + error_xenbus: > + xenbus_transaction_end(xbt, 1); > + xenbus_dev_fatal(dev, ret, "writing xenstore"); > + error: > + pvcalls_front_remove(dev); I think patch 12 (where you implement cleanup) could be moved before this one. I also think you are leaking bedata on error paths. -boris > + 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 = {
On Wed, 26 Jul 2017, Boris Ostrovsky wrote: > On 7/25/2017 5:21 PM, Stefano Stabellini wrote: > > Implement the probe function for the pvcalls frontend. Read the > > supported versions, max-page-order and function-calls nodes from > > xenstore. > > > > 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. > > > > 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> > > CC: boris.ostrovsky@oracle.com > > CC: jgross@suse.com > > --- > > drivers/xen/pvcalls-front.c | 153 > > ++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 153 insertions(+) > > > > diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c > > index a8d38c2..5e0b265 100644 > > --- a/drivers/xen/pvcalls-front.c > > +++ b/drivers/xen/pvcalls-front.c > > @@ -20,6 +20,29 @@ > > #include <xen/xenbus.h> > > #include <xen/interface/io/pvcalls.h> > > +#define PVCALLS_INVALID_ID (UINT_MAX) > > Unnecessary parentheses OK > > +#define RING_ORDER XENBUS_MAX_RING_GRANT_ORDER > > PVCALLS_RING_ORDER? Sure > > +#define PVCALLS_NR_REQ_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; > > + struct list_head socketpass_mappings; > > + spinlock_t pvcallss_lock; > > + > > + wait_queue_head_t inflight_req; > > + struct xen_pvcalls_response rsp[PVCALLS_NR_REQ_PER_RING]; > > +}; > > +struct xenbus_device *pvcalls_front_dev; > > static good point, I'll fix > > + > > +static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) > > +{ > > + return IRQ_HANDLED; > > +} > > + > > static const struct xenbus_device_id pvcalls_front_ids[] = { > > { "pvcalls" }, > > { "" } > > @@ -33,12 +56,142 @@ 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; > > + 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); > > + ret = xenbus_scanf(XBT_NIL, dev->otherend, > > + "max-page-order", "%u", &max_page_order); > > + if (ret <= 0) > > + return -ENODEV; > > + 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) > > + 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; > > + > > + init_waitqueue_head(&bedata->inflight_req); > > + for (i = 0; i < PVCALLS_NR_REQ_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 = ref = gnttab_claim_grant_reference(&gref_head); > > Is ref really needed? No, I'll remove it > > + if (ref < 0) > > + goto error; > > + gnttab_grant_foreign_access_ref(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", 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; > > + } > > + > > + 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; > > + > > + error_xenbus: > > + xenbus_transaction_end(xbt, 1); > > + xenbus_dev_fatal(dev, ret, "writing xenstore"); > > + error: > > + pvcalls_front_remove(dev); > > I think patch 12 (where you implement cleanup) could be moved before this one. I'll move the patch > I also think you are leaking bedata on error paths. bedata is freed by pvcalls_front_remove (kfree(bedata)), why do you say so? > > + 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 = {
>>> static int pvcalls_front_probe(struct xenbus_device *dev, >>> const struct xenbus_device_id *id) >>> { >>> + int ret = -EFAULT, evtchn, ref = -1, 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); >>> + ret = xenbus_scanf(XBT_NIL, dev->otherend, >>> + "max-page-order", "%u", &max_page_order); >>> + if (ret <= 0) >>> + return -ENODEV; >>> + 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) >>> + 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; >>> + >>> + init_waitqueue_head(&bedata->inflight_req); >>> + for (i = 0; i < PVCALLS_NR_REQ_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 = ref = gnttab_claim_grant_reference(&gref_head); >> Is ref really needed? > No, I'll remove it > > >>> + if (ref < 0) >>> + goto error; >>> + gnttab_grant_foreign_access_ref(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", 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; >>> + } >>> + >>> + 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; >>> + >>> + error_xenbus: >>> + xenbus_transaction_end(xbt, 1); >>> + xenbus_dev_fatal(dev, ret, "writing xenstore"); >>> + error: >>> + pvcalls_front_remove(dev); >> I think patch 12 (where you implement cleanup) could be moved before this one. > I'll move the patch > > >> I also think you are leaking bedata on error paths. > bedata is freed by pvcalls_front_remove (kfree(bedata)), why do you say > so? bedata there is read from dev_get_drvdata() and here you assign drvdata at the very end. Come think of it, pvcalls_front_remove() should probably first check whether bedata is valid. Or drvdata should be assigned right away in this routine, before any 'got error/error_xenbus'. -boris > > >>> + return ret; >>> } >>>
On Thu, 27 Jul 2017, Boris Ostrovsky wrote: > >>> static int pvcalls_front_probe(struct xenbus_device *dev, > >>> const struct xenbus_device_id *id) > >>> { > >>> + int ret = -EFAULT, evtchn, ref = -1, 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); > >>> + ret = xenbus_scanf(XBT_NIL, dev->otherend, > >>> + "max-page-order", "%u", &max_page_order); > >>> + if (ret <= 0) > >>> + return -ENODEV; > >>> + 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) > >>> + 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; > >>> + > >>> + init_waitqueue_head(&bedata->inflight_req); > >>> + for (i = 0; i < PVCALLS_NR_REQ_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 = ref = gnttab_claim_grant_reference(&gref_head); > >> Is ref really needed? > > No, I'll remove it > > > > > >>> + if (ref < 0) > >>> + goto error; > >>> + gnttab_grant_foreign_access_ref(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", 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; > >>> + } > >>> + > >>> + 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; > >>> + > >>> + error_xenbus: > >>> + xenbus_transaction_end(xbt, 1); > >>> + xenbus_dev_fatal(dev, ret, "writing xenstore"); > >>> + error: > >>> + pvcalls_front_remove(dev); > >> I think patch 12 (where you implement cleanup) could be moved before this one. > > I'll move the patch > > > > > >> I also think you are leaking bedata on error paths. > > bedata is freed by pvcalls_front_remove (kfree(bedata)), why do you say > > so? > > bedata there is read from dev_get_drvdata() and here you assign drvdata > at the very end. > > Come think of it, pvcalls_front_remove() should probably first check > whether bedata is valid. Or drvdata should be assigned right away in > this routine, before any 'got error/error_xenbus'. Yes, I'll do that
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index a8d38c2..5e0b265 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -20,6 +20,29 @@ #include <xen/xenbus.h> #include <xen/interface/io/pvcalls.h> +#define PVCALLS_INVALID_ID (UINT_MAX) +#define RING_ORDER XENBUS_MAX_RING_GRANT_ORDER +#define PVCALLS_NR_REQ_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; + struct list_head socketpass_mappings; + spinlock_t pvcallss_lock; + + wait_queue_head_t inflight_req; + struct xen_pvcalls_response rsp[PVCALLS_NR_REQ_PER_RING]; +}; +struct xenbus_device *pvcalls_front_dev; + +static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) +{ + return IRQ_HANDLED; +} + static const struct xenbus_device_id pvcalls_front_ids[] = { { "pvcalls" }, { "" } @@ -33,12 +56,142 @@ 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; + 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); + ret = xenbus_scanf(XBT_NIL, dev->otherend, + "max-page-order", "%u", &max_page_order); + if (ret <= 0) + return -ENODEV; + 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) + 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; + + init_waitqueue_head(&bedata->inflight_req); + for (i = 0; i < PVCALLS_NR_REQ_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 = ref = gnttab_claim_grant_reference(&gref_head); + if (ref < 0) + goto error; + gnttab_grant_foreign_access_ref(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", 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; + } + + 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; + + 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 = {
Implement the probe function for the pvcalls frontend. Read the supported versions, max-page-order and function-calls nodes from xenstore. 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. 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> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com --- drivers/xen/pvcalls-front.c | 153 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 153 insertions(+)