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-rw-r--r--net/9p/Kconfig9
-rw-r--r--net/9p/Makefile4
-rw-r--r--net/9p/trans_xen.c545
3 files changed, 558 insertions, 0 deletions
diff --git a/net/9p/Kconfig b/net/9p/Kconfig
index a75174a33723..e6014e0e51f7 100644
--- a/net/9p/Kconfig
+++ b/net/9p/Kconfig
@@ -22,6 +22,15 @@ config NET_9P_VIRTIO
This builds support for a transports between
guest partitions and a host partition.
+config NET_9P_XEN
+ depends on XEN
+ select XEN_XENBUS_FRONTEND
+ tristate "9P Xen Transport"
+ help
+ This builds support for a transport for 9pfs between
+ two Xen domains.
+
+
config NET_9P_RDMA
depends on INET && INFINIBAND && INFINIBAND_ADDR_TRANS
tristate "9P RDMA Transport (Experimental)"
diff --git a/net/9p/Makefile b/net/9p/Makefile
index a0874cc1f718..697ea7caf466 100644
--- a/net/9p/Makefile
+++ b/net/9p/Makefile
@@ -1,4 +1,5 @@
obj-$(CONFIG_NET_9P) := 9pnet.o
+obj-$(CONFIG_NET_9P_XEN) += 9pnet_xen.o
obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
obj-$(CONFIG_NET_9P_RDMA) += 9pnet_rdma.o
@@ -14,5 +15,8 @@ obj-$(CONFIG_NET_9P_RDMA) += 9pnet_rdma.o
9pnet_virtio-objs := \
trans_virtio.o \
+9pnet_xen-objs := \
+ trans_xen.o \
+
9pnet_rdma-objs := \
trans_rdma.o \
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
new file mode 100644
index 000000000000..71e85643b3f9
--- /dev/null
+++ b/net/9p/trans_xen.c
@@ -0,0 +1,545 @@
+/*
+ * linux/fs/9p/trans_xen
+ *
+ * Xen transport layer.
+ *
+ * Copyright (C) 2017 by Stefano Stabellini <stefano@aporeto.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <xen/events.h>
+#include <xen/grant_table.h>
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+#include <xen/interface/io/9pfs.h>
+
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/rwlock.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+#include <net/9p/transport.h>
+
+#define XEN_9PFS_NUM_RINGS 2
+#define XEN_9PFS_RING_ORDER 6
+#define XEN_9PFS_RING_SIZE XEN_FLEX_RING_SIZE(XEN_9PFS_RING_ORDER)
+
+struct xen_9pfs_header {
+ uint32_t size;
+ uint8_t id;
+ uint16_t tag;
+
+ /* uint8_t sdata[]; */
+} __attribute__((packed));
+
+/* One per ring, more than one per 9pfs share */
+struct xen_9pfs_dataring {
+ struct xen_9pfs_front_priv *priv;
+
+ struct xen_9pfs_data_intf *intf;
+ grant_ref_t ref;
+ int evtchn;
+ int irq;
+ /* protect a ring from concurrent accesses */
+ spinlock_t lock;
+
+ struct xen_9pfs_data data;
+ wait_queue_head_t wq;
+ struct work_struct work;
+};
+
+/* One per 9pfs share */
+struct xen_9pfs_front_priv {
+ struct list_head list;
+ struct xenbus_device *dev;
+ char *tag;
+ struct p9_client *client;
+
+ int num_rings;
+ struct xen_9pfs_dataring *rings;
+};
+
+static LIST_HEAD(xen_9pfs_devs);
+static DEFINE_RWLOCK(xen_9pfs_lock);
+
+/* We don't currently allow canceling of requests */
+static int p9_xen_cancel(struct p9_client *client, struct p9_req_t *req)
+{
+ return 1;
+}
+
+static int p9_xen_create(struct p9_client *client, const char *addr, char *args)
+{
+ struct xen_9pfs_front_priv *priv;
+
+ read_lock(&xen_9pfs_lock);
+ list_for_each_entry(priv, &xen_9pfs_devs, list) {
+ if (!strcmp(priv->tag, addr)) {
+ priv->client = client;
+ read_unlock(&xen_9pfs_lock);
+ return 0;
+ }
+ }
+ read_unlock(&xen_9pfs_lock);
+ return -EINVAL;
+}
+
+static void p9_xen_close(struct p9_client *client)
+{
+ struct xen_9pfs_front_priv *priv;
+
+ read_lock(&xen_9pfs_lock);
+ list_for_each_entry(priv, &xen_9pfs_devs, list) {
+ if (priv->client == client) {
+ priv->client = NULL;
+ read_unlock(&xen_9pfs_lock);
+ return;
+ }
+ }
+ read_unlock(&xen_9pfs_lock);
+}
+
+static bool p9_xen_write_todo(struct xen_9pfs_dataring *ring, RING_IDX size)
+{
+ RING_IDX cons, prod;
+
+ cons = ring->intf->out_cons;
+ prod = ring->intf->out_prod;
+ virt_mb();
+
+ return XEN_9PFS_RING_SIZE -
+ xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE) >= size;
+}
+
+static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req)
+{
+ struct xen_9pfs_front_priv *priv = NULL;
+ RING_IDX cons, prod, masked_cons, masked_prod;
+ unsigned long flags;
+ u32 size = p9_req->tc->size;
+ struct xen_9pfs_dataring *ring;
+ int num;
+
+ read_lock(&xen_9pfs_lock);
+ list_for_each_entry(priv, &xen_9pfs_devs, list) {
+ if (priv->client == client)
+ break;
+ }
+ read_unlock(&xen_9pfs_lock);
+ if (!priv || priv->client != client)
+ return -EINVAL;
+
+ num = p9_req->tc->tag % priv->num_rings;
+ ring = &priv->rings[num];
+
+again:
+ while (wait_event_interruptible(ring->wq,
+ p9_xen_write_todo(ring, size)) != 0)
+ ;
+
+ spin_lock_irqsave(&ring->lock, flags);
+ cons = ring->intf->out_cons;
+ prod = ring->intf->out_prod;
+ virt_mb();
+
+ if (XEN_9PFS_RING_SIZE - xen_9pfs_queued(prod, cons,
+ XEN_9PFS_RING_SIZE) < size) {
+ spin_unlock_irqrestore(&ring->lock, flags);
+ goto again;
+ }
+
+ masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
+ masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
+
+ xen_9pfs_write_packet(ring->data.out, p9_req->tc->sdata, size,
+ &masked_prod, masked_cons, XEN_9PFS_RING_SIZE);
+
+ p9_req->status = REQ_STATUS_SENT;
+ virt_wmb(); /* write ring before updating pointer */
+ prod += size;
+ ring->intf->out_prod = prod;
+ spin_unlock_irqrestore(&ring->lock, flags);
+ notify_remote_via_irq(ring->irq);
+
+ return 0;
+}
+
+static void p9_xen_response(struct work_struct *work)
+{
+ struct xen_9pfs_front_priv *priv;
+ struct xen_9pfs_dataring *ring;
+ RING_IDX cons, prod, masked_cons, masked_prod;
+ struct xen_9pfs_header h;
+ struct p9_req_t *req;
+ int status;
+
+ ring = container_of(work, struct xen_9pfs_dataring, work);
+ priv = ring->priv;
+
+ while (1) {
+ cons = ring->intf->in_cons;
+ prod = ring->intf->in_prod;
+ virt_rmb();
+
+ if (xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE) <
+ sizeof(h)) {
+ notify_remote_via_irq(ring->irq);
+ return;
+ }
+
+ masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
+ masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
+
+ /* First, read just the header */
+ xen_9pfs_read_packet(&h, ring->data.in, sizeof(h),
+ masked_prod, &masked_cons,
+ XEN_9PFS_RING_SIZE);
+
+ req = p9_tag_lookup(priv->client, h.tag);
+ if (!req || req->status != REQ_STATUS_SENT) {
+ dev_warn(&priv->dev->dev, "Wrong req tag=%x\n", h.tag);
+ cons += h.size;
+ virt_mb();
+ ring->intf->in_cons = cons;
+ continue;
+ }
+
+ memcpy(req->rc, &h, sizeof(h));
+ req->rc->offset = 0;
+
+ masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
+ /* Then, read the whole packet (including the header) */
+ xen_9pfs_read_packet(req->rc->sdata, ring->data.in, h.size,
+ masked_prod, &masked_cons,
+ XEN_9PFS_RING_SIZE);
+
+ virt_mb();
+ cons += h.size;
+ ring->intf->in_cons = cons;
+
+ status = (req->status != REQ_STATUS_ERROR) ?
+ REQ_STATUS_RCVD : REQ_STATUS_ERROR;
+
+ p9_client_cb(priv->client, req, status);
+ }
+}
+
+static irqreturn_t xen_9pfs_front_event_handler(int irq, void *r)
+{
+ struct xen_9pfs_dataring *ring = r;
+
+ if (!ring || !ring->priv->client) {
+ /* ignore spurious interrupt */
+ return IRQ_HANDLED;
+ }
+
+ wake_up_interruptible(&ring->wq);
+ schedule_work(&ring->work);
+
+ return IRQ_HANDLED;
+}
+
+static struct p9_trans_module p9_xen_trans = {
+ .name = "xen",
+ .maxsize = 1 << (XEN_9PFS_RING_ORDER + XEN_PAGE_SHIFT),
+ .def = 1,
+ .create = p9_xen_create,
+ .close = p9_xen_close,
+ .request = p9_xen_request,
+ .cancel = p9_xen_cancel,
+ .owner = THIS_MODULE,
+};
+
+static const struct xenbus_device_id xen_9pfs_front_ids[] = {
+ { "9pfs" },
+ { "" }
+};
+
+static void xen_9pfs_front_free(struct xen_9pfs_front_priv *priv)
+{
+ int i, j;
+
+ write_lock(&xen_9pfs_lock);
+ list_del(&priv->list);
+ write_unlock(&xen_9pfs_lock);
+
+ for (i = 0; i < priv->num_rings; i++) {
+ if (!priv->rings[i].intf)
+ break;
+ if (priv->rings[i].irq > 0)
+ unbind_from_irqhandler(priv->rings[i].irq, priv->dev);
+ if (priv->rings[i].data.in) {
+ for (j = 0; j < (1 << XEN_9PFS_RING_ORDER); j++) {
+ grant_ref_t ref;
+
+ ref = priv->rings[i].intf->ref[j];
+ gnttab_end_foreign_access(ref, 0, 0);
+ }
+ free_pages((unsigned long)priv->rings[i].data.in,
+ XEN_9PFS_RING_ORDER -
+ (PAGE_SHIFT - XEN_PAGE_SHIFT));
+ }
+ gnttab_end_foreign_access(priv->rings[i].ref, 0, 0);
+ free_page((unsigned long)priv->rings[i].intf);
+ }
+ kfree(priv->rings);
+ kfree(priv->tag);
+ kfree(priv);
+}
+
+static int xen_9pfs_front_remove(struct xenbus_device *dev)
+{
+ struct xen_9pfs_front_priv *priv = dev_get_drvdata(&dev->dev);
+
+ dev_set_drvdata(&dev->dev, NULL);
+ xen_9pfs_front_free(priv);
+ return 0;
+}
+
+static int xen_9pfs_front_alloc_dataring(struct xenbus_device *dev,
+ struct xen_9pfs_dataring *ring)
+{
+ int i = 0;
+ int ret = -ENOMEM;
+ void *bytes = NULL;
+
+ init_waitqueue_head(&ring->wq);
+ spin_lock_init(&ring->lock);
+ INIT_WORK(&ring->work, p9_xen_response);
+
+ ring->intf = (struct xen_9pfs_data_intf *)get_zeroed_page(GFP_KERNEL);
+ if (!ring->intf)
+ return ret;
+ ret = gnttab_grant_foreign_access(dev->otherend_id,
+ virt_to_gfn(ring->intf), 0);
+ if (ret < 0)
+ goto out;
+ ring->ref = ret;
+ bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+ XEN_9PFS_RING_ORDER - (PAGE_SHIFT - XEN_PAGE_SHIFT));
+ if (!bytes) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ for (; i < (1 << XEN_9PFS_RING_ORDER); i++) {
+ ret = gnttab_grant_foreign_access(
+ dev->otherend_id, virt_to_gfn(bytes) + i, 0);
+ if (ret < 0)
+ goto out;
+ ring->intf->ref[i] = ret;
+ }
+ ring->intf->ring_order = XEN_9PFS_RING_ORDER;
+ ring->data.in = bytes;
+ ring->data.out = bytes + XEN_9PFS_RING_SIZE;
+
+ ret = xenbus_alloc_evtchn(dev, &ring->evtchn);
+ if (ret)
+ goto out;
+ ring->irq = bind_evtchn_to_irqhandler(ring->evtchn,
+ xen_9pfs_front_event_handler,
+ 0, "xen_9pfs-frontend", ring);
+ if (ring->irq >= 0)
+ return 0;
+
+ xenbus_free_evtchn(dev, ring->evtchn);
+ ret = ring->irq;
+out:
+ if (bytes) {
+ for (i--; i >= 0; i--)
+ gnttab_end_foreign_access(ring->intf->ref[i], 0, 0);
+ free_pages((unsigned long)bytes,
+ XEN_9PFS_RING_ORDER -
+ (PAGE_SHIFT - XEN_PAGE_SHIFT));
+ }
+ gnttab_end_foreign_access(ring->ref, 0, 0);
+ free_page((unsigned long)ring->intf);
+ return ret;
+}
+
+static int xen_9pfs_front_probe(struct xenbus_device *dev,
+ const struct xenbus_device_id *id)
+{
+ int ret, i;
+ struct xenbus_transaction xbt;
+ struct xen_9pfs_front_priv *priv = NULL;
+ char *versions;
+ unsigned int max_rings, max_ring_order, len = 0;
+
+ versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len);
+ if (!len)
+ return -EINVAL;
+ if (strcmp(versions, "1")) {
+ kfree(versions);
+ return -EINVAL;
+ }
+ kfree(versions);
+ max_rings = xenbus_read_unsigned(dev->otherend, "max-rings", 0);
+ if (max_rings < XEN_9PFS_NUM_RINGS)
+ return -EINVAL;
+ max_ring_order = xenbus_read_unsigned(dev->otherend,
+ "max-ring-page-order", 0);
+ if (max_ring_order < XEN_9PFS_RING_ORDER)
+ return -EINVAL;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = dev;
+ priv->num_rings = XEN_9PFS_NUM_RINGS;
+ priv->rings = kcalloc(priv->num_rings, sizeof(*priv->rings),
+ GFP_KERNEL);
+ if (!priv->rings) {
+ kfree(priv);
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < priv->num_rings; i++) {
+ priv->rings[i].priv = priv;
+ ret = xen_9pfs_front_alloc_dataring(dev, &priv->rings[i]);
+ if (ret < 0)
+ goto error;
+ }
+
+ 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, "num-rings", "%u",
+ priv->num_rings);
+ if (ret)
+ goto error_xenbus;
+ for (i = 0; i < priv->num_rings; i++) {
+ char str[16];
+
+ BUILD_BUG_ON(XEN_9PFS_NUM_RINGS > 9);
+ sprintf(str, "ring-ref%u", i);
+ ret = xenbus_printf(xbt, dev->nodename, str, "%d",
+ priv->rings[i].ref);
+ if (ret)
+ goto error_xenbus;
+
+ sprintf(str, "event-channel-%u", i);
+ ret = xenbus_printf(xbt, dev->nodename, str, "%u",
+ priv->rings[i].evtchn);
+ if (ret)
+ goto error_xenbus;
+ }
+ priv->tag = xenbus_read(xbt, dev->nodename, "tag", NULL);
+ if (!priv->tag) {
+ ret = -EINVAL;
+ 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;
+ }
+
+ write_lock(&xen_9pfs_lock);
+ list_add_tail(&priv->list, &xen_9pfs_devs);
+ write_unlock(&xen_9pfs_lock);
+ dev_set_drvdata(&dev->dev, priv);
+ xenbus_switch_state(dev, XenbusStateInitialised);
+
+ return 0;
+
+ error_xenbus:
+ xenbus_transaction_end(xbt, 1);
+ xenbus_dev_fatal(dev, ret, "writing xenstore");
+ error:
+ dev_set_drvdata(&dev->dev, NULL);
+ xen_9pfs_front_free(priv);
+ return ret;
+}
+
+static int xen_9pfs_front_resume(struct xenbus_device *dev)
+{
+ dev_warn(&dev->dev, "suspsend/resume unsupported\n");
+ return 0;
+}
+
+static void xen_9pfs_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 xen_9pfs_front_driver = {
+ .ids = xen_9pfs_front_ids,
+ .probe = xen_9pfs_front_probe,
+ .remove = xen_9pfs_front_remove,
+ .resume = xen_9pfs_front_resume,
+ .otherend_changed = xen_9pfs_front_changed,
+};
+
+int p9_trans_xen_init(void)
+{
+ if (!xen_domain())
+ return -ENODEV;
+
+ pr_info("Initialising Xen transport for 9pfs\n");
+
+ v9fs_register_trans(&p9_xen_trans);
+ return xenbus_register_frontend(&xen_9pfs_front_driver);
+}
+module_init(p9_trans_xen_init);
+
+void p9_trans_xen_exit(void)
+{
+ v9fs_unregister_trans(&p9_xen_trans);
+ return xenbus_unregister_driver(&xen_9pfs_front_driver);
+}
+module_exit(p9_trans_xen_exit);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-21 12:51:14 +0000