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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /net/9p/trans_xen.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/9p/trans_xen.c')
-rw-r--r--net/9p/trans_xen.c571
1 files changed, 571 insertions, 0 deletions
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
new file mode 100644
index 0000000000..1fffe2bed5
--- /dev/null
+++ b/net/9p/trans_xen.c
@@ -0,0 +1,571 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/9p/trans_xen
+ *
+ * Xen transport layer.
+ *
+ * Copyright (C) 2017 by Stefano Stabellini <stefano@aporeto.com>
+ */
+
+#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 <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 9
+#define XEN_9PFS_RING_SIZE(ring) XEN_FLEX_RING_SIZE(ring->intf->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;
+
+ if (addr == NULL)
+ return -EINVAL;
+
+ 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(ring) -
+ xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE(ring)) >= size;
+}
+
+static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req)
+{
+ struct xen_9pfs_front_priv *priv;
+ 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 (list_entry_is_head(priv, &xen_9pfs_devs, list))
+ return -EINVAL;
+
+ num = p9_req->tc.tag % priv->num_rings;
+ ring = &priv->rings[num];
+
+again:
+ while (wait_event_killable(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(ring) -
+ xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE(ring)) < size) {
+ spin_unlock_irqrestore(&ring->lock, flags);
+ goto again;
+ }
+
+ masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE(ring));
+ masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE(ring));
+
+ xen_9pfs_write_packet(ring->data.out, p9_req->tc.sdata, size,
+ &masked_prod, masked_cons,
+ XEN_9PFS_RING_SIZE(ring));
+
+ WRITE_ONCE(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);
+ p9_req_put(client, p9_req);
+
+ 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(ring)) <
+ sizeof(h)) {
+ notify_remote_via_irq(ring->irq);
+ return;
+ }
+
+ masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE(ring));
+ masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE(ring));
+
+ /* First, read just the header */
+ xen_9pfs_read_packet(&h, ring->data.in, sizeof(h),
+ masked_prod, &masked_cons,
+ XEN_9PFS_RING_SIZE(ring));
+
+ 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;
+ }
+
+ if (h.size > req->rc.capacity) {
+ dev_warn(&priv->dev->dev,
+ "requested packet size too big: %d for tag %d with capacity %zd\n",
+ h.size, h.tag, req->rc.capacity);
+ WRITE_ONCE(req->status, REQ_STATUS_ERROR);
+ goto recv_error;
+ }
+
+ req->rc.size = h.size;
+ req->rc.id = h.id;
+ req->rc.tag = h.tag;
+ req->rc.offset = 0;
+
+ masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE(ring));
+ /* 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(ring));
+
+recv_error:
+ 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 - 2),
+ .pooled_rbuffers = false,
+ .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++) {
+ struct xen_9pfs_dataring *ring = &priv->rings[i];
+
+ cancel_work_sync(&ring->work);
+
+ 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 << priv->rings[i].intf->ring_order);
+ j++) {
+ grant_ref_t ref;
+
+ ref = priv->rings[i].intf->ref[j];
+ gnttab_end_foreign_access(ref, NULL);
+ }
+ free_pages_exact(priv->rings[i].data.in,
+ 1UL << (priv->rings[i].intf->ring_order +
+ XEN_PAGE_SHIFT));
+ }
+ gnttab_end_foreign_access(priv->rings[i].ref, NULL);
+ free_page((unsigned long)priv->rings[i].intf);
+ }
+ kfree(priv->rings);
+ kfree(priv->tag);
+ kfree(priv);
+}
+
+static void 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);
+}
+
+static int xen_9pfs_front_alloc_dataring(struct xenbus_device *dev,
+ struct xen_9pfs_dataring *ring,
+ unsigned int order)
+{
+ 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 = alloc_pages_exact(1UL << (order + XEN_PAGE_SHIFT),
+ GFP_KERNEL | __GFP_ZERO);
+ if (!bytes) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ for (; i < (1 << 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 = order;
+ ring->data.in = bytes;
+ ring->data.out = bytes + XEN_FLEX_RING_SIZE(order);
+
+ 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], NULL);
+ free_pages_exact(bytes, 1UL << (order + XEN_PAGE_SHIFT));
+ }
+ gnttab_end_foreign_access(ring->ref, NULL);
+ free_page((unsigned long)ring->intf);
+ return ret;
+}
+
+static int xen_9pfs_front_init(struct xenbus_device *dev)
+{
+ int ret, i;
+ struct xenbus_transaction xbt;
+ struct xen_9pfs_front_priv *priv = dev_get_drvdata(&dev->dev);
+ char *versions, *v;
+ unsigned int max_rings, max_ring_order, len = 0;
+
+ versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len);
+ if (IS_ERR(versions))
+ return PTR_ERR(versions);
+ for (v = versions; *v; v++) {
+ if (simple_strtoul(v, &v, 10) == 1) {
+ v = NULL;
+ break;
+ }
+ }
+ if (v) {
+ 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)
+ max_ring_order = XEN_9PFS_RING_ORDER;
+ if (p9_xen_trans.maxsize > XEN_FLEX_RING_SIZE(max_ring_order))
+ p9_xen_trans.maxsize = XEN_FLEX_RING_SIZE(max_ring_order) / 2;
+
+ 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],
+ max_ring_order);
+ 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%d", i);
+ ret = xenbus_printf(xbt, dev->nodename, str, "%d",
+ priv->rings[i].ref);
+ if (ret)
+ goto error_xenbus;
+
+ sprintf(str, "event-channel-%d", 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 (IS_ERR(priv->tag)) {
+ ret = PTR_ERR(priv->tag);
+ 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;
+ }
+
+ return 0;
+
+ error_xenbus:
+ xenbus_transaction_end(xbt, 1);
+ xenbus_dev_fatal(dev, ret, "writing xenstore");
+ error:
+ xen_9pfs_front_free(priv);
+ return ret;
+}
+
+static int xen_9pfs_front_probe(struct xenbus_device *dev,
+ const struct xenbus_device_id *id)
+{
+ struct xen_9pfs_front_priv *priv = NULL;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = dev;
+ dev_set_drvdata(&dev->dev, priv);
+
+ write_lock(&xen_9pfs_lock);
+ list_add_tail(&priv->list, &xen_9pfs_devs);
+ write_unlock(&xen_9pfs_lock);
+
+ return 0;
+}
+
+static int xen_9pfs_front_resume(struct xenbus_device *dev)
+{
+ dev_warn(&dev->dev, "suspend/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:
+ if (!xen_9pfs_front_init(dev))
+ xenbus_switch_state(dev, XenbusStateInitialised);
+ break;
+
+ case XenbusStateConnected:
+ xenbus_switch_state(dev, XenbusStateConnected);
+ break;
+
+ case XenbusStateClosed:
+ if (dev->state == XenbusStateClosed)
+ break;
+ fallthrough; /* Missed the backend's CLOSING state */
+ 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,
+};
+
+static int __init p9_trans_xen_init(void)
+{
+ int rc;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ pr_info("Initialising Xen transport for 9pfs\n");
+
+ v9fs_register_trans(&p9_xen_trans);
+ rc = xenbus_register_frontend(&xen_9pfs_front_driver);
+ if (rc)
+ v9fs_unregister_trans(&p9_xen_trans);
+
+ return rc;
+}
+module_init(p9_trans_xen_init);
+MODULE_ALIAS_9P("xen");
+
+static void __exit 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);
+
+MODULE_ALIAS("xen:9pfs");
+MODULE_AUTHOR("Stefano Stabellini <stefano@aporeto.com>");
+MODULE_DESCRIPTION("Xen Transport for 9P");
+MODULE_LICENSE("GPL");