Merge tag 'for-linus-4.12b-rc0b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from Juergen Gross:
 "Xen fixes and featrues for 4.12. The main changes are:

   - enable building the kernel with Xen support but without enabling
     paravirtualized mode (Vitaly Kuznetsov)

   - add a new 9pfs xen frontend driver (Stefano Stabellini)

   - simplify Xen's cpuid handling by making use of cpu capabilities
     (Juergen Gross)

   - add/modify some headers for new Xen paravirtualized devices
     (Oleksandr Andrushchenko)

   - EFI reset_system support under Xen (Julien Grall)

   - and the usual cleanups and corrections"

* tag 'for-linus-4.12b-rc0b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (57 commits)
  xen: Move xen_have_vector_callback definition to enlighten.c
  xen: Implement EFI reset_system callback
  arm/xen: Consolidate calls to shutdown hypercall in a single helper
  xen: Export xen_reboot
  xen/x86: Call xen_smp_intr_init_pv() on BSP
  xen: Revert commits da72ff5bfcb0 and 72a9b186292d
  xen/pvh: Do not fill kernel's e820 map in init_pvh_bootparams()
  xen/scsifront: use offset_in_page() macro
  xen/arm,arm64: rename __generic_dma_ops to xen_get_dma_ops
  xen/arm,arm64: fix xen_dma_ops after 815dd18 "Consolidate get_dma_ops..."
  xen/9pfs: select CONFIG_XEN_XENBUS_FRONTEND
  x86/cpu: remove hypervisor specific set_cpu_features
  vmware: set cpu capabilities during platform initialization
  x86/xen: use capabilities instead of fake cpuid values for xsave
  x86/xen: use capabilities instead of fake cpuid values for x2apic
  x86/xen: use capabilities instead of fake cpuid values for mwait
  x86/xen: use capabilities instead of fake cpuid values for acpi
  x86/xen: use capabilities instead of fake cpuid values for acc
  x86/xen: use capabilities instead of fake cpuid values for mtrr
  x86/xen: use capabilities instead of fake cpuid values for aperf
  ...

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);