virt: Add vboxguest driver for Virtual Box Guest integration

This commit adds a driver for the Virtual Box Guest PCI device used in
Virtual Box virtual machines. Enabling this driver will add support for
Virtual Box Guest integration features such as copy-and-paste, seamless
mode and OpenGL pass-through.

This driver also offers vboxguest IPC functionality which is needed
for the vboxfs driver which offers folder sharing support.

Signed-off-by: Hans de Goede <[e-mail]>
Reviewed-by: Larry Finger <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/virt/Kconfig

···
           4) A kernel interface for receiving callbacks when a managed
 	     partition shuts down.
 
+source "drivers/virt/vboxguest/Kconfig"
 endif

drivers/virt/Makefile

···
 #
 
 obj-$(CONFIG_FSL_HV_MANAGER)	+= fsl_hypervisor.o
+obj-y				+= vboxguest/

drivers/virt/vboxguest/Kconfig

···
+config VBOXGUEST
+	tristate "Virtual Box Guest integration support"
+	depends on X86 && PCI && INPUT
+	help
+	  This is a driver for the Virtual Box Guest PCI device used in
+	  Virtual Box virtual machines. Enabling this driver will add
+	  support for Virtual Box Guest integration features such as
+	  copy-and-paste, seamless mode and OpenGL pass-through.
+
+	  This driver also offers vboxguest IPC functionality which is needed
+	  for the vboxfs driver which offers folder sharing support.
+
+	  If you enable this driver you should also enable the VBOXVIDEO option.
+
+	  Although it is possible to build this module in, it is advised
+	  to build this driver as a module, so that it can be updated
+	  independently of the kernel. Select M to build this driver as a
+	  module.

drivers/virt/vboxguest/Makefile

···
+vboxguest-y := vboxguest_linux.o vboxguest_core.o vboxguest_utils.o
+
+obj-$(CONFIG_VBOXGUEST) += vboxguest.o

drivers/virt/vboxguest/vboxguest_core.c

···
+/* SPDX-License-Identifier: (GPL-2.0 OR CDDL-1.0) */
+/*
+ * vboxguest core guest-device handling code, VBoxGuest.cpp in upstream svn.
+ *
+ * Copyright (C) 2007-2016 Oracle Corporation
+ */
+
+#include <linux/device.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/vbox_err.h>
+#include <linux/vbox_utils.h>
+#include <linux/vmalloc.h>
+#include "vboxguest_core.h"
+#include "vboxguest_version.h"
+
+/* Get the pointer to the first HGCM parameter. */
+#define VBG_IOCTL_HGCM_CALL_PARMS(a) \
+	((struct vmmdev_hgcm_function_parameter *)( \
+		(u8 *)(a) + sizeof(struct vbg_ioctl_hgcm_call)))
+/* Get the pointer to the first HGCM parameter in a 32-bit request. */
+#define VBG_IOCTL_HGCM_CALL_PARMS32(a) \
+	((struct vmmdev_hgcm_function_parameter32 *)( \
+		(u8 *)(a) + sizeof(struct vbg_ioctl_hgcm_call)))
+
+#define GUEST_MAPPINGS_TRIES	5
+
+/**
+ * Reserves memory in which the VMM can relocate any guest mappings
+ * that are floating around.
+ *
+ * This operation is a little bit tricky since the VMM might not accept
+ * just any address because of address clashes between the three contexts
+ * it operates in, so we try several times.
+ *
+ * Failure to reserve the guest mappings is ignored.
+ *
+ * @gdev:		The Guest extension device.
+ */
+static void vbg_guest_mappings_init(struct vbg_dev *gdev)
+{
+	struct vmmdev_hypervisorinfo *req;
+	void *guest_mappings[GUEST_MAPPINGS_TRIES];
+	struct page **pages = NULL;
+	u32 size, hypervisor_size;
+	int i, rc;
+
+	/* Query the required space. */
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_GET_HYPERVISOR_INFO);
+	if (!req)
+		return;
+
+	req->hypervisor_start = 0;
+	req->hypervisor_size = 0;
+	rc = vbg_req_perform(gdev, req);
+	if (rc < 0)
+		goto out;
+
+	/*
+	 * The VMM will report back if there is nothing it wants to map, like
+	 * for instance in VT-x and AMD-V mode.
+	 */
+	if (req->hypervisor_size == 0)
+		goto out;
+
+	hypervisor_size = req->hypervisor_size;
+	/* Add 4M so that we can align the vmap to 4MiB as the host requires. */
+	size = PAGE_ALIGN(req->hypervisor_size) + SZ_4M;
+
+	pages = kmalloc(sizeof(*pages) * (size >> PAGE_SHIFT), GFP_KERNEL);
+	if (!pages)
+		goto out;
+
+	gdev->guest_mappings_dummy_page = alloc_page(GFP_HIGHUSER);
+	if (!gdev->guest_mappings_dummy_page)
+		goto out;
+
+	for (i = 0; i < (size >> PAGE_SHIFT); i++)
+		pages[i] = gdev->guest_mappings_dummy_page;
+
+	/*
+	 * Try several times, the VMM might not accept some addresses because
+	 * of address clashes between the three contexts.
+	 */
+	for (i = 0; i < GUEST_MAPPINGS_TRIES; i++) {
+		guest_mappings[i] = vmap(pages, (size >> PAGE_SHIFT),
+					 VM_MAP, PAGE_KERNEL_RO);
+		if (!guest_mappings[i])
+			break;
+
+		req->header.request_type = VMMDEVREQ_SET_HYPERVISOR_INFO;
+		req->header.rc = VERR_INTERNAL_ERROR;
+		req->hypervisor_size = hypervisor_size;
+		req->hypervisor_start =
+			(unsigned long)PTR_ALIGN(guest_mappings[i], SZ_4M);
+
+		rc = vbg_req_perform(gdev, req);
+		if (rc >= 0) {
+			gdev->guest_mappings = guest_mappings[i];
+			break;
+		}
+	}
+
+	/* Free vmap's from failed attempts. */
+	while (--i >= 0)
+		vunmap(guest_mappings[i]);
+
+	/* On failure free the dummy-page backing the vmap */
+	if (!gdev->guest_mappings) {
+		__free_page(gdev->guest_mappings_dummy_page);
+		gdev->guest_mappings_dummy_page = NULL;
+	}
+
+out:
+	kfree(req);
+	kfree(pages);
+}
+
+/**
+ * Undo what vbg_guest_mappings_init did.
+ *
+ * @gdev:		The Guest extension device.
+ */
+static void vbg_guest_mappings_exit(struct vbg_dev *gdev)
+{
+	struct vmmdev_hypervisorinfo *req;
+	int rc;
+
+	if (!gdev->guest_mappings)
+		return;
+
+	/*
+	 * Tell the host that we're going to free the memory we reserved for
+	 * it, the free it up. (Leak the memory if anything goes wrong here.)
+	 */
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_SET_HYPERVISOR_INFO);
+	if (!req)
+		return;
+
+	req->hypervisor_start = 0;
+	req->hypervisor_size = 0;
+
+	rc = vbg_req_perform(gdev, req);
+
+	kfree(req);
+
+	if (rc < 0) {
+		vbg_err("%s error: %d\n", __func__, rc);
+		return;
+	}
+
+	vunmap(gdev->guest_mappings);
+	gdev->guest_mappings = NULL;
+
+	__free_page(gdev->guest_mappings_dummy_page);
+	gdev->guest_mappings_dummy_page = NULL;
+}
+
+/**
+ * Report the guest information to the host.
+ * Return: 0 or negative errno value.
+ * @gdev:		The Guest extension device.
+ */
+static int vbg_report_guest_info(struct vbg_dev *gdev)
+{
+	/*
+	 * Allocate and fill in the two guest info reports.
+	 */
+	struct vmmdev_guest_info *req1 = NULL;
+	struct vmmdev_guest_info2 *req2 = NULL;
+	int rc, ret = -ENOMEM;
+
+	req1 = vbg_req_alloc(sizeof(*req1), VMMDEVREQ_REPORT_GUEST_INFO);
+	req2 = vbg_req_alloc(sizeof(*req2), VMMDEVREQ_REPORT_GUEST_INFO2);
+	if (!req1 || !req2)
+		goto out_free;
+
+	req1->interface_version = VMMDEV_VERSION;
+	req1->os_type = VMMDEV_OSTYPE_LINUX26;
+#if __BITS_PER_LONG == 64
+	req1->os_type |= VMMDEV_OSTYPE_X64;
+#endif
+
+	req2->additions_major = VBG_VERSION_MAJOR;
+	req2->additions_minor = VBG_VERSION_MINOR;
+	req2->additions_build = VBG_VERSION_BUILD;
+	req2->additions_revision = VBG_SVN_REV;
+	/* (no features defined yet) */
+	req2->additions_features = 0;
+	strlcpy(req2->name, VBG_VERSION_STRING,
+		sizeof(req2->name));
+
+	/*
+	 * There are two protocols here:
+	 *      1. INFO2 + INFO1. Supported by >=3.2.51.
+	 *      2. INFO1 and optionally INFO2. The old protocol.
+	 *
+	 * We try protocol 2 first.  It will fail with VERR_NOT_SUPPORTED
+	 * if not supported by the VMMDev (message ordering requirement).
+	 */
+	rc = vbg_req_perform(gdev, req2);
+	if (rc >= 0) {
+		rc = vbg_req_perform(gdev, req1);
+	} else if (rc == VERR_NOT_SUPPORTED || rc == VERR_NOT_IMPLEMENTED) {
+		rc = vbg_req_perform(gdev, req1);
+		if (rc >= 0) {
+			rc = vbg_req_perform(gdev, req2);
+			if (rc == VERR_NOT_IMPLEMENTED)
+				rc = VINF_SUCCESS;
+		}
+	}
+	ret = vbg_status_code_to_errno(rc);
+
+out_free:
+	kfree(req2);
+	kfree(req1);
+	return ret;
+}
+
+/**
+ * Report the guest driver status to the host.
+ * Return: 0 or negative errno value.
+ * @gdev:		The Guest extension device.
+ * @active:		Flag whether the driver is now active or not.
+ */
+static int vbg_report_driver_status(struct vbg_dev *gdev, bool active)
+{
+	struct vmmdev_guest_status *req;
+	int rc;
+
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_REPORT_GUEST_STATUS);
+	if (!req)
+		return -ENOMEM;
+
+	req->facility = VBOXGUEST_FACILITY_TYPE_VBOXGUEST_DRIVER;
+	if (active)
+		req->status = VBOXGUEST_FACILITY_STATUS_ACTIVE;
+	else
+		req->status = VBOXGUEST_FACILITY_STATUS_INACTIVE;
+	req->flags = 0;
+
+	rc = vbg_req_perform(gdev, req);
+	if (rc == VERR_NOT_IMPLEMENTED)	/* Compatibility with older hosts. */
+		rc = VINF_SUCCESS;
+
+	kfree(req);
+
+	return vbg_status_code_to_errno(rc);
+}
+
+/**
+ * Inflate the balloon by one chunk. The caller owns the balloon mutex.
+ * Return: 0 or negative errno value.
+ * @gdev:		The Guest extension device.
+ * @chunk_idx:		Index of the chunk.
+ */
+static int vbg_balloon_inflate(struct vbg_dev *gdev, u32 chunk_idx)
+{
+	struct vmmdev_memballoon_change *req = gdev->mem_balloon.change_req;
+	struct page **pages;
+	int i, rc, ret;
+
+	pages = kmalloc(sizeof(*pages) * VMMDEV_MEMORY_BALLOON_CHUNK_PAGES,
+			GFP_KERNEL | __GFP_NOWARN);
+	if (!pages)
+		return -ENOMEM;
+
+	req->header.size = sizeof(*req);
+	req->inflate = true;
+	req->pages = VMMDEV_MEMORY_BALLOON_CHUNK_PAGES;
+
+	for (i = 0; i < VMMDEV_MEMORY_BALLOON_CHUNK_PAGES; i++) {
+		pages[i] = alloc_page(GFP_KERNEL | __GFP_NOWARN);
+		if (!pages[i]) {
+			ret = -ENOMEM;
+			goto out_error;
+		}
+
+		req->phys_page[i] = page_to_phys(pages[i]);
+	}
+
+	rc = vbg_req_perform(gdev, req);
+	if (rc < 0) {
+		vbg_err("%s error, rc: %d\n", __func__, rc);
+		ret = vbg_status_code_to_errno(rc);
+		goto out_error;
+	}
+
+	gdev->mem_balloon.pages[chunk_idx] = pages;
+
+	return 0;
+
+out_error:
+	while (--i >= 0)
+		__free_page(pages[i]);
+	kfree(pages);
+
+	return ret;
+}
+
+/**
+ * Deflate the balloon by one chunk. The caller owns the balloon mutex.
+ * Return: 0 or negative errno value.
+ * @gdev:		The Guest extension device.
+ * @chunk_idx:		Index of the chunk.
+ */
+static int vbg_balloon_deflate(struct vbg_dev *gdev, u32 chunk_idx)
+{
+	struct vmmdev_memballoon_change *req = gdev->mem_balloon.change_req;
+	struct page **pages = gdev->mem_balloon.pages[chunk_idx];
+	int i, rc;
+
+	req->header.size = sizeof(*req);
+	req->inflate = false;
+	req->pages = VMMDEV_MEMORY_BALLOON_CHUNK_PAGES;
+
+	for (i = 0; i < VMMDEV_MEMORY_BALLOON_CHUNK_PAGES; i++)
+		req->phys_page[i] = page_to_phys(pages[i]);
+
+	rc = vbg_req_perform(gdev, req);
+	if (rc < 0) {
+		vbg_err("%s error, rc: %d\n", __func__, rc);
+		return vbg_status_code_to_errno(rc);
+	}
+
+	for (i = 0; i < VMMDEV_MEMORY_BALLOON_CHUNK_PAGES; i++)
+		__free_page(pages[i]);
+	kfree(pages);
+	gdev->mem_balloon.pages[chunk_idx] = NULL;
+
+	return 0;
+}
+
+/**
+ * Respond to VMMDEV_EVENT_BALLOON_CHANGE_REQUEST events, query the size
+ * the host wants the balloon to be and adjust accordingly.
+ */
+static void vbg_balloon_work(struct work_struct *work)
+{
+	struct vbg_dev *gdev =
+		container_of(work, struct vbg_dev, mem_balloon.work);
+	struct vmmdev_memballoon_info *req = gdev->mem_balloon.get_req;
+	u32 i, chunks;
+	int rc, ret;
+
+	/*
+	 * Setting this bit means that we request the value from the host and
+	 * change the guest memory balloon according to the returned value.
+	 */
+	req->event_ack = VMMDEV_EVENT_BALLOON_CHANGE_REQUEST;
+	rc = vbg_req_perform(gdev, req);
+	if (rc < 0) {
+		vbg_err("%s error, rc: %d)\n", __func__, rc);
+		return;
+	}
+
+	/*
+	 * The host always returns the same maximum amount of chunks, so
+	 * we do this once.
+	 */
+	if (!gdev->mem_balloon.max_chunks) {
+		gdev->mem_balloon.pages =
+			devm_kcalloc(gdev->dev, req->phys_mem_chunks,
+				     sizeof(struct page **), GFP_KERNEL);
+		if (!gdev->mem_balloon.pages)
+			return;
+
+		gdev->mem_balloon.max_chunks = req->phys_mem_chunks;
+	}
+
+	chunks = req->balloon_chunks;
+	if (chunks > gdev->mem_balloon.max_chunks) {
+		vbg_err("%s: illegal balloon size %u (max=%u)\n",
+			__func__, chunks, gdev->mem_balloon.max_chunks);
+		return;
+	}
+
+	if (chunks > gdev->mem_balloon.chunks) {
+		/* inflate */
+		for (i = gdev->mem_balloon.chunks; i < chunks; i++) {
+			ret = vbg_balloon_inflate(gdev, i);
+			if (ret < 0)
+				return;
+
+			gdev->mem_balloon.chunks++;
+		}
+	} else {
+		/* deflate */
+		for (i = gdev->mem_balloon.chunks; i-- > chunks;) {
+			ret = vbg_balloon_deflate(gdev, i);
+			if (ret < 0)
+				return;
+
+			gdev->mem_balloon.chunks--;
+		}
+	}
+}
+
+/**
+ * Callback for heartbeat timer.
+ */
+static void vbg_heartbeat_timer(struct timer_list *t)
+{
+	struct vbg_dev *gdev = from_timer(gdev, t, heartbeat_timer);
+
+	vbg_req_perform(gdev, gdev->guest_heartbeat_req);
+	mod_timer(&gdev->heartbeat_timer,
+		  msecs_to_jiffies(gdev->heartbeat_interval_ms));
+}
+
+/**
+ * Configure the host to check guest's heartbeat
+ * and get heartbeat interval from the host.
+ * Return: 0 or negative errno value.
+ * @gdev:		The Guest extension device.
+ * @enabled:		Set true to enable guest heartbeat checks on host.
+ */
+static int vbg_heartbeat_host_config(struct vbg_dev *gdev, bool enabled)
+{
+	struct vmmdev_heartbeat *req;
+	int rc;
+
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_HEARTBEAT_CONFIGURE);
+	if (!req)
+		return -ENOMEM;
+
+	req->enabled = enabled;
+	req->interval_ns = 0;
+	rc = vbg_req_perform(gdev, req);
+	do_div(req->interval_ns, 1000000); /* ns -> ms */
+	gdev->heartbeat_interval_ms = req->interval_ns;
+	kfree(req);
+
+	return vbg_status_code_to_errno(rc);
+}
+
+/**
+ * Initializes the heartbeat timer. This feature may be disabled by the host.
+ * Return: 0 or negative errno value.
+ * @gdev:		The Guest extension device.
+ */
+static int vbg_heartbeat_init(struct vbg_dev *gdev)
+{
+	int ret;
+
+	/* Make sure that heartbeat checking is disabled if we fail. */
+	ret = vbg_heartbeat_host_config(gdev, false);
+	if (ret < 0)
+		return ret;
+
+	ret = vbg_heartbeat_host_config(gdev, true);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Preallocate the request to use it from the timer callback because:
+	 *    1) on Windows vbg_req_alloc must be called at IRQL <= APC_LEVEL
+	 *       and the timer callback runs at DISPATCH_LEVEL;
+	 *    2) avoid repeated allocations.
+	 */
+	gdev->guest_heartbeat_req = vbg_req_alloc(
+					sizeof(*gdev->guest_heartbeat_req),
+					VMMDEVREQ_GUEST_HEARTBEAT);
+	if (!gdev->guest_heartbeat_req)
+		return -ENOMEM;
+
+	vbg_info("%s: Setting up heartbeat to trigger every %d milliseconds\n",
+		 __func__, gdev->heartbeat_interval_ms);
+	mod_timer(&gdev->heartbeat_timer, 0);
+
+	return 0;
+}
+
+/**
+ * Cleanup hearbeat code, stop HB timer and disable host heartbeat checking.
+ * @gdev:		The Guest extension device.
+ */
+static void vbg_heartbeat_exit(struct vbg_dev *gdev)
+{
+	del_timer_sync(&gdev->heartbeat_timer);
+	vbg_heartbeat_host_config(gdev, false);
+	kfree(gdev->guest_heartbeat_req);
+
+}
+
+/**
+ * Applies a change to the bit usage tracker.
+ * Return: true if the mask changed, false if not.
+ * @tracker:		The bit usage tracker.
+ * @changed:		The bits to change.
+ * @previous:		The previous value of the bits.
+ */
+static bool vbg_track_bit_usage(struct vbg_bit_usage_tracker *tracker,
+				u32 changed, u32 previous)
+{
+	bool global_change = false;
+
+	while (changed) {
+		u32 bit = ffs(changed) - 1;
+		u32 bitmask = BIT(bit);
+
+		if (bitmask & previous) {
+			tracker->per_bit_usage[bit] -= 1;
+			if (tracker->per_bit_usage[bit] == 0) {
+				global_change = true;
+				tracker->mask &= ~bitmask;
+			}
+		} else {
+			tracker->per_bit_usage[bit] += 1;
+			if (tracker->per_bit_usage[bit] == 1) {
+				global_change = true;
+				tracker->mask |= bitmask;
+			}
+		}
+
+		changed &= ~bitmask;
+	}
+
+	return global_change;
+}
+
+/**
+ * Init and termination worker for resetting the (host) event filter on the host
+ * Return: 0 or negative errno value.
+ * @gdev:		   The Guest extension device.
+ * @fixed_events:	   Fixed events (init time).
+ */
+static int vbg_reset_host_event_filter(struct vbg_dev *gdev,
+				       u32 fixed_events)
+{
+	struct vmmdev_mask *req;
+	int rc;
+
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_CTL_GUEST_FILTER_MASK);
+	if (!req)
+		return -ENOMEM;
+
+	req->not_mask = U32_MAX & ~fixed_events;
+	req->or_mask = fixed_events;
+	rc = vbg_req_perform(gdev, req);
+	if (rc < 0)
+		vbg_err("%s error, rc: %d\n", __func__, rc);
+
+	kfree(req);
+	return vbg_status_code_to_errno(rc);
+}
+
+/**
+ * Changes the event filter mask for the given session.
+ *
+ * This is called in response to VBG_IOCTL_CHANGE_FILTER_MASK as well as to
+ * do session cleanup. Takes the session spinlock.
+ *
+ * Return: 0 or negative errno value.
+ * @gdev:			The Guest extension device.
+ * @session:			The session.
+ * @or_mask:			The events to add.
+ * @not_mask:			The events to remove.
+ * @session_termination:	Set if we're called by the session cleanup code.
+ *				This tweaks the error handling so we perform
+ *				proper session cleanup even if the host
+ *				misbehaves.
+ */
+static int vbg_set_session_event_filter(struct vbg_dev *gdev,
+					struct vbg_session *session,
+					u32 or_mask, u32 not_mask,
+					bool session_termination)
+{
+	struct vmmdev_mask *req;
+	u32 changed, previous;
+	int rc, ret = 0;
+
+	/* Allocate a request buffer before taking the spinlock */
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_CTL_GUEST_FILTER_MASK);
+	if (!req) {
+		if (!session_termination)
+			return -ENOMEM;
+		/* Ignore allocation failure, we must do session cleanup. */
+	}
+
+	mutex_lock(&gdev->session_mutex);
+
+	/* Apply the changes to the session mask. */
+	previous = session->event_filter;
+	session->event_filter |= or_mask;
+	session->event_filter &= ~not_mask;
+
+	/* If anything actually changed, update the global usage counters. */
+	changed = previous ^ session->event_filter;
+	if (!changed)
+		goto out;
+
+	vbg_track_bit_usage(&gdev->event_filter_tracker, changed, previous);
+	or_mask = gdev->fixed_events | gdev->event_filter_tracker.mask;
+
+	if (gdev->event_filter_host == or_mask || !req)
+		goto out;
+
+	gdev->event_filter_host = or_mask;
+	req->or_mask = or_mask;
+	req->not_mask = ~or_mask;
+	rc = vbg_req_perform(gdev, req);
+	if (rc < 0) {
+		ret = vbg_status_code_to_errno(rc);
+
+		/* Failed, roll back (unless it's session termination time). */
+		gdev->event_filter_host = U32_MAX;
+		if (session_termination)
+			goto out;
+
+		vbg_track_bit_usage(&gdev->event_filter_tracker, changed,
+				    session->event_filter);
+		session->event_filter = previous;
+	}
+
+out:
+	mutex_unlock(&gdev->session_mutex);
+	kfree(req);
+
+	return ret;
+}
+
+/**
+ * Init and termination worker for set guest capabilities to zero on the host.
+ * Return: 0 or negative errno value.
+ * @gdev:		The Guest extension device.
+ */
+static int vbg_reset_host_capabilities(struct vbg_dev *gdev)
+{
+	struct vmmdev_mask *req;
+	int rc;
+
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_SET_GUEST_CAPABILITIES);
+	if (!req)
+		return -ENOMEM;
+
+	req->not_mask = U32_MAX;
+	req->or_mask = 0;
+	rc = vbg_req_perform(gdev, req);
+	if (rc < 0)
+		vbg_err("%s error, rc: %d\n", __func__, rc);
+
+	kfree(req);
+	return vbg_status_code_to_errno(rc);
+}
+
+/**
+ * Sets the guest capabilities for a session. Takes the session spinlock.
+ * Return: 0 or negative errno value.
+ * @gdev:			The Guest extension device.
+ * @session:			The session.
+ * @or_mask:			The capabilities to add.
+ * @not_mask:			The capabilities to remove.
+ * @session_termination:	Set if we're called by the session cleanup code.
+ *				This tweaks the error handling so we perform
+ *				proper session cleanup even if the host
+ *				misbehaves.
+ */
+static int vbg_set_session_capabilities(struct vbg_dev *gdev,
+					struct vbg_session *session,
+					u32 or_mask, u32 not_mask,
+					bool session_termination)
+{
+	struct vmmdev_mask *req;
+	u32 changed, previous;
+	int rc, ret = 0;
+
+	/* Allocate a request buffer before taking the spinlock */
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_SET_GUEST_CAPABILITIES);
+	if (!req) {
+		if (!session_termination)
+			return -ENOMEM;
+		/* Ignore allocation failure, we must do session cleanup. */
+	}
+
+	mutex_lock(&gdev->session_mutex);
+
+	/* Apply the changes to the session mask. */
+	previous = session->guest_caps;
+	session->guest_caps |= or_mask;
+	session->guest_caps &= ~not_mask;
+
+	/* If anything actually changed, update the global usage counters. */
+	changed = previous ^ session->guest_caps;
+	if (!changed)
+		goto out;
+
+	vbg_track_bit_usage(&gdev->guest_caps_tracker, changed, previous);
+	or_mask = gdev->guest_caps_tracker.mask;
+
+	if (gdev->guest_caps_host == or_mask || !req)
+		goto out;
+
+	gdev->guest_caps_host = or_mask;
+	req->or_mask = or_mask;
+	req->not_mask = ~or_mask;
+	rc = vbg_req_perform(gdev, req);
+	if (rc < 0) {
+		ret = vbg_status_code_to_errno(rc);
+
+		/* Failed, roll back (unless it's session termination time). */
+		gdev->guest_caps_host = U32_MAX;
+		if (session_termination)
+			goto out;
+
+		vbg_track_bit_usage(&gdev->guest_caps_tracker, changed,
+				    session->guest_caps);
+		session->guest_caps = previous;
+	}
+
+out:
+	mutex_unlock(&gdev->session_mutex);
+	kfree(req);
+
+	return ret;
+}
+
+/**
+ * vbg_query_host_version get the host feature mask and version information.
+ * Return: 0 or negative errno value.
+ * @gdev:		The Guest extension device.
+ */
+static int vbg_query_host_version(struct vbg_dev *gdev)
+{
+	struct vmmdev_host_version *req;
+	int rc, ret;
+
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_GET_HOST_VERSION);
+	if (!req)
+		return -ENOMEM;
+
+	rc = vbg_req_perform(gdev, req);
+	ret = vbg_status_code_to_errno(rc);
+	if (ret)
+		goto out;
+
+	snprintf(gdev->host_version, sizeof(gdev->host_version), "%u.%u.%ur%u",
+		 req->major, req->minor, req->build, req->revision);
+	gdev->host_features = req->features;
+
+	vbg_info("vboxguest: host-version: %s %#x\n", gdev->host_version,
+		 gdev->host_features);
+
+	if (!(req->features & VMMDEV_HVF_HGCM_PHYS_PAGE_LIST)) {
+		vbg_err("vboxguest: Error host too old (does not support page-lists)\n");
+		ret = -ENODEV;
+	}
+
+out:
+	kfree(req);
+	return ret;
+}
+
+/**
+ * Initializes the VBoxGuest device extension when the
+ * device driver is loaded.
+ *
+ * The native code locates the VMMDev on the PCI bus and retrieve
+ * the MMIO and I/O port ranges, this function will take care of
+ * mapping the MMIO memory (if present). Upon successful return
+ * the native code should set up the interrupt handler.
+ *
+ * Return: 0 or negative errno value.
+ *
+ * @gdev:		The Guest extension device.
+ * @fixed_events:	Events that will be enabled upon init and no client
+ *			will ever be allowed to mask.
+ */
+int vbg_core_init(struct vbg_dev *gdev, u32 fixed_events)
+{
+	int ret = -ENOMEM;
+
+	gdev->fixed_events = fixed_events | VMMDEV_EVENT_HGCM;
+	gdev->event_filter_host = U32_MAX;	/* forces a report */
+	gdev->guest_caps_host = U32_MAX;	/* forces a report */
+
+	init_waitqueue_head(&gdev->event_wq);
+	init_waitqueue_head(&gdev->hgcm_wq);
+	spin_lock_init(&gdev->event_spinlock);
+	mutex_init(&gdev->session_mutex);
+	mutex_init(&gdev->cancel_req_mutex);
+	timer_setup(&gdev->heartbeat_timer, vbg_heartbeat_timer, 0);
+	INIT_WORK(&gdev->mem_balloon.work, vbg_balloon_work);
+
+	gdev->mem_balloon.get_req =
+		vbg_req_alloc(sizeof(*gdev->mem_balloon.get_req),
+			      VMMDEVREQ_GET_MEMBALLOON_CHANGE_REQ);
+	gdev->mem_balloon.change_req =
+		vbg_req_alloc(sizeof(*gdev->mem_balloon.change_req),
+			      VMMDEVREQ_CHANGE_MEMBALLOON);
+	gdev->cancel_req =
+		vbg_req_alloc(sizeof(*(gdev->cancel_req)),
+			      VMMDEVREQ_HGCM_CANCEL2);
+	gdev->ack_events_req =
+		vbg_req_alloc(sizeof(*gdev->ack_events_req),
+			      VMMDEVREQ_ACKNOWLEDGE_EVENTS);
+	gdev->mouse_status_req =
+		vbg_req_alloc(sizeof(*gdev->mouse_status_req),
+			      VMMDEVREQ_GET_MOUSE_STATUS);
+
+	if (!gdev->mem_balloon.get_req || !gdev->mem_balloon.change_req ||
+	    !gdev->cancel_req || !gdev->ack_events_req ||
+	    !gdev->mouse_status_req)
+		goto err_free_reqs;
+
+	ret = vbg_query_host_version(gdev);
+	if (ret)
+		goto err_free_reqs;
+
+	ret = vbg_report_guest_info(gdev);
+	if (ret) {
+		vbg_err("vboxguest: vbg_report_guest_info error: %d\n", ret);
+		goto err_free_reqs;
+	}
+
+	ret = vbg_reset_host_event_filter(gdev, gdev->fixed_events);
+	if (ret) {
+		vbg_err("vboxguest: Error setting fixed event filter: %d\n",
+			ret);
+		goto err_free_reqs;
+	}
+
+	ret = vbg_reset_host_capabilities(gdev);
+	if (ret) {
+		vbg_err("vboxguest: Error clearing guest capabilities: %d\n",
+			ret);
+		goto err_free_reqs;
+	}
+
+	ret = vbg_core_set_mouse_status(gdev, 0);
+	if (ret) {
+		vbg_err("vboxguest: Error clearing mouse status: %d\n", ret);
+		goto err_free_reqs;
+	}
+
+	/* These may fail without requiring the driver init to fail. */
+	vbg_guest_mappings_init(gdev);
+	vbg_heartbeat_init(gdev);
+
+	/* All Done! */
+	ret = vbg_report_driver_status(gdev, true);
+	if (ret < 0)
+		vbg_err("vboxguest: Error reporting driver status: %d\n", ret);
+
+	return 0;
+
+err_free_reqs:
+	kfree(gdev->mouse_status_req);
+	kfree(gdev->ack_events_req);
+	kfree(gdev->cancel_req);
+	kfree(gdev->mem_balloon.change_req);
+	kfree(gdev->mem_balloon.get_req);
+	return ret;
+}
+
+/**
+ * Call this on exit to clean-up vboxguest-core managed resources.
+ *
+ * The native code should call this before the driver is loaded,
+ * but don't call this on shutdown.
+ * @gdev:		The Guest extension device.
+ */
+void vbg_core_exit(struct vbg_dev *gdev)
+{
+	vbg_heartbeat_exit(gdev);
+	vbg_guest_mappings_exit(gdev);
+
+	/* Clear the host flags (mouse status etc). */
+	vbg_reset_host_event_filter(gdev, 0);
+	vbg_reset_host_capabilities(gdev);
+	vbg_core_set_mouse_status(gdev, 0);
+
+	kfree(gdev->mouse_status_req);
+	kfree(gdev->ack_events_req);
+	kfree(gdev->cancel_req);
+	kfree(gdev->mem_balloon.change_req);
+	kfree(gdev->mem_balloon.get_req);
+}
+
+/**
+ * Creates a VBoxGuest user session.
+ *
+ * vboxguest_linux.c calls this when userspace opens the char-device.
+ * Return: A pointer to the new session or an ERR_PTR on error.
+ * @gdev:		The Guest extension device.
+ * @user:		Set if this is a session for the vboxuser device.
+ */
+struct vbg_session *vbg_core_open_session(struct vbg_dev *gdev, bool user)
+{
+	struct vbg_session *session;
+
+	session = kzalloc(sizeof(*session), GFP_KERNEL);
+	if (!session)
+		return ERR_PTR(-ENOMEM);
+
+	session->gdev = gdev;
+	session->user_session = user;
+
+	return session;
+}
+
+/**
+ * Closes a VBoxGuest session.
+ * @session:		The session to close (and free).
+ */
+void vbg_core_close_session(struct vbg_session *session)
+{
+	struct vbg_dev *gdev = session->gdev;
+	int i, rc;
+
+	vbg_set_session_capabilities(gdev, session, 0, U32_MAX, true);
+	vbg_set_session_event_filter(gdev, session, 0, U32_MAX, true);
+
+	for (i = 0; i < ARRAY_SIZE(session->hgcm_client_ids); i++) {
+		if (!session->hgcm_client_ids[i])
+			continue;
+
+		vbg_hgcm_disconnect(gdev, session->hgcm_client_ids[i], &rc);
+	}
+
+	kfree(session);
+}
+
+static int vbg_ioctl_chk(struct vbg_ioctl_hdr *hdr, size_t in_size,
+			 size_t out_size)
+{
+	if (hdr->size_in  != (sizeof(*hdr) + in_size) ||
+	    hdr->size_out != (sizeof(*hdr) + out_size))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int vbg_ioctl_driver_version_info(
+	struct vbg_ioctl_driver_version_info *info)
+{
+	const u16 vbg_maj_version = VBG_IOC_VERSION >> 16;
+	u16 min_maj_version, req_maj_version;
+
+	if (vbg_ioctl_chk(&info->hdr, sizeof(info->u.in), sizeof(info->u.out)))
+		return -EINVAL;
+
+	req_maj_version = info->u.in.req_version >> 16;
+	min_maj_version = info->u.in.min_version >> 16;
+
+	if (info->u.in.min_version > info->u.in.req_version ||
+	    min_maj_version != req_maj_version)
+		return -EINVAL;
+
+	if (info->u.in.min_version <= VBG_IOC_VERSION &&
+	    min_maj_version == vbg_maj_version) {
+		info->u.out.session_version = VBG_IOC_VERSION;
+	} else {
+		info->u.out.session_version = U32_MAX;
+		info->hdr.rc = VERR_VERSION_MISMATCH;
+	}
+
+	info->u.out.driver_version  = VBG_IOC_VERSION;
+	info->u.out.driver_revision = 0;
+	info->u.out.reserved1      = 0;
+	info->u.out.reserved2      = 0;
+
+	return 0;
+}
+
+static bool vbg_wait_event_cond(struct vbg_dev *gdev,
+				struct vbg_session *session,
+				u32 event_mask)
+{
+	unsigned long flags;
+	bool wakeup;
+	u32 events;
+
+	spin_lock_irqsave(&gdev->event_spinlock, flags);
+
+	events = gdev->pending_events & event_mask;
+	wakeup = events || session->cancel_waiters;
+
+	spin_unlock_irqrestore(&gdev->event_spinlock, flags);
+
+	return wakeup;
+}
+
+/* Must be called with the event_lock held */
+static u32 vbg_consume_events_locked(struct vbg_dev *gdev,
+				     struct vbg_session *session,
+				     u32 event_mask)
+{
+	u32 events = gdev->pending_events & event_mask;
+
+	gdev->pending_events &= ~events;
+	return events;
+}
+
+static int vbg_ioctl_wait_for_events(struct vbg_dev *gdev,
+				     struct vbg_session *session,
+				     struct vbg_ioctl_wait_for_events *wait)
+{
+	u32 timeout_ms = wait->u.in.timeout_ms;
+	u32 event_mask = wait->u.in.events;
+	unsigned long flags;
+	long timeout;
+	int ret = 0;
+
+	if (vbg_ioctl_chk(&wait->hdr, sizeof(wait->u.in), sizeof(wait->u.out)))
+		return -EINVAL;
+
+	if (timeout_ms == U32_MAX)
+		timeout = MAX_SCHEDULE_TIMEOUT;
+	else
+		timeout = msecs_to_jiffies(timeout_ms);
+
+	wait->u.out.events = 0;
+	do {
+		timeout = wait_event_interruptible_timeout(
+				gdev->event_wq,
+				vbg_wait_event_cond(gdev, session, event_mask),
+				timeout);
+
+		spin_lock_irqsave(&gdev->event_spinlock, flags);
+
+		if (timeout < 0 || session->cancel_waiters) {
+			ret = -EINTR;
+		} else if (timeout == 0) {
+			ret = -ETIMEDOUT;
+		} else {
+			wait->u.out.events =
+			   vbg_consume_events_locked(gdev, session, event_mask);
+		}
+
+		spin_unlock_irqrestore(&gdev->event_spinlock, flags);
+
+		/*
+		 * Someone else may have consumed the event(s) first, in
+		 * which case we go back to waiting.
+		 */
+	} while (ret == 0 && wait->u.out.events == 0);
+
+	return ret;
+}
+
+static int vbg_ioctl_interrupt_all_wait_events(struct vbg_dev *gdev,
+					       struct vbg_session *session,
+					       struct vbg_ioctl_hdr *hdr)
+{
+	unsigned long flags;
+
+	if (hdr->size_in != sizeof(*hdr) || hdr->size_out != sizeof(*hdr))
+		return -EINVAL;
+
+	spin_lock_irqsave(&gdev->event_spinlock, flags);
+	session->cancel_waiters = true;
+	spin_unlock_irqrestore(&gdev->event_spinlock, flags);
+
+	wake_up(&gdev->event_wq);
+
+	return 0;
+}
+
+/**
+ * Checks if the VMM request is allowed in the context of the given session.
+ * Return: 0 or negative errno value.
+ * @gdev:		The Guest extension device.
+ * @session:		The calling session.
+ * @req:		The request.
+ */
+static int vbg_req_allowed(struct vbg_dev *gdev, struct vbg_session *session,
+			   const struct vmmdev_request_header *req)
+{
+	const struct vmmdev_guest_status *guest_status;
+	bool trusted_apps_only;
+
+	switch (req->request_type) {
+	/* Trusted users apps only. */
+	case VMMDEVREQ_QUERY_CREDENTIALS:
+	case VMMDEVREQ_REPORT_CREDENTIALS_JUDGEMENT:
+	case VMMDEVREQ_REGISTER_SHARED_MODULE:
+	case VMMDEVREQ_UNREGISTER_SHARED_MODULE:
+	case VMMDEVREQ_WRITE_COREDUMP:
+	case VMMDEVREQ_GET_CPU_HOTPLUG_REQ:
+	case VMMDEVREQ_SET_CPU_HOTPLUG_STATUS:
+	case VMMDEVREQ_CHECK_SHARED_MODULES:
+	case VMMDEVREQ_GET_PAGE_SHARING_STATUS:
+	case VMMDEVREQ_DEBUG_IS_PAGE_SHARED:
+	case VMMDEVREQ_REPORT_GUEST_STATS:
+	case VMMDEVREQ_REPORT_GUEST_USER_STATE:
+	case VMMDEVREQ_GET_STATISTICS_CHANGE_REQ:
+		trusted_apps_only = true;
+		break;
+
+	/* Anyone. */
+	case VMMDEVREQ_GET_MOUSE_STATUS:
+	case VMMDEVREQ_SET_MOUSE_STATUS:
+	case VMMDEVREQ_SET_POINTER_SHAPE:
+	case VMMDEVREQ_GET_HOST_VERSION:
+	case VMMDEVREQ_IDLE:
+	case VMMDEVREQ_GET_HOST_TIME:
+	case VMMDEVREQ_SET_POWER_STATUS:
+	case VMMDEVREQ_ACKNOWLEDGE_EVENTS:
+	case VMMDEVREQ_CTL_GUEST_FILTER_MASK:
+	case VMMDEVREQ_REPORT_GUEST_STATUS:
+	case VMMDEVREQ_GET_DISPLAY_CHANGE_REQ:
+	case VMMDEVREQ_VIDEMODE_SUPPORTED:
+	case VMMDEVREQ_GET_HEIGHT_REDUCTION:
+	case VMMDEVREQ_GET_DISPLAY_CHANGE_REQ2:
+	case VMMDEVREQ_VIDEMODE_SUPPORTED2:
+	case VMMDEVREQ_VIDEO_ACCEL_ENABLE:
+	case VMMDEVREQ_VIDEO_ACCEL_FLUSH:
+	case VMMDEVREQ_VIDEO_SET_VISIBLE_REGION:
+	case VMMDEVREQ_GET_DISPLAY_CHANGE_REQEX:
+	case VMMDEVREQ_GET_SEAMLESS_CHANGE_REQ:
+	case VMMDEVREQ_GET_VRDPCHANGE_REQ:
+	case VMMDEVREQ_LOG_STRING:
+	case VMMDEVREQ_GET_SESSION_ID:
+		trusted_apps_only = false;
+		break;
+
+	/* Depends on the request parameters... */
+	case VMMDEVREQ_REPORT_GUEST_CAPABILITIES:
+		guest_status = (const struct vmmdev_guest_status *)req;
+		switch (guest_status->facility) {
+		case VBOXGUEST_FACILITY_TYPE_ALL:
+		case VBOXGUEST_FACILITY_TYPE_VBOXGUEST_DRIVER:
+			vbg_err("Denying userspace vmm report guest cap. call facility %#08x\n",
+				guest_status->facility);
+			return -EPERM;
+		case VBOXGUEST_FACILITY_TYPE_VBOX_SERVICE:
+			trusted_apps_only = true;
+			break;
+		case VBOXGUEST_FACILITY_TYPE_VBOX_TRAY_CLIENT:
+		case VBOXGUEST_FACILITY_TYPE_SEAMLESS:
+		case VBOXGUEST_FACILITY_TYPE_GRAPHICS:
+		default:
+			trusted_apps_only = false;
+			break;
+		}
+		break;
+
+	/* Anything else is not allowed. */
+	default:
+		vbg_err("Denying userspace vmm call type %#08x\n",
+			req->request_type);
+		return -EPERM;
+	}
+
+	if (trusted_apps_only && session->user_session) {
+		vbg_err("Denying userspace vmm call type %#08x through vboxuser device node\n",
+			req->request_type);
+		return -EPERM;
+	}
+
+	return 0;
+}
+
+static int vbg_ioctl_vmmrequest(struct vbg_dev *gdev,
+				struct vbg_session *session, void *data)
+{
+	struct vbg_ioctl_hdr *hdr = data;
+	int ret;
+
+	if (hdr->size_in != hdr->size_out)
+		return -EINVAL;
+
+	if (hdr->size_in > VMMDEV_MAX_VMMDEVREQ_SIZE)
+		return -E2BIG;
+
+	if (hdr->type == VBG_IOCTL_HDR_TYPE_DEFAULT)
+		return -EINVAL;
+
+	ret = vbg_req_allowed(gdev, session, data);
+	if (ret < 0)
+		return ret;
+
+	vbg_req_perform(gdev, data);
+	WARN_ON(hdr->rc == VINF_HGCM_ASYNC_EXECUTE);
+
+	return 0;
+}
+
+static int vbg_ioctl_hgcm_connect(struct vbg_dev *gdev,
+				  struct vbg_session *session,
+				  struct vbg_ioctl_hgcm_connect *conn)
+{
+	u32 client_id;
+	int i, ret;
+
+	if (vbg_ioctl_chk(&conn->hdr, sizeof(conn->u.in), sizeof(conn->u.out)))
+		return -EINVAL;
+
+	/* Find a free place in the sessions clients array and claim it */
+	mutex_lock(&gdev->session_mutex);
+	for (i = 0; i < ARRAY_SIZE(session->hgcm_client_ids); i++) {
+		if (!session->hgcm_client_ids[i]) {
+			session->hgcm_client_ids[i] = U32_MAX;
+			break;
+		}
+	}
+	mutex_unlock(&gdev->session_mutex);
+
+	if (i >= ARRAY_SIZE(session->hgcm_client_ids))
+		return -EMFILE;
+
+	ret = vbg_hgcm_connect(gdev, &conn->u.in.loc, &client_id,
+			       &conn->hdr.rc);
+
+	mutex_lock(&gdev->session_mutex);
+	if (ret == 0 && conn->hdr.rc >= 0) {
+		conn->u.out.client_id = client_id;
+		session->hgcm_client_ids[i] = client_id;
+	} else {
+		conn->u.out.client_id = 0;
+		session->hgcm_client_ids[i] = 0;
+	}
+	mutex_unlock(&gdev->session_mutex);
+
+	return ret;
+}
+
+static int vbg_ioctl_hgcm_disconnect(struct vbg_dev *gdev,
+				     struct vbg_session *session,
+				     struct vbg_ioctl_hgcm_disconnect *disconn)
+{
+	u32 client_id;
+	int i, ret;
+
+	if (vbg_ioctl_chk(&disconn->hdr, sizeof(disconn->u.in), 0))
+		return -EINVAL;
+
+	client_id = disconn->u.in.client_id;
+	if (client_id == 0 || client_id == U32_MAX)
+		return -EINVAL;
+
+	mutex_lock(&gdev->session_mutex);
+	for (i = 0; i < ARRAY_SIZE(session->hgcm_client_ids); i++) {
+		if (session->hgcm_client_ids[i] == client_id) {
+			session->hgcm_client_ids[i] = U32_MAX;
+			break;
+		}
+	}
+	mutex_unlock(&gdev->session_mutex);
+
+	if (i >= ARRAY_SIZE(session->hgcm_client_ids))
+		return -EINVAL;
+
+	ret = vbg_hgcm_disconnect(gdev, client_id, &disconn->hdr.rc);
+
+	mutex_lock(&gdev->session_mutex);
+	if (ret == 0 && disconn->hdr.rc >= 0)
+		session->hgcm_client_ids[i] = 0;
+	else
+		session->hgcm_client_ids[i] = client_id;
+	mutex_unlock(&gdev->session_mutex);
+
+	return ret;
+}
+
+static int vbg_ioctl_hgcm_call(struct vbg_dev *gdev,
+			       struct vbg_session *session, bool f32bit,
+			       struct vbg_ioctl_hgcm_call *call)
+{
+	size_t actual_size;
+	u32 client_id;
+	int i, ret;
+
+	if (call->hdr.size_in < sizeof(*call))
+		return -EINVAL;
+
+	if (call->hdr.size_in != call->hdr.size_out)
+		return -EINVAL;
+
+	if (call->parm_count > VMMDEV_HGCM_MAX_PARMS)
+		return -E2BIG;
+
+	client_id = call->client_id;
+	if (client_id == 0 || client_id == U32_MAX)
+		return -EINVAL;
+
+	actual_size = sizeof(*call);
+	if (f32bit)
+		actual_size += call->parm_count *
+			       sizeof(struct vmmdev_hgcm_function_parameter32);
+	else
+		actual_size += call->parm_count *
+			       sizeof(struct vmmdev_hgcm_function_parameter);
+	if (call->hdr.size_in < actual_size) {
+		vbg_debug("VBG_IOCTL_HGCM_CALL: hdr.size_in %d required size is %zd\n",
+			  call->hdr.size_in, actual_size);
+		return -EINVAL;
+	}
+	call->hdr.size_out = actual_size;
+
+	/*
+	 * Validate the client id.
+	 */
+	mutex_lock(&gdev->session_mutex);
+	for (i = 0; i < ARRAY_SIZE(session->hgcm_client_ids); i++)
+		if (session->hgcm_client_ids[i] == client_id)
+			break;
+	mutex_unlock(&gdev->session_mutex);
+	if (i >= ARRAY_SIZE(session->hgcm_client_ids)) {
+		vbg_debug("VBG_IOCTL_HGCM_CALL: INVALID handle. u32Client=%#08x\n",
+			  client_id);
+		return -EINVAL;
+	}
+
+	if (f32bit)
+		ret = vbg_hgcm_call32(gdev, client_id,
+				      call->function, call->timeout_ms,
+				      VBG_IOCTL_HGCM_CALL_PARMS32(call),
+				      call->parm_count, &call->hdr.rc);
+	else
+		ret = vbg_hgcm_call(gdev, client_id,
+				    call->function, call->timeout_ms,
+				    VBG_IOCTL_HGCM_CALL_PARMS(call),
+				    call->parm_count, &call->hdr.rc);
+
+	if (ret == -E2BIG) {
+		/* E2BIG needs to be reported through the hdr.rc field. */
+		call->hdr.rc = VERR_OUT_OF_RANGE;
+		ret = 0;
+	}
+
+	if (ret && ret != -EINTR && ret != -ETIMEDOUT)
+		vbg_err("VBG_IOCTL_HGCM_CALL error: %d\n", ret);
+
+	return ret;
+}
+
+static int vbg_ioctl_log(struct vbg_ioctl_log *log)
+{
+	if (log->hdr.size_out != sizeof(log->hdr))
+		return -EINVAL;
+
+	vbg_info("%.*s", (int)(log->hdr.size_in - sizeof(log->hdr)),
+		 log->u.in.msg);
+
+	return 0;
+}
+
+static int vbg_ioctl_change_filter_mask(struct vbg_dev *gdev,
+					struct vbg_session *session,
+					struct vbg_ioctl_change_filter *filter)
+{
+	u32 or_mask, not_mask;
+
+	if (vbg_ioctl_chk(&filter->hdr, sizeof(filter->u.in), 0))
+		return -EINVAL;
+
+	or_mask = filter->u.in.or_mask;
+	not_mask = filter->u.in.not_mask;
+
+	if ((or_mask | not_mask) & ~VMMDEV_EVENT_VALID_EVENT_MASK)
+		return -EINVAL;
+
+	return vbg_set_session_event_filter(gdev, session, or_mask, not_mask,
+					    false);
+}
+
+static int vbg_ioctl_change_guest_capabilities(struct vbg_dev *gdev,
+	     struct vbg_session *session, struct vbg_ioctl_set_guest_caps *caps)
+{
+	u32 or_mask, not_mask;
+	int ret;
+
+	if (vbg_ioctl_chk(&caps->hdr, sizeof(caps->u.in), sizeof(caps->u.out)))
+		return -EINVAL;
+
+	or_mask = caps->u.in.or_mask;
+	not_mask = caps->u.in.not_mask;
+
+	if ((or_mask | not_mask) & ~VMMDEV_EVENT_VALID_EVENT_MASK)
+		return -EINVAL;
+
+	ret = vbg_set_session_capabilities(gdev, session, or_mask, not_mask,
+					   false);
+	if (ret)
+		return ret;
+
+	caps->u.out.session_caps = session->guest_caps;
+	caps->u.out.global_caps = gdev->guest_caps_host;
+
+	return 0;
+}
+
+static int vbg_ioctl_check_balloon(struct vbg_dev *gdev,
+				   struct vbg_ioctl_check_balloon *balloon_info)
+{
+	if (vbg_ioctl_chk(&balloon_info->hdr, 0, sizeof(balloon_info->u.out)))
+		return -EINVAL;
+
+	balloon_info->u.out.balloon_chunks = gdev->mem_balloon.chunks;
+	/*
+	 * Under Linux we handle VMMDEV_EVENT_BALLOON_CHANGE_REQUEST
+	 * events entirely in the kernel, see vbg_core_isr().
+	 */
+	balloon_info->u.out.handle_in_r3 = false;
+
+	return 0;
+}
+
+static int vbg_ioctl_write_core_dump(struct vbg_dev *gdev,
+				     struct vbg_ioctl_write_coredump *dump)
+{
+	struct vmmdev_write_core_dump *req;
+
+	if (vbg_ioctl_chk(&dump->hdr, sizeof(dump->u.in), 0))
+		return -EINVAL;
+
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_WRITE_COREDUMP);
+	if (!req)
+		return -ENOMEM;
+
+	req->flags = dump->u.in.flags;
+	dump->hdr.rc = vbg_req_perform(gdev, req);
+
+	kfree(req);
+	return 0;
+}
+
+/**
+ * Common IOCtl for user to kernel communication.
+ * Return: 0 or negative errno value.
+ * @session:	The client session.
+ * @req:	The requested function.
+ * @data:	The i/o data buffer, minimum size sizeof(struct vbg_ioctl_hdr).
+ */
+int vbg_core_ioctl(struct vbg_session *session, unsigned int req, void *data)
+{
+	unsigned int req_no_size = req & ~IOCSIZE_MASK;
+	struct vbg_dev *gdev = session->gdev;
+	struct vbg_ioctl_hdr *hdr = data;
+	bool f32bit = false;
+
+	hdr->rc = VINF_SUCCESS;
+	if (!hdr->size_out)
+		hdr->size_out = hdr->size_in;
+
+	/*
+	 * hdr->version and hdr->size_in / hdr->size_out minimum size are
+	 * already checked by vbg_misc_device_ioctl().
+	 */
+
+	/* For VMMDEV_REQUEST hdr->type != VBG_IOCTL_HDR_TYPE_DEFAULT */
+	if (req_no_size == VBG_IOCTL_VMMDEV_REQUEST(0) ||
+	    req == VBG_IOCTL_VMMDEV_REQUEST_BIG)
+		return vbg_ioctl_vmmrequest(gdev, session, data);
+
+	if (hdr->type != VBG_IOCTL_HDR_TYPE_DEFAULT)
+		return -EINVAL;
+
+	/* Fixed size requests. */
+	switch (req) {
+	case VBG_IOCTL_DRIVER_VERSION_INFO:
+		return vbg_ioctl_driver_version_info(data);
+	case VBG_IOCTL_HGCM_CONNECT:
+		return vbg_ioctl_hgcm_connect(gdev, session, data);
+	case VBG_IOCTL_HGCM_DISCONNECT:
+		return vbg_ioctl_hgcm_disconnect(gdev, session, data);
+	case VBG_IOCTL_WAIT_FOR_EVENTS:
+		return vbg_ioctl_wait_for_events(gdev, session, data);
+	case VBG_IOCTL_INTERRUPT_ALL_WAIT_FOR_EVENTS:
+		return vbg_ioctl_interrupt_all_wait_events(gdev, session, data);
+	case VBG_IOCTL_CHANGE_FILTER_MASK:
+		return vbg_ioctl_change_filter_mask(gdev, session, data);
+	case VBG_IOCTL_CHANGE_GUEST_CAPABILITIES:
+		return vbg_ioctl_change_guest_capabilities(gdev, session, data);
+	case VBG_IOCTL_CHECK_BALLOON:
+		return vbg_ioctl_check_balloon(gdev, data);
+	case VBG_IOCTL_WRITE_CORE_DUMP:
+		return vbg_ioctl_write_core_dump(gdev, data);
+	}
+
+	/* Variable sized requests. */
+	switch (req_no_size) {
+#ifdef CONFIG_COMPAT
+	case VBG_IOCTL_HGCM_CALL_32(0):
+		f32bit = true;
+		/* Fall through */
+#endif
+	case VBG_IOCTL_HGCM_CALL(0):
+		return vbg_ioctl_hgcm_call(gdev, session, f32bit, data);
+	case VBG_IOCTL_LOG(0):
+		return vbg_ioctl_log(data);
+	}
+
+	vbg_debug("VGDrvCommonIoCtl: Unknown req %#08x\n", req);
+	return -ENOTTY;
+}
+
+/**
+ * Report guest supported mouse-features to the host.
+ *
+ * Return: 0 or negative errno value.
+ * @gdev:		The Guest extension device.
+ * @features:		The set of features to report to the host.
+ */
+int vbg_core_set_mouse_status(struct vbg_dev *gdev, u32 features)
+{
+	struct vmmdev_mouse_status *req;
+	int rc;
+
+	req = vbg_req_alloc(sizeof(*req), VMMDEVREQ_SET_MOUSE_STATUS);
+	if (!req)
+		return -ENOMEM;
+
+	req->mouse_features = features;
+	req->pointer_pos_x = 0;
+	req->pointer_pos_y = 0;
+
+	rc = vbg_req_perform(gdev, req);
+	if (rc < 0)
+		vbg_err("%s error, rc: %d\n", __func__, rc);
+
+	kfree(req);
+	return vbg_status_code_to_errno(rc);
+}
+
+/** Core interrupt service routine. */
+irqreturn_t vbg_core_isr(int irq, void *dev_id)
+{
+	struct vbg_dev *gdev = dev_id;
+	struct vmmdev_events *req = gdev->ack_events_req;
+	bool mouse_position_changed = false;
+	unsigned long flags;
+	u32 events = 0;
+	int rc;
+
+	if (!gdev->mmio->V.V1_04.have_events)
+		return IRQ_NONE;
+
+	/* Get and acknowlegde events. */
+	req->header.rc = VERR_INTERNAL_ERROR;
+	req->events = 0;
+	rc = vbg_req_perform(gdev, req);
+	if (rc < 0) {
+		vbg_err("Error performing events req, rc: %d\n", rc);
+		return IRQ_NONE;
+	}
+
+	events = req->events;
+
+	if (events & VMMDEV_EVENT_MOUSE_POSITION_CHANGED) {
+		mouse_position_changed = true;
+		events &= ~VMMDEV_EVENT_MOUSE_POSITION_CHANGED;
+	}
+
+	if (events & VMMDEV_EVENT_HGCM) {
+		wake_up(&gdev->hgcm_wq);
+		events &= ~VMMDEV_EVENT_HGCM;
+	}
+
+	if (events & VMMDEV_EVENT_BALLOON_CHANGE_REQUEST) {
+		schedule_work(&gdev->mem_balloon.work);
+		events &= ~VMMDEV_EVENT_BALLOON_CHANGE_REQUEST;
+	}
+
+	if (events) {
+		spin_lock_irqsave(&gdev->event_spinlock, flags);
+		gdev->pending_events |= events;
+		spin_unlock_irqrestore(&gdev->event_spinlock, flags);
+
+		wake_up(&gdev->event_wq);
+	}
+
+	if (mouse_position_changed)
+		vbg_linux_mouse_event(gdev);
+
+	return IRQ_HANDLED;
+}

drivers/virt/vboxguest/vboxguest_core.h

···
+/* SPDX-License-Identifier: (GPL-2.0 OR CDDL-1.0) */
+/* Copyright (C) 2010-2016 Oracle Corporation */
+
+#ifndef __VBOXGUEST_CORE_H__
+#define __VBOXGUEST_CORE_H__
+
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+#include <linux/vboxguest.h>
+#include "vmmdev.h"
+
+struct vbg_session;
+
+/** VBox guest memory balloon. */
+struct vbg_mem_balloon {
+	/** Work handling VMMDEV_EVENT_BALLOON_CHANGE_REQUEST events */
+	struct work_struct work;
+	/** Pre-allocated vmmdev_memballoon_info req for query */
+	struct vmmdev_memballoon_info *get_req;
+	/** Pre-allocated vmmdev_memballoon_change req for inflate / deflate */
+	struct vmmdev_memballoon_change *change_req;
+	/** The current number of chunks in the balloon. */
+	u32 chunks;
+	/** The maximum number of chunks in the balloon. */
+	u32 max_chunks;
+	/**
+	 * Array of pointers to page arrays. A page * array is allocated for
+	 * each chunk when inflating, and freed when the deflating.
+	 */
+	struct page ***pages;
+};
+
+/**
+ * Per bit usage tracker for a u32 mask.
+ *
+ * Used for optimal handling of guest properties and event filter.
+ */
+struct vbg_bit_usage_tracker {
+	/** Per bit usage counters. */
+	u32 per_bit_usage[32];
+	/** The current mask according to per_bit_usage. */
+	u32 mask;
+};
+
+/** VBox guest device (data) extension. */
+struct vbg_dev {
+	struct device *dev;
+	/** The base of the adapter I/O ports. */
+	u16 io_port;
+	/** Pointer to the mapping of the VMMDev adapter memory. */
+	struct vmmdev_memory *mmio;
+	/** Host version */
+	char host_version[64];
+	/** Host features */
+	unsigned int host_features;
+	/**
+	 * Dummy page and vmap address for reserved kernel virtual-address
+	 * space for the guest mappings, only used on hosts lacking vtx.
+	 */
+	struct page *guest_mappings_dummy_page;
+	void *guest_mappings;
+	/** Spinlock protecting pending_events. */
+	spinlock_t event_spinlock;
+	/** Preallocated struct vmmdev_events for the IRQ handler. */
+	struct vmmdev_events *ack_events_req;
+	/** Wait-for-event list for threads waiting for multiple events. */
+	wait_queue_head_t event_wq;
+	/** Mask of pending events. */
+	u32 pending_events;
+	/** Wait-for-event list for threads waiting on HGCM async completion. */
+	wait_queue_head_t hgcm_wq;
+	/** Pre-allocated hgcm cancel2 req. for cancellation on timeout */
+	struct vmmdev_hgcm_cancel2 *cancel_req;
+	/** Mutex protecting cancel_req accesses */
+	struct mutex cancel_req_mutex;
+	/** Pre-allocated mouse-status request for the input-device handling. */
+	struct vmmdev_mouse_status *mouse_status_req;
+	/** Input device for reporting abs mouse coordinates to the guest. */
+	struct input_dev *input;
+
+	/** Memory balloon information. */
+	struct vbg_mem_balloon mem_balloon;
+
+	/** Lock for session related items in vbg_dev and vbg_session */
+	struct mutex session_mutex;
+	/** Events we won't permit anyone to filter out. */
+	u32 fixed_events;
+	/**
+	 * Usage counters for the host events (excludes fixed events),
+	 * Protected by session_mutex.
+	 */
+	struct vbg_bit_usage_tracker event_filter_tracker;
+	/**
+	 * The event filter last reported to the host (or UINT32_MAX).
+	 * Protected by session_mutex.
+	 */
+	u32 event_filter_host;
+
+	/**
+	 * Usage counters for guest capabilities. Indexed by capability bit
+	 * number, one count per session using a capability.
+	 * Protected by session_mutex.
+	 */
+	struct vbg_bit_usage_tracker guest_caps_tracker;
+	/**
+	 * The guest capabilities last reported to the host (or UINT32_MAX).
+	 * Protected by session_mutex.
+	 */
+	u32 guest_caps_host;
+
+	/**
+	 * Heartbeat timer which fires with interval
+	 * cNsHearbeatInterval and its handler sends
+	 * VMMDEVREQ_GUEST_HEARTBEAT to VMMDev.
+	 */
+	struct timer_list heartbeat_timer;
+	/** Heartbeat timer interval in ms. */
+	int heartbeat_interval_ms;
+	/** Preallocated VMMDEVREQ_GUEST_HEARTBEAT request. */
+	struct vmmdev_request_header *guest_heartbeat_req;
+
+	/** "vboxguest" char-device */
+	struct miscdevice misc_device;
+	/** "vboxuser" char-device */
+	struct miscdevice misc_device_user;
+};
+
+/** The VBoxGuest per session data. */
+struct vbg_session {
+	/** Pointer to the device extension. */
+	struct vbg_dev *gdev;
+
+	/**
+	 * Array containing HGCM client IDs associated with this session.
+	 * These will be automatically disconnected when the session is closed.
+	 * Protected by vbg_gdev.session_mutex.
+	 */
+	u32 hgcm_client_ids[64];
+	/**
+	 * Host events requested by the session.
+	 * An event type requested in any guest session will be added to the
+	 * host filter. Protected by vbg_gdev.session_mutex.
+	 */
+	u32 event_filter;
+	/**
+	 * Guest capabilities for this session.
+	 * A capability claimed by any guest session will be reported to the
+	 * host. Protected by vbg_gdev.session_mutex.
+	 */
+	u32 guest_caps;
+	/** Does this session belong to a root process or a user one? */
+	bool user_session;
+	/** Set on CANCEL_ALL_WAITEVENTS, protected by vbg_devevent_spinlock. */
+	bool cancel_waiters;
+};
+
+int  vbg_core_init(struct vbg_dev *gdev, u32 fixed_events);
+void vbg_core_exit(struct vbg_dev *gdev);
+struct vbg_session *vbg_core_open_session(struct vbg_dev *gdev, bool user);
+void vbg_core_close_session(struct vbg_session *session);
+int  vbg_core_ioctl(struct vbg_session *session, unsigned int req, void *data);
+int  vbg_core_set_mouse_status(struct vbg_dev *gdev, u32 features);
+
+irqreturn_t vbg_core_isr(int irq, void *dev_id);
+
+void vbg_linux_mouse_event(struct vbg_dev *gdev);
+
+#endif

drivers/virt/vboxguest/vboxguest_linux.c

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * vboxguest linux pci driver, char-dev and input-device code,
+ *
+ * Copyright (C) 2006-2016 Oracle Corporation
+ */
+
+#include <linux/input.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/poll.h>
+#include <linux/vbox_utils.h>
+#include "vboxguest_core.h"
+
+/** The device name. */
+#define DEVICE_NAME		"vboxguest"
+/** The device name for the device node open to everyone. */
+#define DEVICE_NAME_USER	"vboxuser"
+/** VirtualBox PCI vendor ID. */
+#define VBOX_VENDORID		0x80ee
+/** VMMDev PCI card product ID. */
+#define VMMDEV_DEVICEID		0xcafe
+
+/** Mutex protecting the global vbg_gdev pointer used by vbg_get/put_gdev. */
+static DEFINE_MUTEX(vbg_gdev_mutex);
+/** Global vbg_gdev pointer used by vbg_get/put_gdev. */
+static struct vbg_dev *vbg_gdev;
+
+static int vbg_misc_device_open(struct inode *inode, struct file *filp)
+{
+	struct vbg_session *session;
+	struct vbg_dev *gdev;
+
+	/* misc_open sets filp->private_data to our misc device */
+	gdev = container_of(filp->private_data, struct vbg_dev, misc_device);
+
+	session = vbg_core_open_session(gdev, false);
+	if (IS_ERR(session))
+		return PTR_ERR(session);
+
+	filp->private_data = session;
+	return 0;
+}
+
+static int vbg_misc_device_user_open(struct inode *inode, struct file *filp)
+{
+	struct vbg_session *session;
+	struct vbg_dev *gdev;
+
+	/* misc_open sets filp->private_data to our misc device */
+	gdev = container_of(filp->private_data, struct vbg_dev,
+			    misc_device_user);
+
+	session = vbg_core_open_session(gdev, false);
+	if (IS_ERR(session))
+		return PTR_ERR(session);
+
+	filp->private_data = session;
+	return 0;
+}
+
+/**
+ * Close device.
+ * Return: 0 on success, negated errno on failure.
+ * @inode:		Pointer to inode info structure.
+ * @filp:		Associated file pointer.
+ */
+static int vbg_misc_device_close(struct inode *inode, struct file *filp)
+{
+	vbg_core_close_session(filp->private_data);
+	filp->private_data = NULL;
+	return 0;
+}
+
+/**
+ * Device I/O Control entry point.
+ * Return: 0 on success, negated errno on failure.
+ * @filp:		Associated file pointer.
+ * @req:		The request specified to ioctl().
+ * @arg:		The argument specified to ioctl().
+ */
+static long vbg_misc_device_ioctl(struct file *filp, unsigned int req,
+				  unsigned long arg)
+{
+	struct vbg_session *session = filp->private_data;
+	size_t returned_size, size;
+	struct vbg_ioctl_hdr hdr;
+	int ret = 0;
+	void *buf;
+
+	if (copy_from_user(&hdr, (void *)arg, sizeof(hdr)))
+		return -EFAULT;
+
+	if (hdr.version != VBG_IOCTL_HDR_VERSION)
+		return -EINVAL;
+
+	if (hdr.size_in < sizeof(hdr) ||
+	    (hdr.size_out && hdr.size_out < sizeof(hdr)))
+		return -EINVAL;
+
+	size = max(hdr.size_in, hdr.size_out);
+	if (_IOC_SIZE(req) && _IOC_SIZE(req) != size)
+		return -EINVAL;
+	if (size > SZ_16M)
+		return -E2BIG;
+
+	/* __GFP_DMA32 because IOCTL_VMMDEV_REQUEST passes this to the host */
+	buf = kmalloc(size, GFP_KERNEL | __GFP_DMA32);
+	if (!buf)
+		return -ENOMEM;
+
+	if (copy_from_user(buf, (void *)arg, hdr.size_in)) {
+		ret = -EFAULT;
+		goto out;
+	}
+	if (hdr.size_in < size)
+		memset(buf + hdr.size_in, 0, size -  hdr.size_in);
+
+	ret = vbg_core_ioctl(session, req, buf);
+	if (ret)
+		goto out;
+
+	returned_size = ((struct vbg_ioctl_hdr *)buf)->size_out;
+	if (returned_size > size) {
+		vbg_debug("%s: too much output data %zu > %zu\n",
+			  __func__, returned_size, size);
+		returned_size = size;
+	}
+	if (copy_to_user((void *)arg, buf, returned_size) != 0)
+		ret = -EFAULT;
+
+out:
+	kfree(buf);
+
+	return ret;
+}
+
+/** The file_operations structures. */
+static const struct file_operations vbg_misc_device_fops = {
+	.owner			= THIS_MODULE,
+	.open			= vbg_misc_device_open,
+	.release		= vbg_misc_device_close,
+	.unlocked_ioctl		= vbg_misc_device_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl		= vbg_misc_device_ioctl,
+#endif
+};
+static const struct file_operations vbg_misc_device_user_fops = {
+	.owner			= THIS_MODULE,
+	.open			= vbg_misc_device_user_open,
+	.release		= vbg_misc_device_close,
+	.unlocked_ioctl		= vbg_misc_device_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl		= vbg_misc_device_ioctl,
+#endif
+};
+
+/**
+ * Called when the input device is first opened.
+ *
+ * Sets up absolute mouse reporting.
+ */
+static int vbg_input_open(struct input_dev *input)
+{
+	struct vbg_dev *gdev = input_get_drvdata(input);
+	u32 feat = VMMDEV_MOUSE_GUEST_CAN_ABSOLUTE | VMMDEV_MOUSE_NEW_PROTOCOL;
+	int ret;
+
+	ret = vbg_core_set_mouse_status(gdev, feat);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/**
+ * Called if all open handles to the input device are closed.
+ *
+ * Disables absolute reporting.
+ */
+static void vbg_input_close(struct input_dev *input)
+{
+	struct vbg_dev *gdev = input_get_drvdata(input);
+
+	vbg_core_set_mouse_status(gdev, 0);
+}
+
+/**
+ * Creates the kernel input device.
+ *
+ * Return: 0 on success, negated errno on failure.
+ */
+static int vbg_create_input_device(struct vbg_dev *gdev)
+{
+	struct input_dev *input;
+
+	input = devm_input_allocate_device(gdev->dev);
+	if (!input)
+		return -ENOMEM;
+
+	input->id.bustype = BUS_PCI;
+	input->id.vendor = VBOX_VENDORID;
+	input->id.product = VMMDEV_DEVICEID;
+	input->open = vbg_input_open;
+	input->close = vbg_input_close;
+	input->dev.parent = gdev->dev;
+	input->name = "VirtualBox mouse integration";
+
+	input_set_abs_params(input, ABS_X, VMMDEV_MOUSE_RANGE_MIN,
+			     VMMDEV_MOUSE_RANGE_MAX, 0, 0);
+	input_set_abs_params(input, ABS_Y, VMMDEV_MOUSE_RANGE_MIN,
+			     VMMDEV_MOUSE_RANGE_MAX, 0, 0);
+	input_set_capability(input, EV_KEY, BTN_MOUSE);
+	input_set_drvdata(input, gdev);
+
+	gdev->input = input;
+
+	return input_register_device(gdev->input);
+}
+
+static ssize_t host_version_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct vbg_dev *gdev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", gdev->host_version);
+}
+
+static ssize_t host_features_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct vbg_dev *gdev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%#x\n", gdev->host_features);
+}
+
+static DEVICE_ATTR_RO(host_version);
+static DEVICE_ATTR_RO(host_features);
+
+/**
+ * Does the PCI detection and init of the device.
+ *
+ * Return: 0 on success, negated errno on failure.
+ */
+static int vbg_pci_probe(struct pci_dev *pci, const struct pci_device_id *id)
+{
+	struct device *dev = &pci->dev;
+	resource_size_t io, io_len, mmio, mmio_len;
+	struct vmmdev_memory *vmmdev;
+	struct vbg_dev *gdev;
+	int ret;
+
+	gdev = devm_kzalloc(dev, sizeof(*gdev), GFP_KERNEL);
+	if (!gdev)
+		return -ENOMEM;
+
+	ret = pci_enable_device(pci);
+	if (ret != 0) {
+		vbg_err("vboxguest: Error enabling device: %d\n", ret);
+		return ret;
+	}
+
+	ret = -ENODEV;
+
+	io = pci_resource_start(pci, 0);
+	io_len = pci_resource_len(pci, 0);
+	if (!io || !io_len) {
+		vbg_err("vboxguest: Error IO-port resource (0) is missing\n");
+		goto err_disable_pcidev;
+	}
+	if (devm_request_region(dev, io, io_len, DEVICE_NAME) == NULL) {
+		vbg_err("vboxguest: Error could not claim IO resource\n");
+		ret = -EBUSY;
+		goto err_disable_pcidev;
+	}
+
+	mmio = pci_resource_start(pci, 1);
+	mmio_len = pci_resource_len(pci, 1);
+	if (!mmio || !mmio_len) {
+		vbg_err("vboxguest: Error MMIO resource (1) is missing\n");
+		goto err_disable_pcidev;
+	}
+
+	if (devm_request_mem_region(dev, mmio, mmio_len, DEVICE_NAME) == NULL) {
+		vbg_err("vboxguest: Error could not claim MMIO resource\n");
+		ret = -EBUSY;
+		goto err_disable_pcidev;
+	}
+
+	vmmdev = devm_ioremap(dev, mmio, mmio_len);
+	if (!vmmdev) {
+		vbg_err("vboxguest: Error ioremap failed; MMIO addr=%p size=%d\n",
+			(void *)mmio, (int)mmio_len);
+		goto err_disable_pcidev;
+	}
+
+	/* Validate MMIO region version and size. */
+	if (vmmdev->version != VMMDEV_MEMORY_VERSION ||
+	    vmmdev->size < 32 || vmmdev->size > mmio_len) {
+		vbg_err("vboxguest: Bogus VMMDev memory; version=%08x (expected %08x) size=%d (expected <= %d)\n",
+			vmmdev->version, VMMDEV_MEMORY_VERSION,
+			vmmdev->size, (int)mmio_len);
+		goto err_disable_pcidev;
+	}
+
+	gdev->io_port = io;
+	gdev->mmio = vmmdev;
+	gdev->dev = dev;
+	gdev->misc_device.minor = MISC_DYNAMIC_MINOR;
+	gdev->misc_device.name = DEVICE_NAME;
+	gdev->misc_device.fops = &vbg_misc_device_fops;
+	gdev->misc_device_user.minor = MISC_DYNAMIC_MINOR;
+	gdev->misc_device_user.name = DEVICE_NAME_USER;
+	gdev->misc_device_user.fops = &vbg_misc_device_user_fops;
+
+	ret = vbg_core_init(gdev, VMMDEV_EVENT_MOUSE_POSITION_CHANGED);
+	if (ret)
+		goto err_disable_pcidev;
+
+	ret = vbg_create_input_device(gdev);
+	if (ret) {
+		vbg_err("vboxguest: Error creating input device: %d\n", ret);
+		goto err_vbg_core_exit;
+	}
+
+	ret = devm_request_irq(dev, pci->irq, vbg_core_isr, IRQF_SHARED,
+			       DEVICE_NAME, gdev);
+	if (ret) {
+		vbg_err("vboxguest: Error requesting irq: %d\n", ret);
+		goto err_vbg_core_exit;
+	}
+
+	ret = misc_register(&gdev->misc_device);
+	if (ret) {
+		vbg_err("vboxguest: Error misc_register %s failed: %d\n",
+			DEVICE_NAME, ret);
+		goto err_vbg_core_exit;
+	}
+
+	ret = misc_register(&gdev->misc_device_user);
+	if (ret) {
+		vbg_err("vboxguest: Error misc_register %s failed: %d\n",
+			DEVICE_NAME_USER, ret);
+		goto err_unregister_misc_device;
+	}
+
+	mutex_lock(&vbg_gdev_mutex);
+	if (!vbg_gdev)
+		vbg_gdev = gdev;
+	else
+		ret = -EBUSY;
+	mutex_unlock(&vbg_gdev_mutex);
+
+	if (ret) {
+		vbg_err("vboxguest: Error more then 1 vbox guest pci device\n");
+		goto err_unregister_misc_device_user;
+	}
+
+	pci_set_drvdata(pci, gdev);
+	device_create_file(dev, &dev_attr_host_version);
+	device_create_file(dev, &dev_attr_host_features);
+
+	vbg_info("vboxguest: misc device minor %d, IRQ %d, I/O port %x, MMIO at %p (size %d)\n",
+		 gdev->misc_device.minor, pci->irq, gdev->io_port,
+		 (void *)mmio, (int)mmio_len);
+
+	return 0;
+
+err_unregister_misc_device_user:
+	misc_deregister(&gdev->misc_device_user);
+err_unregister_misc_device:
+	misc_deregister(&gdev->misc_device);
+err_vbg_core_exit:
+	vbg_core_exit(gdev);
+err_disable_pcidev:
+	pci_disable_device(pci);
+
+	return ret;
+}
+
+static void vbg_pci_remove(struct pci_dev *pci)
+{
+	struct vbg_dev *gdev = pci_get_drvdata(pci);
+
+	mutex_lock(&vbg_gdev_mutex);
+	vbg_gdev = NULL;
+	mutex_unlock(&vbg_gdev_mutex);
+
+	device_remove_file(gdev->dev, &dev_attr_host_features);
+	device_remove_file(gdev->dev, &dev_attr_host_version);
+	misc_deregister(&gdev->misc_device_user);
+	misc_deregister(&gdev->misc_device);
+	vbg_core_exit(gdev);
+	pci_disable_device(pci);
+}
+
+struct vbg_dev *vbg_get_gdev(void)
+{
+	mutex_lock(&vbg_gdev_mutex);
+
+	/*
+	 * Note on success we keep the mutex locked until vbg_put_gdev(),
+	 * this stops vbg_pci_remove from removing the device from underneath
+	 * vboxsf. vboxsf will only hold a reference for a short while.
+	 */
+	if (vbg_gdev)
+		return vbg_gdev;
+
+	mutex_unlock(&vbg_gdev_mutex);
+	return ERR_PTR(-ENODEV);
+}
+EXPORT_SYMBOL(vbg_get_gdev);
+
+void vbg_put_gdev(struct vbg_dev *gdev)
+{
+	WARN_ON(gdev != vbg_gdev);
+	mutex_unlock(&vbg_gdev_mutex);
+}
+EXPORT_SYMBOL(vbg_put_gdev);
+
+/**
+ * Callback for mouse events.
+ *
+ * This is called at the end of the ISR, after leaving the event spinlock, if
+ * VMMDEV_EVENT_MOUSE_POSITION_CHANGED was raised by the host.
+ *
+ * @gdev:		The device extension.
+ */
+void vbg_linux_mouse_event(struct vbg_dev *gdev)
+{
+	int rc;
+
+	/* Report events to the kernel input device */
+	gdev->mouse_status_req->mouse_features = 0;
+	gdev->mouse_status_req->pointer_pos_x = 0;
+	gdev->mouse_status_req->pointer_pos_y = 0;
+	rc = vbg_req_perform(gdev, gdev->mouse_status_req);
+	if (rc >= 0) {
+		input_report_abs(gdev->input, ABS_X,
+				 gdev->mouse_status_req->pointer_pos_x);
+		input_report_abs(gdev->input, ABS_Y,
+				 gdev->mouse_status_req->pointer_pos_y);
+		input_sync(gdev->input);
+	}
+}
+
+static const struct pci_device_id vbg_pci_ids[] = {
+	{ .vendor = VBOX_VENDORID, .device = VMMDEV_DEVICEID },
+	{}
+};
+MODULE_DEVICE_TABLE(pci,  vbg_pci_ids);
+
+static struct pci_driver vbg_pci_driver = {
+	.name		= DEVICE_NAME,
+	.id_table	= vbg_pci_ids,
+	.probe		= vbg_pci_probe,
+	.remove		= vbg_pci_remove,
+};
+
+module_pci_driver(vbg_pci_driver);
+
+MODULE_AUTHOR("Oracle Corporation");
+MODULE_DESCRIPTION("Oracle VM VirtualBox Guest Additions for Linux Module");
+MODULE_LICENSE("GPL");

drivers/virt/vboxguest/vboxguest_version.h

···
+/* SPDX-License-Identifier: (GPL-2.0 OR CDDL-1.0) */
+/*
+ * VBox Guest additions version info, this is used by the host to determine
+ * supported guest-addition features in some cases. So this will need to be
+ * synced with vbox upstreams versioning scheme when we implement / port
+ * new features from the upstream out-of-tree vboxguest driver.
+ */
+
+#ifndef __VBOX_VERSION_H__
+#define __VBOX_VERSION_H__
+
+/* Last synced October 4th 2017 */
+#define VBG_VERSION_MAJOR 5
+#define VBG_VERSION_MINOR 2
+#define VBG_VERSION_BUILD 0
+#define VBG_SVN_REV 68940
+#define VBG_VERSION_STRING "5.2.0"
+
+#endif