1 files changed, 273 insertions, 0 deletions
diff --git a/drivers/virt/acrn/ioeventfd.c b/drivers/virt/acrn/ioeventfd.c
new file mode 100644
index 000000000000..ac4037e9f947
--- /dev/null
+++ b/drivers/virt/acrn/ioeventfd.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ACRN HSM eventfd - use eventfd objects to signal expected I/O requests
+ *
+ * Copyright (C) 2020 Intel Corporation. All rights reserved.
+ *
+ * Authors:
+ *	Shuo Liu <shuo.a.liu@intel.com>
+ *	Yakui Zhao <yakui.zhao@intel.com>
+ */
+
+#include <linux/eventfd.h>
+#include <linux/slab.h>
+
+#include "acrn_drv.h"
+
+/**
+ * struct hsm_ioeventfd - Properties of HSM ioeventfd
+ * @list:	Entry within &acrn_vm.ioeventfds of ioeventfds of a VM
+ * @eventfd:	Eventfd of the HSM ioeventfd
+ * @addr:	Address of I/O range
+ * @data:	Data for matching
+ * @length:	Length of I/O range
+ * @type:	Type of I/O range (ACRN_IOREQ_TYPE_MMIO/ACRN_IOREQ_TYPE_PORTIO)
+ * @wildcard:	Data matching or not
+ */
+struct hsm_ioeventfd {
+	struct list_head	list;
+	struct eventfd_ctx	*eventfd;
+	u64			addr;
+	u64			data;
+	int			length;
+	int			type;
+	bool			wildcard;
+};
+
+static inline int ioreq_type_from_flags(int flags)
+{
+	return flags & ACRN_IOEVENTFD_FLAG_PIO ?
+		       ACRN_IOREQ_TYPE_PORTIO : ACRN_IOREQ_TYPE_MMIO;
+}
+
+static void acrn_ioeventfd_shutdown(struct acrn_vm *vm, struct hsm_ioeventfd *p)
+{
+	lockdep_assert_held(&vm->ioeventfds_lock);
+
+	eventfd_ctx_put(p->eventfd);
+	list_del(&p->list);
+	kfree(p);
+}
+
+static bool hsm_ioeventfd_is_conflict(struct acrn_vm *vm,
+				      struct hsm_ioeventfd *ioeventfd)
+{
+	struct hsm_ioeventfd *p;
+
+	lockdep_assert_held(&vm->ioeventfds_lock);
+
+	/* Either one is wildcard, the data matching will be skipped. */
+	list_for_each_entry(p, &vm->ioeventfds, list)
+		if (p->eventfd == ioeventfd->eventfd &&
+		    p->addr == ioeventfd->addr &&
+		    p->type == ioeventfd->type &&
+		    (p->wildcard || ioeventfd->wildcard ||
+			p->data == ioeventfd->data))
+			return true;
+
+	return false;
+}
+
+/*
+ * Assign an eventfd to a VM and create a HSM ioeventfd associated with the
+ * eventfd. The properties of the HSM ioeventfd are built from a &struct
+ * acrn_ioeventfd.
+ */
+static int acrn_ioeventfd_assign(struct acrn_vm *vm,
+				 struct acrn_ioeventfd *args)
+{
+	struct eventfd_ctx *eventfd;
+	struct hsm_ioeventfd *p;
+	int ret;
+
+	/* Check for range overflow */
+	if (args->addr + args->len < args->addr)
+		return -EINVAL;
+
+	/*
+	 * Currently, acrn_ioeventfd is used to support vhost. 1,2,4,8 width
+	 * accesses can cover vhost's requirements.
+	 */
+	if (!(args->len == 1 || args->len == 2 ||
+	      args->len == 4 || args->len == 8))
+		return -EINVAL;
+
+	eventfd = eventfd_ctx_fdget(args->fd);
+	if (IS_ERR(eventfd))
+		return PTR_ERR(eventfd);
+
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	if (!p) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	INIT_LIST_HEAD(&p->list);
+	p->addr = args->addr;
+	p->length = args->len;
+	p->eventfd = eventfd;
+	p->type = ioreq_type_from_flags(args->flags);
+
+	/*
+	 * ACRN_IOEVENTFD_FLAG_DATAMATCH flag is set in virtio 1.0 support, the
+	 * writing of notification register of each virtqueue may trigger the
+	 * notification. There is no data matching requirement.
+	 */
+	if (args->flags & ACRN_IOEVENTFD_FLAG_DATAMATCH)
+		p->data = args->data;
+	else
+		p->wildcard = true;
+
+	mutex_lock(&vm->ioeventfds_lock);
+
+	if (hsm_ioeventfd_is_conflict(vm, p)) {
+		ret = -EEXIST;
+		goto unlock_fail;
+	}
+
+	/* register the I/O range into ioreq client */
+	ret = acrn_ioreq_range_add(vm->ioeventfd_client, p->type,
+				   p->addr, p->addr + p->length - 1);
+	if (ret < 0)
+		goto unlock_fail;
+
+	list_add_tail(&p->list, &vm->ioeventfds);
+	mutex_unlock(&vm->ioeventfds_lock);
+
+	return 0;
+
+unlock_fail:
+	mutex_unlock(&vm->ioeventfds_lock);
+	kfree(p);
+fail:
+	eventfd_ctx_put(eventfd);
+	return ret;
+}
+
+static int acrn_ioeventfd_deassign(struct acrn_vm *vm,
+				   struct acrn_ioeventfd *args)
+{
+	struct hsm_ioeventfd *p;
+	struct eventfd_ctx *eventfd;
+
+	eventfd = eventfd_ctx_fdget(args->fd);
+	if (IS_ERR(eventfd))
+		return PTR_ERR(eventfd);
+
+	mutex_lock(&vm->ioeventfds_lock);
+	list_for_each_entry(p, &vm->ioeventfds, list) {
+		if (p->eventfd != eventfd)
+			continue;
+
+		acrn_ioreq_range_del(vm->ioeventfd_client, p->type,
+				     p->addr, p->addr + p->length - 1);
+		acrn_ioeventfd_shutdown(vm, p);
+		break;
+	}
+	mutex_unlock(&vm->ioeventfds_lock);
+
+	eventfd_ctx_put(eventfd);
+	return 0;
+}
+
+static struct hsm_ioeventfd *hsm_ioeventfd_match(struct acrn_vm *vm, u64 addr,
+						 u64 data, int len, int type)
+{
+	struct hsm_ioeventfd *p = NULL;
+
+	lockdep_assert_held(&vm->ioeventfds_lock);
+
+	list_for_each_entry(p, &vm->ioeventfds, list) {
+		if (p->type == type && p->addr == addr && p->length >= len &&
+		    (p->wildcard || p->data == data))
+			return p;
+	}
+
+	return NULL;
+}
+
+static int acrn_ioeventfd_handler(struct acrn_ioreq_client *client,
+				  struct acrn_io_request *req)
+{
+	struct hsm_ioeventfd *p;
+	u64 addr, val;
+	int size;
+
+	if (req->type == ACRN_IOREQ_TYPE_MMIO) {
+		/*
+		 * I/O requests are dispatched by range check only, so a
+		 * acrn_ioreq_client need process both READ and WRITE accesses
+		 * of same range. READ accesses are safe to be ignored here
+		 * because virtio PCI devices write the notify registers for
+		 * notification.
+		 */
+		if (req->reqs.mmio_request.direction == ACRN_IOREQ_DIR_READ) {
+			/* reading does nothing and return 0 */
+			req->reqs.mmio_request.value = 0;
+			return 0;
+		}
+		addr = req->reqs.mmio_request.address;
+		size = req->reqs.mmio_request.size;
+		val = req->reqs.mmio_request.value;
+	} else {
+		if (req->reqs.pio_request.direction == ACRN_IOREQ_DIR_READ) {
+			/* reading does nothing and return 0 */
+			req->reqs.pio_request.value = 0;
+			return 0;
+		}
+		addr = req->reqs.pio_request.address;
+		size = req->reqs.pio_request.size;
+		val = req->reqs.pio_request.value;
+	}
+
+	mutex_lock(&client->vm->ioeventfds_lock);
+	p = hsm_ioeventfd_match(client->vm, addr, val, size, req->type);
+	if (p)
+		eventfd_signal(p->eventfd, 1);
+	mutex_unlock(&client->vm->ioeventfds_lock);
+
+	return 0;
+}
+
+int acrn_ioeventfd_config(struct acrn_vm *vm, struct acrn_ioeventfd *args)
+{
+	int ret;
+
+	if (args->flags & ACRN_IOEVENTFD_FLAG_DEASSIGN)
+		ret = acrn_ioeventfd_deassign(vm, args);
+	else
+		ret = acrn_ioeventfd_assign(vm, args);
+
+	return ret;
+}
+
+int acrn_ioeventfd_init(struct acrn_vm *vm)
+{
+	char name[ACRN_NAME_LEN];
+
+	mutex_init(&vm->ioeventfds_lock);
+	INIT_LIST_HEAD(&vm->ioeventfds);
+	snprintf(name, sizeof(name), "ioeventfd-%u", vm->vmid);
+	vm->ioeventfd_client = acrn_ioreq_client_create(vm,
+							acrn_ioeventfd_handler,
+							NULL, false, name);
+	if (!vm->ioeventfd_client) {
+		dev_err(acrn_dev.this_device, "Failed to create ioeventfd ioreq client!\n");
+		return -EINVAL;
+	}
+
+	dev_dbg(acrn_dev.this_device, "VM %u ioeventfd init.\n", vm->vmid);
+	return 0;
+}
+
+void acrn_ioeventfd_deinit(struct acrn_vm *vm)
+{
+	struct hsm_ioeventfd *p, *next;
+
+	dev_dbg(acrn_dev.this_device, "VM %u ioeventfd deinit.\n", vm->vmid);
+	acrn_ioreq_client_destroy(vm->ioeventfd_client);
+	mutex_lock(&vm->ioeventfds_lock);
+	list_for_each_entry_safe(p, next, &vm->ioeventfds, list)
+		acrn_ioeventfd_shutdown(vm, p);
+	mutex_unlock(&vm->ioeventfds_lock);
+}