VMCI: queue pairs implementation.

VMCI queue pairs allow for bi-directional ordered communication between host and guests.
Signed-off-by: George Zhang <georgezhang@vmware.com>
Acked-by: Andy king <acking@vmware.com>
Acked-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/vmw_vmci/vmci_queue_pair.h

+/*
+ * VMware VMCI Driver
+ *
+ * Copyright (C) 2012 VMware, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation version 2 and no later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#ifndef _VMCI_QUEUE_PAIR_H_
+#define _VMCI_QUEUE_PAIR_H_
+
+#include <linux/vmw_vmci_defs.h>
+#include <linux/types.h>
+
+#include "vmci_context.h"
+
+/* Callback needed for correctly waiting on events. */
+typedef int (*vmci_event_release_cb) (void *client_data);
+
+/* Guest device port I/O. */
+struct PPNSet {
+	u64 num_produce_pages;
+	u64 num_consume_pages;
+	u32 *produce_ppns;
+	u32 *consume_ppns;
+	bool initialized;
+};
+
+/* VMCIqueue_pairAllocInfo */
+struct vmci_qp_alloc_info {
+	struct vmci_handle handle;
+	u32 peer;
+	u32 flags;
+	u64 produce_size;
+	u64 consume_size;
+	u64 ppn_va;	/* Start VA of queue pair PPNs. */
+	u64 num_ppns;
+	s32 result;
+	u32 version;
+};
+
+/* VMCIqueue_pairSetVAInfo */
+struct vmci_qp_set_va_info {
+	struct vmci_handle handle;
+	u64 va;		/* Start VA of queue pair PPNs. */
+	u64 num_ppns;
+	u32 version;
+	s32 result;
+};
+
+/*
+ * For backwards compatibility, here is a version of the
+ * VMCIqueue_pairPageFileInfo before host support end-points was added.
+ * Note that the current version of that structure requires VMX to
+ * pass down the VA of the mapped file.  Before host support was added
+ * there was nothing of the sort.  So, when the driver sees the ioctl
+ * with a parameter that is the sizeof
+ * VMCIqueue_pairPageFileInfo_NoHostQP then it can infer that the version
+ * of VMX running can't attach to host end points because it doesn't
+ * provide the VA of the mapped files.
+ *
+ * The Linux driver doesn't get an indication of the size of the
+ * structure passed down from user space.  So, to fix a long standing
+ * but unfiled bug, the _pad field has been renamed to version.
+ * Existing versions of VMX always initialize the PageFileInfo
+ * structure so that _pad, er, version is set to 0.
+ *
+ * A version value of 1 indicates that the size of the structure has
+ * been increased to include two UVA's: produce_uva and consume_uva.
+ * These UVA's are of the mmap()'d queue contents backing files.
+ *
+ * In addition, if when VMX is sending down the
+ * VMCIqueue_pairPageFileInfo structure it gets an error then it will
+ * try again with the _NoHostQP version of the file to see if an older
+ * VMCI kernel module is running.
+ */
+
+/* VMCIqueue_pairPageFileInfo */
+struct vmci_qp_page_file_info {
+	struct vmci_handle handle;
+	u64 produce_page_file;	  /* User VA. */
+	u64 consume_page_file;	  /* User VA. */
+	u64 produce_page_file_size;  /* Size of the file name array. */
+	u64 consume_page_file_size;  /* Size of the file name array. */
+	s32 result;
+	u32 version;	/* Was _pad. */
+	u64 produce_va;	/* User VA of the mapped file. */
+	u64 consume_va;	/* User VA of the mapped file. */
+};
+
+/* vmci queuepair detach info */
+struct vmci_qp_dtch_info {
+	struct vmci_handle handle;
+	s32 result;
+	u32 _pad;
+};
+
+/*
+ * struct vmci_qp_page_store describes how the memory of a given queue pair
+ * is backed. When the queue pair is between the host and a guest, the
+ * page store consists of references to the guest pages. On vmkernel,
+ * this is a list of PPNs, and on hosted, it is a user VA where the
+ * queue pair is mapped into the VMX address space.
+ */
+struct vmci_qp_page_store {
+	/* Reference to pages backing the queue pair. */
+	u64 pages;
+	/* Length of pageList/virtual addres range (in pages). */
+	u32 len;
+};
+
+/*
+ * This data type contains the information about a queue.
+ * There are two queues (hence, queue pairs) per transaction model between a
+ * pair of end points, A & B.  One queue is used by end point A to transmit
+ * commands and responses to B.  The other queue is used by B to transmit
+ * commands and responses.
+ *
+ * struct vmci_queue_kern_if is a per-OS defined Queue structure.  It contains
+ * either a direct pointer to the linear address of the buffer contents or a
+ * pointer to structures which help the OS locate those data pages.  See
+ * vmciKernelIf.c for each platform for its definition.
+ */
+struct vmci_queue {
+	struct vmci_queue_header *q_header;
+	struct vmci_queue_header *saved_header;
+	struct vmci_queue_kern_if *kernel_if;
+};
+
+/*
+ * Utility function that checks whether the fields of the page
+ * store contain valid values.
+ * Result:
+ * true if the page store is wellformed. false otherwise.
+ */
+static inline bool
+VMCI_QP_PAGESTORE_IS_WELLFORMED(struct vmci_qp_page_store *page_store)
+{
+	return page_store->len >= 2;
+}
+
+/*
+ * Helper function to check if the non-blocking flag
+ * is set for a given queue pair.
+ */
+static inline bool vmci_can_block(u32 flags)
+{
+	return !(flags & VMCI_QPFLAG_NONBLOCK);
+}
+
+/*
+ * Helper function to check if the queue pair is pinned
+ * into memory.
+ */
+static inline bool vmci_qp_pinned(u32 flags)
+{
+	return flags & VMCI_QPFLAG_PINNED;
+}
+
+void vmci_qp_broker_exit(void);
+int vmci_qp_broker_alloc(struct vmci_handle handle, u32 peer,
+			 u32 flags, u32 priv_flags,
+			 u64 produce_size, u64 consume_size,
+			 struct vmci_qp_page_store *page_store,
+			 struct vmci_ctx *context);
+int vmci_qp_broker_set_page_store(struct vmci_handle handle,
+				  u64 produce_uva, u64 consume_uva,
+				  struct vmci_ctx *context);
+int vmci_qp_broker_detach(struct vmci_handle handle, struct vmci_ctx *context);
+
+void vmci_qp_guest_endpoints_exit(void);
+
+int vmci_qp_alloc(struct vmci_handle *handle,
+		  struct vmci_queue **produce_q, u64 produce_size,
+		  struct vmci_queue **consume_q, u64 consume_size,
+		  u32 peer, u32 flags, u32 priv_flags,
+		  bool guest_endpoint, vmci_event_release_cb wakeup_cb,
+		  void *client_data);
+int vmci_qp_broker_map(struct vmci_handle handle,
+		       struct vmci_ctx *context, u64 guest_mem);
+int vmci_qp_broker_unmap(struct vmci_handle handle,
+			 struct vmci_ctx *context, u32 gid);
+
+#endif /* _VMCI_QUEUE_PAIR_H_ */