misc: mic: SCIF RMA header file

This patch adds the internal data structures required to perform SCIF
RMAs. The data structures required to maintain per SCIF endpoint, RMA
information are contained in scif_endpt_rma_info. scif_pinned_pages
describes a set of SCIF pinned pages maintained locally. The
scif_window is a data structure which contains all the fields required
to describe a SCIF registered window on self and remote nodes. It
contains an offset which is used as a key to perform SCIF DMAs and CPU
copies between self and remote registered windows.
Reviewed-by: Nikhil Rao <nikhil.rao@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mic/scif/scif_rma.h

+/*
+ * Intel MIC Platform Software Stack (MPSS)
+ *
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2015 Intel Corporation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in
+ *   the documentation and/or other materials provided with the
+ *   distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ *   contributors may be used to endorse or promote products derived
+ *   from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Intel SCIF driver.
+ *
+ */
+#ifndef SCIF_RMA_H
+#define SCIF_RMA_H
+
+#include <linux/dma_remapping.h>
+#include <linux/mmu_notifier.h>
+
+#include "../bus/scif_bus.h"
+
+/* If this bit is set then the mark is a remote fence mark */
+#define SCIF_REMOTE_FENCE_BIT          31
+/* Magic value used to indicate a remote fence request */
+#define SCIF_REMOTE_FENCE BIT_ULL(SCIF_REMOTE_FENCE_BIT)
+
+#define SCIF_MAX_UNALIGNED_BUF_SIZE (1024 * 1024ULL)
+#define SCIF_KMEM_UNALIGNED_BUF_SIZE (SCIF_MAX_UNALIGNED_BUF_SIZE + \
+				      (L1_CACHE_BYTES << 1))
+
+#define SCIF_IOVA_START_PFN		(1)
+#define SCIF_IOVA_PFN(addr) ((addr) >> PAGE_SHIFT)
+#define SCIF_DMA_64BIT_PFN SCIF_IOVA_PFN(DMA_BIT_MASK(64))
+#define SCIF_DMA_63BIT_PFN SCIF_IOVA_PFN(DMA_BIT_MASK(63))
+
+/*
+ * struct scif_endpt_rma_info - Per Endpoint Remote Memory Access Information
+ *
+ * @reg_list: List of registration windows for self
+ * @remote_reg_list: List of registration windows for peer
+ * @iovad: Offset generator
+ * @rma_lock: Synchronizes access to self/remote list and also protects the
+ *	      window from being destroyed while RMAs are in progress.
+ * @tc_lock: Synchronizes access to temporary cached windows list
+ *	     for SCIF Registration Caching.
+ * @mmn_lock: Synchronizes access to the list of MMU notifiers registered
+ * @tw_refcount: Keeps track of number of outstanding temporary registered
+ *		 windows created by scif_vreadfrom/scif_vwriteto which have
+ *		 not been destroyed.
+ * @tcw_refcount: Same as tw_refcount but for temporary cached windows
+ * @tcw_total_pages: Same as tcw_refcount but in terms of pages pinned
+ * @mmn_list: MMU notifier so that we can destroy the windows when required
+ * @fence_refcount: Keeps track of number of outstanding remote fence
+ *		    requests which have been received by the peer.
+ * @dma_chan: DMA channel used for all DMA transfers for this endpoint.
+ * @async_list_del: Detect asynchronous list entry deletion
+ * @vma_list: List of vmas with remote memory mappings
+ * @markwq: Wait queue used for scif_fence_mark/scif_fence_wait
+*/
+struct scif_endpt_rma_info {
+	struct list_head reg_list;
+	struct list_head remote_reg_list;
+	struct iova_domain iovad;
+	struct mutex rma_lock;
+	spinlock_t tc_lock;
+	struct mutex mmn_lock;
+	atomic_t tw_refcount;
+	atomic_t tcw_refcount;
+	atomic_t tcw_total_pages;
+	struct list_head mmn_list;
+	atomic_t fence_refcount;
+	struct dma_chan	*dma_chan;
+	int async_list_del;
+	struct list_head vma_list;
+	wait_queue_head_t markwq;
+};
+
+/*
+ * struct scif_fence_info - used for tracking fence requests
+ *
+ * @state: State of this transfer
+ * @wq: Fences wait on this queue
+ * @dma_mark: Used for storing the DMA mark
+ */
+struct scif_fence_info {
+	enum scif_msg_state state;
+	struct completion comp;
+	int dma_mark;
+};
+
+/*
+ * struct scif_remote_fence_info - used for tracking remote fence requests
+ *
+ * @msg: List of SCIF node QP fence messages
+ * @list: Link to list of remote fence requests
+ */
+struct scif_remote_fence_info {
+	struct scifmsg msg;
+	struct list_head list;
+};
+
+/*
+ * Specifies whether an RMA operation can span across partial windows, a single
+ * window or multiple contiguous windows. Mmaps can span across partial windows.
+ * Unregistration can span across complete windows. scif_get_pages() can span a
+ * single window. A window can also be of type self or peer.
+ */
+enum scif_window_type {
+	SCIF_WINDOW_PARTIAL,
+	SCIF_WINDOW_SINGLE,
+	SCIF_WINDOW_FULL,
+	SCIF_WINDOW_SELF,
+	SCIF_WINDOW_PEER
+};
+
+/* The number of physical addresses that can be stored in a PAGE. */
+#define SCIF_NR_ADDR_IN_PAGE   (0x1000 >> 3)
+
+/*
+ * struct scif_rma_lookup - RMA lookup data structure for page list transfers
+ *
+ * Store an array of lookup offsets. Each offset in this array maps
+ * one 4K page containing 512 physical addresses i.e. 2MB. 512 such
+ * offsets in a 4K page will correspond to 1GB of registered address space.
+
+ * @lookup: Array of offsets
+ * @offset: DMA offset of lookup array
+ */
+struct scif_rma_lookup {
+	dma_addr_t *lookup;
+	dma_addr_t offset;
+};
+
+/*
+ * struct scif_pinned_pages - A set of pinned pages obtained with
+ * scif_pin_pages() which could be part of multiple registered
+ * windows across different end points.
+ *
+ * @nr_pages: Number of pages which is defined as a s64 instead of an int
+ * to avoid sign extension with buffers >= 2GB
+ * @prot: read/write protections
+ * @map_flags: Flags specified during the pin operation
+ * @ref_count: Reference count bumped in terms of number of pages
+ * @magic: A magic value
+ * @pages: Array of pointers to struct pages populated with get_user_pages(..)
+ */
+struct scif_pinned_pages {
+	s64 nr_pages;
+	int prot;
+	int map_flags;
+	atomic_t ref_count;
+	u64 magic;
+	struct page **pages;
+};
+
+/*
+ * struct scif_status - Stores DMA status update information
+ *
+ * @src_dma_addr: Source buffer DMA address
+ * @val: src location for value to be written to the destination
+ * @ep: SCIF endpoint
+ */
+struct scif_status {
+	dma_addr_t src_dma_addr;
+	u64 val;
+	struct scif_endpt *ep;
+};
+
+/*
+ * struct scif_window - Registration Window for Self and Remote
+ *
+ * @nr_pages: Number of pages which is defined as a s64 instead of an int
+ * to avoid sign extension with buffers >= 2GB
+ * @nr_contig_chunks: Number of contiguous physical chunks
+ * @prot: read/write protections
+ * @ref_count: reference count in terms of number of pages
+ * @magic: Cookie to detect corruption
+ * @offset: registered offset
+ * @va_for_temp: va address that this window represents
+ * @dma_mark: Used to determine if all DMAs against the window are done
+ * @ep: Pointer to EP. Useful for passing EP around with messages to
+	avoid expensive list traversals.
+ * @list: link to list of windows for the endpoint
+ * @type: self or peer window
+ * @peer_window: Pointer to peer window. Useful for sending messages to peer
+ *		 without requiring an extra list traversal
+ * @unreg_state: unregistration state
+ * @offset_freed: True if the offset has been freed
+ * @temp: True for temporary windows created via scif_vreadfrom/scif_vwriteto
+ * @mm: memory descriptor for the task_struct which initiated the RMA
+ * @st: scatter gather table for DMA mappings with IOMMU enabled
+ * @pinned_pages: The set of pinned_pages backing this window
+ * @alloc_handle: Handle for sending ALLOC_REQ
+ * @regwq: Wait Queue for an registration (N)ACK
+ * @reg_state: Registration state
+ * @unregwq: Wait Queue for an unregistration (N)ACK
+ * @dma_addr_lookup: Lookup for physical addresses used for DMA
+ * @nr_lookup: Number of entries in lookup
+ * @mapped_offset: Offset used to map the window by the peer
+ * @dma_addr: Array of physical addresses used for Mgmt node & MIC initiated DMA
+ * @num_pages: Array specifying number of pages for each physical address
+ */
+struct scif_window {
+	s64 nr_pages;
+	int nr_contig_chunks;
+	int prot;
+	int ref_count;
+	u64 magic;
+	s64 offset;
+	unsigned long va_for_temp;
+	int dma_mark;
+	u64 ep;
+	struct list_head list;
+	enum scif_window_type type;
+	u64 peer_window;
+	enum scif_msg_state unreg_state;
+	bool offset_freed;
+	bool temp;
+	struct mm_struct *mm;
+	struct sg_table *st;
+	union {
+		struct {
+			struct scif_pinned_pages *pinned_pages;
+			struct scif_allocmsg alloc_handle;
+			wait_queue_head_t regwq;
+			enum scif_msg_state reg_state;
+			wait_queue_head_t unregwq;
+		};
+		struct {
+			struct scif_rma_lookup dma_addr_lookup;
+			struct scif_rma_lookup num_pages_lookup;
+			int nr_lookup;
+			dma_addr_t mapped_offset;
+		};
+	};
+	dma_addr_t *dma_addr;
+	u64 *num_pages;
+} __packed;
+
+/*
+ * scif_mmu_notif - SCIF mmu notifier information
+ *
+ * @mmu_notifier ep_mmu_notifier: MMU notifier operations
+ * @tc_reg_list: List of temp registration windows for self
+ * @mm: memory descriptor for the task_struct which initiated the RMA
+ * @ep: SCIF endpoint
+ * @list: link to list of MMU notifier information
+ */
+struct scif_mmu_notif {
+#ifdef CONFIG_MMU_NOTIFIER
+	struct mmu_notifier ep_mmu_notifier;
+#endif
+	struct list_head tc_reg_list;
+	struct mm_struct *mm;
+	struct scif_endpt *ep;
+	struct list_head list;
+};
+
+enum scif_rma_dir {
+	SCIF_LOCAL_TO_REMOTE,
+	SCIF_REMOTE_TO_LOCAL
+};
+
+extern struct kmem_cache *unaligned_cache;
+/* Initialize RMA for this EP */
+void scif_rma_ep_init(struct scif_endpt *ep);
+/* Check if epd can be uninitialized */
+int scif_rma_ep_can_uninit(struct scif_endpt *ep);
+/* Obtain a new offset. Callee must grab RMA lock */
+int scif_get_window_offset(struct scif_endpt *ep, int flags,
+			   s64 offset, int nr_pages, s64 *out_offset);
+/* Free offset. Callee must grab RMA lock */
+void scif_free_window_offset(struct scif_endpt *ep,
+			     struct scif_window *window, s64 offset);
+/* Create self registration window */
+struct scif_window *scif_create_window(struct scif_endpt *ep, int nr_pages,
+				       s64 offset, bool temp);
+/* Destroy self registration window.*/
+int scif_destroy_window(struct scif_endpt *ep, struct scif_window *window);
+void scif_unmap_window(struct scif_dev *remote_dev, struct scif_window *window);
+/* Map pages of self window to Aperture/PCI */
+int scif_map_window(struct scif_dev *remote_dev,
+		    struct scif_window *window);
+/* Unregister a self window */
+int scif_unregister_window(struct scif_window *window);
+/* Destroy remote registration window */
+void
+scif_destroy_remote_window(struct scif_window *window);
+/* remove valid remote memory mappings from process address space */
+void scif_zap_mmaps(int node);
+/* Query if any applications have remote memory mappings */
+bool scif_rma_do_apps_have_mmaps(int node);
+/* Cleanup remote registration lists for zombie endpoints */
+void scif_cleanup_rma_for_zombies(int node);
+/* Reserve a DMA channel for a particular endpoint */
+int scif_reserve_dma_chan(struct scif_endpt *ep);
+/* Setup a DMA mark for an endpoint */
+int _scif_fence_mark(scif_epd_t epd, int *mark);
+int scif_prog_signal(scif_epd_t epd, off_t offset, u64 val,
+		     enum scif_window_type type);
+void scif_alloc_req(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_alloc_gnt_rej(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_free_virt(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_reg(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_unreg(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_reg_ack(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_reg_nack(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_unreg_ack(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_unreg_nack(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_munmap(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_mark(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_mark_resp(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_wait(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_wait_resp(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_sig_local(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_sig_remote(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_recv_sig_resp(struct scif_dev *scifdev, struct scifmsg *msg);
+void scif_mmu_notif_handler(struct work_struct *work);
+void scif_rma_handle_remote_fences(void);
+void scif_rma_destroy_windows(void);
+void scif_rma_destroy_tcw_invalid(void);
+int scif_drain_dma_intr(struct scif_hw_dev *sdev, struct dma_chan *chan);
+
+struct scif_window_iter {
+	s64 offset;
+	int index;
+};
+
+static inline void
+scif_init_window_iter(struct scif_window *window, struct scif_window_iter *iter)
+{
+	iter->offset = window->offset;
+	iter->index = 0;
+}
+
+dma_addr_t scif_off_to_dma_addr(struct scif_window *window, s64 off,
+				size_t *nr_bytes,
+				struct scif_window_iter *iter);
+static inline
+dma_addr_t __scif_off_to_dma_addr(struct scif_window *window, s64 off)
+{
+	return scif_off_to_dma_addr(window, off, NULL, NULL);
+}
+
+static inline bool scif_unaligned(off_t src_offset, off_t dst_offset)
+{
+	src_offset = src_offset & (L1_CACHE_BYTES - 1);
+	dst_offset = dst_offset & (L1_CACHE_BYTES - 1);
+	return !(src_offset == dst_offset);
+}
+
+/*
+ * scif_zalloc:
+ * @size: Size of the allocation request.
+ *
+ * Helper API which attempts to allocate zeroed pages via
+ * __get_free_pages(..) first and then falls back on
+ * vzalloc(..) if that fails.
+ */
+static inline void *scif_zalloc(size_t size)
+{
+	void *ret = NULL;
+	size_t align = ALIGN(size, PAGE_SIZE);
+
+	if (align && get_order(align) < MAX_ORDER)
+		ret = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+					       get_order(align));
+	return ret ? ret : vzalloc(align);
+}
+
+/*
+ * scif_free:
+ * @addr: Address to be freed.
+ * @size: Size of the allocation.
+ * Helper API which frees memory allocated via scif_zalloc().
+ */
+static inline void scif_free(void *addr, size_t size)
+{
+	size_t align = ALIGN(size, PAGE_SIZE);
+
+	if (is_vmalloc_addr(addr))
+		vfree(addr);
+	else
+		free_pages((unsigned long)addr, get_order(align));
+}
+
+static inline void scif_get_window(struct scif_window *window, int nr_pages)
+{
+	window->ref_count += nr_pages;
+}
+
+static inline void scif_put_window(struct scif_window *window, int nr_pages)
+{
+	window->ref_count -= nr_pages;
+}
+
+static inline void scif_set_window_ref(struct scif_window *window, int nr_pages)
+{
+	window->ref_count = nr_pages;
+}
+
+static inline void
+scif_queue_for_cleanup(struct scif_window *window, struct list_head *list)
+{
+	spin_lock(&scif_info.rmalock);
+	list_add_tail(&window->list, list);
+	spin_unlock(&scif_info.rmalock);
+	schedule_work(&scif_info.misc_work);
+}
+
+static inline void __scif_rma_destroy_tcw_helper(struct scif_window *window)
+{
+	list_del_init(&window->list);
+	scif_queue_for_cleanup(window, &scif_info.rma_tc);
+}
+
+static inline bool scif_is_iommu_enabled(void)
+{
+#ifdef CONFIG_INTEL_IOMMU
+	return intel_iommu_enabled;
+#else
+	return false;
+#endif
+}
+#endif /* SCIF_RMA_H */