[PATCH char-misc-next v2 16/22] misc: mic: SCIF RMA header file

[Ashutosh Dixit]

From: Sudeep Dutt <sudeep.dutt@xxxxxxxxx>

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@xxxxxxxxx>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
Signed-off-by: Sudeep Dutt <sudeep.dutt@xxxxxxxxx>
---
 drivers/misc/mic/scif/scif_rma.h | 464 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 464 insertions(+)
 create mode 100644 drivers/misc/mic/scif/scif_rma.h

diff --git a/drivers/misc/mic/scif/scif_rma.h b/drivers/misc/mic/scif/scif_rma.h
new file mode 100644
index 0000000..fa67222
--- /dev/null
+++ b/drivers/misc/mic/scif/scif_rma.h
@@ -0,0 +1,464 @@
+/*
+ * 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 */
-- 
2.0.0.rc3.2.g998f840

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