Hierarchical memory region API

The memory API separates the attributes of a memory region (its size, how
reads or writes are handled, dirty logging, and coalescing) from where it
is mapped and whether it is enabled.  This allows a device to configure
a memory region once, then hand it off to its parent bus to map it according
to the bus configuration.

Hierarchical registration also allows a device to compose a region out of
a number of sub-regions with different properties; for example some may be
RAM while others may be MMIO.

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 385 insertions, 0 deletions

diff --git a/memory.h b/memory.h
new file mode 100644
index 0000000..a4c94bd
--- /dev/null
+++ b/memory.h
@@ -0,0 +1,385 @@
+/*
+ * Physical memory management API
+ *
+ * Copyright 2011 Red Hat, Inc. and/or its affiliates
+ *
+ * Authors:
+ *  Avi Kivity <avi@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef MEMORY_H
+#define MEMORY_H
+
+#ifndef CONFIG_USER_ONLY
+
+#include <stdint.h>
+#include <stdbool.h>
+#include "qemu-common.h"
+#include "cpu-common.h"
+#include "targphys.h"
+#include "qemu-queue.h"
+
+typedef struct MemoryRegionOps MemoryRegionOps;
+typedef struct MemoryRegion MemoryRegion;
+
+/* Must match *_DIRTY_FLAGS in cpu-all.h.  To be replaced with dynamic
+ * registration.
+ */
+#define DIRTY_MEMORY_VGA       0
+#define DIRTY_MEMORY_CODE      1
+#define DIRTY_MEMORY_MIGRATION 3
+
+/*
+ * Memory region callbacks
+ */
+struct MemoryRegionOps {
+    /* Read from the memory region. @addr is relative to @mr; @size is
+     * in bytes. */
+    uint64_t (*read)(void *opaque,
+                     target_phys_addr_t addr,
+                     unsigned size);
+    /* Write to the memory region. @addr is relative to @mr; @size is
+     * in bytes. */
+    void (*write)(void *opaque,
+                  target_phys_addr_t addr,
+                  uint64_t data,
+                  unsigned size);
+
+    enum device_endian endianness;
+    /* Guest-visible constraints: */
+    struct {
+        /* If nonzero, specify bounds on access sizes beyond which a machine
+         * check is thrown.
+         */
+        unsigned min_access_size;
+        unsigned max_access_size;
+        /* If true, unaligned accesses are supported.  Otherwise unaligned
+         * accesses throw machine checks.
+         */
+         bool unaligned;
+    } valid;
+    /* Internal implementation constraints: */
+    struct {
+        /* If nonzero, specifies the minimum size implemented.  Smaller sizes
+         * will be rounded upwards and a partial result will be returned.
+         */
+        unsigned min_access_size;
+        /* If nonzero, specifies the maximum size implemented.  Larger sizes
+         * will be done as a series of accesses with smaller sizes.
+         */
+        unsigned max_access_size;
+        /* If true, unaligned accesses are supported.  Otherwise all accesses
+         * are converted to (possibly multiple) naturally aligned accesses.
+         */
+         bool unaligned;
+    } impl;
+};
+
+typedef struct CoalescedMemoryRange CoalescedMemoryRange;
+
+struct MemoryRegion {
+    /* All fields are private - violators will be prosecuted */
+    const MemoryRegionOps *ops;
+    void *opaque;
+    MemoryRegion *parent;
+    uint64_t size;
+    target_phys_addr_t addr;
+    target_phys_addr_t offset;
+    ram_addr_t ram_addr;
+    bool has_ram_addr;
+    MemoryRegion *alias;
+    target_phys_addr_t alias_offset;
+    unsigned priority;
+    bool may_overlap;
+    QTAILQ_HEAD(subregions, MemoryRegion) subregions;
+    QTAILQ_ENTRY(MemoryRegion) subregions_link;
+    QTAILQ_HEAD(coalesced_ranges, CoalescedMemoryRange) coalesced;
+    const char *name;
+};
+
+/**
+ * memory_region_init: Initialize a memory region
+ *
+ * The region typically acts as a container for other memory regions.  Us
+ * memory_region_add_subregion() to add subregions.
+ *
+ * @mr: the #MemoryRegion to be initialized
+ * @name: used for debugging; not visible to the user or ABI
+ * @size: size of the region; any subregions beyond this size will be clipped
+ */
+void memory_region_init(MemoryRegion *mr,
+                        const char *name,
+                        uint64_t size);
+/**
+ * memory_region_init_io: Initialize an I/O memory region.
+ *
+ * Accesses into the region will be cause the callbacks in @ops to be called.
+ * if @size is nonzero, subregions will be clipped to @size.
+ *
+ * @mr: the #MemoryRegion to be initialized.
+ * @ops: a structure containing read and write callbacks to be used when
+ *       I/O is performed on the region.
+ * @opaque: passed to to the read and write callbacks of the @ops structure.
+ * @name: used for debugging; not visible to the user or ABI
+ * @size: size of the region.
+ */
+void memory_region_init_io(MemoryRegion *mr,
+                           const MemoryRegionOps *ops,
+                           void *opaque,
+                           const char *name,
+                           uint64_t size);
+
+/**
+ * memory_region_init_ram:  Initialize RAM memory region.  Accesses into the
+ *                          region will be modify memory directly.
+ *
+ * @mr: the #MemoryRegion to be initialized.
+ * @dev: a device associated with the region; may be %NULL.
+ * @name: the name of the region; the pair (@dev, @name) must be globally
+ *        unique.  The name is part of the save/restore ABI and so cannot be
+ *        changed.
+ * @size: size of the region.
+ */
+void memory_region_init_ram(MemoryRegion *mr,
+                            DeviceState *dev, /* FIXME: layering violation */
+                            const char *name,
+                            uint64_t size);
+
+/**
+ * memory_region_init_ram:  Initialize RAM memory region from a user-provided.
+ *                          pointer.  Accesses into the region will be modify
+ *                          memory directly.
+ *
+ * @mr: the #MemoryRegion to be initialized.
+ * @dev: a device associated with the region; may be %NULL.
+ * @name: the name of the region; the pair (@dev, @name) must be globally
+ *        unique.  The name is part of the save/restore ABI and so cannot be
+ *        changed.
+ * @size: size of the region.
+ * @ptr: memory to be mapped; must contain at least @size bytes.
+ */
+void memory_region_init_ram_ptr(MemoryRegion *mr,
+                                DeviceState *dev, /* FIXME: layering violation */
+                                const char *name,
+                                uint64_t size,
+                                void *ptr);
+
+/**
+ * memory_region_init_alias: Initialize a memory region that aliases all or a
+ *                           part of another memory region.
+ *
+ * @mr: the #MemoryRegion to be initialized.
+ * @name: used for debugging; not visible to the user or ABI
+ * @orig: the region to be referenced; @mr will be equivalent to
+ *        @orig between @offset and @offset + @size - 1.
+ * @offset: start of the section in @orig to be referenced.
+ * @size: size of the region.
+ */
+void memory_region_init_alias(MemoryRegion *mr,
+                              const char *name,
+                              MemoryRegion *orig,
+                              target_phys_addr_t offset,
+                              uint64_t size);
+/**
+ * memory_region_destroy: Destroy a memory region and relaim all resources.
+ *
+ * @mr: the region to be destroyed.  May not currently be a subregion
+ *      (see memory_region_add_subregion()) or referenced in an alias
+ *      (see memory_region_init_alias()).
+ */
+void memory_region_destroy(MemoryRegion *mr);
+
+/**
+ * memory_region_size: get a memory region's size.
+ *
+ * @mr: the memory region being queried.
+ */
+uint64_t memory_region_size(MemoryRegion *mr);
+
+/**
+ * memory_region_get_ram_ptr: Get a pointer into a RAM memory region.
+ *
+ * Returns a host pointer to a RAM memory region (created with
+ * memory_region_init_ram() or memory_region_init_ram_ptr()).  Use with
+ * care.
+ *
+ * @mr: the memory region being queried.
+ */
+void *memory_region_get_ram_ptr(MemoryRegion *mr);
+
+/**
+ * memory_region_set_offset: Sets an offset to be added to MemoryRegionOps
+ *                           callbacks.
+ *
+ * This function is deprecated and should not be used in new code.
+ */
+void memory_region_set_offset(MemoryRegion *mr, target_phys_addr_t offset);
+
+/**
+ * memory_region_set_log: Turn dirty logging on or off for a region.
+ *
+ * Turns dirty logging on or off for a specified client (display, migration).
+ * Only meaningful for RAM regions.
+ *
+ * @mr: the memory region being updated.
+ * @log: whether dirty logging is to be enabled or disabled.
+ * @client: the user of the logging information; %DIRTY_MEMORY_MIGRATION or
+ *          %DIRTY_MEMORY_VGA.
+ */
+void memory_region_set_log(MemoryRegion *mr, bool log, unsigned client);
+
+/**
+ * memory_region_get_dirty: Check whether a page is dirty for a specified
+ *                          client.
+ *
+ * Checks whether a page has been written to since the last
+ * call to memory_region_reset_dirty() with the same @client.  Dirty logging
+ * must be enabled.
+ *
+ * @mr: the memory region being queried.
+ * @addr: the address (relative to the start of the region) being queried.
+ * @client: the user of the logging information; %DIRTY_MEMORY_MIGRATION or
+ *          %DIRTY_MEMORY_VGA.
+ */
+bool memory_region_get_dirty(MemoryRegion *mr, target_phys_addr_t addr,
+                             unsigned client);
+
+/**
+ * memory_region_set_dirty: Mark a page as dirty in a memory region.
+ *
+ * Marks a page as dirty, after it has been dirtied outside guest code.
+ *
+ * @mr: the memory region being queried.
+ * @addr: the address (relative to the start of the region) being dirtied.
+ */
+void memory_region_set_dirty(MemoryRegion *mr, target_phys_addr_t addr);
+
+/**
+ * memory_region_sync_dirty_bitmap: Synchronize a region's dirty bitmap with
+ *                                  any external TLBs (e.g. kvm)
+ *
+ * Flushes dirty information from accelerators such as kvm and vhost-net
+ * and makes it available to users of the memory API.
+ *
+ * @mr: the region being flushed.
+ */
+void memory_region_sync_dirty_bitmap(MemoryRegion *mr);
+
+/**
+ * memory_region_reset_dirty: Mark a range of pages as clean, for a specified
+ *                            client.
+ *
+ * Marks a range of pages as no longer dirty.
+ *
+ * @mr: the region being updated.
+ * @addr: the start of the subrange being cleaned.
+ * @size: the size of the subrange being cleaned.
+ * @client: the user of the logging information; %DIRTY_MEMORY_MIGRATION or
+ *          %DIRTY_MEMORY_VGA.
+ */
+void memory_region_reset_dirty(MemoryRegion *mr, target_phys_addr_t addr,
+                               target_phys_addr_t size, unsigned client);
+
+/**
+ * memory_region_set_readonly: Turn a memory region read-only (or read-write)
+ *
+ * Allows a memory region to be marked as read-only (turning it into a ROM).
+ * only useful on RAM regions.
+ *
+ * @mr: the region being updated.
+ * @readonly: whether rhe region is to be ROM or RAM.
+ */
+void memory_region_set_readonly(MemoryRegion *mr, bool readonly);
+
+/**
+ * memory_region_set_coalescing: Enable memory coalescing for the region.
+ *
+ * Enabled writes to a region to be queued for later processing. MMIO ->write
+ * callbacks may be delayed until a non-coalesced MMIO is issued.
+ * Only useful for IO regions.  Roughly similar to write-combining hardware.
+ *
+ * @mr: the memory region to be write coalesced
+ */
+void memory_region_set_coalescing(MemoryRegion *mr);
+
+/**
+ * memory_region_add_coalescing: Enable memory coalescing for a sub-range of
+ *                               a region.
+ *
+ * Like memory_region_set_coalescing(), but works on a sub-range of a region.
+ * Multiple calls can be issued coalesced disjoint ranges.
+ *
+ * @mr: the memory region to be updated.
+ * @offset: the start of the range within the region to be coalesced.
+ * @size: the size of the subrange to be coalesced.
+ */
+void memory_region_add_coalescing(MemoryRegion *mr,
+                                  target_phys_addr_t offset,
+                                  uint64_t size);
+
+/**
+ * memory_region_clear_coalescing: Disable MMIO coalescing for the region.
+ *
+ * Disables any coalescing caused by memory_region_set_coalescing() or
+ * memory_region_add_coalescing().  Roughly equivalent to uncacheble memory
+ * hardware.
+ *
+ * @mr: the memory region to be updated.
+ */
+void memory_region_clear_coalescing(MemoryRegion *mr);
+
+/**
+ * memory_region_add_subregion: Add a sub-region to a container.
+ *
+ * Adds a sub-region at @offset.  The sub-region may not overlap with other
+ * subregions (except for those explicitly marked as overlapping).  A region
+ * may only be added once as a subregion (unless removed with
+ * memory_region_del_subregion()); use memory_region_init_alias() if you
+ * want a region to be a subregion in multiple locations.
+ *
+ * @mr: the region to contain the new subregion; must be a container
+ *      initialized with memory_region_init().
+ * @offset: the offset relative to @mr where @subregion is added.
+ * @subregion: the subregion to be added.
+ */
+void memory_region_add_subregion(MemoryRegion *mr,
+                                 target_phys_addr_t offset,
+                                 MemoryRegion *subregion);
+/**
+ * memory_region_add_subregion: Add a sub-region to a container, with overlap.
+ *
+ * Adds a sub-region at @offset.  The sub-region may overlap with other
+ * subregions.  Conflicts are resolved by having a higher @priority hide a
+ * lower @priority. Subregions without priority are taken as @priority 0.
+ * A region may only be added once as a subregion (unless removed with
+ * memory_region_del_subregion()); use memory_region_init_alias() if you
+ * want a region to be a subregion in multiple locations.
+ *
+ * @mr: the region to contain the new subregion; must be a container
+ *      initialized with memory_region_init().
+ * @offset: the offset relative to @mr where @subregion is added.
+ * @subregion: the subregion to be added.
+ * @priority: used for resolving overlaps; highest priority wins.
+ */
+void memory_region_add_subregion_overlap(MemoryRegion *mr,
+                                         target_phys_addr_t offset,
+                                         MemoryRegion *subregion,
+                                         unsigned priority);
+/**
+ * memory_region_del_subregion: Remove a subregion.
+ *
+ * Removes a subregion from its container.
+ *
+ * @mr: the container to be updated.
+ * @subregion: the region being removed; must be a current subregion of @mr.
+ */
+void memory_region_del_subregion(MemoryRegion *mr,
+                                 MemoryRegion *subregion);
+
+#endif
+
+#endif