On 12/19/2011 08:13 AM, Avi Kivity wrote:
Given an address space (represented by the top-level memory region),
returns the memory region that maps a given range. Useful for implementing
DMA.
The implementation is a simplistic binary search. Once we have a tree
representation this can be optimized.
Signed-off-by: Avi Kivity<avi@xxxxxxxxxx>
---
memory.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
memory.h | 32 ++++++++++++++++++++++++++++++++
2 files changed, 94 insertions(+), 0 deletions(-)
diff --git a/memory.c b/memory.c
index cbd6988..d8b7c27 100644
--- a/memory.c
+++ b/memory.c
@@ -514,6 +514,20 @@ static void as_io_ioeventfd_del(AddressSpace *as, MemoryRegionIoeventfd *fd)
.ops =&address_space_ops_io,
};
+static AddressSpace *memory_region_to_address_space(MemoryRegion *mr)
+{
+ while (mr->parent) {
+ mr = mr->parent;
+ }
+ if (mr == address_space_memory.root) {
+ return&address_space_memory;
+ }
+ if (mr == address_space_io.root) {
+ return&address_space_io;
+ }
+ abort();
+}
+
/* Render a memory region into the global view. Ranges in @view obscure
* ranges in @mr.
*/
@@ -1309,6 +1323,54 @@ void memory_region_del_subregion(MemoryRegion *mr,
memory_region_update_topology();
}
+static int cmp_flatrange_addr(const void *_addr, const void *_fr)
+{
+ const AddrRange *addr = _addr;
+ const FlatRange *fr = _fr;
Please don't prefix with an underscore.
+
+ if (int128_le(addrrange_end(*addr), fr->addr.start)) {
+ return -1;
+ } else if (int128_ge(addr->start, addrrange_end(fr->addr))) {
+ return 1;
+ }
+ return 0;
+}
+
+static FlatRange *address_space_lookup(AddressSpace *as, AddrRange addr)
+{
+ return bsearch(&addr, as->current_map.ranges, as->current_map.nr,
+ sizeof(FlatRange), cmp_flatrange_addr);
+}
+
+MemoryRegionSection memory_region_find(MemoryRegion *address_space,
+ target_phys_addr_t addr, uint64_t size)
+{
+ AddressSpace *as = memory_region_to_address_space(address_space);
+ AddrRange range = addrrange_make(int128_make64(addr),
+ int128_make64(size));
+ FlatRange *fr = address_space_lookup(as, range);
+ MemoryRegionSection ret = { .mr = NULL };
+
+ if (!fr) {
+ return ret;
+ }
+
+ while (fr> as->current_map.ranges
+&& addrrange_intersects(fr[-1].addr, range)) {
+ --fr;
+ }
+
+ ret.mr = fr->mr;
+ range = addrrange_intersection(range, fr->addr);
+ ret.offset_within_region = fr->offset_in_region;
+ ret.offset_within_region += int128_get64(int128_sub(range.start,
+ fr->addr.start));
+ ret.size = int128_get64(range.size);
+ ret.offset_within_address_space = int128_get64(range.start);
+ return ret;
+}
+
+
void set_system_memory_map(MemoryRegion *mr)
{
address_space_memory.root = mr;
diff --git a/memory.h b/memory.h
index beae127..1d5c414 100644
--- a/memory.h
+++ b/memory.h
@@ -146,6 +146,24 @@ struct MemoryRegionPortio {
#define PORTIO_END_OF_LIST() { }
+typedef struct MemoryRegionSection MemoryRegionSection;
+
+/**
+ * MemoryRegionSection: describes a fragment of a #MemoryRegion
+ *
+ * @mr: the region, or %NULL if empty
+ * @offset_within_region: the beginning of the section, relative to @mr's start
+ * @size: the size of the section; will not exceed @mr's boundaries
+ * @offset_within_address_space: the address of the first byte of the section
+ * relative to the region's address space
+ */
+struct MemoryRegionSection {
+ MemoryRegion *mr;
+ target_phys_addr_t offset_within_region;
+ uint64_t size;
+ target_phys_addr_t offset_within_address_space;
+};
+
/**
* memory_region_init: Initialize a memory region
*
@@ -502,6 +520,20 @@ void memory_region_del_subregion(MemoryRegion *mr,
MemoryRegion *subregion);
/**
+ * memory_region_find: locate a MemoryRegion in an address space
+ *
+ * Locates the first #MemoryRegion within an address space given by
+ * @address_space that overlaps the range given by @addr and @size.
+ *
+ * @address_space: a top-level (i.e. parentless) region that contains
+ * the region to be found
+ * @addr: start of the area within @address_space to be searched
+ * @size: size of the area to be searched
+ */
+MemoryRegionSection memory_region_find(MemoryRegion *address_space,
+ target_phys_addr_t addr, uint64_t size);
Returning structs by value is a bit unexpected.
Otherwise, the patch looks good.
Regards,
Anthony Liguori
+
+/**
* memory_region_transaction_begin: Start a transaction.
*
* During a transaction, changes will be accumulated and made visible
--
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