flatview_add_to_dispatch() registers page based on the condition of
*section*, which may looks like this:
|s|PPPPPPP|s|
where s stands for subpage and P for page.
The procedure of this function could be described as:
- register first subpage
- register page
- register last subpage
This means the procedure could be simplified into these three steps
instead of a loop iteration.
This patch refactors the function into three corresponding steps and
adds some comment to clarify it.
Signed-off-by: Wei Yang <richardw.y...@linux.intel.com>
---
v2:
* removes the loop iteration as suggested by Paolo
---
exec.c | 50 +++++++++++++++++++++++++++++++++-----------------
1 file changed, 33 insertions(+), 17 deletions(-)
diff --git a/exec.c b/exec.c
index 0959b00c06..160b8587d4 100644
--- a/exec.c
+++ b/exec.c
@@ -1598,34 +1598,50 @@ static void register_multipage(FlatView *fv,
phys_page_set(d, start_addr >> TARGET_PAGE_BITS, num_pages, section_index);
}
+/*
+ * The range in *section* may look like this:
+ *
+ * |s|PPPPPPP|s|
+ *
+ * where s stands for subpage and P for page.
+ *
+ * The procedure in following function could be described as:
+ *
+ * - register first subpage
+ * - register page
+ * - register last subpage
+ */
void flatview_add_to_dispatch(FlatView *fv, MemoryRegionSection *section)
{
- MemoryRegionSection now = *section, remain = *section;
+ MemoryRegionSection now, remain = *section;
Int128 page_size = int128_make64(TARGET_PAGE_SIZE);
- if (now.offset_within_address_space & ~TARGET_PAGE_MASK) {
- uint64_t left = TARGET_PAGE_ALIGN(now.offset_within_address_space)
- - now.offset_within_address_space;
+ /* register first subpage */
+ if (remain.offset_within_address_space & ~TARGET_PAGE_MASK) {
+ uint64_t left = TARGET_PAGE_ALIGN(remain.offset_within_address_space)
+ - remain.offset_within_address_space;
+ now = remain;
now.size = int128_min(int128_make64(left), now.size);
+ remain.size = int128_sub(remain.size, now.size);
+ remain.offset_within_address_space += int128_get64(now.size);
+ remain.offset_within_region += int128_get64(now.size);
register_subpage(fv, &now);
- } else {
- now.size = int128_zero();
}
- while (int128_ne(remain.size, now.size)) {
+
+ /* register page */
+ if (int128_ge(remain.size, page_size)) {
+ now = remain;
+ now.size = int128_and(now.size, int128_neg(page_size));
remain.size = int128_sub(remain.size, now.size);
remain.offset_within_address_space += int128_get64(now.size);
remain.offset_within_region += int128_get64(now.size);
- now = remain;
- if (int128_lt(remain.size, page_size)) {
- register_subpage(fv, &now);
- } else if (remain.offset_within_address_space & ~TARGET_PAGE_MASK) {
- now.size = page_size;
- register_subpage(fv, &now);
- } else {
- now.size = int128_and(now.size, int128_neg(page_size));
- register_multipage(fv, &now);
- }
+ register_multipage(fv, &now);
+ }
+
+ /* register last subpage */
+ if (int128_gt(remain.size, 0)) {
+ register_subpage(fv, &remain);
}
}
--
2.19.1
