accel/tcg: Introduce page_find_range_empty

Use the interval tree to locate an unused range in the VM.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230707204054.8792-17-richard.henderson@linaro.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 94f828b109..eb1c54701a 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -237,6 +237,21 @@ int page_check_range(target_ulong start, target_ulong len, int flags);
 bool page_check_range_empty(target_ulong start, target_ulong last);
 
 /**
+ * page_find_range_empty
+ * @min: first byte of search range
+ * @max: last byte of search range
+ * @len: size of the hole required
+ * @align: alignment of the hole required (power of 2)
+ *
+ * If there is a range [x, x+@len) within [@min, @max] such that
+ * x % @align == 0, then return x.  Otherwise return -1.
+ * The memory lock must be held, as the caller will want to ensure
+ * the returned range stays empty until a new mapping can be installed.
+ */
+target_ulong page_find_range_empty(target_ulong min, target_ulong max,
+                                   target_ulong len, target_ulong align);
+
+/**
  * page_get_target_data(address)
  * @address: guest virtual address
  *