On 16/4/25 10:14, Kohei Tokunaga wrote:
Signed-off-by: Kohei Tokunaga <ktokunaga.m...@gmail.com>
---
util/mmap-alloc.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index ed14f9c64d..91f33682e8 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -145,6 +145,7 @@ static bool map_noreserve_effective(int fd, uint32_t
qemu_map_flags)
return false;
}
+#ifndef EMSCRIPTEN
/*
* Reserve a new memory region of the requested size to be used for mapping
* from the given fd (if any).
@@ -176,6 +177,7 @@ static void *mmap_reserve(size_t size, int fd)
return mmap(0, size, PROT_NONE, flags, fd, 0);
}
+#endif
/*
* Activate memory in a reserved region from the given fd (if any), to make
@@ -244,6 +246,21 @@ static inline size_t mmap_guard_pagesize(int fd)
#endif
}
+#ifdef EMSCRIPTEN
+void *qemu_ram_mmap(int fd,
+ size_t size,
+ size_t align,
+ uint32_t qemu_map_flags,
+ off_t map_offset)
+{
+ /*
+ * emscripten doesn't support non-zero first argument for mmap so
+ * mmap a larger region without the hint and return an aligned pointer.
+ */
+ void *ptr = mmap_activate(0, size + align, fd, qemu_map_flags, map_offset);
+ return (void *)QEMU_ALIGN_UP((uintptr_t)ptr, align);
+}
+#else
void *qemu_ram_mmap(int fd,
size_t size,
size_t align,
@@ -293,6 +310,7 @@ void *qemu_ram_mmap(int fd,
return ptr;
}
+#endif /* EMSCRIPTEN */
void qemu_ram_munmap(int fd, void *ptr, size_t size)
{
Can we keep this code generic? I.e. with something in the lines
of (only build-tested):
-- >8 --
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index ed14f9c64de..0e52cce5b29 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -238,3 +238,10 @@ static inline size_t mmap_guard_pagesize(int fd)
{
-#if defined(__powerpc64__) && defined(__linux__)
+#if defined(EMSCRIPTEN)
+ /*
+ * emscripten doesn't support non-zero first argument for mmap so we
+ * don't use any guard, returning 0 to mmap a larger region without the
+ * hint and return an aligned pointer in qemu_ram_mmap().
+ */
+ return 0;
+#elif defined(__powerpc64__) && defined(__linux__)
/* Mappings in the same segment must share the same page size */
@@ -246,2 +253,3 @@ static inline size_t mmap_guard_pagesize(int fd)
+
void *qemu_ram_mmap(int fd,
@@ -253,4 +261,8 @@ void *qemu_ram_mmap(int fd,
const size_t guard_pagesize = mmap_guard_pagesize(fd);
- size_t offset, total;
- void *ptr, *guardptr;
+ size_t offset = 0, total;
+ void *ptr, *guardptr = NULL;
+
+ assert(is_power_of_2(align));
+ /* Always align to host page size */
+ assert(align >= guard_pagesize);
@@ -262,13 +274,11 @@ void *qemu_ram_mmap(int fd,
- guardptr = mmap_reserve(total, fd);
- if (guardptr == MAP_FAILED) {
- return MAP_FAILED;
+ if (guard_pagesize) {
+ guardptr = mmap_reserve(total, fd);
+ if (guardptr == MAP_FAILED) {
+ return MAP_FAILED;
+ }
+
+ offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) -
(uintptr_t)guardptr;
}
- assert(is_power_of_2(align));
- /* Always align to host page size */
- assert(align >= guard_pagesize);
-
- offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) -
(uintptr_t)guardptr;
-
ptr = mmap_activate(guardptr + offset, size, fd, qemu_map_flags,
---
