[PATCH v3 09/12] util/mmap-alloc: Pass flags instead of separate bools to qemu_ram_mmap()

[David Hildenbrand]

Let's introduce a new set of flags that abstract mmap logic and replace
our current set of bools, to prepare for another flag.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 include/qemu/mmap-alloc.h | 17 +++++++++++------
 softmmu/physmem.c         |  8 +++++---
 util/mmap-alloc.c         | 14 +++++++-------
 util/oslib-posix.c        |  3 ++-
 4 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
index 456ff87df1..55664ea9f3 100644
--- a/include/qemu/mmap-alloc.h
+++ b/include/qemu/mmap-alloc.h
@@ -6,6 +6,15 @@ size_t qemu_fd_getpagesize(int fd);
 
 size_t qemu_mempath_getpagesize(const char *mem_path);
 
+/* Map PROT_READ instead of PROT_READ|PROT_WRITE. */
+#define QEMU_RAM_MMAP_READONLY      (1 << 0)
+
+/* Map MAP_SHARED instead of MAP_PRIVATE. */
+#define QEMU_RAM_MMAP_SHARED        (1 << 1)
+
+/* Map MAP_SYNC|MAP_SHARED_VALIDATE if possible, fallback and warn otherwise. 
*/
+#define QEMU_RAM_MMAP_PMEM          (1 << 2)
+
 /**
  * qemu_ram_mmap: mmap the specified file or device.
  *
@@ -14,9 +23,7 @@ size_t qemu_mempath_getpagesize(const char *mem_path);
  *  @size: the number of bytes to be mmaped
  *  @align: if not zero, specify the alignment of the starting mapping address;
  *          otherwise, the alignment in use will be determined by QEMU.
- *  @readonly: true for a read-only mapping, false for read/write.
- *  @shared: map has RAM_SHARED flag.
- *  @is_pmem: map has RAM_PMEM flag.
+ *  @mmap_flags: QEMU_RAM_MMAP_* flags
  *  @map_offset: map starts at offset of map_offset from the start of fd
  *
  * Return:
@@ -26,9 +33,7 @@ size_t qemu_mempath_getpagesize(const char *mem_path);
 void *qemu_ram_mmap(int fd,
                     size_t size,
                     size_t align,
-                    bool readonly,
-                    bool shared,
-                    bool is_pmem,
+                    uint32_t mmap_flags,
                     off_t map_offset);
 
 void qemu_ram_munmap(int fd, void *ptr, size_t size);
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 8f90cb4cd2..ec7a382ccd 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1533,6 +1533,7 @@ static void *file_ram_alloc(RAMBlock *block,
                             off_t offset,
                             Error **errp)
 {
+    uint32_t mmap_flags;
     void *area;
 
     block->page_size = qemu_fd_getpagesize(fd);
@@ -1580,9 +1581,10 @@ static void *file_ram_alloc(RAMBlock *block,
         perror("ftruncate");
     }
 
-    area = qemu_ram_mmap(fd, memory, block->mr->align, readonly,
-                         block->flags & RAM_SHARED, block->flags & RAM_PMEM,
-                         offset);
+    mmap_flags = readonly ? QEMU_RAM_MMAP_READONLY : 0;
+    mmap_flags |= (block->flags & RAM_SHARED) ? QEMU_RAM_MMAP_SHARED : 0;
+    mmap_flags |= (block->flags & RAM_PMEM) ? QEMU_RAM_MMAP_PMEM : 0;
+    area = qemu_ram_mmap(fd, memory, block->mr->align, mmap_flags, offset);
     if (area == MAP_FAILED) {
         error_setg_errno(errp, errno,
                          "unable to map backing store for guest RAM");
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index 0e2bd7bc0e..bd8f7ab547 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -118,9 +118,12 @@ static void *mmap_reserve(size_t size, int fd)
  * Activate memory in a reserved region from the given fd (if any), to make
  * it accessible.
  */
-static void *mmap_activate(void *ptr, size_t size, int fd, bool readonly,
-                           bool shared, bool is_pmem, off_t map_offset)
+static void *mmap_activate(void *ptr, size_t size, int fd, uint32_t mmap_flags,
+                           off_t map_offset)
 {
+    const bool readonly = mmap_flags & QEMU_RAM_MMAP_READONLY;
+    const bool shared = mmap_flags & QEMU_RAM_MMAP_SHARED;
+    const bool is_pmem = mmap_flags & QEMU_RAM_MMAP_PMEM;
     const int prot = PROT_READ | (readonly ? 0 : PROT_WRITE);
     int map_sync_flags = 0;
     int flags = MAP_FIXED;
@@ -173,9 +176,7 @@ static inline size_t mmap_guard_pagesize(int fd)
 void *qemu_ram_mmap(int fd,
                     size_t size,
                     size_t align,
-                    bool readonly,
-                    bool shared,
-                    bool is_pmem,
+                    uint32_t mmap_flags,
                     off_t map_offset)
 {
     const size_t guard_pagesize = mmap_guard_pagesize(fd);
@@ -199,8 +200,7 @@ void *qemu_ram_mmap(int fd,
 
     offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr;
 
-    ptr = mmap_activate(guardptr + offset, size, fd, readonly, shared, is_pmem,
-                        map_offset);
+    ptr = mmap_activate(guardptr + offset, size, fd, mmap_flags, map_offset);
     if (ptr == MAP_FAILED) {
         munmap(guardptr, total);
         return MAP_FAILED;
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 36820fec16..1d250416f1 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -229,8 +229,9 @@ void *qemu_memalign(size_t alignment, size_t size)
 /* alloc shared memory pages */
 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
 {
+    const uint32_t mmap_flags = shared ? QEMU_RAM_MMAP_SHARED : 0;
     size_t align = QEMU_VMALLOC_ALIGN;
-    void *ptr = qemu_ram_mmap(-1, size, align, false, shared, false, 0);
+    void *ptr = qemu_ram_mmap(-1, size, align, mmap_flags, 0);
 
     if (ptr == MAP_FAILED) {
         return NULL;
-- 
2.29.2