util/mmap-alloc: Add a 'is_pmem' parameter to qemu_ram_mmap

besides the existing 'shared' flags, we are going to add
'is_pmem' to qemu_ram_mmap(), which indicated the memory backend
file is a persist memory.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com>
Reviewed-by: Pankaj Gupta <pagupta@redhat.com>
Message-Id: <786c46862cfeb253ee0ea2f44d62ffe76edb7fa4.1549555521.git.yi.z.zhang@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Pankaj Gupta <pagupta@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

exec.c

@@ -1883,7 +1883,7 @@ static void *file_ram_alloc(RAMBlock *block,
     }
 
     area = qemu_ram_mmap(fd, memory, block->mr->align,
-                         block->flags & RAM_SHARED);
+                         block->flags & RAM_SHARED, block->flags & RAM_PMEM);
     if (area == MAP_FAILED) {
         error_setg_errno(errp, errno,
                          "unable to map backing store for guest RAM");

include/qemu/mmap-alloc.h

@@ -7,7 +7,26 @@ size_t qemu_fd_getpagesize(int fd);
 
 size_t qemu_mempath_getpagesize(const char *mem_path);
 
-void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared);
+/**
+ * qemu_ram_mmap: mmap the specified file or device.
+ *
+ * Parameters:
+ *  @fd: the file or the device to mmap
+ *  @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.
+ *  @shared: map has RAM_SHARED flag.
+ *  @is_pmem: map has RAM_PMEM flag.
+ *
+ * Return:
+ *  On success, return a pointer to the mapped area.
+ *  On failure, return MAP_FAILED.
+ */
+void *qemu_ram_mmap(int fd,
+                    size_t size,
+                    size_t align,
+                    bool shared,
+                    bool is_pmem);
 
 void qemu_ram_munmap(int fd, void *ptr, size_t size);
 

util/mmap-alloc.c

@@ -75,7 +75,11 @@ size_t qemu_mempath_getpagesize(const char *mem_path)
     return getpagesize();
 }
 
-void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared)
+void *qemu_ram_mmap(int fd,
+                    size_t size,
+                    size_t align,
+                    bool shared,
+                    bool is_pmem)
 {
     int flags;
     int guardfd;

util/oslib-posix.c

@@ -203,7 +203,7 @@ void *qemu_memalign(size_t alignment, size_t size)
 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
 {
     size_t align = QEMU_VMALLOC_ALIGN;
-    void *ptr = qemu_ram_mmap(-1, size, align, shared);
+    void *ptr = qemu_ram_mmap(-1, size, align, shared, false);
 
     if (ptr == MAP_FAILED) {
         return NULL;