mem: add share parameter to memory-backend-ram

Currently only file backed memory backend can
be created with a "share" flag in order to allow
sharing guest RAM with other processes in the host.

Add the "share" flag also to RAM Memory Backend
in order to allow remapping parts of the guest RAM
to different host virtual addresses. This is needed
by the RDMA devices in order to remap non-contiguous
QEMU virtual addresses to a contiguous virtual address range.

Moved the "share" flag to the Host Memory base class,
modified phys_mem_alloc to include the new parameter
and a new interface memory_region_init_ram_shared_nomigrate.

There are no functional changes if the new flag is not used.

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>

2 files changed, 3 insertions, 3 deletions

diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 4655bc1f89..13b6f8d776 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -127,10 +127,10 @@ void *qemu_memalign(size_t alignment, size_t size)
 }
 
 /* alloc shared memory pages */
-void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment)
+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, false);
+    void *ptr = qemu_ram_mmap(-1, size, align, shared);
 
     if (ptr == MAP_FAILED) {
         return NULL;
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index 69a6286d50..bb5ad28bd3 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -67,7 +67,7 @@ void *qemu_memalign(size_t alignment, size_t size)
     return qemu_oom_check(qemu_try_memalign(alignment, size));
 }
 
-void *qemu_anon_ram_alloc(size_t size, uint64_t *align)
+void *qemu_anon_ram_alloc(size_t size, uint64_t *align, bool shared)
 {
     void *ptr;