[RFC PATCH v2 03/21] HostMem: Add private property and associate it with RAM_KVM_GMEM

[Xiaoyao Li <xiaoyao.li@xxxxxxxxx>]

From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

Add a new property "private" to memory backends. When it's set to true,
it indicates the RAMblock of the backend also requires kvm gmem.

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
 backends/hostmem-file.c  |  1 +
 backends/hostmem-memfd.c |  1 +
 backends/hostmem-ram.c   |  1 +
 backends/hostmem.c       | 18 ++++++++++++++++++
 include/sysemu/hostmem.h |  2 +-
 qapi/qom.json            |  4 ++++
 6 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c
index b4335a80e6da..861f76f2de8a 100644
--- a/backends/hostmem-file.c
+++ b/backends/hostmem-file.c
@@ -56,6 +56,7 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
     name = host_memory_backend_get_name(backend);
     ram_flags = backend->share ? RAM_SHARED : 0;
     ram_flags |= backend->reserve ? 0 : RAM_NORESERVE;
+    ram_flags |= backend->private ? RAM_KVM_GMEM : 0;
     ram_flags |= fb->is_pmem ? RAM_PMEM : 0;
     ram_flags |= RAM_NAMED_FILE;
     memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name,
diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c
index 3fc85c3db81b..f49990ce3bbd 100644
--- a/backends/hostmem-memfd.c
+++ b/backends/hostmem-memfd.c
@@ -55,6 +55,7 @@ memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
     name = host_memory_backend_get_name(backend);
     ram_flags = backend->share ? RAM_SHARED : 0;
     ram_flags |= backend->reserve ? 0 : RAM_NORESERVE;
+    ram_flags |= backend->private ? RAM_KVM_GMEM : 0;
     memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend), name,
                                    backend->size, ram_flags, fd, 0, errp);
     g_free(name);
diff --git a/backends/hostmem-ram.c b/backends/hostmem-ram.c
index b8e55cdbd0f8..d6c46250dcfd 100644
--- a/backends/hostmem-ram.c
+++ b/backends/hostmem-ram.c
@@ -30,6 +30,7 @@ ram_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
     name = host_memory_backend_get_name(backend);
     ram_flags = backend->share ? RAM_SHARED : 0;
     ram_flags |= backend->reserve ? 0 : RAM_NORESERVE;
+    ram_flags |= backend->private ? RAM_KVM_GMEM : 0;
     memory_region_init_ram_flags_nomigrate(&backend->mr, OBJECT(backend), name,
                                            backend->size, ram_flags, errp);
     g_free(name);
diff --git a/backends/hostmem.c b/backends/hostmem.c
index 747e7838c031..dbdbb0aafd45 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -461,6 +461,20 @@ static void host_memory_backend_set_reserve(Object *o, bool value, Error **errp)
     }
     backend->reserve = value;
 }
+
+static bool host_memory_backend_get_private(Object *o, Error **errp)
+{
+    HostMemoryBackend *backend = MEMORY_BACKEND(o);
+
+    return backend->private;
+}
+
+static void host_memory_backend_set_private(Object *o, bool value, Error **errp)
+{
+    HostMemoryBackend *backend = MEMORY_BACKEND(o);
+
+    backend->private = value;
+}
 #endif /* CONFIG_LINUX */
 
 static bool
@@ -541,6 +555,10 @@ host_memory_backend_class_init(ObjectClass *oc, void *data)
         host_memory_backend_get_reserve, host_memory_backend_set_reserve);
     object_class_property_set_description(oc, "reserve",
         "Reserve swap space (or huge pages) if applicable");
+    object_class_property_add_bool(oc, "private",
+        host_memory_backend_get_private, host_memory_backend_set_private);
+    object_class_property_set_description(oc, "private",
+        "Use KVM gmem private memory");
 #endif /* CONFIG_LINUX */
     /*
      * Do not delete/rename option. This option must be considered stable
diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h
index 39326f1d4f9c..d88970395618 100644
--- a/include/sysemu/hostmem.h
+++ b/include/sysemu/hostmem.h
@@ -65,7 +65,7 @@ struct HostMemoryBackend {
     /* protected */
     uint64_t size;
     bool merge, dump, use_canonical_path;
-    bool prealloc, is_mapped, share, reserve;
+    bool prealloc, is_mapped, share, reserve, private;
     uint32_t prealloc_threads;
     ThreadContext *prealloc_context;
     DECLARE_BITMAP(host_nodes, MAX_NODES + 1);
diff --git a/qapi/qom.json b/qapi/qom.json
index fa3e88c8e6ab..d28c5403bc0f 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -605,6 +605,9 @@
 # @reserve: if true, reserve swap space (or huge pages) if applicable
 #     (default: true) (since 6.1)
 #
+# @private: if true, use KVM gmem private memory (default: false)
+#     (since 8.2)
+#
 # @size: size of the memory region in bytes
 #
 # @x-use-canonical-path-for-ramblock-id: if true, the canonical path
@@ -631,6 +634,7 @@
             '*prealloc-context': 'str',
             '*share': 'bool',
             '*reserve': 'bool',
+            '*private': 'bool',
             'size': 'size',
             '*x-use-canonical-path-for-ramblock-id': 'bool' } }
 
-- 
2.34.1