[PATCH V8 04/39] memory: RAM_ANON flag

[Steve Sistare]

A memory-backend-ram or a memory-backend-memfd block with the RAM_SHARED
flag set is not migrated when migrate_ignore_shared() is true, but this
is wrong, because it has no named backing store, and its contents will be
lost.  Define a new flag RAM_ANON to distinguish this case.  Cpr will also
test this flag, for similar reasons.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 backends/hostmem-epc.c   |  2 +-
 backends/hostmem-memfd.c |  1 +
 backends/hostmem-ram.c   |  1 +
 include/exec/memory.h    |  3 +++
 include/exec/ram_addr.h  |  1 +
 migration/ram.c          |  3 ++-
 softmmu/physmem.c        | 12 +++++++++---
 7 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/backends/hostmem-epc.c b/backends/hostmem-epc.c
index 037292d..cb06255 100644
--- a/backends/hostmem-epc.c
+++ b/backends/hostmem-epc.c
@@ -37,7 +37,7 @@ sgx_epc_backend_memory_alloc(HostMemoryBackend *backend, 
Error **errp)
     }
 
     name = object_get_canonical_path(OBJECT(backend));
-    ram_flags = (backend->share ? RAM_SHARED : 0) | RAM_PROTECTED;
+    ram_flags = (backend->share ? RAM_SHARED : 0) | RAM_PROTECTED | MAP_ANON;
     memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend),
                                    name, backend->size, ram_flags,
                                    fd, 0, errp);
diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c
index 3fc85c3..c9d8001 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 |= RAM_ANON;
     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 b8e55cd..5e80149 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 |= RAM_ANON;
     memory_region_init_ram_flags_nomigrate(&backend->mr, OBJECT(backend), name,
                                            backend->size, ram_flags, errp);
     g_free(name);
diff --git a/include/exec/memory.h b/include/exec/memory.h
index f1c1945..0daddd7 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -203,6 +203,9 @@ typedef struct IOMMUTLBEvent {
 /* RAM that isn't accessible through normal means. */
 #define RAM_PROTECTED (1 << 8)
 
+/* RAM has no name outside the qemu process. */
+#define RAM_ANON (1 << 9)
+
 static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn,
                                        IOMMUNotifierFlag flags,
                                        hwaddr start, hwaddr end,
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index f3e0c78..56188b8 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -94,6 +94,7 @@ static inline unsigned long int 
ramblock_recv_bitmap_offset(void *host_addr,
 }
 
 bool ramblock_is_pmem(RAMBlock *rb);
+bool ramblock_is_anon(RAMBlock *rb);
 
 long qemu_minrampagesize(void);
 long qemu_maxrampagesize(void);
diff --git a/migration/ram.c b/migration/ram.c
index 5f5e37f..5cdb93d 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -164,7 +164,8 @@ out:
 bool ramblock_is_ignored(RAMBlock *block)
 {
     return !qemu_ram_is_migratable(block) ||
-           (migrate_ignore_shared() && qemu_ram_is_shared(block));
+           (migrate_ignore_shared() && qemu_ram_is_shared(block) &&
+            !ramblock_is_anon(block));
 }
 
 #undef RAMBLOCK_FOREACH
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 657841e..0f1ce28 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1975,6 +1975,7 @@ static void ram_block_add(RAMBlock *new_block, Error 
**errp)
     new_block->offset = find_ram_offset(new_block->max_length);
 
     if (!new_block->host) {
+        new_block->flags |= RAM_ANON;
         if (xen_enabled()) {
             xen_ram_alloc(new_block->offset, new_block->max_length,
                           new_block->mr, &err);
@@ -2059,7 +2060,7 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, 
MemoryRegion *mr,
 
     /* Just support these ram flags by now. */
     assert((ram_flags & ~(RAM_SHARED | RAM_PMEM | RAM_NORESERVE |
-                          RAM_PROTECTED)) == 0);
+                          RAM_PROTECTED | RAM_ANON)) == 0);
 
     if (xen_enabled()) {
         error_setg(errp, "-mem-path not supported with Xen");
@@ -2151,7 +2152,7 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, 
ram_addr_t max_size,
     Error *local_err = NULL;
 
     assert((ram_flags & ~(RAM_SHARED | RAM_RESIZEABLE | RAM_PREALLOC |
-                          RAM_NORESERVE)) == 0);
+                          RAM_NORESERVE | RAM_ANON)) == 0);
     assert(!host ^ (ram_flags & RAM_PREALLOC));
 
     size = HOST_PAGE_ALIGN(size);
@@ -2185,7 +2186,7 @@ RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void 
*host,
 RAMBlock *qemu_ram_alloc(ram_addr_t size, uint32_t ram_flags,
                          MemoryRegion *mr, Error **errp)
 {
-    assert((ram_flags & ~(RAM_SHARED | RAM_NORESERVE)) == 0);
+    assert((ram_flags & ~(RAM_SHARED | RAM_NORESERVE | RAM_ANON)) == 0);
     return qemu_ram_alloc_internal(size, size, NULL, NULL, ram_flags, mr, 
errp);
 }
 
@@ -3664,6 +3665,11 @@ bool ramblock_is_pmem(RAMBlock *rb)
     return rb->flags & RAM_PMEM;
 }
 
+bool ramblock_is_anon(RAMBlock *rb)
+{
+    return rb->flags & RAM_ANON;
+}
+
 static void mtree_print_phys_entries(int start, int end, int skip, int ptr)
 {
     if (start == end - 1) {
-- 
1.8.3.1