hostmem: use object id for memory region name with >= 4.0

hostmem-file and hostmem-memfd use the whole object path for the
memory region name, and hostname-ram uses only the path component (the
object id, or canonical path basename):

qemu -m 1024 -object memory-backend-file,id=mem,size=1G,mem-path=/tmp/foo -numa node,memdev=mem -monitor stdio
(qemu) info ramblock
              Block Name    PSize              Offset               Used              Total
            /objects/mem    4 KiB  0x0000000000000000 0x0000000040000000 0x0000000040000000

qemu -m 1024 -object memory-backend-memfd,id=mem,size=1G -numa node,memdev=mem -monitor stdio
(qemu) info ramblock
              Block Name    PSize              Offset               Used              Total
            /objects/mem    4 KiB  0x0000000000000000 0x0000000040000000 0x0000000040000000

qemu -m 1024 -object memory-backend-ram,id=mem,size=1G -numa node,memdev=mem -monitor stdio
(qemu) info ramblock
              Block Name    PSize              Offset               Used              Total
                     mem    4 KiB  0x0000000000000000 0x0000000040000000 0x0000000040000000

For consistency, change to use object id for -file and -memfd as well
with >= 4.0.

Having a consistent naming allows to migrate to different hostmem
backends.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 84a4c8cdc3..f8563efb86 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -32,6 +32,14 @@ GlobalProperty hw_compat_3_1[] = {
         .driver   = "pcie-root-port",
         .property = "x-width",
         .value    = "1",
+    },{
+        .driver   = "memory-backend-file",
+        .property = "x-use-canonical-path-for-ramblock-id",
+        .value    = "true",
+    },{
+        .driver   = "memory-backend-memfd",
+        .property = "x-use-canonical-path-for-ramblock-id",
+        .value    = "true",
     },
 };
 const size_t hw_compat_3_1_len = G_N_ELEMENTS(hw_compat_3_1);