Merge tag 'mem-2023-09-19' of https://github.com/davidhildenbrand/qemu into staging

Hi,

"Host Memory Backends" and "Memory devices" queue ("mem"):
- Support and document VM templating with R/O files using a new "rom"
  parameter for memory-backend-file
- Some cleanups and fixes around NVDIMMs and R/O file handling for guest
  RAM
- Optimize ioeventfd updates by skipping address spaces that are not
  applicable

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# gpg: Signature made Tue 19 Sep 2023 06:25:45 EDT
# gpg:                using RSA key 1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A
# gpg:                issuer "david@redhat.com"
# gpg: Good signature from "David Hildenbrand <david@redhat.com>" [unknown]
# gpg:                 aka "David Hildenbrand <davidhildenbrand@gmail.com>" [full]
# gpg:                 aka "David Hildenbrand <hildenbr@in.tum.de>" [unknown]
# gpg: WARNING: The key's User ID is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 1BD9 CAAD 735C 4C3A 460D  FCCA 4DDE 10F7 00FF 835A

* tag 'mem-2023-09-19' of https://github.com/davidhildenbrand/qemu:
  memory: avoid updating ioeventfds for some address_space
  machine: Improve error message when using default RAM backend id
  softmmu/physmem: Hint that "readonly=on,rom=off" exists when opening file R/W for private mapping fails
  docs: Start documenting VM templating
  docs: Don't mention "-mem-path" in multi-process.rst
  softmmu/physmem: Never return directories from file_ram_open()
  softmmu/physmem: Fail creation of new files in file_ram_open() with readonly=true
  softmmu/physmem: Bail out early in ram_block_discard_range() with readonly files
  softmmu/physmem: Remap with proper protection in qemu_ram_remap()
  backends/hostmem-file: Add "rom" property to support VM templating with R/O files
  softmmu/physmem: Distinguish between file access mode and mmap protection
  nvdimm: Reject writing label data to ROM instead of crashing QEMU

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 230aab819c..59208e611e 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -1359,6 +1359,7 @@ out:
 
 void machine_run_board_init(MachineState *machine, const char *mem_path, Error **errp)
 {
+    ERRP_GUARD();
     MachineClass *machine_class = MACHINE_GET_CLASS(machine);
     ObjectClass *oc = object_class_by_name(machine->cpu_type);
     CPUClass *cc;
@@ -1387,9 +1388,13 @@ void machine_run_board_init(MachineState *machine, const char *mem_path, Error *
                numa_uses_legacy_mem()) {
         if (object_property_find(object_get_objects_root(),
                                  machine_class->default_ram_id)) {
-            error_setg(errp, "object name '%s' is reserved for the default"
-                " RAM backend, it can't be used for any other purposes."
-                " Change the object's 'id' to something else",
+            error_setg(errp, "object's id '%s' is reserved for the default"
+                " RAM backend, it can't be used for any other purposes",
+                machine_class->default_ram_id);
+            error_append_hint(errp,
+                "Change the object's 'id' to something else or disable"
+                " automatic creation of the default RAM backend by setting"
+                " 'memory-backend=%s' with '-machine'.\n",
                 machine_class->default_ram_id);
             return;
         }