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

# -----BEGIN PGP SIGNATURE-----
#
# iQJFBAABCAAvFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAmUJdykRHGRhdmlkQHJl
# ZGhhdC5jb20ACgkQTd4Q9wD/g1pf2w//akOUoYMuamySGjXtKLVyMKZkjIys+Ama
# k2C0xzsWAHBP572ezwHi8uxf5j9kzAjsw6GxDZ7FAamD9MhiohkEvkecloBx6f/c
# q3fVHblBNkG7v2urtf4+6PJtJvhzOST2SFXfWeYhO/vaA04AYCDgexv82JN3gA6B
# OS8WyOX62b8wILPSY2GLZ8IqpE9XnOYZwzVBn6YB1yo7ZkYEfXO6cA8nykNuNcOE
# vppqDo7uVIX6317FWj8ygxmzFfOaj0WT2MT2XFzEIDfg8BInQN8HC4mTn0hcVKMa
# N1y+eZH733CQKT+uNBRZ5YOeljOi4d6gEEyvkkA/L7e5D3Qg9hIdvHb4uryCFSWX
# Vt07OP1XLBwCZFobOC6sg+2gtTZJxxYK89e6ZzEd0454S24w5bnEteRAaCGOP0XL
# ww9xYULqhtZs55UC4rvZHJwdUAk1fIY4VqynwkeQXegvz6BxedNeEkJiiEU0Tizx
# N2VpsxAJ7H/LLSFeZoCRESo4azrH6U4n7S/eS1tkCniFqibfe2yIQCDoJVfb42ec
# gfg/vThCrDwHkIHzkMmoV8NndA7Q7SIkyMfYeEEBeZMeg8JzYll4DJEw/jQCacxh
# KRUa+AZvGlTJUq0mkvyOVfLki+iaehoIUuY1yvMrmdWijPO8n3YybmP9Ljhr8VdR
# 9MSYZe+I2v8=
# =iraT
# -----END PGP SIGNATURE-----
# 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>

include/exec/memory.h

@@ -235,6 +235,12 @@ typedef struct IOMMUTLBEvent {
 /* RAM is an mmap-ed named file */
 #define RAM_NAMED_FILE (1 << 9)
 
+/* RAM is mmap-ed read-only */
+#define RAM_READONLY (1 << 10)
+
+/* RAM FD is opened read-only */
+#define RAM_READONLY_FD (1 << 11)
+
 static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn,
                                        IOMMUNotifierFlag flags,
                                        hwaddr start, hwaddr end,
@@ -1089,6 +1095,7 @@ struct AddressSpace {
     struct FlatView *current_map;
 
     int ioeventfd_nb;
+    int ioeventfd_notifiers;
     struct MemoryRegionIoeventfd *ioeventfds;
     QTAILQ_HEAD(, MemoryListener) listeners;
     QTAILQ_ENTRY(AddressSpace) address_spaces_link;
@@ -1331,10 +1338,10 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr,
  * @align: alignment of the region base address; if 0, the default alignment
  *         (getpagesize()) will be used.
  * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM,
- *             RAM_NORESERVE,
+ *             RAM_NORESERVE, RAM_PROTECTED, RAM_NAMED_FILE, RAM_READONLY,
+ *             RAM_READONLY_FD
  * @path: the path in which to allocate the RAM.
  * @offset: offset within the file referenced by path
- * @readonly: true to open @path for reading, false for read/write.
  * @errp: pointer to Error*, to store an error if it happens.
  *
  * Note that this function does not do anything to cause the data in the
@@ -1348,7 +1355,6 @@ void memory_region_init_ram_from_file(MemoryRegion *mr,
                                       uint32_t ram_flags,
                                       const char *path,
                                       ram_addr_t offset,
-                                      bool readonly,
                                       Error **errp);
 
 /**
@@ -1360,7 +1366,8 @@ void memory_region_init_ram_from_file(MemoryRegion *mr,
  * @name: the name of the region.
  * @size: size of the region.
  * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM,
- *             RAM_NORESERVE, RAM_PROTECTED.
+ *             RAM_NORESERVE, RAM_PROTECTED, RAM_NAMED_FILE, RAM_READONLY,
+ *             RAM_READONLY_FD
  * @fd: the fd to mmap.
  * @offset: offset within the file referenced by fd
  * @errp: pointer to Error*, to store an error if it happens.

include/exec/ram_addr.h

@@ -108,10 +108,10 @@ long qemu_maxrampagesize(void);
  *  @size: the size in bytes of the ram block
  *  @mr: the memory region where the ram block is
  *  @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM,
- *              RAM_NORESERVE.
+ *              RAM_NORESERVE, RAM_PROTECTED, RAM_NAMED_FILE, RAM_READONLY,
+ *              RAM_READONLY_FD
  *  @mem_path or @fd: specify the backing file or device
  *  @offset: Offset into target file
- *  @readonly: true to open @path for reading, false for read/write.
  *  @errp: pointer to Error*, to store an error if it happens
  *
  * Return:
@@ -120,10 +120,10 @@ long qemu_maxrampagesize(void);
  */
 RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
                                    uint32_t ram_flags, const char *mem_path,
-                                   off_t offset, bool readonly, Error **errp);
+                                   off_t offset, Error **errp);
 RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
                                  uint32_t ram_flags, int fd, off_t offset,
-                                 bool readonly, Error **errp);
+                                 Error **errp);
 
 RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
                                   MemoryRegion *mr, Error **errp);