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softmmu/physmem: Distinguish between file access mode and mmap protection

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There is a difference between how we open a file and how we mmap it,
and we want to support writable private mappings of readonly files. Let's
define RAM_READONLY and RAM_READONLY_FD flags, to replace the single
"readonly" parameter for file-related functions.

In memory_region_init_ram_from_fd() and memory_region_init_ram_from_file(),
initialize mr->readonly based on the new RAM_READONLY flag.

While at it, add some RAM_* flags we missed to add to the list of accepted
flags in the documentation of some functions.

No change in functionality intended. We'll make use of both flags next
and start setting them independently for memory-backend-file.

Message-ID: <20230906120503.359863-3-david@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
This commit is contained in:
David Hildenbrand 2023-09-06 14:04:54 +02:00
parent 3a1258399b
commit 5c52a219bb
5 changed files with 30 additions and 25 deletions
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14
include/exec/memory.h
View file

@ -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,
@ -1331,10 +1337,10 @@ 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 +1354,6 @@ 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 +1365,8 @@ 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.