diff options
| author | Stefan Hajnoczi <stefanha@redhat.com> | 2021-01-04 17:13:18 +0000 |
|---|---|---|
| committer | Eduardo Habkost <ehabkost@redhat.com> | 2021-02-01 17:07:34 -0500 |
| commit | 369d6dc4de45b8e5e35a851f5719e7fd59a0462f (patch) | |
| tree | 9b7bf91786c4866c63bab05090e83964a7bbbf33 /include/exec | |
| parent | 74208cd252c5da9d867270a178799abd802b9338 (diff) | |
memory: add readonly support to memory_region_init_ram_from_file()
There is currently no way to open(O_RDONLY) and mmap(PROT_READ) when
creating a memory region from a file. This functionality is needed since
the underlying host file may not allow writing.
Add a bool readonly argument to memory_region_init_ram_from_file() and
the APIs it calls.
Extend memory_region_init_ram_from_file() rather than introducing a
memory_region_init_rom_from_file() API so that callers can easily make a
choice between read/write and read-only at runtime without calling
different APIs.
No new RAMBlock flag is introduced for read-only because it's unclear
whether RAMBlocks need to know that they are read-only. Pass a bool
readonly argument instead.
Both of these design decisions can be changed in the future. It just
seemed like the simplest approach to me.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20210104171320.575838-2-stefanha@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Diffstat (limited to 'include/exec')
| -rw-r--r-- | include/exec/memory.h | 2 | ||||
| -rw-r--r-- | include/exec/ram_addr.h | 5 |
2 files changed, 5 insertions, 2 deletions
diff --git a/include/exec/memory.h b/include/exec/memory.h index 521d9901d7..c6ce74fb79 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -966,6 +966,7 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr, * - RAM_PMEM: the memory is persistent memory * Other bits are ignored now. * @path: the path in which to allocate the RAM. + * @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 @@ -978,6 +979,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr, uint64_t align, uint32_t ram_flags, const char *path, + bool readonly, Error **errp); /** diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index c6d2ef1d07..40b16609ab 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -110,6 +110,7 @@ long qemu_maxrampagesize(void); * - RAM_PMEM: the backend @mem_path or @fd is persistent memory * Other bits are ignored. * @mem_path or @fd: specify the backing file or device + * @readonly: true to open @path for reading, false for read/write. * @errp: pointer to Error*, to store an error if it happens * * Return: @@ -118,9 +119,9 @@ long qemu_maxrampagesize(void); */ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, uint32_t ram_flags, const char *mem_path, - Error **errp); + bool readonly, Error **errp); RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, - uint32_t ram_flags, int fd, + uint32_t ram_flags, int fd, bool readonly, Error **errp); RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, |