From: Jagannathan Raman <jag.ra...@oracle.com>
Allow RAM MemoryRegion to be created from an offset in a file, instead
of allocating at offset of 0 by default. This is needed to synchronize
RAM between QEMU & remote process.
Signed-off-by: Jagannathan Raman <jag.ra...@oracle.com>
Signed-off-by: John G Johnson <john.g.john...@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimts...@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
---
include/exec/memory.h | 2 ++
include/exec/ram_addr.h | 2 +-
include/qemu/mmap-alloc.h | 4 +++-
backends/hostmem-memfd.c | 2 +-
hw/misc/ivshmem.c | 3 ++-
softmmu/memory.c | 3 ++-
softmmu/physmem.c | 11 +++++++----
util/mmap-alloc.c | 7 ++++---
util/oslib-posix.c | 2 +-
9 files changed, 23 insertions(+), 13 deletions(-)
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 521d9901d7..a9d2b669e8 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -990,6 +990,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr,
* @size: size of the region.
* @share: %true if memory must be mmaped with the MAP_SHARED flag
* @fd: the fd to mmap.
+ * @offset: offset within the file referenced by fd
* @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
@@ -1001,6 +1002,7 @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,
uint64_t size,
bool share,
int fd,
+ ram_addr_t offset,
Error **errp);
#endif
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index c6d2ef1d07..d465a483c6 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -121,7 +121,7 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size,
MemoryRegion *mr,
Error **errp);
RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
uint32_t ram_flags, int fd,
- Error **errp);
+ off_t offset, Error **errp);
RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
MemoryRegion *mr, Error **errp);
diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
index e786266b92..b096ffb7e9 100644
--- a/include/qemu/mmap-alloc.h
+++ b/include/qemu/mmap-alloc.h
@@ -16,6 +16,7 @@ size_t qemu_mempath_getpagesize(const char *mem_path);
* otherwise, the alignment in use will be determined by QEMU.
* @shared: map has RAM_SHARED flag.
* @is_pmem: map has RAM_PMEM flag.
+ * @map_offset: map starts at offset of map_offset from the start of fd
*
* Return:
* On success, return a pointer to the mapped area.
@@ -25,7 +26,8 @@ void *qemu_ram_mmap(int fd,
size_t size,
size_t align,
bool shared,
- bool is_pmem);
+ bool is_pmem,
+ off_t map_offset);
void qemu_ram_munmap(int fd, void *ptr, size_t size);
diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c
index e5626d4330..69b0ae30bb 100644
--- a/backends/hostmem-memfd.c
+++ b/backends/hostmem-memfd.c
@@ -55,7 +55,7 @@ memfd_backend_memory_alloc(HostMemoryBackend *backend, Error
**errp)
name = host_memory_backend_get_name(backend);
memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend),
name, backend->size,
- backend->share, fd, errp);
+ backend->share, fd, 0, errp);
g_free(name);
}
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index e321e5cb69..8d3e1eedbd 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -494,7 +494,8 @@ static void process_msg_shmem(IVShmemState *s, int fd,
Error **errp)
/* mmap the region and map into the BAR2 */
memory_region_init_ram_from_fd(&s->server_bar2, OBJECT(s),
- "ivshmem.bar2", size, true, fd, &local_err);
+ "ivshmem.bar2", size, true, fd, 0,
+ &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
diff --git a/softmmu/memory.c b/softmmu/memory.c
index 333e1ed7b0..fa65f45532 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -1609,6 +1609,7 @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,
uint64_t size,
bool share,
int fd,
+ ram_addr_t offset,
Error **errp)
{
Error *err = NULL;
@@ -1618,7 +1619,7 @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,
mr->destructor = memory_region_destructor_ram;
mr->ram_block = qemu_ram_alloc_from_fd(size, mr,
share ? RAM_SHARED : 0,
- fd, &err);
+ fd, offset, &err);
if (err) {
mr->size = int128_zero();
object_unparent(OBJECT(mr));
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 2cd1de4a2c..4206dec857 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1461,6 +1461,7 @@ static void *file_ram_alloc(RAMBlock *block,
ram_addr_t memory,
int fd,
bool truncate,
+ off_t offset,
Error **errp)
{
void *area;
@@ -1511,7 +1512,8 @@ static void *file_ram_alloc(RAMBlock *block,
}
area = qemu_ram_mmap(fd, memory, block->mr->align,
- block->flags & RAM_SHARED, block->flags & RAM_PMEM);
+ block->flags & RAM_SHARED, block->flags & RAM_PMEM,
+ offset);
if (area == MAP_FAILED) {
error_setg_errno(errp, errno,
"unable to map backing store for guest RAM");
@@ -1943,7 +1945,7 @@ static void ram_block_add(RAMBlock *new_block, Error
**errp, bool shared)
#ifdef CONFIG_POSIX
RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
uint32_t ram_flags, int fd,
- Error **errp)
+ off_t offset, Error **errp)
{
RAMBlock *new_block;
Error *local_err = NULL;
@@ -1996,7 +1998,8 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size,
MemoryRegion *mr,
new_block->used_length = size;
new_block->max_length = size;
new_block->flags = ram_flags;
- new_block->host = file_ram_alloc(new_block, size, fd, !file_size, errp);
+ new_block->host = file_ram_alloc(new_block, size, fd, !file_size, offset,
+ errp);
if (!new_block->host) {
g_free(new_block);
return NULL;
@@ -2026,7 +2029,7 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size,
MemoryRegion *mr,
return NULL;
}
- block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, errp);
+ block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, 0, errp);
if (!block) {
if (created) {
unlink(mem_path);
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index 27dcccd8ec..ddffa0db4e 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -86,7 +86,8 @@ void *qemu_ram_mmap(int fd,
size_t size,
size_t align,
bool shared,
- bool is_pmem)
+ bool is_pmem,
+ off_t map_offset)
{
int flags;
int map_sync_flags = 0;
@@ -147,7 +148,7 @@ void *qemu_ram_mmap(int fd,
offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr;
ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE,
- flags | map_sync_flags, fd, 0);
+ flags | map_sync_flags, fd, map_offset);
if (ptr == MAP_FAILED && map_sync_flags) {
if (errno == ENOTSUP) {
@@ -172,7 +173,7 @@ void *qemu_ram_mmap(int fd,
* we will remove these flags to handle compatibility.
*/
ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE,
- flags, fd, 0);
+ flags, fd, map_offset);
}
if (ptr == MAP_FAILED) {
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index f15234b5c0..93874dfc9b 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -227,7 +227,7 @@ void *qemu_memalign(size_t alignment, size_t size)
void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared)
{
size_t align = QEMU_VMALLOC_ALIGN;
- void *ptr = qemu_ram_mmap(-1, size, align, shared, false);
+ void *ptr = qemu_ram_mmap(-1, size, align, shared, false, 0);
if (ptr == MAP_FAILED) {
return NULL;
--
2.25.GIT
