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authorJagannathan Raman <jag.raman@oracle.com>2021-01-29 11:46:04 -0500
committerStefan Hajnoczi <stefanha@redhat.com>2021-02-09 20:53:56 +0000
commit44a4ff31c01082ffce08ec3b9a87a4fdf15919d5 (patch)
tree12d221ae0ba47bf3a853248b3b42bae208a07c6b /softmmu
parent639090d85057e7e8251e2509fa136f1a2384f131 (diff)
memory: alloc RAM from file at offset
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.raman@oracle.com> Signed-off-by: John G Johnson <john.g.johnson@oracle.com> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 609996697ad8617e3b01df38accc5c208c24d74e.1611938319.git.jag.raman@oracle.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'softmmu')
-rw-r--r--softmmu/memory.c3
-rw-r--r--softmmu/physmem.c12
2 files changed, 9 insertions, 6 deletions
diff --git a/softmmu/memory.c b/softmmu/memory.c
index 23e8e33001..874a8fccde 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -1612,6 +1612,7 @@ 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;
@@ -1621,7 +1622,7 @@ 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, false, &err);
+ fd, offset, false, &err);
if (err) {
mr->size = int128_zero();
object_unparent(OBJECT(mr));
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 96efaef97a..19e0aa9836 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1543,6 +1543,7 @@ static void *file_ram_alloc(RAMBlock *block,
int fd,
bool readonly,
bool truncate,
+ off_t offset,
Error **errp)
{
void *area;
@@ -1593,7 +1594,8 @@ static void *file_ram_alloc(RAMBlock *block,
}
area = qemu_ram_mmap(fd, memory, block->mr->align, readonly,
- 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");
@@ -2024,8 +2026,8 @@ 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, bool readonly,
- Error **errp)
+ uint32_t ram_flags, int fd, off_t offset,
+ bool readonly, Error **errp)
{
RAMBlock *new_block;
Error *local_err = NULL;
@@ -2079,7 +2081,7 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
new_block->max_length = size;
new_block->flags = ram_flags;
new_block->host = file_ram_alloc(new_block, size, fd, readonly,
- !file_size, errp);
+ !file_size, offset, errp);
if (!new_block->host) {
g_free(new_block);
return NULL;
@@ -2110,7 +2112,7 @@ 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, readonly, errp);
+ block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, 0, readonly, errp);
if (!block) {
if (created) {
unlink(mem_path);