commit 44a4ff31c01082ffce08ec3b9a87a4fdf15919d5
author Jagannathan Raman <jag.raman@oracle.com> Fri Jan 29 11:46:04 2021 -0500
committer Stefan Hajnoczi <stefanha@redhat.com> Tue Feb 09 20:53:56 2021 +0000
tree 12d221ae0ba47bf3a853248b3b42bae208a07c6b
parent 639090d85057e7e8251e2509fa136f1a2384f131

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>

include/exec/memory.h

diff --git a/include/exec/memory.h b/include/exec/memory.h
index ed29276..c6fb714 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -998,6 +998,7 @@
  * @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
@@ -1009,6 +1010,7 @@
                                     uint64_t size,
                                     bool share,
                                     int fd,
+                                    ram_addr_t offset,
                                     Error **errp);
 #endif
 

include/exec/ram_addr.h

diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index 40b1660..3cb9791 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -121,8 +121,8 @@
                                    uint32_t ram_flags, const char *mem_path,
                                    bool readonly, Error **errp);
 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 *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
                                   MemoryRegion *mr, Error **errp);

include/qemu/mmap-alloc.h

diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
index 8b7a5c7..456ff87 100644
--- a/include/qemu/mmap-alloc.h
+++ b/include/qemu/mmap-alloc.h
@@ -17,6 +17,7 @@
  *  @readonly: true for a read-only mapping, false for read/write.
  *  @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.
@@ -27,7 +28,8 @@
                     size_t align,
                     bool readonly,
                     bool shared,
-                    bool is_pmem);
+                    bool is_pmem,
+                    off_t map_offset);
 
 void qemu_ram_munmap(int fd, void *ptr, size_t size);