* Peter Xu (pet...@redhat.com) wrote:
> Add a helper to do mmap() for a ramblock based on the cached informations.
>
> A trivial thing to mention is we need to move ramblock->fd setup to be
> earlier, before the ramblock_file_map() call, because it'll need to
> reference the fd being mapped. However that should not be a problem at
> all, majorly because the fd won't be freed if successful, and if it failed
> the fd will be freeed (or to be explicit, close()ed) by the caller.
>
> Export it - prepare to be used outside this file.
>
> Signed-off-by: Peter Xu <pet...@redhat.com>
> ---
> include/exec/ram_addr.h | 1 +
> softmmu/physmem.c | 25 +++++++++++++++++--------
> 2 files changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
> index 0bf9cfc659..56db25009a 100644
> --- a/include/exec/ram_addr.h
> +++ b/include/exec/ram_addr.h
> @@ -98,6 +98,7 @@ bool ramblock_is_pmem(RAMBlock *rb);
>
> long qemu_minrampagesize(void);
> long qemu_maxrampagesize(void);
> +void *ramblock_file_map(RAMBlock *block);
>
> /**
> * qemu_ram_alloc_from_file,
> diff --git a/softmmu/physmem.c b/softmmu/physmem.c
> index 6096eac286..cdda7eaea5 100644
> --- a/softmmu/physmem.c
> +++ b/softmmu/physmem.c
> @@ -1532,17 +1532,31 @@ static int file_ram_open(const char *path,
> return fd;
> }
>
> +/* Do the mmap() for a ramblock based on information already setup */
> +void *ramblock_file_map(RAMBlock *block)
> +{
> + uint32_t qemu_map_flags;
> +
> + qemu_map_flags = (block->flags & RAM_READONLY) ? QEMU_MAP_READONLY : 0;
> + qemu_map_flags |= (block->flags & RAM_SHARED) ? QEMU_MAP_SHARED : 0;
> + qemu_map_flags |= (block->flags & RAM_PMEM) ? QEMU_MAP_SYNC : 0;
> + qemu_map_flags |= (block->flags & RAM_NORESERVE) ? QEMU_MAP_NORESERVE :
> 0;
> +
> + return qemu_ram_mmap(block->fd, block->mmap_length, block->mr->align,
> + qemu_map_flags, block->file_offset);
> +}
> +
> static void *file_ram_alloc(RAMBlock *block,
> int fd,
> bool truncate,
> off_t offset,
> Error **errp)
> {
> - uint32_t qemu_map_flags;
> void *area;
>
> /* Remember the offset just in case we'll need to map the range again */
Note that this comment is now wrong; you need to always set that for the
map call.
Other than that,
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> block->file_offset = offset;
> + block->fd = fd;
> block->page_size = qemu_fd_getpagesize(fd);
> if (block->mr->align % block->page_size) {
> error_setg(errp, "alignment 0x%" PRIx64
> @@ -1588,19 +1602,14 @@ static void *file_ram_alloc(RAMBlock *block,
> perror("ftruncate");
> }
>
> - qemu_map_flags = (block->flags & RAM_READONLY) ? QEMU_MAP_READONLY : 0;
> - qemu_map_flags |= (block->flags & RAM_SHARED) ? QEMU_MAP_SHARED : 0;
> - qemu_map_flags |= (block->flags & RAM_PMEM) ? QEMU_MAP_SYNC : 0;
> - qemu_map_flags |= (block->flags & RAM_NORESERVE) ? QEMU_MAP_NORESERVE :
> 0;
> - area = qemu_ram_mmap(fd, block->mmap_length, block->mr->align,
> - qemu_map_flags, offset);
> + area = ramblock_file_map(block);
> +
> if (area == MAP_FAILED) {
> error_setg_errno(errp, errno,
> "unable to map backing store for guest RAM");
> return NULL;
> }
>
> - block->fd = fd;
> return area;
> }
> #endif
> --
> 2.37.3
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
