On Mon, Aug 17, 2026 at 10:24 PM Peter Xu <[email protected]> wrote:
>
> This is guaranteed to be true. There seems to have support for some
> dynamically allocated buffers but it was never really supported. Remove
> dead code.
>
> As a side effect, this patch closes a report by removing the buggy code
> completely.
>
> Reported-by: Tristan (@TristanInSec)
> Closes: https://gitlab.com/qemu-project/qemu/-/work_items/4006
> Signed-off-by: Peter Xu <[email protected]>
> ---
> migration/rdma.c | 73 ++++++++++++++----------------------------------
> 1 file changed, 21 insertions(+), 52 deletions(-)
>
> diff --git a/migration/rdma.c b/migration/rdma.c
> index ffae0a887f..354935433c 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -196,7 +196,6 @@ typedef struct RDMALocalBlock {
> uint32_t remote_rkey; /* rkeys for non-chunk-level
> registration */
> int index; /* which block are we */
> unsigned int src_index; /* (Only used on dest) */
> - bool is_ram_block;
> int nb_chunks;
> unsigned long *transit_bitmap;
> unsigned long *unregister_bitmap;
> @@ -441,14 +440,12 @@ static void register_to_network(RDMAContext *rdma,
> RDMARegister *reg)
> RDMALocalBlock *local_block;
> local_block = &rdma->local_ram_blocks.block[reg->current_index];
>
> - if (local_block->is_ram_block) {
> - /*
> - * current_addr as passed in is an address in the local ram_addr_t
> - * space, we need to translate this for the destination
> - */
> - reg->key.current_addr -= local_block->offset;
> - reg->key.current_addr +=
> rdma->dest_blocks[reg->current_index].offset;
> - }
> + /*
> + * current_addr as passed in is an address in the local ram_addr_t
> + * space, we need to translate this for the destination
> + */
> + reg->key.current_addr -= local_block->offset;
> + reg->key.current_addr += rdma->dest_blocks[reg->current_index].offset;
> reg->key.current_addr = htonll(reg->key.current_addr);
> reg->current_index = htonl(reg->current_index);
> reg->chunks = htonll(reg->chunks);
> @@ -585,8 +582,6 @@ static void rdma_add_block(RDMAContext *rdma, const char
> *block_name,
> bitmap_clear(block->unregister_bitmap, 0, block->nb_chunks);
> block->remote_keys = g_new0(uint32_t, block->nb_chunks);
>
> - block->is_ram_block = local->init ? false : true;
this local->init is only used here, can be removed too.
> -
> if (rdma->blockmap) {
> g_hash_table_insert(rdma->blockmap, (void *)(uintptr_t)block_offset,
> block);
> }
> @@ -1767,19 +1762,10 @@ retry:
> chunk = ram_chunk_index(block->local_host_addr,
> (uint8_t *)(uintptr_t)sge.addr);
> chunk_start = ram_chunk_start(block, chunk);
> + chunks = length / chunk_size;
>
> - if (block->is_ram_block) {
> - chunks = length / chunk_size;
> -
> - if (chunks && ((length % chunk_size) == 0)) {
> - chunks--;
> - }
> - } else {
> - chunks = block->length / chunk_size;
> -
> - if (chunks && ((block->length % chunk_size) == 0)) {
> - chunks--;
> - }
> + if (chunks && ((length % chunk_size) == 0)) {
> + chunks--;
> }
>
> trace_rdma_write_one_top(chunks + 1,
> @@ -1804,7 +1790,7 @@ retry:
> }
> }
>
> - if (!rdma->pin_all || !block->is_ram_block) {
> + if (!rdma->pin_all) {
> if (!block->remote_keys[chunk]) {
> /*
> * This chunk has not yet been registered, so first check to see
> @@ -1853,11 +1839,7 @@ retry:
> * Otherwise, tell other side to register.
> */
> reg.current_index = current_index;
> - if (block->is_ram_block) {
> - reg.key.current_addr = current_addr;
> - } else {
> - reg.key.chunk = chunk;
> - }
> + reg.key.current_addr = current_addr;
> reg.chunks = chunks;
>
> trace_rdma_write_one_sendreg(chunk, sge.length, current_index,
> @@ -3408,30 +3390,17 @@ int rdma_registration_handle(QEMUFile *f)
> goto err;
> }
> block = &(rdma->local_ram_blocks.block[reg->current_index]);
> - if (block->is_ram_block) {
> - if (block->offset > reg->key.current_addr) {
> - error_report("rdma: bad register address for block
> %s"
> - " offset: %" PRIx64 " current_addr: %" PRIx64,
> - block->block_name, block->offset,
> - reg->key.current_addr);
> - goto err;
> - }
> - host_addr = (block->local_host_addr +
> - (reg->key.current_addr - block->offset));
> - chunk = ram_chunk_index(block->local_host_addr,
> - (uint8_t *) host_addr);
> - } else {
> - chunk = reg->key.chunk;
> - host_addr = block->local_host_addr +
> - (reg->key.chunk * migrate_rdma_chunk_size());
> - /* Check for particularly bad chunk value */
> - if (host_addr < (void *)block->local_host_addr) {
> - error_report("rdma: bad chunk for block %s"
> - " chunk: %" PRIx64,
> - block->block_name, reg->key.chunk);
> - goto err;
> - }
> + if (block->offset > reg->key.current_addr) {
> + error_report("rdma: bad register address for block %s"
> + " offset: %" PRIx64 " current_addr: %" PRIx64,
> + block->block_name, block->offset,
> + reg->key.current_addr);
> + goto err;
> }
> + host_addr = (block->local_host_addr +
> + (reg->key.current_addr - block->offset));
> + chunk = ram_chunk_index(block->local_host_addr,
> + (uint8_t *) host_addr);
> chunk_start = ram_chunk_start(block, chunk);
> chunk_end = ram_chunk_end(block, chunk + reg->chunks);
> /* avoid "-Waddress-of-packed-member" warning */
> --
> 2.54.0
>
other than the leftover above. lgtm.
Reviewed-by: Jack Wang <[email protected]>
