On 1/2/24 05:57, Richard Henderson wrote:
> Replace with the maximum of the real host page size
> and the target page size. This is an exact replacement.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> migration/ram.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index 8c7886ab79..aa3109fca3 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2936,7 +2936,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
> {
> RAMState **rsp = opaque;
> RAMBlock *block;
> - int ret;
> + int ret, max_hg_page_size;
>
> if (compress_threads_save_setup()) {
> return -1;
> @@ -2951,6 +2951,12 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
> }
> (*rsp)->pss[RAM_CHANNEL_PRECOPY].pss_channel = f;
>
> + /*
> + * ??? Mirrors the previous value of qemu_host_page_size,
> + * but is this really what was intended for the migration?
> + */
> + max_hg_page_size = MAX(qemu_real_host_page_size(), TARGET_PAGE_SIZE);
> +
> WITH_RCU_READ_LOCK_GUARD() {
> qemu_put_be64(f, ram_bytes_total_with_ignored()
> | RAM_SAVE_FLAG_MEM_SIZE);
> @@ -2959,8 +2965,8 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
> qemu_put_byte(f, strlen(block->idstr));
> qemu_put_buffer(f, (uint8_t *)block->idstr, strlen(block->idstr));
> qemu_put_be64(f, block->used_length);
> - if (migrate_postcopy_ram() && block->page_size !=
> - qemu_host_page_size) {
> + if (migrate_postcopy_ram() &&
> + block->page_size != max_hg_page_size) {
> qemu_put_be64(f, block->page_size);
> }
> if (migrate_ignore_shared()) {
> @@ -3794,6 +3800,7 @@ static int parse_ramblock(QEMUFile *f, RAMBlock *block, ram_addr_t length)
> int ret = 0;
> /* ADVISE is earlier, it shows the source has the postcopy capability on */
> bool postcopy_advised = migration_incoming_postcopy_advised();
> + int max_hg_page_size;
>
> assert(block);
>
> @@ -3811,9 +3818,16 @@ static int parse_ramblock(QEMUFile *f, RAMBlock *block, ram_addr_t length)
> return ret;
> }
> }
> +
> + /*
> + * ??? Mirrors the previous value of qemu_host_page_size,
> + * but is this really what was intended for the migration?
> + */
> + max_hg_page_size = MAX(qemu_real_host_page_size(), TARGET_PAGE_SIZE);
> +
> /* For postcopy we need to check hugepage sizes match */
> if (postcopy_advised && migrate_postcopy_ram() &&
> - block->page_size != qemu_host_page_size) {
> + block->page_size != max_hg_page_size) {
> uint64_t remote_page_size = qemu_get_be64(f);
> if (remote_page_size != block->page_size) {
> error_report("Mismatched RAM page size %s "
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>