* Markus Armbruster ([email protected]) wrote:
> migrate-set-parameters passes the size to xbzrle_cache_resize().
> xbzrle_cache_resize() checks it fits into size_t before it passes it
> on to cache_init(). cache_init() checks it is a power of two no
> smaller than @page_size.
>
> cache_init() is also called from xbzrle_init(), bypassing
> xbzrle_cache_resize()'s check.
>
> Drop xbzrle_cache_resize()'s check, and check more carefully in
> cache_init().
>
> Signed-off-by: Markus Armbruster <[email protected]>
> ---
> migration/page_cache.c | 15 ++++-----------
> migration/ram.c | 7 -------
> 2 files changed, 4 insertions(+), 18 deletions(-)
>
> diff --git a/migration/page_cache.c b/migration/page_cache.c
> index b384f265fb..e07f4ad1dc 100644
> --- a/migration/page_cache.c
> +++ b/migration/page_cache.c
> @@ -41,17 +41,10 @@ struct PageCache {
> PageCache *cache_init(uint64_t new_size, size_t page_size, Error **errp)
> {
> int64_t i;
> - size_t num_pages = new_size / page_size;
> + uint64_t num_pages = new_size / page_size;
> PageCache *cache;
>
> - if (new_size < page_size) {
> - error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
> - "is smaller than one target page size");
> - return NULL;
> - }
> -
> - /* round down to the nearest power of 2 */
> - if (!is_power_of_2(num_pages)) {
> + if (num_pages != (size_t)num_pages || !is_power_of_2(num_pages)) {
> error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
> "is not a power of two number of pages");
That error message is now wrong since it includes a whole bunch of
reasons.
Also, the comparison is now on the divided num_pages, it's not that
obvious to me that checking the num_pages makes sense in acomparison to
checking the actual cache size.
(Arguably the check should also happen in migrate_params_test_apply)
Dave
> return NULL;
> @@ -71,8 +64,8 @@ PageCache *cache_init(uint64_t new_size, size_t page_size,
> Error **errp)
> trace_migration_pagecache_init(cache->max_num_items);
>
> /* We prefer not to abort if there is no memory */
> - cache->page_cache = g_try_malloc((cache->max_num_items) *
> - sizeof(*cache->page_cache));
> + cache->page_cache = g_try_malloc_n(cache->max_num_items,
> + sizeof(*cache->page_cache));
> if (!cache->page_cache) {
> error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
> "Failed to allocate page cache");
> diff --git a/migration/ram.c b/migration/ram.c
> index a84425d04f..d632ae694c 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -131,13 +131,6 @@ int xbzrle_cache_resize(uint64_t new_size, Error **errp)
> PageCache *new_cache;
> int64_t ret = 0;
>
> - /* Check for truncation */
> - if (new_size != (size_t)new_size) {
> - error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
> - "exceeding address space");
> - return -1;
> - }
> -
> if (new_size == migrate_xbzrle_cache_size()) {
> /* nothing to do */
> return 0;
> --
> 2.26.2
>
--
Dr. David Alan Gilbert / [email protected] / Manchester, UK
