Re: [PATCH] Bug #1829242 correction

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* - - (nevilad@yahoo.com) wrote:
> Bug #1829242 correction. Added type conversions to ram_addr_t
> before all left shifts of page indexes to TARGET_PAGE_BITS, to correct
> overflows when the page address was 4Gb and more.
> 
> Signed-off-by: Alexey Romko <nevilad@yahoo.com>

Hi Alexey,
  (Your git settings are a bit odd, your name isn't on the mail header,
but that's minor since you have the signed-off ok).

Thanks for this, this is probably a fix for Juan's a935e30
which started using 'page' rather than 'offset' in the PageSearchStatus,
and I guess on windows 'long' isn't long enough.

I think this is fine, (with perhaps a better Subject, that Juan can
add);

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

I think in the long term we probably need to stop using 'long' for
offsets.

Dave

> ---
>  migration/ram.c | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index 5078f94490..90a09de620 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1730,7 +1730,7 @@ static inline bool migration_bitmap_clear_dirty(RAMState *rs,
>      if (rb->clear_bmap && clear_bmap_test_and_clear(rb, page)) {
>          uint8_t shift = rb->clear_bmap_shift;
>          hwaddr size = 1ULL << (TARGET_PAGE_BITS + shift);
> -        hwaddr start = (page << TARGET_PAGE_BITS) & (-size);
> +        hwaddr start = (((ram_addr_t)page) << TARGET_PAGE_BITS) & (-size);
>  
>          /*
>           * CLEAR_BITMAP_SHIFT_MIN should always guarantee this... this
> @@ -1967,7 +1967,7 @@ static void ram_release_pages(const char *rbname, uint64_t offset, int pages)
>          return;
>      }
>  
> -    ram_discard_range(rbname, offset, pages << TARGET_PAGE_BITS);
> +    ram_discard_range(rbname, offset, ((ram_addr_t)pages) << TARGET_PAGE_BITS);
>  }
>  
>  /*
> @@ -2055,7 +2055,7 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)
>      uint8_t *p;
>      bool send_async = true;
>      RAMBlock *block = pss->block;
> -    ram_addr_t offset = pss->page << TARGET_PAGE_BITS;
> +    ram_addr_t offset = ((ram_addr_t)pss->page) << TARGET_PAGE_BITS;
>      ram_addr_t current_addr = block->offset + offset;
>  
>      p = block->host + offset;
> @@ -2242,7 +2242,7 @@ static bool find_dirty_block(RAMState *rs, PageSearchStatus *pss, bool *again)
>          *again = false;
>          return false;
>      }
> -    if ((pss->page << TARGET_PAGE_BITS) >= pss->block->used_length) {
> +    if ((((ram_addr_t)pss->page) << TARGET_PAGE_BITS) >= pss->block->used_length) {
>          /* Didn't find anything in this RAM Block */
>          pss->page = 0;
>          pss->block = QLIST_NEXT_RCU(pss->block, next);
> @@ -2536,7 +2536,7 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss,
>                                  bool last_stage)
>  {
>      RAMBlock *block = pss->block;
> -    ram_addr_t offset = pss->page << TARGET_PAGE_BITS;
> +    ram_addr_t offset = ((ram_addr_t)pss->page) << TARGET_PAGE_BITS;
>      int res;
>  
>      if (control_save_page(rs, block, offset, &res)) {
> @@ -2617,7 +2617,7 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
>          pages += tmppages;
>          pss->page++;
>      } while ((pss->page & (pagesize_bits - 1)) &&
> -             offset_in_ramblock(pss->block, pss->page << TARGET_PAGE_BITS));
> +             offset_in_ramblock(pss->block, ((ram_addr_t)pss->page) << TARGET_PAGE_BITS));
>  
>      /* The offset we leave with is the last one we looked at */
>      pss->page--;
> @@ -2834,8 +2834,8 @@ void ram_postcopy_migrated_memory_release(MigrationState *ms)
>  
>          while (run_start < range) {
>              unsigned long run_end = find_next_bit(bitmap, range, run_start + 1);
> -            ram_discard_range(block->idstr, run_start << TARGET_PAGE_BITS,
> -                              (run_end - run_start) << TARGET_PAGE_BITS);
> +            ram_discard_range(block->idstr, ((ram_addr_t)run_start) << TARGET_PAGE_BITS,
> +                              ((ram_addr_t)(run_end - run_start)) << TARGET_PAGE_BITS);
>              run_start = find_next_zero_bit(bitmap, range, run_end + 1);
>          }
>      }
> @@ -4201,13 +4201,13 @@ static void colo_flush_ram_cache(void)
>          while (block) {
>              offset = migration_bitmap_find_dirty(ram_state, block, offset);
>  
> -            if (offset << TARGET_PAGE_BITS >= block->used_length) {
> +            if (((ram_addr_t)offset) << TARGET_PAGE_BITS >= block->used_length) {
>                  offset = 0;
>                  block = QLIST_NEXT_RCU(block, next);
>              } else {
>                  migration_bitmap_clear_dirty(ram_state, block, offset);
> -                dst_host = block->host + (offset << TARGET_PAGE_BITS);
> -                src_host = block->colo_cache + (offset << TARGET_PAGE_BITS);
> +                dst_host = block->host + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
> +                src_host = block->colo_cache + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
>                  memcpy(dst_host, src_host, TARGET_PAGE_SIZE);
>              }
>          }
> -- 
> 2.15.0.windows.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK