Currently ram_block_discard_range() is called only by the postcopy code,
using length=block->used_length.  However, new code will use
ram_block_discard_range() to discard the contents of the entire
RAMBlock, so change the limit check to use max_length instead of
used_length.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 exec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exec.c b/exec.c
index a93e209625..585d6ed6d7 100644
--- a/exec.c
+++ b/exec.c
@@ -3522,7 +3522,7 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
         goto err;
     }
 
-    if ((start + length) <= rb->used_length) {
+    if ((start + length) <= rb->max_length) {
         uint8_t *host_endaddr = host_startaddr + length;
         if ((uintptr_t)host_endaddr & (rb->page_size - 1)) {
             error_report("ram_block_discard_range: Unaligned end address: %p",
-- 
2.11.0.259.g40922b1

* Eduardo Habkost (ehabkost@redhat.com) wrote:
> Currently ram_block_discard_range() is called only by the postcopy code,
> using length=block->used_length.  However, new code will use
> ram_block_discard_range() to discard the contents of the entire
> RAMBlock, so change the limit check to use max_length instead of
> used_length.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

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

> ---
>  exec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/exec.c b/exec.c
> index a93e209625..585d6ed6d7 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -3522,7 +3522,7 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
>          goto err;
>      }
>  
> -    if ((start + length) <= rb->used_length) {
> +    if ((start + length) <= rb->max_length) {
>          uint8_t *host_endaddr = host_startaddr + length;
>          if ((uintptr_t)host_endaddr & (rb->page_size - 1)) {
>              error_report("ram_block_discard_range: Unaligned end address: %p",
> -- 
> 2.11.0.259.g40922b1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK