Re: [Qemu-devel] [RFC PATCH 15/56] migration: Make XBZRLE cache size unsigned in QAPI/QMP

[Juan Quintela <quintela@redhat.com>]

Markus Armbruster <armbru@redhat.com> wrote:
> Sizes should use QAPI type 'size' (uint64_t).  migrate-set-cache-size
> parameter @value is 'int' (int64_t).  qmp_migrate_set_cache_size()
> ensures it fits into size_t.  page_cache.c implicitly converts the
> signed size to unsigned types (it can't quite decide whether to use
> uint64_t or size_t for cache offsets, but that's not something I can
> tackle now).
>
> XBZRLECacheStats member @cache-size and query-migrate-cache-size's
> result are also 'int'.
>
> Change the migrate-set-cache-size parameter and the XBZRLECacheStats
> members to 'size', fix up hmp_migrate_set_cache_size(), and tweak a
> few variable types to reduce implicit conversions.
>
> migrate-set-cache-size now accepts size values between 2^63 and
> 2^64-1.  It accepts negative values as before, because that's how the
> QObject input visitor works for backward compatibility.
>
> So does HMP's migrate_set_cache_size.
>
> query-migrate and query-migrate-cache-size now report cache sizes
> above 2^63-1 correctly instead of their (negative) two's complement.
>
> So does HMP's "info migrate_cache_size".  HMP's "info migrate" already
> reported the cache size correctly, because it printed the signed
> integer with PRIu32.
>

Reviewed-by: Juan Quintela <quintela@redhat.com>


> diff --git a/qapi-schema.json b/qapi-schema.json
> index c8cceb9..ecabff6 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -646,7 +646,7 @@
>  # Since: 1.2
>  ##
>  { 'struct': 'XBZRLECacheStats',
> -  'data': {'cache-size': 'int', 'bytes': 'int', 'pages': 'int',
> +  'data': {'cache-size': 'size', 'bytes': 'int', 'pages': 'int',
>             'cache-miss': 'int', 'cache-miss-rate': 'number',
>             'overflow': 'int' } }
>  
> @@ -2875,7 +2875,7 @@
>  # <- { "return": {} }
>  #
>  ##
> -{ 'command': 'migrate-set-cache-size', 'data': {'value': 'int'} }
> +{ 'command': 'migrate-set-cache-size', 'data': {'value': 'size'} }
>  
>  ##
>  # @query-migrate-cache-size:
> @@ -2892,7 +2892,7 @@
>  # <- { "return": 67108864 }
>  #
>  ##
> -{ 'command': 'query-migrate-cache-size', 'returns': 'int' }
> +{ 'command': 'query-migrate-cache-size', 'returns': 'size' }
>  
>  ##
>  # @ObjectPropertyInfo:

I am ussming this bits are backward compatible (I don't understand QMP
to assure this)