[PATCH v3] tools/xl: fix autoballoon regex

[Dmitry Isaykin <isaikin-dmitry@xxxxxxxxx>]

This regex is used for auto-balloon mode detection based on Xen command line.

The case of specifying a negative size was handled incorrectly.
>From misc/xen-command-line documentation:

    dom0_mem (x86)
    = List of ( min:<sz> | max:<sz> | <sz> )

    If a size is positive, it represents an absolute value.
    If a size is negative, it is subtracted from the total available memory.

Also add support for [tT] granularity suffix.
Also add support for memory fractions (i.e. '50%' or '1G+25%').

Signed-off-by: Dmitry Isaykin <isaikin-dmitry@xxxxxxxxx>
---
Changes in v3:
- add support for [tT] granularity suffix
- add support for memory fractions

Changes in v2:
- add missing Signed-off-by tag
---
 tools/xl/xl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/xl/xl.c b/tools/xl/xl.c
index 4107d10fd4..8500b3ac57 100644
--- a/tools/xl/xl.c
+++ b/tools/xl/xl.c
@@ -81,7 +81,7 @@ static int auto_autoballoon(void)
         return 1; /* default to on */
 
     ret = regcomp(&regex,
-                  "(^| )dom0_mem=((|min:|max:)[0-9]+[bBkKmMgG]?,?)+($| )",
+                  "(^| 
)dom0_mem=((|min:|max:)(-?[0-9]+[bBkKmMgGtT]?)?(\+?[0-9]+%)?,?)+($| )",
                   REG_NOSUB | REG_EXTENDED);
     if (ret)
         return 1;
-- 
2.33.0