[XEN] Extend dom0_mem syntax to support min/max clamps.

dom0_mem=[min:<min_amt>,][max:<max_amt>,][<amt>]

<min_amt>: The minimum amount of memory which should be allocated for dom0.
<max_amt>: The maximum amount of memory which should be allocated for dom0.
<amt>:     The precise amount of memory to allocate for dom0.

Notes:
 1. <amt> is clamped from below by <min_amt> and from above by available
    memory and <max_amt>
 2. <min_amt> is clamped from above by available memory and <max_amt>
 3. <min_amt> is ignored if it is greater than <max_amt>
 4. If <amt> is not specified, it is calculated as follows:
    "All of memory is allocated to domain 0, minus 1/16th which is reserved
     for uses such as DMA buffers (the reservation is clamped to 128MB)."

Each value can be specified as positive or negative:
 If +ve: The specified amount is an absolute value.
 If -ve: The specified amount is subtracted from total available memory.

Signed-off-by: Keir Fraser <keir@xensource.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/xen/common/lib.c b/xen/common/lib.c
index 408e8eefe6..0eb58f19d2 100644
--- a/xen/common/lib.c
+++ b/xen/common/lib.c
@@ -439,21 +439,28 @@ s64 __moddi3(s64 a, s64 b)
 
 #endif /* BITS_PER_LONG == 32 */
 
-unsigned long long parse_size_and_unit(char *s)
+unsigned long long parse_size_and_unit(const char *s, char **ps)
 {
-	unsigned long long ret = simple_strtoull(s, &s, 0);
+	unsigned long long ret = simple_strtoull(s, (char **)&s, 0);
 
 	switch (*s) {
 	case 'G': case 'g':
 		ret <<= 10;
 	case 'M': case 'm':
 		ret <<= 10;
-	case 'K': case 'k': default:
+	case 'K': case 'k':
 		ret <<= 10;
 	case 'B': case 'b':
+		s++;
+		break;
+	default:
+		ret <<= 10; /* default to kB */
 		break;
 	}
 
+	if (ps != NULL)
+		*ps = (char *)s;
+
 	return ret;
 }