[RFC 37/38] x86/hyperlaunch: generalize domid assignment

["Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>]

Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
 xen/arch/x86/domain-builder/fdt.c | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/domain-builder/fdt.c 
b/xen/arch/x86/domain-builder/fdt.c
index 9c6c0ae09a24..543a0c92adb4 100644
--- a/xen/arch/x86/domain-builder/fdt.c
+++ b/xen/arch/x86/domain-builder/fdt.c
@@ -15,6 +15,21 @@
 
 #include "fdt.h"
 
+#define MAX_DOMID  DOMID_FIRST_RESERVED
+static __initdata DECLARE_BITMAP(domid_alloc, MAX_DOMID);
+
+static domid_t find_next_domid(void)
+{
+    unsigned long n = find_next_zero_bit(domid_alloc, MAX_DOMID, 1);
+
+    if ( n == MAX_DOMID )
+        return DOMID_INVALID;
+
+    set_bit(n, domid_alloc);
+
+    return (domid_t) n;
+}
+
 /*
  * Unpacks a "reg" property into its address and size constituents.
  *
@@ -186,11 +201,21 @@ static int __init process_domain_node(
                 printk("  failed processing domain id for domain %s\n", name);
                 return -EINVAL;
             }
+
             if ( val >= DOMID_FIRST_RESERVED )
             {
-                printk("  invalid domain id for domain %s\n", name);
-                return -EINVAL;
+                if ( (val = find_next_domid()) == DOMID_INVALID )
+                {
+                    printk("  unable to allocate domid for domain %s\n", name);
+                    return -EFAULT;
+                }
             }
+            else if ( test_and_set_bit(val, domid_alloc) )
+            {
+                printk(XENLOG_ERR "ERR: domid (%d) already assigned\n", val);
+                return -EFAULT;
+            }
+
             bd->domid = (domid_t)val;
             printk("  domid: %d\n", bd->domid);
         }
-- 
2.30.2