[PATCH v5 2/2] xen/domain: adjust domain ID allocation for Arm

[dmkhn@xxxxxxxxx]

From: Denis Mukhin <dmukhin@xxxxxxxx>

Remove the hardcoded domain ID 0 allocation for hardware domain and replace it
with a call to get_initial_domain_id() (returns the value of hardware_domid on
Arm).

Update domid_alloc(DOMID_INVALID) case to ensure that get_initial_domain_id()
ID is skipped during domain ID allocation to cover domU case.

Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
Changes since v4:
- new patch
---
 xen/arch/arm/dom0less-build.c | 9 +++------
 xen/arch/arm/domain_build.c   | 4 ++--
 xen/common/domain.c           | 5 ++++-
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/xen/arch/arm/dom0less-build.c b/xen/arch/arm/dom0less-build.c
index 9eb64ec60d..61e01b7306 100644
--- a/xen/arch/arm/dom0less-build.c
+++ b/xen/arch/arm/dom0less-build.c
@@ -1216,14 +1216,11 @@ void __init create_domUs(void)
         if ( !llc_coloring_enabled && llc_colors_str )
             panic("'llc-colors' found, but LLC coloring is disabled\n");
 
-        /*
-         * The variable max_init_domid is initialized with zero, so here it's
-         * very important to use the pre-increment operator to call
-         * domain_create() with a domid > 0. (domid == 0 is reserved for Dom0)
-         */
-        domid = domid_alloc(++max_init_domid);
+        domid = domid_alloc(DOMID_INVALID);
         if ( domid == DOMID_INVALID )
             panic("Error allocating ID for domain %s\n", dt_node_name(node));
+        if ( max_init_domid < domid )
+            max_init_domid = domid;
 
         d = domain_create(domid, &d_cfg, flags);
         if ( IS_ERR(d) )
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 29e22a8809..c85d72fdf1 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -2396,9 +2396,9 @@ void __init create_dom0(void)
     if ( !llc_coloring_enabled )
         flags |= CDF_directmap;
 
-    domid = domid_alloc(0);
+    domid = domid_alloc(get_initial_domain_id());
     if ( domid == DOMID_INVALID )
-        panic("Error allocating domain ID 0\n");
+        panic("Error allocating domain ID %d\n", get_initial_domain_id());
 
     dom0 = domain_create(domid, &dom0_cfg, flags);
     if ( IS_ERR(dom0) )
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 0ba3cdc47d..055397b5aa 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -85,7 +85,7 @@ void __init domid_init(void)
  *
  * If hint is outside of valid [0..DOMID_FIRST_RESERVED - 1] range of IDs,
  * perform an exhaustive search starting from the end of the used domain ID
- * range.
+ * range, excluding get_initial_domain_id() ID.
  */
 domid_t domid_alloc(domid_t domid)
 {
@@ -103,6 +103,9 @@ domid_t domid_alloc(domid_t domid)
             if ( domid == DOMID_FIRST_RESERVED )
                 domid = 0;
 
+            if ( domid == get_initial_domain_id() )
+                continue;
+
             if ( !rangeset_contains_singleton(domid_rangeset, domid) )
                 break;
         }
-- 
2.34.1