[PATCH 09/36] xen/arch: add default colors selection function

[Marco Solieri <marco.solieri@xxxxxxxxxxxxxxx>]

From: Luca Miccio <lucmiccio@xxxxxxxxx>

When cache coloring support is enabled, a color assignment is needed for
every domain. Introduce a function computing a default configuration
with a safe and common value -- the dom0 color selection.

Do not access directly the array of color indices of dom0. Instead make
use of the dom0 color configuration as a bitmask.
Add a helper function that converts the color configuration bitmask into
the indices array.

Signed-off-by: Luca Miccio <lucmiccio@xxxxxxxxx>
Signed-off-by: Marco Solieri <marco.solieri@xxxxxxxxxxxxxxx>
---
 xen/arch/arm/coloring.c             | 36 +++++++++++++++++++++++++++++
 xen/arch/arm/include/asm/coloring.h |  7 ++++++
 2 files changed, 43 insertions(+)

diff --git a/xen/arch/arm/coloring.c b/xen/arch/arm/coloring.c
index af75b536a7..f6e6d09477 100644
--- a/xen/arch/arm/coloring.c
+++ b/xen/arch/arm/coloring.c
@@ -143,6 +143,42 @@ static __init uint64_t calculate_addr_col_mask(uint64_t 
llc_way_size)
     return addr_col_mask;
 }
 
+static int copy_mask_to_list(
+    uint32_t *col_mask, uint32_t *col_list, uint64_t col_num)
+{
+    unsigned int i, k, c;
+
+    if ( !col_list )
+        return -EINVAL;
+
+    for ( i = 0, k = 0; i < MAX_COLORS_CELLS; i++ )
+        for ( c = 0; k < col_num && c < 32; c++ )
+            if ( col_mask[i] & (1 << (c + (i*32))) )
+                col_list[k++] = c + (i * 32);
+
+    return 0;
+}
+
+uint32_t *setup_default_colors(uint32_t *col_num)
+{
+    uint32_t *col_list;
+
+    if ( dom0_col_num )
+    {
+        *col_num = dom0_col_num;
+        col_list = xzalloc_array(uint32_t, dom0_col_num);
+        if ( !col_list )
+        {
+            printk(XENLOG_ERR "setup_default_colors: Alloc failed\n");
+            return NULL;
+        }
+        copy_mask_to_list(dom0_col_mask, col_list, dom0_col_num);
+        return col_list;
+    }
+
+    return NULL;
+}
+
 bool __init coloring_init(void)
 {
     int i;
diff --git a/xen/arch/arm/include/asm/coloring.h 
b/xen/arch/arm/include/asm/coloring.h
index 70e1dbd09b..8f24acf082 100644
--- a/xen/arch/arm/include/asm/coloring.h
+++ b/xen/arch/arm/include/asm/coloring.h
@@ -27,6 +27,13 @@
 
 #ifdef CONFIG_COLORING
 bool __init coloring_init(void);
+
+/*
+ * Return an array with default colors selection and store the number of
+ * colors in @param col_num. The array selection will be equal to the dom0
+ * color configuration.
+ */
+uint32_t *setup_default_colors(uint32_t *col_num);
 #else /* !CONFIG_COLORING */
 static inline bool __init coloring_init(void)
 {
-- 
2.30.2