[PATCH 23/36] xen/arch: coloring: manually calculate Xen physical addresses

[Marco Solieri <marco.solieri@xxxxxxxxxxxxxxx>]

From: Luca Miccio <lucmiccio@xxxxxxxxx>

During Xen coloring procedure, we need to manually calculate consecutive
physical addresses that conform to the color selection. Add an helper
function that does this operation. The latter will return the next
address that conforms to Xen color selection.

The next_colored function is architecture dependent and the provided
implementation is for ARMv8.

Signed-off-by: Luca Miccio <lucmiccio@xxxxxxxxx>
Signed-off-by: Marco Solieri <marco.solieri@xxxxxxxxxxxxxxx>
---
 xen/arch/arm/coloring.c             | 43 +++++++++++++++++++++++++++++
 xen/arch/arm/include/asm/coloring.h | 14 ++++++++++
 2 files changed, 57 insertions(+)

diff --git a/xen/arch/arm/coloring.c b/xen/arch/arm/coloring.c
index 761414fcd7..aae3c77a7b 100644
--- a/xen/arch/arm/coloring.c
+++ b/xen/arch/arm/coloring.c
@@ -222,6 +222,49 @@ uint32_t get_max_colors(void)
     return max_col_num;
 }
 
+paddr_t next_xen_colored(paddr_t phys)
+{
+    unsigned int i;
+    unsigned int col_next_number = 0;
+    unsigned int col_cur_number = (phys & addr_col_mask) >> PAGE_SHIFT;
+    int overrun = 0;
+    paddr_t ret;
+
+    /*
+     * Check if address color conforms to Xen selection. If it does, return
+     * the address as is.
+     */
+    for( i = 0; i < xen_col_num; i++)
+        if ( col_cur_number == xen_col_list[i] )
+            return phys;
+
+    /* Find next col */
+    for( i = xen_col_num -1 ; i >= 0; i--)
+    {
+        if ( col_cur_number > xen_col_list[i])
+        {
+            /* Need to start to first element and add a way_size */
+            if ( i == (xen_col_num - 1) )
+            {
+                col_next_number = xen_col_list[0];
+                overrun = 1;
+            }
+            else
+            {
+                col_next_number = xen_col_list[i+1];
+                overrun = 0;
+            }
+            break;
+        }
+    }
+
+    /* Align phys to way_size */
+    ret = phys - (PAGE_SIZE * col_cur_number);
+    /* Add the offset based on color selection*/
+    ret += (PAGE_SIZE * (col_next_number)) + (way_size*overrun);
+    return ret;
+}
+
 bool __init coloring_init(void)
 {
     int i, rc;
diff --git a/xen/arch/arm/include/asm/coloring.h 
b/xen/arch/arm/include/asm/coloring.h
index 22e67dc9d8..8c4525677c 100644
--- a/xen/arch/arm/include/asm/coloring.h
+++ b/xen/arch/arm/include/asm/coloring.h
@@ -28,6 +28,20 @@
 
 bool __init coloring_init(void);
 
+/*
+ * Return physical page address that conforms to the colors selection
+ * given in col_selection_mask after @param phys.
+ *
+ * @param phys         Physical address start.
+ * @param addr_col_mask        Mask specifying the bits available for coloring.
+ * @param col_selection_mask   Mask asserting the color bits to be used,
+ * must not be 0.
+ *
+ * @return The lowest physical page address being greater or equal than
+ * 'phys' and belonging to Xen color selection
+ */
+paddr_t next_xen_colored(paddr_t phys);
+
 /*
  * Check colors of a given domain.
  * Return true if check passed, false otherwise.
-- 
2.30.2