[PATCH 16/36] xen/color alloc: implement color_from_page for ARM64

[Marco Solieri <marco.solieri@xxxxxxxxxxxxxxx>]

From: Luca Miccio <lucmiccio@xxxxxxxxx>

The colored allocator should not make any assumptions on how a color is
defined, since the definition may change depending on the architecture.
Use a generic function "color_from_page" that returns the color id based
on the page address.
Add a definition for ARMv8 architectures.

Signed-off-by: Luca Miccio <lucmiccio@xxxxxxxxx>
Signed-off-by: Marco Solieri <marco.solieri@xxxxxxxxxxxxxxx>
---
 xen/arch/arm/coloring.c             | 13 +++++++++++++
 xen/arch/arm/include/asm/coloring.h |  7 +++++++
 2 files changed, 20 insertions(+)

diff --git a/xen/arch/arm/coloring.c b/xen/arch/arm/coloring.c
index 8061c3824f..4748d717d6 100644
--- a/xen/arch/arm/coloring.c
+++ b/xen/arch/arm/coloring.c
@@ -196,6 +196,19 @@ bool check_domain_colors(struct domain *d)
     return !ret;
 }
 
+/*
+ * Compute color id from the page @param pg.
+ * Page size determines the lowest available bit, while add_col_mask is used to
+ * select the rest.
+ *
+ * @param pg              Page address
+ * @return unsigned long  Color id
+ */
+unsigned long color_from_page(struct page_info *pg)
+{
+  return ((addr_col_mask & page_to_maddr(pg)) >> PAGE_SHIFT);
+}
+
 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 8609e17e80..318e2a4521 100644
--- a/xen/arch/arm/include/asm/coloring.h
+++ b/xen/arch/arm/include/asm/coloring.h
@@ -42,6 +42,13 @@ bool check_domain_colors(struct domain *d);
 uint32_t *setup_default_colors(uint32_t *col_num);
 
 void coloring_dump_info(struct domain *d);
+
+/*
+ * Compute the color of the given page address.
+ * This function should change depending on the cache architecture
+ * specifications.
+ */
+unsigned long color_from_page(struct page_info *pg);
 #else /* !CONFIG_COLORING */
 static inline bool __init coloring_init(void)
 {
-- 
2.30.2