[PATCH v2 2/2] xen/arm: Restrict Kconfig configuration for LLC coloring

[Luca Fancellu <luca.fancellu@xxxxxxx>]

LLC coloring can be used only on MMU system, move the code
that selects it from ARM_64 to MMU and add the ARM_64
dependency.

While there, add a clarification comment in the startup
code related to the LLC coloring, because boot_fdt_info()
is required to be called before llc_coloring_init(), because
it parses the memory banks from the DT, but to discover that
the developer needs to dig into the function.

Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
---
v2 changes:
 - dropped part of the v1 code, now this one is simpler, I will
   discuss better how to design a common boot flow for MPU and
   implement on another patch.

---
---
 xen/arch/arm/Kconfig | 2 +-
 xen/arch/arm/setup.c | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index a26d3e11827c..ffdff1f0a36c 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -8,7 +8,6 @@ config ARM_64
        depends on !ARM_32
        select 64BIT
        select HAS_FAST_MULTIPLY
-       select HAS_LLC_COLORING if !NUMA
 
 config ARM
        def_bool y
@@ -76,6 +75,7 @@ choice
 
 config MMU
        bool "MMU"
+       select HAS_LLC_COLORING if !NUMA && ARM_64
        select HAS_PMAP
        select HAS_VMAP
        select HAS_PASSTHROUGH
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index c1f2d1b89d43..91fa579e73e5 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -328,6 +328,7 @@ void asmlinkage __init start_xen(unsigned long fdt_paddr)
                              (paddr_t)(uintptr_t)(_end - _start), false);
     BUG_ON(!xen_bootmodule);
 
+    /* This parses memory banks needed for LLC coloring */
     fdt_size = boot_fdt_info(device_tree_flattened, fdt_paddr);
 
     cmdline = boot_fdt_cmdline(device_tree_flattened);
-- 
2.34.1