[RFC 20/24] xen/arm: Add new platform specific callback device_is_blacklist

[Julien Grall <julien.grall@linaro.org>]

Each platform code will list the device that must not pass-through to a guest.
Theses devices are used for: power management, timer,...

When theses devices are given to DOM0, it can controls the hardware and then
break the whole platform.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
---
 xen/arch/arm/domain_build.c    |    2 +-
 xen/arch/arm/platform.c        |   10 ++++++++++
 xen/include/asm-arm/platform.h |    7 +++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index d8d67a6..93f77c6 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -419,7 +419,7 @@ static int handle_node(struct domain *d, struct kernel_info *kinfo,
     DPRINT("handle %s\n", dt_node_full_name(np));
 
     /* Skip theses nodes and the sub-nodes */
-    if ( dt_match_node(skip_matches, np ) )
+    if ( dt_match_node(skip_matches, np ) || platform_device_is_blacklist(np) )
         return 0;
 
     if ( dt_device_used_by(np) != DOMID_XEN &&
diff --git a/xen/arch/arm/platform.c b/xen/arch/arm/platform.c
index afda302..cae0580 100644
--- a/xen/arch/arm/platform.c
+++ b/xen/arch/arm/platform.c
@@ -127,6 +127,16 @@ bool_t platform_has_quirk(uint32_t quirk)
     return !!(quirks & quirk);
 }
 
+bool_t platform_device_is_blacklist(const struct dt_device_node *node)
+{
+    const struct dt_device_match *blacklist = NULL;
+
+    if ( platform && platform->blacklist_dev )
+        blacklist = platform->blacklist_dev;
+
+    return dt_match_node(blacklist, node);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/asm-arm/platform.h b/xen/include/asm-arm/platform.h
index f460e9c..4b511ed 100644
--- a/xen/include/asm-arm/platform.h
+++ b/xen/include/asm-arm/platform.h
@@ -4,6 +4,7 @@
 #include <xen/init.h>
 #include <xen/sched.h>
 #include <xen/mm.h>
+#include <xen/device_tree.h>
 
 /* Describe specific operation for a board */
 struct platform_desc {
@@ -26,6 +27,11 @@ struct platform_desc {
      * board with different quirk on each
      */
     uint32_t (*quirks)(void);
+    /*
+     * Platform blacklist devices
+     * List of devices which must not pass-through to a guest
+     */
+    const struct dt_device_match *blacklist_dev;
 };
 
 /*
@@ -40,6 +46,7 @@ int __init platform_specific_mapping(struct domain *d);
 void platform_reset(void);
 void platform_poweroff(void);
 bool_t platform_has_quirk(uint32_t quirk);
+bool_t platform_device_is_blacklist(const struct dt_device_node *node);
 
 #define PLATFORM_START(_name, _namestr)                         \
 static const struct platform_desc  __plat_desc_##_name __used   \
-- 
1.7.10.4