[PATCH 3/8] xen/arm: Implement p2m_type_t as an enum

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

Until now, Xen doesn't know the type of the page (ram, foreign page, mmio,...).
Introduce p2m_type_t with basic types:
    - p2m_invalid: Nothing is mapped here
    - p2m_ram_rw: Normal read/write guest RAM
    - p2m_ram_ro: Read-only guest RAM
    - p2m_mmio_direct: Read/write mapping of device memory
    - p2m_map_foreign: RAM page from foreign guest

Signed-off-by: Julien Grall <julien.grall@linaro.org>
---
 xen/include/asm-arm/p2m.h |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
index f079f00..b24f94a 100644
--- a/xen/include/asm-arm/p2m.h
+++ b/xen/include/asm-arm/p2m.h
@@ -20,6 +20,16 @@ struct p2m_domain {
     uint8_t vmid;
 };
 
+typedef enum {
+    p2m_invalid = 0,        /* Nothing mapped here */
+    p2m_ram_rw = 1,         /* Normal read/write guest RAM */
+    p2m_ram_ro = 2,         /* Read-only; writes are silently dropped */
+    p2m_mmio_direct = 3,    /* Read/write mapping of genuine MMIO area */
+    p2m_map_foreign = 4,    /* Ram pages from foreign domain */
+} p2m_type_t;
+
+#define p2m_is_foreign(_t) ((_t) == p2m_map_foreign)
+
 /* Initialise vmid allocator */
 void p2m_vmid_allocator_init(void);
 
@@ -72,7 +82,6 @@ p2m_pod_decrease_reservation(struct domain *d,
                              unsigned int order);
 
 /* Look up a GFN and take a reference count on the backing page. */
-typedef int p2m_type_t;
 typedef unsigned int p2m_query_t;
 #define P2M_ALLOC    (1u<<0)   /* Populate PoD and paged-out entries */
 #define P2M_UNSHARE  (1u<<1)   /* Break CoW sharing */
@@ -110,8 +119,6 @@ static inline int get_page_and_type(struct page_info *page,
     return rc;
 }
 
-#define p2m_is_foreign(_t) (0)
-
 #endif /* _XEN_P2M_H */
 
 /*
-- 
1.7.10.4