@@ -142,6 +142,8 @@ static lpae_t mfn_to_p2m_entry(unsigned long mfn, unsigned int mattr)
.p2m.valid = 1,
};
+ BUILD_BUG_ON(p2m_max_real_type > (1 << 4));
+
ASSERT(!(pa & ~PAGE_MASK));
ASSERT(!(pa & ~PADDR_MASK));
@@ -20,6 +20,25 @@ struct p2m_domain {
uint8_t vmid;
};
+/* List of possible type for each page in the p2m entry.
+ * The number of available bit per page in the pte for this purpose is 4 bits.
+ * So it's possible to only have 16 fields. If we run out of value in the
+ * future, it's possible to use higher value for pseudo-type and don't store
+ * them in the p2m entry.
+ */
+typedef enum {
+ p2m_invalid = 0, /* Nothing mapped here */
+ p2m_ram_rw, /* Normal read/write guest RAM */
+ p2m_ram_ro, /* Read-only; writes are silently dropped */
+ p2m_mmio_direct, /* Read/write mapping of genuine MMIO area */
+ p2m_map_foreign, /* Ram pages from foreign domain */
+ p2m_grant_map_rw, /* Read/write grant mapping */
+ p2m_grant_map_ro, /* Read-only grant mapping */
+ p2m_max_real_type, /* Types after this won't be store in the p2m */
+} p2m_type_t;
+
+#define p2m_is_foreign(_t) ((_t) == p2m_map_foreign)
+
/* Initialise vmid allocator */
void p2m_vmid_allocator_init(void);
@@ -72,7 +91,6 @@ 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 */
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 - p2m_grant_map_rw: Read/write grant mapping - p2m_grant_map_ro: Read-only grant mapping Signed-off-by: Julien Grall <julien.grall@linaro.org> Acked-by: Ian Campbell <ian.campbell@citrix.com> --- Changes in v3: - s/ / / - Replace p2m by either pte or p2m entry - Fix compilation (unitialized value) - Add BUILD_BUG_ON (from patch #4) and fix it Changes in v2: - Add comment for future improvement - Add p2m_max_real_type. Will be use later to check the size of the enum - Let the compiler choose the value for each name of the enum - Add grant mapping type --- xen/arch/arm/p2m.c | 2 ++ xen/include/asm-arm/p2m.h | 20 +++++++++++++++++++- 2 files changed, 21 insertions(+), 1 deletion(-)