[PATCH v4 07/18] xen/riscv: add new p2m types and helper macros for type classification

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

- Extended p2m_type_t with additional types: p2m_mmio_direct,
  p2m_ext_storage.
- Added macros to classify memory types: P2M_RAM_TYPES.
- Introduced helper predicates: p2m_is_ram(), p2m_is_any_ram().
- Introduce arch_dt_passthrough() to tell handle_passthrough_prop()
  from common code how to map device memory.
- Introduce p2m_first_external for detection for relational operations
  with p2m type which is stored outside P2M's PTE bits.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in V4:
 - Drop underscode in p2m_to_mask()'s argument and for other similar helpers.
 - Introduce arch_dt_passthrough_p2m_type() instead of p2m_mmio_direct.
 - Drop for the moment grant tables related stuff as it isn't going to be used 
in the nearest future.
---
Changes in V3:
 - Drop p2m_ram_ro.
 - Rename p2m_mmio_direct_dev to p2m_mmio_direct_io to make it more RISC-V 
specicific.
 - s/p2m_mmio_direct_dev/p2m_mmio_direct_io.
---
Changes in V2:
 - Drop stuff connected to foreign mapping as it isn't necessary for RISC-V
   right now.
---
 xen/arch/riscv/include/asm/p2m.h | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/xen/arch/riscv/include/asm/p2m.h b/xen/arch/riscv/include/asm/p2m.h
index 7b263cb354..8a6f5f3092 100644
--- a/xen/arch/riscv/include/asm/p2m.h
+++ b/xen/arch/riscv/include/asm/p2m.h
@@ -64,8 +64,29 @@ struct p2m_domain {
 typedef enum {
     p2m_invalid = 0,    /* Nothing mapped here */
     p2m_ram_rw,         /* Normal read/write domain RAM */
+    p2m_mmio_direct_io, /* Read/write mapping of genuine Device MMIO area,
+                           PTE_PBMT_IO will be used for such mappings */
+    p2m_ext_storage,    /* Following types'll be stored outsude PTE bits: */
+
+    /* Sentinel — not a real type, just a marker for comparison */
+    p2m_first_external = p2m_ext_storage,
 } p2m_type_t;
 
+static inline p2m_type_t arch_dt_passthrough_p2m_type(void)
+{
+    return p2m_mmio_direct_io;
+}
+
+/* We use bitmaps and mask to handle groups of types */
+#define p2m_to_mask(t) BIT(t, UL)
+
+/* RAM types, which map to real machine frames */
+#define P2M_RAM_TYPES (p2m_to_mask(p2m_ram_rw))
+
+/* Useful predicates */
+#define p2m_is_ram(t_) (p2m_to_mask(t_) & P2M_RAM_TYPES)
+#define p2m_is_any_ram(t_) (p2m_to_mask(t_) & P2M_RAM_TYPES)
+
 #include <xen/p2m-common.h>
 
 static inline int get_page_and_type(struct page_info *page,
-- 
2.51.0