From: Brijesh Singh <brijesh.singh@amd.com>

The new callbacks can be used to display the guest memory of an SEV guest
by registering callbacks to the SEV memory encryption/decryption APIs.

Typical usage:

mem_read(uint8_t *dest,
         const uint8_t *hva_src, hwaddr gpa_src,
         uint32_t len, MemTxAttrs attrs);
mem_write(uint8_t *hva_dest, hwaddr gpa_des,
          const uint8_t *src, uint32_t len, MemTxAttrs attrs);

MemoryRegionRAMReadWriteOps ops;
ops.read = mem_read;
ops.write = mem_write;

memory_region_init_ram(mem, NULL, "memory", size, NULL);
memory_region_set_ram_debug_ops(mem, ops);

Yuan Yao:
 - Add the gpa_src/gpa_des for read/write interface

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Yuan Yao <yuan.yao@intel.com>

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 5728a681b2..7e6fdcb8e4 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -444,6 +444,19 @@ struct IOMMUMemoryRegionClass {
 typedef struct CoalescedMemoryRange CoalescedMemoryRange;
 typedef struct MemoryRegionIoeventfd MemoryRegionIoeventfd;
 
+/* Memory Region RAM debug callback */
+typedef struct MemoryRegionRAMReadWriteOps MemoryRegionRAMReadWriteOps;
+
+struct MemoryRegionRAMReadWriteOps {
+    /* Write data into guest memory */
+    int (*write) (uint8_t *hva_dest, hwaddr gpa_des,
+                  const uint8_t *src, uint32_t len, MemTxAttrs attrs);
+    /* Read data from guest memory */
+    int (*read) (uint8_t *dest,
+                 const uint8_t *hva_src, hwaddr gpa_src,
+                 uint32_t len, MemTxAttrs attrs);
+};
+
 /** MemoryRegion:
  *
  * A struct representing a memory region.
@@ -487,6 +500,7 @@ struct MemoryRegion {
     const char *name;
     unsigned ioeventfd_nb;
     MemoryRegionIoeventfd *ioeventfds;
+    const MemoryRegionRAMReadWriteOps *ram_debug_ops;
 };
 
 struct IOMMUMemoryRegion {
@@ -1130,6 +1144,20 @@ void memory_region_init_rom_nomigrate(MemoryRegion *mr,
                                       uint64_t size,
                                       Error **errp);
 
+/**
+ * memory_region_set_ram_debug_ops: Set access ops for a give memory region.
+ *
+ * @mr: the #MemoryRegion to be initialized
+ * @ops: a function that will be used when accessing @target region during
+ *       debug
+ */
+static inline void
+memory_region_set_ram_debug_ops(MemoryRegion *mr,
+                                const MemoryRegionRAMReadWriteOps *ops)
+{
+    mr->ram_debug_ops = ops;
+}
+
 /**
  * memory_region_init_rom_device_nomigrate:  Initialize a ROM memory region.
  *                                 Writes are handled via callbacks.
-- 
2.20.1