[RFC PATCH 03/16] exec: Add RISC-V WorldGuard WID to MemTxAttrs

[Jim Shu]

RISC-V WorldGuard will add 5-bit world_id (WID) to the each memory
transaction on the bus. The wgChecker in front of RAM or peripherals
MMIO could do the access control based on the WID. It is similar to ARM
TrustZone NS bit, but the WID is 5-bit.

The common implementation of WID is AXI4 AxUSER signal.

Signed-off-by: Jim Shu <jim.shu@sifive.com>
---
 include/exec/memattrs.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/exec/memattrs.h b/include/exec/memattrs.h
index 14cdd8d582..d00f3c5500 100644
--- a/include/exec/memattrs.h
+++ b/include/exec/memattrs.h
@@ -52,6 +52,11 @@ typedef struct MemTxAttrs {
     unsigned int memory:1;
     /* Requester ID (for MSI for example) */
     unsigned int requester_id:16;
+
+    /*
+     * RISC-V WorldGuard: the 5-bit WID of memory access.
+     */
+    uint8_t world_id;
 } MemTxAttrs;
 
 /* Bus masters which don't specify any attributes will get this,
-- 
2.17.1