[Qemu-devel] [PATCH] target/riscv/pmp.c: Fix PMP NAPOT decoding bug

[Qemu-devel] [PATCH] target/riscv/pmp.c: Fix PMP NAPOT decoding bug

[Dayeol Lee]

According to the RISC-V priv. v1.10 ISA document,
pmpaddr register stores (base_addr | (size/2 - 1)) >> 2 for a
NAPOT-encoded address.
However, the current code decodes (base_addr | (size - 1)) >> 3 which
leads to a wrong base address and size.

Signed-off-by: Dayeol Lee <dayeol@berkeley.edu>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/pmp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index f432f3b..c4c6b09 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -138,7 +138,7 @@ static void pmp_decode_napot(target_ulong a, target_ulong *sa, target_ulong *ea)
         return;
     } else {
         target_ulong t1 = ctz64(~a);
-        target_ulong base = (a & ~(((target_ulong)1 << t1) - 1)) << 3;
+        target_ulong base = (a & ~(((target_ulong)1 << t1) - 1)) << 2;
         target_ulong range = ((target_ulong)1 << (t1 + 3)) - 1;
         *sa = base;
         *ea = base + range;
-- 
2.7.4