[PATCH v4 1/2] target/riscv: Align pmp size to pmp-granularity

[Jay Chang <jay.chang@sifive.com>]

When configuring pmpcfg (TOR, NA4, or NAPOT) and pmpaddr, if the
value is smaller than the PMP granularity, it needs to be aligned
to the PMP granularity.

Signed-off-by: Jay Chang <jay.chang@sifive.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com>
---
 target/riscv/pmp.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index a71091a316..de2157c830 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -179,11 +179,12 @@ static bool pmp_write_cfg(CPURISCVState *env, uint32_t pmp_index, uint8_t val)
             }
             /*
              * When granularity g >= 1 (i.e., granularity > 4 bytes),
-             * the NA4 (Naturally Aligned 4-byte) mode is not selectable
+             * the NA4 (Naturally Aligned 4-byte) mode is not selectable.
+             * In this case, an NA4 setting is reinterpreted as a NAPOT mode.
              */
             if ((riscv_cpu_cfg(env)->pmp_granularity >
                 MIN_RISCV_PMP_GRANULARITY) && (a_field == PMP_AMATCH_NA4)) {
-                    return false;
+                    val |= PMP_AMATCH;
             }
             env->pmp_state.pmp[pmp_index].cfg_reg = val;
             pmp_update_rule_addr(env, pmp_index);
@@ -263,6 +264,11 @@ void pmp_update_rule_addr(CPURISCVState *env, uint32_t pmp_index)
         break;
 
     case PMP_AMATCH_NAPOT:
+        /* Bits [g-2:0] need to be all one to align pmp granularity */
+        if (g >= 2) {
+            this_addr |= ((1ULL << (g - 1ULL)) - 1ULL);
+        }
+
         pmp_decode_napot(this_addr, &sa, &ea);
         break;
 
-- 
2.48.1