[PATCH v5 4/9] target/riscv/cpu.c: error out if EPMP is enabled without PMP

[Daniel Henrique Barboza <dbarboza@ventanamicro.com>]

Instead of silently ignoring the EPMP setting if there is no PMP
available, error out informing the user that EPMP depends on PMP
support:

$ ./qemu-system-riscv64 -cpu rv64,pmp=false,x-epmp=true
qemu-system-riscv64: Invalid configuration: EPMP requires PMP support

This will force users to pick saner options in the QEMU command line.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
---
 target/riscv/cpu.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index e34a5e3f11..4585ca74dc 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -925,13 +925,18 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
 
     if (cpu->cfg.pmp) {
         riscv_set_feature(env, RISCV_FEATURE_PMP);
+    }
+
+    if (cpu->cfg.epmp) {
+        riscv_set_feature(env, RISCV_FEATURE_EPMP);
 
         /*
          * Enhanced PMP should only be available
          * on harts with PMP support
          */
-        if (cpu->cfg.epmp) {
-            riscv_set_feature(env, RISCV_FEATURE_EPMP);
+        if (!cpu->cfg.pmp) {
+            error_setg(errp, "Invalid configuration: EPMP requires PMP support");
+            return;
         }
     }
 
-- 
2.39.1