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From: Weiwei Li <liweiwei@iscas.ac.cn>
To: qemu-riscv@nongnu.org, qemu-devel@nongnu.org
Cc: palmer@dabbelt.com, alistair.francis@wdc.com,
	bin.meng@windriver.com, dbarboza@ventanamicro.com,
	zhiwei_liu@linux.alibaba.com, richard.henderson@linaro.org,
	wangjunqiang@iscas.ac.cn, lazyparser@gmail.com,
	Weiwei Li <liweiwei@iscas.ac.cn>
Subject: [PATCH 4/6] target/riscv: Flush TLB only when pmpcfg/pmpaddr really changes
Date: Thu, 13 Apr 2023 17:01:20 +0800	[thread overview]
Message-ID: <20230413090122.65228-5-liweiwei@iscas.ac.cn> (raw)
In-Reply-To: <20230413090122.65228-1-liweiwei@iscas.ac.cn>

TLB needn't be flushed when pmpcfg/pmpaddr don't changes.

Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
---
 target/riscv/pmp.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index 6d4813806b..aced23c4d5 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -26,7 +26,7 @@
 #include "trace.h"
 #include "exec/exec-all.h"
 
-static void pmp_write_cfg(CPURISCVState *env, uint32_t addr_index,
+static bool pmp_write_cfg(CPURISCVState *env, uint32_t addr_index,
                           uint8_t val);
 static uint8_t pmp_read_cfg(CPURISCVState *env, uint32_t addr_index);
 static void pmp_update_rule(CPURISCVState *env, uint32_t pmp_index);
@@ -83,7 +83,7 @@ static inline uint8_t pmp_read_cfg(CPURISCVState *env, uint32_t pmp_index)
  * Accessor to set the cfg reg for a specific PMP/HART
  * Bounds checks and relevant lock bit.
  */
-static void pmp_write_cfg(CPURISCVState *env, uint32_t pmp_index, uint8_t val)
+static bool pmp_write_cfg(CPURISCVState *env, uint32_t pmp_index, uint8_t val)
 {
     if (pmp_index < MAX_RISCV_PMPS) {
         bool locked = true;
@@ -119,14 +119,17 @@ static void pmp_write_cfg(CPURISCVState *env, uint32_t pmp_index, uint8_t val)
 
         if (locked) {
             qemu_log_mask(LOG_GUEST_ERROR, "ignoring pmpcfg write - locked\n");
-        } else {
+        } else if (env->pmp_state.pmp[pmp_index].cfg_reg != val) {
             env->pmp_state.pmp[pmp_index].cfg_reg = val;
             pmp_update_rule(env, pmp_index);
+            return true;
         }
     } else {
         qemu_log_mask(LOG_GUEST_ERROR,
                       "ignoring pmpcfg write - out of bounds\n");
     }
+
+    return false;
 }
 
 static void pmp_decode_napot(target_ulong a, target_ulong *sa,
@@ -477,16 +480,19 @@ void pmpcfg_csr_write(CPURISCVState *env, uint32_t reg_index,
     int i;
     uint8_t cfg_val;
     int pmpcfg_nums = 2 << riscv_cpu_mxl(env);
+    bool modified = false;
 
     trace_pmpcfg_csr_write(env->mhartid, reg_index, val);
 
     for (i = 0; i < pmpcfg_nums; i++) {
         cfg_val = (val >> 8 * i)  & 0xff;
-        pmp_write_cfg(env, (reg_index * 4) + i, cfg_val);
+        modified |= pmp_write_cfg(env, (reg_index * 4) + i, cfg_val);
     }
 
     /* If PMP permission of any addr has been changed, flush TLB pages. */
-    tlb_flush(env_cpu(env));
+    if (modified) {
+        tlb_flush(env_cpu(env));
+    }
 }
 
 
@@ -535,9 +541,11 @@ void pmpaddr_csr_write(CPURISCVState *env, uint32_t addr_index,
         }
 
         if (!pmp_is_locked(env, addr_index)) {
-            env->pmp_state.pmp[addr_index].addr_reg = val;
-            pmp_update_rule(env, addr_index);
-            tlb_flush(env_cpu(env));
+            if (env->pmp_state.pmp[addr_index].addr_reg != val) {
+                env->pmp_state.pmp[addr_index].addr_reg = val;
+                pmp_update_rule(env, addr_index);
+                tlb_flush(env_cpu(env));
+            }
         } else {
             qemu_log_mask(LOG_GUEST_ERROR,
                           "ignoring pmpaddr write - locked\n");
-- 
2.25.1



  parent reply	other threads:[~2023-04-13  9:03 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-13  9:01 [PATCH 0/6] target/riscv: Fix PMP related problem Weiwei Li
2023-04-13  9:01 ` [PATCH 1/6] target/riscv: Update pmp_get_tlb_size() Weiwei Li
2023-04-18  2:53   ` Alistair Francis
2023-04-18  3:05     ` Weiwei Li
2023-04-18  5:18       ` LIU Zhiwei
2023-04-18  6:09         ` Weiwei Li
2023-04-18  7:08           ` LIU Zhiwei
2023-04-18  8:01             ` Weiwei Li
2023-04-13  9:01 ` [PATCH 2/6] target/riscv: Move pmp_get_tlb_size apart from get_physical_address_pmp Weiwei Li
2023-04-18  2:54   ` Alistair Francis
2023-04-13  9:01 ` [PATCH 3/6] target/riscv: flush tlb when pmpaddr is updated Weiwei Li
2023-04-18  2:36   ` Alistair Francis
2023-04-18  7:11   ` LIU Zhiwei
2023-04-18  8:13     ` Weiwei Li
2023-04-13  9:01 ` Weiwei Li [this message]
2023-04-18  2:39   ` [PATCH 4/6] target/riscv: Flush TLB only when pmpcfg/pmpaddr really changes Alistair Francis
2023-04-18  7:14   ` LIU Zhiwei
2023-04-13  9:01 ` [PATCH 5/6] target/riscv: flush tb when PMP entry changes Weiwei Li
2023-04-18  7:28   ` LIU Zhiwei
2023-04-13  9:01 ` [PATCH 6/6] accel/tcg: Remain TLB_INVALID_MASK in the address when TLB is re-filled Weiwei Li
2023-04-17 16:25   ` Daniel Henrique Barboza
2023-04-18  0:48     ` Weiwei Li
2023-04-18  7:18     ` Richard Henderson
2023-04-18  7:36       ` Richard Henderson
2023-04-18  8:18         ` Weiwei Li
2023-04-18  3:07 ` [PATCH 0/6] target/riscv: Fix PMP related problem LIU Zhiwei
2023-04-18  3:36   ` Weiwei Li
2023-04-18  4:47     ` LIU Zhiwei
2023-04-18  6:11       ` Weiwei Li

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