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From: Jay Chang <jay.chang@sifive.com>
To: qemu-devel@nongnu.org, qemu-riscv@nongnu.org
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
	Alistair Francis <alistair.francis@wdc.com>,
	Weiwei Li <liwei1518@gmail.com>,
	Daniel Henrique Barboza <dbarboza@ventanamicro.com>,
	Liu Zhiwei <zhiwei_liu@linux.alibaba.com>,
	Jay Chang <jay.chang@sifive.com>,
	Frank Chang <frank.chang@sifive.com>
Subject: [PATCH 1/2] hw/riscv: Don't insert DDT cache in Bare mode
Date: Thu, 11 Dec 2025 10:56:10 +0800	[thread overview]
Message-ID: <20251211025611.99038-2-jay.chang@sifive.com> (raw)
In-Reply-To: <20251211025611.99038-1-jay.chang@sifive.com>

In Bare mode the IOMMU does not perform DDT look-ups, therefore
caching DDT entries is unnecessary.

Signed-off-by: Jay Chang <jay.chang@sifive.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
---
 hw/riscv/riscv-iommu.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/hw/riscv/riscv-iommu.c b/hw/riscv/riscv-iommu.c
index 69852f4f13..79eee2e85e 100644
--- a/hw/riscv/riscv-iommu.c
+++ b/hw/riscv/riscv-iommu.c
@@ -1312,16 +1312,23 @@ static RISCVIOMMUContext *riscv_iommu_ctx(RISCVIOMMUState *s,
 
     int fault = riscv_iommu_ctx_fetch(s, ctx);
     if (!fault) {
-        if (g_hash_table_size(ctx_cache) >= LIMIT_CACHE_CTX) {
+        if (mode != RISCV_IOMMU_DDTP_MODE_BARE) {
+            if (g_hash_table_size(ctx_cache) >= LIMIT_CACHE_CTX) {
+                g_hash_table_unref(ctx_cache);
+                ctx_cache = g_hash_table_new_full(riscv_iommu_ctx_hash,
+                                                  riscv_iommu_ctx_equal,
+                                                  g_free, NULL);
+                g_hash_table_ref(ctx_cache);
+                g_hash_table_unref(qatomic_xchg(&s->ctx_cache, ctx_cache));
+            }
+
+            g_hash_table_add(ctx_cache, ctx);
+            *ref = ctx_cache;
+        } else {
             g_hash_table_unref(ctx_cache);
-            ctx_cache = g_hash_table_new_full(riscv_iommu_ctx_hash,
-                                              riscv_iommu_ctx_equal,
-                                              g_free, NULL);
-            g_hash_table_ref(ctx_cache);
-            g_hash_table_unref(qatomic_xchg(&s->ctx_cache, ctx_cache));
+            /* Remember ctx so it can be freed */
+            *ref = ctx;
         }
-        g_hash_table_add(ctx_cache, ctx);
-        *ref = ctx_cache;
         return ctx;
     }
 
-- 
2.48.1



  reply	other threads:[~2025-12-11  2:57 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-11  2:56 [PATCH 0/2] Don't insert DDT cache in Bare mode Jay Chang
2025-12-11  2:56 ` Jay Chang [this message]
2025-12-11  2:56 ` [PATCH 2/2] hw/riscv: Refactor riscv_iommu_ctx_put() for Bare mode handling Jay Chang

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