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From: "Philippe Mathieu-Daudé" <philmd@linaro.org>
To: qemu-devel@nongnu.org
Cc: "Riku Voipio" <riku.voipio@iki.fi>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Pierrick Bouvier" <pierrick.bouvier@linaro.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Anton Johansson" <anjo@rev.ng>,
	"Ilya Leoshkevich" <iii@linux.ibm.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>
Subject: [PATCH 4/5] accel/tcg: Avoid using lock_user() in cpu_memory_rw_debug()
Date: Mon, 17 Feb 2025 14:06:09 +0100	[thread overview]
Message-ID: <20250217130610.18313-5-philmd@linaro.org> (raw)
In-Reply-To: <20250217130610.18313-1-philmd@linaro.org>

We checked the page flags with page_get_flags(), so
locking the page is superfluous. Remove the lock_user()
calls and directly use g2h() in place.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 cpu-target.c | 17 ++---------------
 1 file changed, 2 insertions(+), 15 deletions(-)

diff --git a/cpu-target.c b/cpu-target.c
index b5230ce1837..3892ce12229 100644
--- a/cpu-target.c
+++ b/cpu-target.c
@@ -374,7 +374,6 @@ int cpu_memory_rw_debug(CPUState *cpu, vaddr addr,
 {
     int flags;
     vaddr l, page;
-    void * p;
     uint8_t *buf = ptr;
     ssize_t written;
     int ret = -1;
@@ -393,13 +392,7 @@ int cpu_memory_rw_debug(CPUState *cpu, vaddr addr,
         }
         if (is_write) {
             if (flags & PAGE_WRITE) {
-                /* XXX: this code should not depend on lock_user */
-                p = lock_user(VERIFY_WRITE, addr, l, 0);
-                if (!p) {
-                    goto out_close;
-                }
-                memcpy(p, buf, l);
-                unlock_user(p, addr, l);
+                memcpy(g2h(cpu, addr), buf, l);
             } else {
                 /* Bypass the host page protection using ptrace. */
                 if (fd == -1) {
@@ -424,13 +417,7 @@ int cpu_memory_rw_debug(CPUState *cpu, vaddr addr,
                 }
             }
         } else if (flags & PAGE_READ) {
-            /* XXX: this code should not depend on lock_user */
-            p = lock_user(VERIFY_READ, addr, l, 1);
-            if (!p) {
-                goto out_close;
-            }
-            memcpy(buf, p, l);
-            unlock_user(p, addr, 0);
+            memcpy(buf, g2h(cpu, addr), l);
         } else {
             /* Bypass the host page protection using ptrace. */
             if (fd == -1) {
-- 
2.47.1



  parent reply	other threads:[~2025-02-17 13:07 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-17 13:06 [PATCH 0/5] accel/tcg: Clean cpu_memory_rw_debug() up Philippe Mathieu-Daudé
2025-02-17 13:06 ` [PATCH 1/5] accel/accel-cpu-target.h: Include missing 'cpu.h' header Philippe Mathieu-Daudé
2025-02-17 13:06 ` [PATCH 2/5] accel/tcg: Include missing bswap headers in user-exec.c Philippe Mathieu-Daudé
2025-02-17 19:36   ` Richard Henderson
2025-02-17 13:06 ` [PATCH 3/5] accel/tcg: Take mmap lock in the whole cpu_memory_rw_debug() function Philippe Mathieu-Daudé
2025-02-17 19:37   ` Richard Henderson
2025-02-17 13:06 ` Philippe Mathieu-Daudé [this message]
2025-02-17 19:39   ` [PATCH 4/5] accel/tcg: Avoid using lock_user() in cpu_memory_rw_debug() Richard Henderson
2025-02-17 13:06 ` [PATCH 5/5] accel/tcg: Move cpu_memory_rw_debug() user implementation to user-exec.c Philippe Mathieu-Daudé
2025-02-17 19:40   ` Richard Henderson
2025-02-20 15:28 ` [PATCH 0/5] accel/tcg: Clean cpu_memory_rw_debug() up Philippe Mathieu-Daudé

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