accel/tcg: Move cpu_memory_rw_debug() user implementation to user-exec.c

cpu_memory_rw_debug() system implementation is defined in
system/physmem.c. Move the user one to accel/tcg/user-exec.c
to simplify cpu-target.c maintenance.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20250217130610.18313-6-philmd@linaro.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
index 9d53c9440e..2322181b15 100644
--- a/accel/tcg/user-exec.c
+++ b/accel/tcg/user-exec.c
@@ -19,6 +19,7 @@
 #include "qemu/osdep.h"
 #include "accel/tcg/cpu-ops.h"
 #include "disas/disas.h"
+#include "exec/vaddr.h"
 #include "exec/exec-all.h"
 #include "tcg/tcg.h"
 #include "qemu/bitops.h"
@@ -971,6 +972,85 @@ static void *cpu_mmu_lookup(CPUState *cpu, vaddr addr,
     return ret;
 }
 
+/* physical memory access (slow version, mainly for debug) */
+int cpu_memory_rw_debug(CPUState *cpu, vaddr addr,
+                        void *ptr, size_t len, bool is_write)
+{
+    int flags;
+    vaddr l, page;
+    uint8_t *buf = ptr;
+    ssize_t written;
+    int ret = -1;
+    int fd = -1;
+
+    mmap_lock();
+
+    while (len > 0) {
+        page = addr & TARGET_PAGE_MASK;
+        l = (page + TARGET_PAGE_SIZE) - addr;
+        if (l > len) {
+            l = len;
+        }
+        flags = page_get_flags(page);
+        if (!(flags & PAGE_VALID)) {
+            goto out_close;
+        }
+        if (is_write) {
+            if (flags & PAGE_WRITE) {
+                memcpy(g2h(cpu, addr), buf, l);
+            } else {
+                /* Bypass the host page protection using ptrace. */
+                if (fd == -1) {
+                    fd = open("/proc/self/mem", O_WRONLY);
+                    if (fd == -1) {
+                        goto out;
+                    }
+                }
+                /*
+                 * If there is a TranslationBlock and we weren't bypassing the
+                 * host page protection, the memcpy() above would SEGV,
+                 * ultimately leading to page_unprotect(). So invalidate the
+                 * translations manually. Both invalidation and pwrite() must
+                 * be under mmap_lock() in order to prevent the creation of
+                 * another TranslationBlock in between.
+                 */
+                tb_invalidate_phys_range(addr, addr + l - 1);
+                written = pwrite(fd, buf, l,
+                                 (off_t)(uintptr_t)g2h_untagged(addr));
+                if (written != l) {
+                    goto out_close;
+                }
+            }
+        } else if (flags & PAGE_READ) {
+            memcpy(buf, g2h(cpu, addr), l);
+        } else {
+            /* Bypass the host page protection using ptrace. */
+            if (fd == -1) {
+                fd = open("/proc/self/mem", O_RDONLY);
+                if (fd == -1) {
+                    goto out;
+                }
+            }
+            if (pread(fd, buf, l,
+                      (off_t)(uintptr_t)g2h_untagged(addr)) != l) {
+                goto out_close;
+            }
+        }
+        len -= l;
+        buf += l;
+        addr += l;
+    }
+    ret = 0;
+out_close:
+    if (fd != -1) {
+        close(fd);
+    }
+out:
+    mmap_unlock();
+
+    return ret;
+}
+
 #include "ldst_atomicity.c.inc"
 
 static uint8_t do_ld1_mmu(CPUState *cpu, vaddr addr, MemOpIdx oi,