[Qemu-devel] [PATCH v11 20/20] gdbstub: Implement qemu physical memory mode

[Jon Doron]

Add a new query/set which changes the memory GDB sees to physical memory
only.

gdb> maint packet qqemu.PhyMemMode
will reply the current phy_mem_mode state (1 for enabled, 0 for disabled)
gdb> maint packet Qqemu.PhyMemMode:1
Will make GDB read/write only to physical memory, set to 0 to disable

Signed-off-by: Jon Doron <ari...@gmail.com>
---
 gdbstub.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 60 insertions(+), 2 deletions(-)

diff --git a/gdbstub.c b/gdbstub.c
index 9dd934a079..c9269319d8 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -46,11 +46,27 @@
 #define GDB_ATTACHED "1"
 #endif
 
+#ifndef CONFIG_USER_ONLY
+static int phy_memory_mode;
+#endif
+
 static inline int target_memory_rw_debug(CPUState *cpu, target_ulong addr,
                                          uint8_t *buf, int len, bool is_write)
 {
-    CPUClass *cc = CPU_GET_CLASS(cpu);
+    CPUClass *cc;
 
+#ifndef CONFIG_USER_ONLY
+    if (phy_memory_mode) {
+        if (is_write) {
+            cpu_physical_memory_write(addr, buf, len);
+        } else {
+            cpu_physical_memory_read(addr, buf, len);
+        }
+        return 0;
+    }
+#endif
+
+    cc = CPU_GET_CLASS(cpu);
     if (cc->memory_rw_debug) {
         return cc->memory_rw_debug(cpu, addr, buf, len, is_write);
     }
@@ -2118,8 +2134,36 @@ static void handle_query_attached(GdbCmdContext 
*gdb_ctx, void *user_ctx)
 
 static void handle_query_qemu_supported(GdbCmdContext *gdb_ctx, void *user_ctx)
 {
-    put_packet(gdb_ctx->s, "sstepbits;sstep");
+    snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "sstepbits;sstep");
+#ifndef CONFIG_USER_ONLY
+    pstrcat(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), ";PhyMemMode");
+#endif
+    put_packet(gdb_ctx->s, gdb_ctx->str_buf);
+}
+
+#ifndef CONFIG_USER_ONLY
+static void handle_query_qemu_phy_mem_mode(GdbCmdContext *gdb_ctx,
+                                           void *user_ctx)
+{
+    snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "%d", 
phy_memory_mode);
+    put_packet(gdb_ctx->s, gdb_ctx->str_buf);
+}
+
+static void handle_set_qemu_phy_mem_mode(GdbCmdContext *gdb_ctx, void 
*user_ctx)
+{
+    if (!gdb_ctx->num_params) {
+        put_packet(gdb_ctx->s, "E22");
+        return;
+    }
+
+    if (!gdb_ctx->params[0].val_ul) {
+        phy_memory_mode = 0;
+    } else {
+        phy_memory_mode = 1;
+    }
+    put_packet(gdb_ctx->s, "OK");
 }
+#endif
 
 static GdbCmdParseEntry gdb_gen_query_set_common_table[] = {
     /* Order is important if has same prefix */
@@ -2201,6 +2245,12 @@ static GdbCmdParseEntry gdb_gen_query_table[] = {
         .handler = handle_query_qemu_supported,
         .cmd = "qemu.Supported",
     },
+#ifndef CONFIG_USER_ONLY
+    {
+        .handler = handle_query_qemu_phy_mem_mode,
+        .cmd = "qemu.PhyMemMode",
+    },
+#endif
 };
 
 static GdbCmdParseEntry gdb_gen_set_table[] = {
@@ -2211,6 +2261,14 @@ static GdbCmdParseEntry gdb_gen_set_table[] = {
         .cmd_startswith = 1,
         .schema = "l0"
     },
+#ifndef CONFIG_USER_ONLY
+    {
+        .handler = handle_set_qemu_phy_mem_mode,
+        .cmd = "qemu.PhyMemMode:",
+        .cmd_startswith = 1,
+        .schema = "l0"
+    },
+#endif
 };
 
 static void handle_gen_query(GdbCmdContext *gdb_ctx, void *user_ctx)
-- 
2.21.0