gdbstub: move breakpoint logic to accel ops

As HW virtualization requires specific support to handle breakpoints
lets push out special casing out of the core gdbstub code and into
AccelOpsClass. This will make it easier to add other accelerator
support and reduces some of the stub shenanigans.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Mads Ynddal <mads@ynddal.dk>
Message-Id: <20220929114231.583801-45-alex.bennee@linaro.org>

1 files changed, 92 insertions, 0 deletions

diff --git a/accel/tcg/tcg-accel-ops.c b/accel/tcg/tcg-accel-ops.c
index 786d90c08f..965c2ad581 100644
--- a/accel/tcg/tcg-accel-ops.c
+++ b/accel/tcg/tcg-accel-ops.c
@@ -32,6 +32,8 @@
 #include "qemu/main-loop.h"
 #include "qemu/guest-random.h"
 #include "exec/exec-all.h"
+#include "exec/hwaddr.h"
+#include "exec/gdbstub.h"
 
 #include "tcg-accel-ops.h"
 #include "tcg-accel-ops-mttcg.h"
@@ -91,6 +93,92 @@ void tcg_handle_interrupt(CPUState *cpu, int mask)
     }
 }
 
+/* Translate GDB watchpoint type to a flags value for cpu_watchpoint_* */
+static inline int xlat_gdb_type(CPUState *cpu, int gdbtype)
+{
+    static const int xlat[] = {
+        [GDB_WATCHPOINT_WRITE]  = BP_GDB | BP_MEM_WRITE,
+        [GDB_WATCHPOINT_READ]   = BP_GDB | BP_MEM_READ,
+        [GDB_WATCHPOINT_ACCESS] = BP_GDB | BP_MEM_ACCESS,
+    };
+
+    CPUClass *cc = CPU_GET_CLASS(cpu);
+    int cputype = xlat[gdbtype];
+
+    if (cc->gdb_stop_before_watchpoint) {
+        cputype |= BP_STOP_BEFORE_ACCESS;
+    }
+    return cputype;
+}
+
+static int tcg_insert_breakpoint(CPUState *cs, int type, hwaddr addr, hwaddr len)
+{
+    CPUState *cpu;
+    int err = 0;
+
+    switch (type) {
+    case GDB_BREAKPOINT_SW:
+    case GDB_BREAKPOINT_HW:
+        CPU_FOREACH(cpu) {
+            err = cpu_breakpoint_insert(cpu, addr, BP_GDB, NULL);
+            if (err) {
+                break;
+            }
+        }
+        return err;
+    case GDB_WATCHPOINT_WRITE:
+    case GDB_WATCHPOINT_READ:
+    case GDB_WATCHPOINT_ACCESS:
+        CPU_FOREACH(cpu) {
+            err = cpu_watchpoint_insert(cpu, addr, len,
+                                        xlat_gdb_type(cpu, type), NULL);
+            if (err) {
+                break;
+            }
+        }
+        return err;
+    default:
+        return -ENOSYS;
+    }
+}
+
+static int tcg_remove_breakpoint(CPUState *cs, int type, hwaddr addr, hwaddr len)
+{
+    CPUState *cpu;
+    int err = 0;
+
+    switch (type) {
+    case GDB_BREAKPOINT_SW:
+    case GDB_BREAKPOINT_HW:
+        CPU_FOREACH(cpu) {
+            err = cpu_breakpoint_remove(cpu, addr, BP_GDB);
+            if (err) {
+                break;
+            }
+        }
+        return err;
+    case GDB_WATCHPOINT_WRITE:
+    case GDB_WATCHPOINT_READ:
+    case GDB_WATCHPOINT_ACCESS:
+        CPU_FOREACH(cpu) {
+            err = cpu_watchpoint_remove(cpu, addr, len,
+                                        xlat_gdb_type(cpu, type));
+            if (err) {
+                break;
+            }
+        }
+        return err;
+    default:
+        return -ENOSYS;
+    }
+}
+
+static inline void tcg_remove_all_breakpoints(CPUState *cpu)
+{
+    cpu_breakpoint_remove_all(cpu, BP_GDB);
+    cpu_watchpoint_remove_all(cpu, BP_GDB);
+}
+
 static void tcg_accel_ops_init(AccelOpsClass *ops)
 {
     if (qemu_tcg_mttcg_enabled()) {
@@ -109,6 +197,10 @@ static void tcg_accel_ops_init(AccelOpsClass *ops)
             ops->handle_interrupt = tcg_handle_interrupt;
         }
     }
+
+    ops->insert_breakpoint = tcg_insert_breakpoint;
+    ops->remove_breakpoint = tcg_remove_breakpoint;
+    ops->remove_all_breakpoints = tcg_remove_all_breakpoints;
 }
 
 static void tcg_accel_ops_class_init(ObjectClass *oc, void *data)