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>

5 files changed, 106 insertions, 37 deletions

diff --git a/accel/kvm/kvm-accel-ops.c b/accel/kvm/kvm-accel-ops.c
index c4244a23c6..5c0e37514c 100644
--- a/accel/kvm/kvm-accel-ops.c
+++ b/accel/kvm/kvm-accel-ops.c
@@ -16,12 +16,14 @@
 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
+#include "sysemu/kvm.h"
 #include "sysemu/kvm_int.h"
 #include "sysemu/runstate.h"
 #include "sysemu/cpus.h"
 #include "qemu/guest-random.h"
 #include "qapi/error.h"
 
+#include <linux/kvm.h>
 #include "kvm-cpus.h"
 
 static void *kvm_vcpu_thread_fn(void *arg)
@@ -95,6 +97,12 @@ static void kvm_accel_ops_class_init(ObjectClass *oc, void *data)
     ops->synchronize_post_init = kvm_cpu_synchronize_post_init;
     ops->synchronize_state = kvm_cpu_synchronize_state;
     ops->synchronize_pre_loadvm = kvm_cpu_synchronize_pre_loadvm;
+
+#ifdef KVM_CAP_SET_GUEST_DEBUG
+    ops->insert_breakpoint = kvm_insert_breakpoint;
+    ops->remove_breakpoint = kvm_remove_breakpoint;
+    ops->remove_all_breakpoints = kvm_remove_all_breakpoints;
+#endif
 }
 
 static const TypeInfo kvm_accel_ops_type = {
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index c55938453a..b8c734fe3a 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -3287,8 +3287,7 @@ int kvm_update_guest_debug(CPUState *cpu, unsigned long reinject_trap)
     return data.err;
 }
 
-int kvm_insert_breakpoint(CPUState *cpu, target_ulong addr,
-                          target_ulong len, int type)
+int kvm_insert_breakpoint(CPUState *cpu, int type, hwaddr addr, hwaddr len)
 {
     struct kvm_sw_breakpoint *bp;
     int err;
@@ -3326,8 +3325,7 @@ int kvm_insert_breakpoint(CPUState *cpu, target_ulong addr,
     return 0;
 }
 
-int kvm_remove_breakpoint(CPUState *cpu, target_ulong addr,
-                          target_ulong len, int type)
+int kvm_remove_breakpoint(CPUState *cpu, int type, hwaddr addr, hwaddr len)
 {
     struct kvm_sw_breakpoint *bp;
     int err;
@@ -3393,26 +3391,10 @@ void kvm_remove_all_breakpoints(CPUState *cpu)
 
 #else /* !KVM_CAP_SET_GUEST_DEBUG */
 
-int kvm_update_guest_debug(CPUState *cpu, unsigned long reinject_trap)
+static int kvm_update_guest_debug(CPUState *cpu, unsigned long reinject_trap)
 {
     return -EINVAL;
 }
-
-int kvm_insert_breakpoint(CPUState *cpu, target_ulong addr,
-                          target_ulong len, int type)
-{
-    return -EINVAL;
-}
-
-int kvm_remove_breakpoint(CPUState *cpu, target_ulong addr,
-                          target_ulong len, int type)
-{
-    return -EINVAL;
-}
-
-void kvm_remove_all_breakpoints(CPUState *cpu)
-{
-}
 #endif /* !KVM_CAP_SET_GUEST_DEBUG */
 
 static int kvm_set_signal_mask(CPUState *cpu, const sigset_t *sigset)
diff --git a/accel/kvm/kvm-cpus.h b/accel/kvm/kvm-cpus.h
index bf0bd1bee4..33e435d62b 100644
--- a/accel/kvm/kvm-cpus.h
+++ b/accel/kvm/kvm-cpus.h
@@ -18,5 +18,8 @@ void kvm_destroy_vcpu(CPUState *cpu);
 void kvm_cpu_synchronize_post_reset(CPUState *cpu);
 void kvm_cpu_synchronize_post_init(CPUState *cpu);
 void kvm_cpu_synchronize_pre_loadvm(CPUState *cpu);
+int kvm_insert_breakpoint(CPUState *cpu, int type, hwaddr addr, hwaddr len);
+int kvm_remove_breakpoint(CPUState *cpu, int type, hwaddr addr, hwaddr len);
+void kvm_remove_all_breakpoints(CPUState *cpu);
 
 #endif /* KVM_CPUS_H */
diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c
index 2ac5f9c036..2d79333143 100644
--- a/accel/stubs/kvm-stub.c
+++ b/accel/stubs/kvm-stub.c
@@ -51,22 +51,6 @@ int kvm_update_guest_debug(CPUState *cpu, unsigned long reinject_trap)
     return -ENOSYS;
 }
 
-int kvm_insert_breakpoint(CPUState *cpu, target_ulong addr,
-                          target_ulong len, int type)
-{
-    return -EINVAL;
-}
-
-int kvm_remove_breakpoint(CPUState *cpu, target_ulong addr,
-                          target_ulong len, int type)
-{
-    return -EINVAL;
-}
-
-void kvm_remove_all_breakpoints(CPUState *cpu)
-{
-}
-
 int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr)
 {
     return 1;
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)