[PATCH 03/16] exec: Add cpu_probe_watchpoint

[Richard Henderson]

Allow probing of a watchpoint *without* raising an exception.
This is of most use for no-fault loads, which should indicate
via some architectural means that the load did not occur.

Signed-off-by: Richard Henderson <address@hidden>
---
 include/hw/core/cpu.h |  7 +++++++
 exec.c                | 19 +++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 73e9a869a4..8ec44267a4 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -1090,6 +1090,12 @@ static inline void cpu_check_watchpoint(CPUState *cpu, 
vaddr addr, vaddr len,
 {
 }
 
+static inline bool cpu_probe_watchpoint(CPUState *cpu, vaddr addr, vaddr len,
+                                        int flags)
+{
+    return false;
+}
+
 static inline int cpu_watchpoint_address_matches(CPUState *cpu,
                                                  vaddr addr, vaddr len)
 {
@@ -1104,6 +1110,7 @@ void cpu_watchpoint_remove_by_ref(CPUState *cpu, 
CPUWatchpoint *watchpoint);
 void cpu_watchpoint_remove_all(CPUState *cpu, int mask);
 void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len,
                           MemTxAttrs attrs, int flags, uintptr_t ra);
+bool cpu_probe_watchpoint(CPUState *cpu, vaddr addr, vaddr len, int flags);
 int cpu_watchpoint_address_matches(CPUState *cpu, vaddr addr, vaddr len);
 #endif
 
diff --git a/exec.c b/exec.c
index 0cc500d53a..2b8f601b9e 100644
--- a/exec.c
+++ b/exec.c
@@ -2735,6 +2735,25 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, 
vaddr len,
     }
 }
 
+bool cpu_probe_watchpoint(CPUState *cpu, vaddr addr, vaddr len, int flags)
+{
+    CPUClass *cc = CPU_GET_CLASS(cpu);
+    CPUWatchpoint *wp;
+
+    assert(tcg_enabled());
+
+    addr = cc->adjust_watchpoint_address(cpu, addr, len);
+    QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
+        if (watchpoint_address_matches(wp, addr, len) && 
+            (wp->flags & flags) &&
+            (!(wp->flags & BP_CPU) ||
+             !cc->debug_check_watchpoint(cpu, wp))) {
+            return true;
+        }
+    }
+    return false;
+}
+
 static MemTxResult flatview_read(FlatView *fv, hwaddr addr,
                                  MemTxAttrs attrs, void *buf, hwaddr len);
 static MemTxResult flatview_write(FlatView *fv, hwaddr addr, MemTxAttrs attrs,
-- 
2.20.1