On 7/14/26 05:39, Ilya Leoshkevich wrote:
On 7/10/26 22:53, Richard Henderson wrote:
Use a balanced binary tree rather than a simple list for breakpoints.
Using an interval tree makes it easy to probe for all breakpoints on
a virtual page.
Signed-off-by: Richard Henderson <[email protected]>
---
include/exec/breakpoint.h | 4 +--
include/hw/core/cpu.h | 3 +-
accel/tcg/cpu-exec.c | 58 +++++++++++++++++++++----------------
accel/whpx/whpx-common.c | 9 +++---
cpu-common.c | 46 +++++++++++++++--------------
hw/core/cpu-common.c | 1 -
linux-user/main.c | 14 ++++++---
target/i386/whpx/whpx-all.c | 15 +++++-----
8 files changed, 84 insertions(+), 66 deletions(-)
[...]
@@ -312,33 +312,34 @@ static bool check_for_breakpoints_slow(CPUState *cpu,
vaddr pc,
return false;
}
- QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) {
- /*
- * If we have an exact pc match, trigger the breakpoint.
- * Otherwise, note matches within the page.
- */
- if (pc == bp->pc) {
- bool match_bp = false;
-
- if (bp->flags & BP_GDB) {
- match_bp = true;
- } else if (bp->flags & BP_CPU) {
+ n = interval_tree_iter_first(&cpu->breakpoints, pc, pc);
+ if (n) {
#ifdef CONFIG_USER_ONLY
- g_assert_not_reached();
+ bp = container_of(n, CPUBreakpoint, itree);
+ assert(bp->flags & BP_GDB);
+ goto found;
#else
- const TCGCPUOps *tcg_ops = cpu->cc->tcg_ops;
- assert(tcg_ops->debug_check_breakpoint);
- match_bp = tcg_ops->debug_check_breakpoint(cpu, bp);
-#endif
+ /* Prefer GDB breakpoint over architectural breakpoint. */
+ do {
+ bp = container_of(n, CPUBreakpoint, itree);
+ if (bp->flags & BP_GDB) {
+ goto found;
}
+ n = interval_tree_iter_next(n, pc, pc);
+ } while (n);
- if (match_bp) {
- cpu->exception_index = EXCP_DEBUG;
- return true;
+ const TCGCPUOps *tcg_ops = cpu->cc->tcg_ops;
+ assert(tcg_ops->debug_check_breakpoint);
+
+ for (n = interval_tree_iter_first(&cpu->breakpoints, pc, pc); n;
+ n = interval_tree_iter_next(n, pc, pc)) {
+ bp = container_of(n, CPUBreakpoint, itree);
+ if ((bp->flags & BP_CPU) &&
+ tcg_ops->debug_check_breakpoint(cpu, bp)) {
+ goto found;
}
Walking the tree twice feels slightly inefficient, but the only
alternative I can think of entails calling
tcg_ops->debug_check_breakpoint() for each node, which may be even
worse.
That's what I thought -- if we ever called debug_check_breakpoint when a gdb breakpoint
exists, then we're doing something wrong. The only alternative is to separate the two
types of breakpoints into two different interval trees.
r~
Reviewed-by: Ilya Leoskevich <[email protected]>
