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Re: [Qemu-devel] [PATCH] i386: fix breakpoints handling in icount mode
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] i386: fix breakpoints handling in icount mode |
Date: |
Tue, 26 May 2015 16:56:14 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 |
On 24/05/2015 16:43, Jan Kiszka wrote:
> diff --git a/target-i386/translate.c b/target-i386/translate.c
> index 305ce50..57b607d 100644
> --- a/target-i386/translate.c
> +++ b/target-i386/translate.c
> @@ -8006,6 +8006,7 @@ static inline void
> gen_intermediate_code_internal(X86CPU *cpu,
> if (bp->pc == pc_ptr &&
> !((bp->flags & BP_CPU) && (tb->flags & HF_RF_MASK))) {
> gen_debug(dc, pc_ptr - dc->cs_base);
> + pc_ptr = disas_insn(env, dc, pc_ptr);
> goto done_generating;
> }
> }
>
> pc_ptr is used at the end of the function to calculate the tb size. I
> suspect that the difference prevents that the breakpoint event is
> associated with the stored location. Can someone explain this more
> properly? Then I would happily pass patch credits.
So when a breakpoint is removed at address X, you have to also remove
translation blocks that end exactly at X? That is:
diff --git a/translate-all.c b/translate-all.c
index 536008f..6e50b8f 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -1113,7 +1116,7 @@
tb_start = tb->page_addr[1];
tb_end = tb_start + ((tb->pc + tb->size) & ~TARGET_PAGE_MASK);
}
- if (!(tb_end <= start || tb_start >= end)) {
+ if (tb_start < end && tb_end >= start) {
#ifdef TARGET_HAS_PRECISE_SMC
if (current_tb_not_found) {
current_tb_not_found = 0;
Does this fix the bug? Is there any other case where this
is desirable? Should tb_invalidate_phys_page_range grow another
argument to choose between "tb_end > start" and "tb_end >= start"?
Paolo