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[PATCH v2 05/10] accel/tcg: Handle -singlestep in curr_cflags

Richard Henderson posted 10 patches 3 years, 8 months ago
Maintainers: Laurent Vivier <laurent@vivier.eu>, Eduardo Habkost <ehabkost@redhat.com>, Aurelien Jarno <aurelien@aurel32.net>, Cornelia Huck <cohuck@redhat.com>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>, Bin Meng <bin.meng@windriver.com>, David Hildenbrand <david@redhat.com>, Thomas Huth <thuth@redhat.com>, Marek Vasut <marex@denx.de>, Bastian Koppelmann <kbastian@mail.uni-paderborn.de>, Michael Rolnik <mrolnik@gmail.com>, Peter Maydell <peter.maydell@linaro.org>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, Alistair Francis <alistair.francis@wdc.com>, Greg Kurz <groug@kaod.org>, Richard Henderson <richard.henderson@linaro.org>, Max Filippov <jcmvbkbc@gmail.com>, Taylor Simpson <tsimpson@quicinc.com>, Palmer Dabbelt <palmer@dabbelt.com>, Yoshinori Sato <ysato@users.sourceforge.jp>, Chris Wulff <crwulff@gmail.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Artyom Tarasenko <atar4qemu@gmail.com>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Stafford Horne <shorne@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>, David Gibson <david@gibson.dropbear.id.au>, "Philippe Mathieu-Daudé" <f4bug@amsat.org>
There is a newer version of this series
[PATCH v2 05/10] accel/tcg: Handle -singlestep in curr_cflags
Posted by Richard Henderson 3 years, 8 months ago 
Exchange the test in translator_use_goto_tb for CF_NO_GOTO_TB,
and the test in tb_gen_code for setting CF_COUNT_MASK to 1.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/cpu-exec.c      | 8 +++++++-
 accel/tcg/translate-all.c | 2 +-
 accel/tcg/translator.c    | 2 +-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 70ea3c7d68..2206c463f5 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -149,7 +149,13 @@ uint32_t curr_cflags(CPUState *cpu)
 {
     uint32_t cflags = cpu->tcg_cflags;
 
-    if (qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
+    /*
+     * For singlestep and -d nochain, suppress goto_tb so that
+     * we can log -d cpu,exec after every TB.
+     */
+    if (singlestep) {
+        cflags |= CF_NO_GOTO_TB | 1;
+    } else if (qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
         cflags |= CF_NO_GOTO_TB;
     }
 
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 997e44c73b..491c1a56b2 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1432,7 +1432,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
     }
     QEMU_BUILD_BUG_ON(CF_COUNT_MASK + 1 != TCG_MAX_INSNS);
 
-    if (cpu->singlestep_enabled || singlestep) {
+    if (cpu->singlestep_enabled) {
         max_insns = 1;
     }
 
diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
index 2ea5a74f30..a59eb7c11b 100644
--- a/accel/tcg/translator.c
+++ b/accel/tcg/translator.c
@@ -39,7 +39,7 @@ bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest)
     }
 
     /* Suppress goto_tb in the case of single-steping.  */
-    if (db->singlestep_enabled || singlestep) {
+    if (db->singlestep_enabled) {
         return false;
     }
 
-- 
2.25.1
Re: [PATCH v2 05/10] accel/tcg: Handle -singlestep in curr_cflags
Posted by Peter Maydell 3 years, 8 months ago 
On Mon, 12 Jul 2021 at 16:42, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Exchange the test in translator_use_goto_tb for CF_NO_GOTO_TB,
> and the test in tb_gen_code for setting CF_COUNT_MASK to 1.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  accel/tcg/cpu-exec.c      | 8 +++++++-
>  accel/tcg/translate-all.c | 2 +-
>  accel/tcg/translator.c    | 2 +-
>  3 files changed, 9 insertions(+), 3 deletions(-)

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM
Re: [PATCH v2 05/10] accel/tcg: Handle -singlestep in curr_cflags
Posted by Alex Bennée 3 years, 8 months ago 
Richard Henderson <richard.henderson@linaro.org> writes:

> Exchange the test in translator_use_goto_tb for CF_NO_GOTO_TB,
> and the test in tb_gen_code for setting CF_COUNT_MASK to 1.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  accel/tcg/cpu-exec.c      | 8 +++++++-
>  accel/tcg/translate-all.c | 2 +-
>  accel/tcg/translator.c    | 2 +-
>  3 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
> index 70ea3c7d68..2206c463f5 100644
> --- a/accel/tcg/cpu-exec.c
> +++ b/accel/tcg/cpu-exec.c
> @@ -149,7 +149,13 @@ uint32_t curr_cflags(CPUState *cpu)
>  {
>      uint32_t cflags = cpu->tcg_cflags;
>  
> -    if (qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
> +    /*
> +     * For singlestep and -d nochain, suppress goto_tb so that
> +     * we can log -d cpu,exec after every TB.
> +     */
> +    if (singlestep) {

Hmm we are testing a magic global here and looking at
cpu->singlestep_enabled lower down. We have a transient singlestep which
is turned on an off via cpu->singlestep_enabled and a global as a debug
option. Can we rationalise it further?

> +        cflags |= CF_NO_GOTO_TB | 1;
> +    } else if (qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
>          cflags |= CF_NO_GOTO_TB;
>      }
>  
> diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
> index 997e44c73b..491c1a56b2 100644
> --- a/accel/tcg/translate-all.c
> +++ b/accel/tcg/translate-all.c
> @@ -1432,7 +1432,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
>      }
>      QEMU_BUILD_BUG_ON(CF_COUNT_MASK + 1 != TCG_MAX_INSNS);
>  
> -    if (cpu->singlestep_enabled || singlestep) {
> +    if (cpu->singlestep_enabled) {
>          max_insns = 1;
>      }
>  
> diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
> index 2ea5a74f30..a59eb7c11b 100644
> --- a/accel/tcg/translator.c
> +++ b/accel/tcg/translator.c
> @@ -39,7 +39,7 @@ bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest)
>      }
>  
>      /* Suppress goto_tb in the case of single-steping.  */
> -    if (db->singlestep_enabled || singlestep) {
> +    if (db->singlestep_enabled) {
>          return false;
>      }


-- 
Alex Bennée
Re: [PATCH v2 05/10] accel/tcg: Handle -singlestep in curr_cflags
Posted by Richard Henderson 3 years, 8 months ago 
On 7/17/21 10:42 AM, Alex Bennée wrote:
> 
> Richard Henderson <richard.henderson@linaro.org> writes:
> 
>> Exchange the test in translator_use_goto_tb for CF_NO_GOTO_TB,
>> and the test in tb_gen_code for setting CF_COUNT_MASK to 1.
>>
>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>   accel/tcg/cpu-exec.c      | 8 +++++++-
>>   accel/tcg/translate-all.c | 2 +-
>>   accel/tcg/translator.c    | 2 +-
>>   3 files changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
>> index 70ea3c7d68..2206c463f5 100644
>> --- a/accel/tcg/cpu-exec.c
>> +++ b/accel/tcg/cpu-exec.c
>> @@ -149,7 +149,13 @@ uint32_t curr_cflags(CPUState *cpu)
>>   {
>>       uint32_t cflags = cpu->tcg_cflags;
>>   
>> -    if (qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
>> +    /*
>> +     * For singlestep and -d nochain, suppress goto_tb so that
>> +     * we can log -d cpu,exec after every TB.
>> +     */
>> +    if (singlestep) {
> 
> Hmm we are testing a magic global here and looking at
> cpu->singlestep_enabled lower down. We have a transient singlestep which
> is turned on an off via cpu->singlestep_enabled and a global as a debug
> option. Can we rationalise it further?

Not sure what you're asking.

cpu->singlestep_enabled raises a debug exception after one insn, whereas singlestep merely 
exits the tb after one insn.

What is it that you want me to rationalize?


r~
Re: [PATCH v2 05/10] accel/tcg: Handle -singlestep in curr_cflags
Posted by Peter Maydell 3 years, 8 months ago 
On Sat, 17 Jul 2021 at 19:43, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 7/17/21 10:42 AM, Alex Bennée wrote:
> > Hmm we are testing a magic global here and looking at
> > cpu->singlestep_enabled lower down. We have a transient singlestep which
> > is turned on an off via cpu->singlestep_enabled and a global as a debug
> > option. Can we rationalise it further?
>
> Not sure what you're asking.
>
> cpu->singlestep_enabled raises a debug exception after one insn, whereas singlestep merely
> exits the tb after one insn.

We really should rename 'singlestep' to 'one_insn_per_tb' or something,
because it's continually confusing...

-- PMM

Patchew 2.1-devel-b67e4c2

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