[PATCH v2 4/5] system/vl: Restrict icount to TCG emulation

Philippe Mathieu-Daudé posted 5 patches 11 months, 3 weeks ago
Maintainers: Richard Henderson <richard.henderson@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>, Peter Maydell <peter.maydell@linaro.org>, Stefan Hajnoczi <stefanha@redhat.com>, Fam Zheng <fam@euphon.net>
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[PATCH v2 4/5] system/vl: Restrict icount to TCG emulation
Posted by Philippe Mathieu-Daudé 11 months, 3 weeks ago
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 stubs/icount.c | 6 ------
 system/vl.c    | 6 +++++-
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/stubs/icount.c b/stubs/icount.c
index a5202e2dd9..b060b03a73 100644
--- a/stubs/icount.c
+++ b/stubs/icount.c
@@ -1,5 +1,4 @@
 #include "qemu/osdep.h"
-#include "qapi/error.h"
 #include "sysemu/cpu-timers.h"
 
 /* icount - Instruction Counter API */
@@ -10,11 +9,6 @@ void icount_update(CPUState *cpu)
 {
     abort();
 }
-void icount_configure(QemuOpts *opts, Error **errp)
-{
-    /* signal error */
-    error_setg(errp, "cannot configure icount, TCG support not available");
-}
 int64_t icount_get_raw(void)
 {
     abort();
diff --git a/system/vl.c b/system/vl.c
index 2bcd9efb9a..8c99c5f681 100644
--- a/system/vl.c
+++ b/system/vl.c
@@ -2270,7 +2270,11 @@ static void user_register_global_props(void)
 
 static int do_configure_icount(void *opaque, QemuOpts *opts, Error **errp)
 {
-    icount_configure(opts, errp);
+    if (tcg_enabled()) {
+        icount_configure(opts, errp);
+    } else {
+        error_setg(errp, "cannot configure icount, TCG support not available");
+    }
     return 0;
 }
 
-- 
2.41.0


Re: [PATCH v2 4/5] system/vl: Restrict icount to TCG emulation
Posted by Richard Henderson 11 months, 3 weeks ago
On 12/7/23 07:45, Philippe Mathieu-Daudé wrote:
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>   stubs/icount.c | 6 ------
>   system/vl.c    | 6 +++++-
>   2 files changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/stubs/icount.c b/stubs/icount.c
> index a5202e2dd9..b060b03a73 100644
> --- a/stubs/icount.c
> +++ b/stubs/icount.c
> @@ -1,5 +1,4 @@
>   #include "qemu/osdep.h"
> -#include "qapi/error.h"
>   #include "sysemu/cpu-timers.h"
>   
>   /* icount - Instruction Counter API */
> @@ -10,11 +9,6 @@ void icount_update(CPUState *cpu)
>   {
>       abort();
>   }
> -void icount_configure(QemuOpts *opts, Error **errp)
> -{
> -    /* signal error */
> -    error_setg(errp, "cannot configure icount, TCG support not available");
> -}
>   int64_t icount_get_raw(void)
>   {
>       abort();
> diff --git a/system/vl.c b/system/vl.c
> index 2bcd9efb9a..8c99c5f681 100644
> --- a/system/vl.c
> +++ b/system/vl.c
> @@ -2270,7 +2270,11 @@ static void user_register_global_props(void)
>   
>   static int do_configure_icount(void *opaque, QemuOpts *opts, Error **errp)
>   {
> -    icount_configure(opts, errp);
> +    if (tcg_enabled()) {
> +        icount_configure(opts, errp);
> +    } else {
> +        error_setg(errp, "cannot configure icount, TCG support not available");
> +    }
>       return 0;
>   }

This is called before the accelerator is chosen -- even before the set of available 
accelerators is even found.  Indeed, that's the very next thing that 
configure_accelerators does.

OTOH, I don't see why icount_configure is being called so early.


r~

>   


Re: [PATCH v2 4/5] system/vl: Restrict icount to TCG emulation
Posted by Philippe Mathieu-Daudé 11 months, 3 weeks ago
On 7/12/23 23:38, Richard Henderson wrote:
> On 12/7/23 07:45, Philippe Mathieu-Daudé wrote:
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>>   stubs/icount.c | 6 ------
>>   system/vl.c    | 6 +++++-
>>   2 files changed, 5 insertions(+), 7 deletions(-)
>>
>> diff --git a/stubs/icount.c b/stubs/icount.c
>> index a5202e2dd9..b060b03a73 100644
>> --- a/stubs/icount.c
>> +++ b/stubs/icount.c
>> @@ -1,5 +1,4 @@
>>   #include "qemu/osdep.h"
>> -#include "qapi/error.h"
>>   #include "sysemu/cpu-timers.h"
>>   /* icount - Instruction Counter API */
>> @@ -10,11 +9,6 @@ void icount_update(CPUState *cpu)
>>   {
>>       abort();
>>   }
>> -void icount_configure(QemuOpts *opts, Error **errp)
>> -{
>> -    /* signal error */
>> -    error_setg(errp, "cannot configure icount, TCG support not 
>> available");
>> -}
>>   int64_t icount_get_raw(void)
>>   {
>>       abort();
>> diff --git a/system/vl.c b/system/vl.c
>> index 2bcd9efb9a..8c99c5f681 100644
>> --- a/system/vl.c
>> +++ b/system/vl.c
>> @@ -2270,7 +2270,11 @@ static void user_register_global_props(void)
>>   static int do_configure_icount(void *opaque, QemuOpts *opts, Error 
>> **errp)
>>   {
>> -    icount_configure(opts, errp);
>> +    if (tcg_enabled()) {
>> +        icount_configure(opts, errp);
>> +    } else {
>> +        error_setg(errp, "cannot configure icount, TCG support not 
>> available");
>> +    }
>>       return 0;
>>   }
> 
> This is called before the accelerator is chosen -- even before the set 
> of available accelerators is even found.  Indeed, that's the very next 
> thing that configure_accelerators does.
> 
> OTOH, I don't see why icount_configure is being called so early.

See commit 7f8b6126e7:

     vl: move icount configuration earlier

     Once qemu_tcg_configure is turned into a QOM property setter,
     it will not be able to set a default value for mttcg_enabled.
     Setting the default will move to the TCG instance_init function,
     which currently runs before "-icount" is processed.

     However, it is harmless to do configure_icount for all accelerators;
     we will just fail later if a non-TCG accelerator is selected.  So do
     that.

But few commits after we have 28a0961757 ("vl: merge -accel processing
into configure_accelerators"), so it shouldn't be an issue now. I'll
consolidate.