[Qemu-devel] [PATCH] Disable kqemu by default

[Qemu-devel] [PATCH] Disable kqemu by default

[Glauber Costa]

turns -no-kqemu option into -kqemu
set kqemu_allowed to 0 by default.

Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 kqemu.c         |    2 +-
 qemu-options.hx |    8 ++++----
 vl.c            |    4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/kqemu.c b/kqemu.c
index 1718498..203241e 100644
--- a/kqemu.c
+++ b/kqemu.c
@@ -81,7 +81,7 @@ int kqemu_fd = KQEMU_INVALID_FD;
    1 = user kqemu
    2 = kernel kqemu
 */
-int kqemu_allowed = 1;
+int kqemu_allowed = 0;
 uint64_t *pages_to_flush;
 unsigned int nb_pages_to_flush;
 uint64_t *ram_pages_to_update;
diff --git a/qemu-options.hx b/qemu-options.hx
index 87af798..755dc13 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1329,12 +1329,12 @@ Enable KQEMU full virtualization (default is user mode only).
 ETEXI
 
 #ifdef CONFIG_KQEMU
-DEF("no-kqemu", 0, QEMU_OPTION_no_kqemu, \
-    "-no-kqemu       disable KQEMU kernel module usage\n")
+DEF("-kqemu", 0, QEMU_OPTION_kqemu, \
+    "-kqemu          enable KQEMU kernel module usage\n")
 #endif
 STEXI
-@item -no-kqemu
-Disable KQEMU kernel module usage. KQEMU options are only available if
+@item -kqemu
+Enable KQEMU kernel module usage. KQEMU options are only available if
 KQEMU support is enabled when compiling.
 ETEXI
 
diff --git a/vl.c b/vl.c
index 1a227bb..13d87de 100644
--- a/vl.c
+++ b/vl.c
@@ -5398,8 +5398,8 @@ int main(int argc, char **argv, char **envp)
                 break;
 #endif
 #ifdef CONFIG_KQEMU
-            case QEMU_OPTION_no_kqemu:
-                kqemu_allowed = 0;
+            case QEMU_OPTION_kqemu:
+                kqemu_allowed = 1;
                 break;
             case QEMU_OPTION_kernel_kqemu:
                 kqemu_allowed = 2;
-- 
1.5.6.6

Re: [Qemu-devel] [PATCH] Disable kqemu by default

[Tomasz Chmielewski]

Glauber Costa wrote:
> turns -no-kqemu option into -kqemu
> set kqemu_allowed to 0 by default.

(...)

>  #ifdef CONFIG_KQEMU
> -DEF("no-kqemu", 0, QEMU_OPTION_no_kqemu, \
> -    "-no-kqemu       disable KQEMU kernel module usage\n")
> +DEF("-kqemu", 0, QEMU_OPTION_kqemu, \
> +    "-kqemu          enable KQEMU kernel module usage\n")

Why is this change needed?

Even if changed, wouldn't it be better to leave the -no-kqemu option for 
compatibility reasons? Otherwise, current scripts may break.


-- 
Tomasz Chmielewski
http://wpkg.org

Re: [Qemu-devel] [PATCH] Disable kqemu by default

[Glauber Costa]

On Fri, May 29, 2009 at 02:22:47PM +0200, Tomasz Chmielewski wrote:
> Glauber Costa wrote:
>> turns -no-kqemu option into -kqemu
>> set kqemu_allowed to 0 by default.
>
> (...)
>
>>  #ifdef CONFIG_KQEMU
>> -DEF("no-kqemu", 0, QEMU_OPTION_no_kqemu, \
>> -    "-no-kqemu       disable KQEMU kernel module usage\n")
>> +DEF("-kqemu", 0, QEMU_OPTION_kqemu, \
>> +    "-kqemu          enable KQEMU kernel module usage\n")
>
> Why is this change needed?
Well, we certainly need a -kqemu option to enable it, if it is disabled by default.

>
> Even if changed, wouldn't it be better to leave the -no-kqemu option for  
> compatibility reasons? Otherwise, current scripts may break.
options comes and go every day.

but it's not a big burden, we can leave the old option around...

Re: [Qemu-devel] [PATCH] Disable kqemu by default

[Tomasz Chmielewski]

Glauber Costa wrote:
> On Fri, May 29, 2009 at 02:22:47PM +0200, Tomasz Chmielewski wrote:
>> Glauber Costa wrote:
>>> turns -no-kqemu option into -kqemu
>>> set kqemu_allowed to 0 by default.
>> (...)
>>
>>>  #ifdef CONFIG_KQEMU
>>> -DEF("no-kqemu", 0, QEMU_OPTION_no_kqemu, \
>>> -    "-no-kqemu       disable KQEMU kernel module usage\n")
>>> +DEF("-kqemu", 0, QEMU_OPTION_kqemu, \
>>> +    "-kqemu          enable KQEMU kernel module usage\n")
>> Why is this change needed?
> Well, we certainly need a -kqemu option to enable it, if it is disabled by default.

I meant, why disable kqemu by default.


-- 
Tomasz Chmielewski
http://wpkg.org

Re: [Qemu-devel] [PATCH] Disable kqemu by default

[Daniel P. Berrange]

On Fri, May 29, 2009 at 09:30:47AM -0300, Glauber Costa wrote:
> On Fri, May 29, 2009 at 02:22:47PM +0200, Tomasz Chmielewski wrote:
> > Glauber Costa wrote:
> >> turns -no-kqemu option into -kqemu
> >> set kqemu_allowed to 0 by default.
> >
> > (...)
> >
> >>  #ifdef CONFIG_KQEMU
> >> -DEF("no-kqemu", 0, QEMU_OPTION_no_kqemu, \
> >> -    "-no-kqemu       disable KQEMU kernel module usage\n")
> >> +DEF("-kqemu", 0, QEMU_OPTION_kqemu, \
> >> +    "-kqemu          enable KQEMU kernel module usage\n")
> >
> > Why is this change needed?
> Well, we certainly need a -kqemu option to enable it, if it is disabled by default.
> 
> >
> > Even if changed, wouldn't it be better to leave the -no-kqemu option for  
> > compatibility reasons? Otherwise, current scripts may break.
> options comes and go every day.
> 
> but it's not a big burden, we can leave the old option around...

How about we add an option that's more future proof.

eg, 

     --accel  qemu|kvm|kqemu|xen

if that isn't given, then it'd pick the 'best', use --accel XXX to
override the auto behaviour

Daniel
-- 
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Re: [Qemu-devel] [PATCH] Disable kqemu by default

[Glauber Costa]

On Fri, May 29, 2009 at 02:31:32PM +0200, Tomasz Chmielewski wrote:
> Glauber Costa wrote:
>> On Fri, May 29, 2009 at 02:22:47PM +0200, Tomasz Chmielewski wrote:
>>> Glauber Costa wrote:
>>>> turns -no-kqemu option into -kqemu
>>>> set kqemu_allowed to 0 by default.
>>> (...)
>>>
>>>>  #ifdef CONFIG_KQEMU
>>>> -DEF("no-kqemu", 0, QEMU_OPTION_no_kqemu, \
>>>> -    "-no-kqemu       disable KQEMU kernel module usage\n")
>>>> +DEF("-kqemu", 0, QEMU_OPTION_kqemu, \
>>>> +    "-kqemu          enable KQEMU kernel module usage\n")
>>> Why is this change needed?
>> Well, we certainly need a -kqemu option to enable it, if it is disabled by default.
>
> I meant, why disable kqemu by default.
see thread at http://lists.gnu.org/archive/html/qemu-devel/2009-05/msg01459.html

kqemu is unmaintainable.

[Qemu-devel] Re: [PATCH] Disable kqemu by default

[Jan Kiszka]

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Glauber Costa wrote:
> turns -no-kqemu option into -kqemu
> set kqemu_allowed to 0 by default.
> 
> Signed-off-by: Glauber Costa <glommer@redhat.com>
> ---
>  kqemu.c         |    2 +-
>  qemu-options.hx |    8 ++++----
>  vl.c            |    4 ++--
>  3 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/kqemu.c b/kqemu.c
> index 1718498..203241e 100644
> --- a/kqemu.c
> +++ b/kqemu.c
> @@ -81,7 +81,7 @@ int kqemu_fd = KQEMU_INVALID_FD;
>     1 = user kqemu
>     2 = kernel kqemu
>  */
> -int kqemu_allowed = 1;
> +int kqemu_allowed = 0;
>  uint64_t *pages_to_flush;
>  unsigned int nb_pages_to_flush;
>  uint64_t *ram_pages_to_update;
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 87af798..755dc13 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1329,12 +1329,12 @@ Enable KQEMU full virtualization (default is user mode only).
>  ETEXI
>  
>  #ifdef CONFIG_KQEMU
> -DEF("no-kqemu", 0, QEMU_OPTION_no_kqemu, \
> -    "-no-kqemu       disable KQEMU kernel module usage\n")
> +DEF("-kqemu", 0, QEMU_OPTION_kqemu, \
> +    "-kqemu          enable KQEMU kernel module usage\n")

To be a bit consistent with -enable-kvm, what about -enable-kqemu?

>  #endif
>  STEXI
> -@item -no-kqemu
> -Disable KQEMU kernel module usage. KQEMU options are only available if
> +@item -kqemu
> +Enable KQEMU kernel module usage. KQEMU options are only available if
>  KQEMU support is enabled when compiling.
>  ETEXI
>  
> diff --git a/vl.c b/vl.c
> index 1a227bb..13d87de 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -5398,8 +5398,8 @@ int main(int argc, char **argv, char **envp)
>                  break;
>  #endif
>  #ifdef CONFIG_KQEMU
> -            case QEMU_OPTION_no_kqemu:
> -                kqemu_allowed = 0;
> +            case QEMU_OPTION_kqemu:
> +                kqemu_allowed = 1;
>                  break;
>              case QEMU_OPTION_kernel_kqemu:
>                  kqemu_allowed = 2;

Jan


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Re: [Qemu-devel] [PATCH] Disable kqemu by default

[François Revol]

> > I meant, why disable kqemu by default.
> see thread at http://lists.gnu.org/archive/html/qemu-devel/2009-05/msg01459.html
> >
> kqemu is unmaintainable.

It's the only way to get accel on some platforms...
Though IIRC it has issues in BeOS (it uses DRx) and the port isn't in
git anyway...

> How about we add an option that's more future proof.
>
> eg,
>
>      --accel  qemu|kvm|kqemu|xen

+1

François.