Re: [Qemu-devel] [PATCH 20/24] machine: drop MachineState::cpu_model

2018-01-19 Thread Eduardo Habkost 
On Fri, Jan 19, 2018 at 02:39:49PM +0100, Igor Mammedov wrote:
> On Fri, 19 Jan 2018 11:14:30 -0200
> Eduardo Habkost  wrote:
> 
> > On Fri, Jan 19, 2018 at 11:14:39AM +0100, Igor Mammedov wrote:
> > > On Thu, 18 Jan 2018 17:18:09 -0200
> > > Eduardo Habkost  wrote:
> > > 
> > > > On Thu, Jan 18, 2018 at 11:10:35AM +0100, Igor Mammedov wrote:
> > > > > On Wed, 17 Jan 2018 23:48:46 -0200
> > > > > Eduardo Habkost  wrote:
> > > > >   
> > > > > > On Wed, Jan 17, 2018 at 04:43:32PM +0100, Igor Mammedov wrote:  
> > > > > > > The last user of it was machine type 'none', which used field
> > > > > > > to create CPU id user requested it on CLI with -cpu option.
> > > [...]
> > > 
> > > > It looks like default_cpu_type is being overloaded for two
> > > > different roles: 1) specifying the default CPU type; 2) finding
> > > > the arch-specific class to be used to parse -cpu.
> > > > 
> > > > In the case of null-machine, these two roles conflict with each
> > > > other.  I believe we can find other solutions instead of this
> > > > hack that involves lying on MachineClass::default_cpu_type (and
> > > > then having to work around the lie on machine_none_init()).
> > > > 
> > > > I see multiple options: adding a new MachineClass field for that
> > > > (e.g.  resolving_cpu_type, which defaults to default_cpu_type if
> > > > NULL); moving the CPU parsing code to arch_init.c (so it could
> > > > use CPU_RESOLVING_TYPE or something similar); adding a optional
> > > > MachineClass::parse_cpu_model hook.  We could even try to get rid
> > > > of CPUClass::parse_features completely
> > > Adding hooks just for the sake on null-machine seems to be overkill,
> > > I'd go for arch_init.c but it won't work for linux-user, how about
> > > exec.c as following:
> > > 
> > > diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> > > index 93bd546..0185589 100644
> > > --- a/include/qom/cpu.h
> > > +++ b/include/qom/cpu.h
> > > @@ -661,8 +661,7 @@ ObjectClass *cpu_class_by_name(const char *typename, 
> > > const char *cpu_model);
> > > [...]
> > > 
> > > diff --git a/exec.c b/exec.c
> > > index d28fc0c..4543f06 100644
> > > --- a/exec.c
> > > +++ b/exec.c
> > > @@ -817,6 +817,29 @@ void cpu_exec_realizefn(CPUState *cpu, Error **errp)
> > >  #endif
> > >  }
> > >  
> > > +const char *parse_cpu_model(const char *cpu_model)
> > > +{
> > > +ObjectClass *oc;
> > > +CPUClass *cc;
> > > +gchar **model_pieces;
> > > +const char *cpu_type;
> > > +
> > > +model_pieces = g_strsplit(cpu_model, ",", 2);
> > > +
> > > +oc = cpu_class_by_name(CPU_RESOLVING_TYPE, model_pieces[0]);
> > > +if (oc == NULL) {
> > > +error_report("unable to find CPU model '%s'", model_pieces[0]);
> > > +g_strfreev(model_pieces);
> > > +exit(EXIT_FAILURE);
> > > +}
> > > +
> > > +cpu_type = object_class_get_name(oc);
> > > +cc = CPU_CLASS(oc);
> > > +cc->parse_features(cpu_type, model_pieces[1], _fatal);
> > > +g_strfreev(model_pieces);
> > > +return cpu_type;
> > > +}
> > 
> > Sounds good to me.  Only two comments:
> > 
> > This looks like duplication of cpu_parse_cpu_model().  Should
> > this function body be replaced with:
> >   cpu_parse_cpu_model(CPU_RESOLVING_TYPE, cpu_model)
> it's cpu_parse_cpu_model() which is moved to exec.c
> and first typename argument is replaced by inline CPU_RESOLVING_TYPE
> 
> 
> > I would move this to arch_init.c, because that's where existing
> > target-dependent initialization code lives.
> arch_init.c doesn't fit linux-user, it has only sys emulation code
> while exec.c is used by both and still target depended so CPU_RESOLVING_TYPE
> could be used there

I don't really like adding more code to the mess that is exec.c,
but this looks like the simplest solution.

-- 
Eduardo

Re: [Qemu-devel] [PATCH 20/24] machine: drop MachineState::cpu_model

2018-01-19 Thread Igor Mammedov 
On Fri, 19 Jan 2018 11:14:30 -0200
Eduardo Habkost  wrote:

> On Fri, Jan 19, 2018 at 11:14:39AM +0100, Igor Mammedov wrote:
> > On Thu, 18 Jan 2018 17:18:09 -0200
> > Eduardo Habkost  wrote:
> > 
> > > On Thu, Jan 18, 2018 at 11:10:35AM +0100, Igor Mammedov wrote:
> > > > On Wed, 17 Jan 2018 23:48:46 -0200
> > > > Eduardo Habkost  wrote:
> > > >   
> > > > > On Wed, Jan 17, 2018 at 04:43:32PM +0100, Igor Mammedov wrote:  
> > > > > > The last user of it was machine type 'none', which used field
> > > > > > to create CPU id user requested it on CLI with -cpu option.
> > [...]
> > 
> > > It looks like default_cpu_type is being overloaded for two
> > > different roles: 1) specifying the default CPU type; 2) finding
> > > the arch-specific class to be used to parse -cpu.
> > > 
> > > In the case of null-machine, these two roles conflict with each
> > > other.  I believe we can find other solutions instead of this
> > > hack that involves lying on MachineClass::default_cpu_type (and
> > > then having to work around the lie on machine_none_init()).
> > > 
> > > I see multiple options: adding a new MachineClass field for that
> > > (e.g.  resolving_cpu_type, which defaults to default_cpu_type if
> > > NULL); moving the CPU parsing code to arch_init.c (so it could
> > > use CPU_RESOLVING_TYPE or something similar); adding a optional
> > > MachineClass::parse_cpu_model hook.  We could even try to get rid
> > > of CPUClass::parse_features completely
> > Adding hooks just for the sake on null-machine seems to be overkill,
> > I'd go for arch_init.c but it won't work for linux-user, how about
> > exec.c as following:
> > 
> > diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> > index 93bd546..0185589 100644
> > --- a/include/qom/cpu.h
> > +++ b/include/qom/cpu.h
> > @@ -661,8 +661,7 @@ ObjectClass *cpu_class_by_name(const char *typename, 
> > const char *cpu_model);
> > [...]
> > 
> > diff --git a/exec.c b/exec.c
> > index d28fc0c..4543f06 100644
> > --- a/exec.c
> > +++ b/exec.c
> > @@ -817,6 +817,29 @@ void cpu_exec_realizefn(CPUState *cpu, Error **errp)
> >  #endif
> >  }
> >  
> > +const char *parse_cpu_model(const char *cpu_model)
> > +{
> > +ObjectClass *oc;
> > +CPUClass *cc;
> > +gchar **model_pieces;
> > +const char *cpu_type;
> > +
> > +model_pieces = g_strsplit(cpu_model, ",", 2);
> > +
> > +oc = cpu_class_by_name(CPU_RESOLVING_TYPE, model_pieces[0]);
> > +if (oc == NULL) {
> > +error_report("unable to find CPU model '%s'", model_pieces[0]);
> > +g_strfreev(model_pieces);
> > +exit(EXIT_FAILURE);
> > +}
> > +
> > +cpu_type = object_class_get_name(oc);
> > +cc = CPU_CLASS(oc);
> > +cc->parse_features(cpu_type, model_pieces[1], _fatal);
> > +g_strfreev(model_pieces);
> > +return cpu_type;
> > +}
> 
> Sounds good to me.  Only two comments:
> 
> This looks like duplication of cpu_parse_cpu_model().  Should
> this function body be replaced with:
>   cpu_parse_cpu_model(CPU_RESOLVING_TYPE, cpu_model)
it's cpu_parse_cpu_model() which is moved to exec.c
and first typename argument is replaced by inline CPU_RESOLVING_TYPE


> I would move this to arch_init.c, because that's where existing
> target-dependent initialization code lives.
arch_init.c doesn't fit linux-user, it has only sys emulation code
while exec.c is used by both and still target depended so CPU_RESOLVING_TYPE
could be used there

> 
> 
> > [...]
>

Re: [Qemu-devel] [PATCH 20/24] machine: drop MachineState::cpu_model

2018-01-19 Thread Eduardo Habkost 
On Fri, Jan 19, 2018 at 11:14:39AM +0100, Igor Mammedov wrote:
> On Thu, 18 Jan 2018 17:18:09 -0200
> Eduardo Habkost  wrote:
> 
> > On Thu, Jan 18, 2018 at 11:10:35AM +0100, Igor Mammedov wrote:
> > > On Wed, 17 Jan 2018 23:48:46 -0200
> > > Eduardo Habkost  wrote:
> > >   
> > > > On Wed, Jan 17, 2018 at 04:43:32PM +0100, Igor Mammedov wrote:  
> > > > > The last user of it was machine type 'none', which used field
> > > > > to create CPU id user requested it on CLI with -cpu option.
> [...]
> 
> > It looks like default_cpu_type is being overloaded for two
> > different roles: 1) specifying the default CPU type; 2) finding
> > the arch-specific class to be used to parse -cpu.
> > 
> > In the case of null-machine, these two roles conflict with each
> > other.  I believe we can find other solutions instead of this
> > hack that involves lying on MachineClass::default_cpu_type (and
> > then having to work around the lie on machine_none_init()).
> > 
> > I see multiple options: adding a new MachineClass field for that
> > (e.g.  resolving_cpu_type, which defaults to default_cpu_type if
> > NULL); moving the CPU parsing code to arch_init.c (so it could
> > use CPU_RESOLVING_TYPE or something similar); adding a optional
> > MachineClass::parse_cpu_model hook.  We could even try to get rid
> > of CPUClass::parse_features completely
> Adding hooks just for the sake on null-machine seems to be overkill,
> I'd go for arch_init.c but it won't work for linux-user, how about
> exec.c as following:
> 
> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> index 93bd546..0185589 100644
> --- a/include/qom/cpu.h
> +++ b/include/qom/cpu.h
> @@ -661,8 +661,7 @@ ObjectClass *cpu_class_by_name(const char *typename, 
> const char *cpu_model);
> [...]
> 
> diff --git a/exec.c b/exec.c
> index d28fc0c..4543f06 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -817,6 +817,29 @@ void cpu_exec_realizefn(CPUState *cpu, Error **errp)
>  #endif
>  }
>  
> +const char *parse_cpu_model(const char *cpu_model)
> +{
> +ObjectClass *oc;
> +CPUClass *cc;
> +gchar **model_pieces;
> +const char *cpu_type;
> +
> +model_pieces = g_strsplit(cpu_model, ",", 2);
> +
> +oc = cpu_class_by_name(CPU_RESOLVING_TYPE, model_pieces[0]);
> +if (oc == NULL) {
> +error_report("unable to find CPU model '%s'", model_pieces[0]);
> +g_strfreev(model_pieces);
> +exit(EXIT_FAILURE);
> +}
> +
> +cpu_type = object_class_get_name(oc);
> +cc = CPU_CLASS(oc);
> +cc->parse_features(cpu_type, model_pieces[1], _fatal);
> +g_strfreev(model_pieces);
> +return cpu_type;
> +}

Sounds good to me.  Only two comments:

This looks like duplication of cpu_parse_cpu_model().  Should
this function body be replaced with:
  cpu_parse_cpu_model(CPU_RESOLVING_TYPE, cpu_model)
?

I would move this to arch_init.c, because that's where existing
target-dependent initialization code lives.


> [...]

-- 
Eduardo

Re: [Qemu-devel] [PATCH 20/24] machine: drop MachineState::cpu_model

2018-01-19 Thread Igor Mammedov 
On Thu, 18 Jan 2018 17:18:09 -0200
Eduardo Habkost  wrote:

> On Thu, Jan 18, 2018 at 11:10:35AM +0100, Igor Mammedov wrote:
> > On Wed, 17 Jan 2018 23:48:46 -0200
> > Eduardo Habkost  wrote:
> >   
> > > On Wed, Jan 17, 2018 at 04:43:32PM +0100, Igor Mammedov wrote:  
> > > > The last user of it was machine type 'none', which used field
> > > > to create CPU id user requested it on CLI with -cpu option.
[...]

> It looks like default_cpu_type is being overloaded for two
> different roles: 1) specifying the default CPU type; 2) finding
> the arch-specific class to be used to parse -cpu.
> 
> In the case of null-machine, these two roles conflict with each
> other.  I believe we can find other solutions instead of this
> hack that involves lying on MachineClass::default_cpu_type (and
> then having to work around the lie on machine_none_init()).
> 
> I see multiple options: adding a new MachineClass field for that
> (e.g.  resolving_cpu_type, which defaults to default_cpu_type if
> NULL); moving the CPU parsing code to arch_init.c (so it could
> use CPU_RESOLVING_TYPE or something similar); adding a optional
> MachineClass::parse_cpu_model hook.  We could even try to get rid
> of CPUClass::parse_features completely
Adding hooks just for the sake on null-machine seems to be overkill,
I'd go for arch_init.c but it won't work for linux-user, how about
exec.c as following:

diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 93bd546..0185589 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -661,8 +661,7 @@ ObjectClass *cpu_class_by_name(const char *typename, const 
char *cpu_model);
[...]

diff --git a/exec.c b/exec.c
index d28fc0c..4543f06 100644
--- a/exec.c
+++ b/exec.c
@@ -817,6 +817,29 @@ void cpu_exec_realizefn(CPUState *cpu, Error **errp)
 #endif
 }
 
+const char *parse_cpu_model(const char *cpu_model)
+{
+ObjectClass *oc;
+CPUClass *cc;
+gchar **model_pieces;
+const char *cpu_type;
+
+model_pieces = g_strsplit(cpu_model, ",", 2);
+
+oc = cpu_class_by_name(CPU_RESOLVING_TYPE, model_pieces[0]);
+if (oc == NULL) {
+error_report("unable to find CPU model '%s'", model_pieces[0]);
+g_strfreev(model_pieces);
+exit(EXIT_FAILURE);
+}
+
+cpu_type = object_class_get_name(oc);
+cc = CPU_CLASS(oc);
+cc->parse_features(cpu_type, model_pieces[1], _fatal);
+g_strfreev(model_pieces);
+return cpu_type;
+}
+
 #if defined(CONFIG_USER_ONLY)
 static void breakpoint_invalidate(CPUState *cpu, target_ulong pc)
 {
diff --git a/hw/core/null-machine.c b/hw/core/null-machine.c
index 864832d..cde4d3e 100644
--- a/hw/core/null-machine.c
+++ b/hw/core/null-machine.c
@@ -24,9 +24,9 @@ static void machine_none_init(MachineState *mch)
 {
 CPUState *cpu = NULL;
 
-/* Initialize CPU (if a model has been specified) */
-if (mch->cpu_model) {
-cpu = cpu_init(mch->cpu_model);
+/* Initialize CPU (if user asked for it) */
+if (mch->cpu_type) {
+cpu = cpu_create(mch->cpu_type);
 if (!cpu) {
 error_report("Unable to initialize CPU");
 exit(1);
diff --git a/linux-user/main.c b/linux-user/main.c
index a35477e..0afb3f4 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -4357,10 +4358,13 @@ int main(int argc, char **argv, char **envp)
 cpu_model = "any";
 #endif
 }
+cpu_type = parse_cpu_model(cpu_model);
+
 tcg_exec_init(0);
 /* NOTE: we need to init the CPU at this stage to get
qemu_host_page_size */
-cpu = cpu_init(cpu_model);
+
+cpu = cpu_create(cpu_type);
 env = cpu->env_ptr;
 cpu_reset(cpu);
 
diff --git a/qom/cpu.c b/qom/cpu.c
index e42d9a7..aab8437 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -67,37 +67,6 @@ CPUState *cpu_create(const char *typename)
 return cpu;
 }
 
-const char *cpu_parse_cpu_model(const char *typename, const char *cpu_model)
-{
[...]
-}
-
-CPUState *cpu_generic_init(const char *typename, const char *cpu_model)
-{
[...]
-}
-
 bool cpu_paging_enabled(const CPUState *cpu)
 {
 CPUClass *cc = CPU_GET_CLASS(cpu);
diff --git a/vl.c b/vl.c
index 2586f25..178bca3 100644
--- a/vl.c
+++ b/vl.c
@@ -4609,17 +4609,13 @@ int main(int argc, char **argv, char **envp)
 current_machine->maxram_size = maxram_size;
 current_machine->ram_slots = ram_slots;
 current_machine->boot_order = boot_order;
-current_machine->cpu_model = cpu_model;
 
 parse_numa_opts(current_machine);
 
 /* parse features once if machine provides default cpu_type */
-if (machine_class->default_cpu_type) {
-current_machine->cpu_type = machine_class->default_cpu_type;
-if (cpu_model) {
-current_machine->cpu_type =
-cpu_parse_cpu_model(machine_class->default_cpu_type, 
cpu_model);
-}
+current_machine->cpu_type = machine_class->default_cpu_type;
+if (cpu_model) {
+current_machine->cpu_type = parse_cpu_model(cpu_model);
 }

Re: [Qemu-devel] [PATCH 20/24] machine: drop MachineState::cpu_model

2018-01-18 Thread Eduardo Habkost 
On Thu, Jan 18, 2018 at 11:10:35AM +0100, Igor Mammedov wrote:
> On Wed, 17 Jan 2018 23:48:46 -0200
> Eduardo Habkost  wrote:
> 
> > On Wed, Jan 17, 2018 at 04:43:32PM +0100, Igor Mammedov wrote:
> > > The last user of it was machine type 'none', which used field
> > > to create CPU id user requested it on CLI with -cpu option.
> > > 
> > > We could compare pointers of MachineState::cpu_type and
> > > MachineClass::default_cpu_type to check for the same condition,
> > > and drop cpu_model concept completly from machine/boards code
> > > So that no one would try to reuse obsolete field and only
> > > place to deal with cpu model would be vl.c and
> > > foo_cpu_class_by_name() callbacks.
> > > 
> > > Signed-off-by: Igor Mammedov 
> > > ---
> > > CC: Eduardo Habkost 
> > > CC: Marcel Apfelbaum 
> > > CC: Paolo Bonzini 
> > > ---
> > >  include/hw/boards.h|  1 -
> > >  hw/core/null-machine.c | 10 +++---
> > >  vl.c   |  8 +++-
> > >  3 files changed, 14 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/include/hw/boards.h b/include/hw/boards.h
> > > index 156b16f..decd0ec 100644
> > > --- a/include/hw/boards.h
> > > +++ b/include/hw/boards.h
> > > @@ -246,7 +246,6 @@ struct MachineState {
> > >  char *kernel_filename;
> > >  char *kernel_cmdline;
> > >  char *initrd_filename;
> > > -const char *cpu_model;
> > >  const char *cpu_type;
> > >  AccelState *accelerator;
> > >  CPUArchIdList *possible_cpus;
> > > diff --git a/hw/core/null-machine.c b/hw/core/null-machine.c
> > > index 864832d..c2e466c 100644
> > > --- a/hw/core/null-machine.c
> > > +++ b/hw/core/null-machine.c
> > > @@ -23,10 +23,13 @@
> > >  static void machine_none_init(MachineState *mch)
> > >  {
> > >  CPUState *cpu = NULL;
> > > +MachineClass *mc = MACHINE_GET_CLASS(mch);
> > >  
> > > -/* Initialize CPU (if a model has been specified) */
> > > -if (mch->cpu_model) {
> > > -cpu = cpu_init(mch->cpu_model);
> > > +/* Initialize CPU if cpu_type pointer is user provided
> > > + * (i.e. != to pointer tot static default cpu type string)
> > > + */
> > > +if (mch->cpu_type != mc->default_cpu_type) {
> > > +cpu = cpu_create(mch->cpu_type);  
> > 
> > This is a big assumption about the code that sets mch->cpu_type.
> > A simple g_strdup(machine_class->default_cpu_type) would break
> > this silently (as it won't trigger the assert() below).
> Yes, it's a bit of a hack to figure out is user has requested
> cpu type explicitly. But so far there isn't need to do
>g_strdup(machine_class->default_cpu_type)
> when copying default in vl.c and guarding against it
> looks like overkill currently.
> 
> Cleaner way would be to make cpu_type property, add new property
> API to set/check flags and use that here, there are other places
> that would benefit from such API as well.
> But it looks beyond scope of this series, so I used simple
> hackish way to make it work with current code.
> 
> I can amend comment here:
> /* Initialize CPU if cpu_type pointer is user provided
>  * (i.e. != to pointer to static default cpu type string)
>  * MachineClass::default_cpu_type must be assigned to
>  * MachineState::cpu_type directly for this to work.
>  * TODO:
>  *   - make cpu_type a property
>  *   - add API to add/check user_set flag to property
>  *   - use new API to check if property was user set
>  */
> 
> > 
> > 
> > >  if (!cpu) {
> > >  error_report("Unable to initialize CPU");
> > >  exit(1);
> > > @@ -54,6 +57,7 @@ static void machine_none_machine_init(MachineClass *mc)
> > >  mc->init = machine_none_init;
> > >  mc->max_cpus = 1;
> > >  mc->default_ram_size = 0;
> > > +mc->default_cpu_type = TARGET_DEFAULT_CPU_TYPE;  
> > 
> > Why do you need this?  Isn't it simpler to just leave
> > default_cpu_type=NULL here?
> vl.c "-cpu" parsing depends on default_cpu_type being set
>  ...
>  if (machine_class->default_cpu_type) {
>...
>  }

Right, this makes sense now.

It looks like default_cpu_type is being overloaded for two
different roles: 1) specifying the default CPU type; 2) finding
the arch-specific class to be used to parse -cpu.

In the case of null-machine, these two roles conflict with each
other.  I believe we can find other solutions instead of this
hack that involves lying on MachineClass::default_cpu_type (and
then having to work around the lie on machine_none_init()).

I see multiple options: adding a new MachineClass field for that
(e.g.  resolving_cpu_type, which defaults to default_cpu_type if
NULL); moving the CPU parsing code to arch_init.c (so it could
use CPU_RESOLVING_TYPE or something similar); adding a optional
MachineClass::parse_cpu_model hook.  We could even try to get rid
of CPUClass::parse_features completely


> when we get rid of requirement

Re: [Qemu-devel] [PATCH 20/24] machine: drop MachineState::cpu_model

2018-01-18 Thread Igor Mammedov 
On Wed, 17 Jan 2018 23:48:46 -0200
Eduardo Habkost  wrote:

> On Wed, Jan 17, 2018 at 04:43:32PM +0100, Igor Mammedov wrote:
> > The last user of it was machine type 'none', which used field
> > to create CPU id user requested it on CLI with -cpu option.
> > 
> > We could compare pointers of MachineState::cpu_type and
> > MachineClass::default_cpu_type to check for the same condition,
> > and drop cpu_model concept completly from machine/boards code
> > So that no one would try to reuse obsolete field and only
> > place to deal with cpu model would be vl.c and
> > foo_cpu_class_by_name() callbacks.
> > 
> > Signed-off-by: Igor Mammedov 
> > ---
> > CC: Eduardo Habkost 
> > CC: Marcel Apfelbaum 
> > CC: Paolo Bonzini 
> > ---
> >  include/hw/boards.h|  1 -
> >  hw/core/null-machine.c | 10 +++---
> >  vl.c   |  8 +++-
> >  3 files changed, 14 insertions(+), 5 deletions(-)
> > 
> > diff --git a/include/hw/boards.h b/include/hw/boards.h
> > index 156b16f..decd0ec 100644
> > --- a/include/hw/boards.h
> > +++ b/include/hw/boards.h
> > @@ -246,7 +246,6 @@ struct MachineState {
> >  char *kernel_filename;
> >  char *kernel_cmdline;
> >  char *initrd_filename;
> > -const char *cpu_model;
> >  const char *cpu_type;
> >  AccelState *accelerator;
> >  CPUArchIdList *possible_cpus;
> > diff --git a/hw/core/null-machine.c b/hw/core/null-machine.c
> > index 864832d..c2e466c 100644
> > --- a/hw/core/null-machine.c
> > +++ b/hw/core/null-machine.c
> > @@ -23,10 +23,13 @@
> >  static void machine_none_init(MachineState *mch)
> >  {
> >  CPUState *cpu = NULL;
> > +MachineClass *mc = MACHINE_GET_CLASS(mch);
> >  
> > -/* Initialize CPU (if a model has been specified) */
> > -if (mch->cpu_model) {
> > -cpu = cpu_init(mch->cpu_model);
> > +/* Initialize CPU if cpu_type pointer is user provided
> > + * (i.e. != to pointer tot static default cpu type string)
> > + */
> > +if (mch->cpu_type != mc->default_cpu_type) {
> > +cpu = cpu_create(mch->cpu_type);  
> 
> This is a big assumption about the code that sets mch->cpu_type.
> A simple g_strdup(machine_class->default_cpu_type) would break
> this silently (as it won't trigger the assert() below).
Yes, it's a bit of a hack to figure out is user has requested
cpu type explicitly. But so far there isn't need to do
   g_strdup(machine_class->default_cpu_type)
when copying default in vl.c and guarding against it
looks like overkill currently.

Cleaner way would be to make cpu_type property, add new property
API to set/check flags and use that here, there are other places
that would benefit from such API as well.
But it looks beyond scope of this series, so I used simple
hackish way to make it work with current code.

I can amend comment here:
/* Initialize CPU if cpu_type pointer is user provided
 * (i.e. != to pointer to static default cpu type string)
 * MachineClass::default_cpu_type must be assigned to
 * MachineState::cpu_type directly for this to work.
 * TODO:
 *   - make cpu_type a property
 *   - add API to add/check user_set flag to property
 *   - use new API to check if property was user set
 */

> 
> 
> >  if (!cpu) {
> >  error_report("Unable to initialize CPU");
> >  exit(1);
> > @@ -54,6 +57,7 @@ static void machine_none_machine_init(MachineClass *mc)
> >  mc->init = machine_none_init;
> >  mc->max_cpus = 1;
> >  mc->default_ram_size = 0;
> > +mc->default_cpu_type = TARGET_DEFAULT_CPU_TYPE;  
> 
> Why do you need this?  Isn't it simpler to just leave
> default_cpu_type=NULL here?
vl.c "-cpu" parsing depends on default_cpu_type being set
 ...
 if (machine_class->default_cpu_type) {
   ...
 }
when we get rid of requirement for proxy type in
 cpu_parse_cpu_model()
we can drop this ugliness in null-machine.

I'm doing it dirty way to prevent cpu_model resurgence
in boards code as it happened with nios2, even though
I've tried to monitor list for such patches.
 
> >  }
> >  
> >  DEFINE_MACHINE("none", machine_none_machine_init)
> > diff --git a/vl.c b/vl.c
> > index 2586f25..8aa0131 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -4609,7 +4609,6 @@ int main(int argc, char **argv, char **envp)
> >  current_machine->maxram_size = maxram_size;
> >  current_machine->ram_slots = ram_slots;
> >  current_machine->boot_order = boot_order;
> > -current_machine->cpu_model = cpu_model;
> >  
> >  parse_numa_opts(current_machine);
> >  
> > @@ -4619,6 +4618,13 @@ int main(int argc, char **argv, char **envp)
> >  if (cpu_model) {
> >  current_machine->cpu_type =
> >  cpu_parse_cpu_model(machine_class->default_cpu_type, 
> > cpu_model);
> > +
> > +/* machine 'none' depends on default cpu type pointer not being
> > + * equal to

Re: [Qemu-devel] [PATCH 20/24] machine: drop MachineState::cpu_model

2018-01-17 Thread Eduardo Habkost 
On Wed, Jan 17, 2018 at 04:43:32PM +0100, Igor Mammedov wrote:
> The last user of it was machine type 'none', which used field
> to create CPU id user requested it on CLI with -cpu option.
> 
> We could compare pointers of MachineState::cpu_type and
> MachineClass::default_cpu_type to check for the same condition,
> and drop cpu_model concept completly from machine/boards code
> So that no one would try to reuse obsolete field and only
> place to deal with cpu model would be vl.c and
> foo_cpu_class_by_name() callbacks.
> 
> Signed-off-by: Igor Mammedov 
> ---
> CC: Eduardo Habkost 
> CC: Marcel Apfelbaum 
> CC: Paolo Bonzini 
> ---
>  include/hw/boards.h|  1 -
>  hw/core/null-machine.c | 10 +++---
>  vl.c   |  8 +++-
>  3 files changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 156b16f..decd0ec 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -246,7 +246,6 @@ struct MachineState {
>  char *kernel_filename;
>  char *kernel_cmdline;
>  char *initrd_filename;
> -const char *cpu_model;
>  const char *cpu_type;
>  AccelState *accelerator;
>  CPUArchIdList *possible_cpus;
> diff --git a/hw/core/null-machine.c b/hw/core/null-machine.c
> index 864832d..c2e466c 100644
> --- a/hw/core/null-machine.c
> +++ b/hw/core/null-machine.c
> @@ -23,10 +23,13 @@
>  static void machine_none_init(MachineState *mch)
>  {
>  CPUState *cpu = NULL;
> +MachineClass *mc = MACHINE_GET_CLASS(mch);
>  
> -/* Initialize CPU (if a model has been specified) */
> -if (mch->cpu_model) {
> -cpu = cpu_init(mch->cpu_model);
> +/* Initialize CPU if cpu_type pointer is user provided
> + * (i.e. != to pointer tot static default cpu type string)
> + */
> +if (mch->cpu_type != mc->default_cpu_type) {
> +cpu = cpu_create(mch->cpu_type);

This is a big assumption about the code that sets mch->cpu_type.
A simple g_strdup(machine_class->default_cpu_type) would break
this silently (as it won't trigger the assert() below).


>  if (!cpu) {
>  error_report("Unable to initialize CPU");
>  exit(1);
> @@ -54,6 +57,7 @@ static void machine_none_machine_init(MachineClass *mc)
>  mc->init = machine_none_init;
>  mc->max_cpus = 1;
>  mc->default_ram_size = 0;
> +mc->default_cpu_type = TARGET_DEFAULT_CPU_TYPE;

Why do you need this?  Isn't it simpler to just leave
default_cpu_type=NULL here?


>  }
>  
>  DEFINE_MACHINE("none", machine_none_machine_init)
> diff --git a/vl.c b/vl.c
> index 2586f25..8aa0131 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -4609,7 +4609,6 @@ int main(int argc, char **argv, char **envp)
>  current_machine->maxram_size = maxram_size;
>  current_machine->ram_slots = ram_slots;
>  current_machine->boot_order = boot_order;
> -current_machine->cpu_model = cpu_model;
>  
>  parse_numa_opts(current_machine);
>  
> @@ -4619,6 +4618,13 @@ int main(int argc, char **argv, char **envp)
>  if (cpu_model) {
>  current_machine->cpu_type =
>  cpu_parse_cpu_model(machine_class->default_cpu_type, 
> cpu_model);
> +
> +/* machine 'none' depends on default cpu type pointer not being
> + * equal to resolved type name pointer to fugure out if type was
> + * user provided, make sure that if it becomes not true in future
> + * it won't beark silently */
> +g_assert(
> +current_machine->cpu_type != 
> machine_class->default_cpu_type);
>  }
>  }
>  
> -- 
> 2.7.4
> 

-- 
Eduardo