On Thu, Jan 18, 2018 at 11:10:35AM +0100, Igor Mammedov wrote: > On Wed, 17 Jan 2018 23:48:46 -0200 > Eduardo Habkost <ehabk...@redhat.com> 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 <imamm...@redhat.com> > > > --- > > > CC: Eduardo Habkost <ehabk...@redhat.com> > > > CC: Marcel Apfelbaum <mar...@redhat.com> > > > CC: Paolo Bonzini <pbonz...@redhat.com> > > > --- > > > 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 for proxy type in > cpu_parse_cpu_model() > we can drop this ugliness in null-machine. I'd prefer to not introduce this ugliness in the first place. > > 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. To be honest, I don't think the harm in having new code using MachineState::cpu_model is so big to justify this hack. > > > > } > > > > > > 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