Re: [Qemu-devel] [RFC v1 06/12] cpus: pass CPUState to run_on_cpu helpers

[Eduardo Habkost]

On Fri, Apr 15, 2016 at 03:23:45PM +0100, Alex Bennée wrote:
> CPUState is a fairly common pointer to pass to these helpers. This means
> if you need other arguments for the async_run_on_cpu case you end up
> having to do a g_malloc to stuff additional data into the routine. For
> the current users this isn't a massive deal but for MTTCG this gets
> cumbersome when the only other parameter is often an address.
> 
> This adds the typedef run_on_cpu_func for helper functions which has an
> explicit CPUState * passed as the first parameter. All the users of
> run_on_cpu and async_run_on_cpu have had their helpers updated to use
> CPUState where available.
> 
> Signed-off-by: Alex Bennée <address@hidden>
> ---
>  cpus.c                | 15 +++++++--------
>  hw/i386/kvm/apic.c    |  3 +--
>  hw/i386/kvmvapic.c    |  8 ++++----
>  hw/ppc/ppce500_spin.c |  3 +--
>  hw/ppc/spapr.c        |  6 ++----
>  hw/ppc/spapr_hcall.c  | 12 +++++-------
>  include/qom/cpu.h     |  8 +++++---
>  kvm-all.c             | 20 +++++++-------------
>  target-i386/helper.c  |  3 +--
>  target-i386/kvm.c     |  6 ++----
>  target-s390x/cpu.c    |  4 ++--
>  target-s390x/cpu.h    |  7 ++-----

What about target-s390x/kvm.c and target-s390x/misc_helper.c?

A few other minor comments/questions below. But the patch looks
good overall.

>  12 files changed, 39 insertions(+), 56 deletions(-)
> 
[...]
> diff --git a/hw/ppc/ppce500_spin.c b/hw/ppc/ppce500_spin.c
> index 76bd78b..e2aeef3 100644
> --- a/hw/ppc/ppce500_spin.c
> +++ b/hw/ppc/ppce500_spin.c
> @@ -94,10 +94,9 @@ static void mmubooke_create_initial_mapping(CPUPPCState 
> *env,
>      env->tlb_dirty = true;
>  }
>  
> -static void spin_kick(void *data)
> +static void spin_kick(CPUState *cpu, void *data)
>  {
>      SpinKick *kick = data;
> -    CPUState *cpu = CPU(kick->cpu);
>      CPUPPCState *env = &kick->cpu->env;

I would set env = &cpu->env to avoid confusion. Then the SpinKick
struct can be removed completely.

>      SpinInfo *curspin = kick->spin;
>      hwaddr map_size = 64 * 1024 * 1024;
[...]
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index 2dcb676..4b7fbb7 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -10,19 +10,18 @@
>  #include "kvm_ppc.h"
>  
>  struct SPRSyncState {
> -    CPUState *cs;
>      int spr;
>      target_ulong value;
>      target_ulong mask;
>  };
>  
> -static void do_spr_sync(void *arg)
> +static void do_spr_sync(CPUState *cs, void *arg)
>  {
>      struct SPRSyncState *s = arg;
> -    PowerPCCPU *cpu = POWERPC_CPU(s->cs);
> +    PowerPCCPU *cpu = POWERPC_CPU(cs);
>      CPUPPCState *env = &cpu->env;
>  
> -    cpu_synchronize_state(s->cs);
> +    cpu_synchronize_state(cs);
>      env->spr[s->spr] &= ~s->mask;
>      env->spr[s->spr] |= s->value;
>  }
> @@ -31,7 +30,6 @@ static void set_spr(CPUState *cs, int spr, target_ulong 
> value,
>                      target_ulong mask)
>  {
>      struct SPRSyncState s = {
> -        .cs = cs,
>          .spr = spr,
>          .value = value,
>          .mask = mask
> @@ -911,11 +909,11 @@ typedef struct {
>      Error *err;
>  } SetCompatState;
>  
> -static void do_set_compat(void *arg)
> +static void do_set_compat(CPUState *cs, void *arg)
>  {
>      SetCompatState *s = arg;
>  
> -    cpu_synchronize_state(CPU(s->cpu));
> +    cpu_synchronize_state(cs);
>      ppc_set_compat(s->cpu, s->cpu_version, &s->err);

This is not incorrect, but inconsistent: you replaced s->cpu
usage on the first line, but kept using s->cpu in the second
line.

Is there a specific reason you removed SPRSyncState.cs but kept
SetCompatState.cpu?


>  }
>  
[...]
> diff --git a/target-i386/helper.c b/target-i386/helper.c
> index 5755839..1b50f59 100644
> --- a/target-i386/helper.c
> +++ b/target-i386/helper.c
> @@ -1117,11 +1117,10 @@ typedef struct MCEInjectionParams {
>      int flags;
>  } MCEInjectionParams;
>  
> -static void do_inject_x86_mce(void *data)
> +static void do_inject_x86_mce(CPUState *cpu, void *data)
>  {
>      MCEInjectionParams *params = data;
>      CPUX86State *cenv = &params->cpu->env;

I would eliminate MCEInjectionParams.cpu and set cenv = &cpu->env
above, to avoid confusion.

> -    CPUState *cpu = CPU(params->cpu);
>      uint64_t *banks = cenv->mce_banks + 4 * params->bank;
>  
>      cpu_synchronize_state(cpu);
[...]
> diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
> index 6d97c08..2112994 100644
> --- a/target-s390x/cpu.h
> +++ b/target-s390x/cpu.h
> @@ -454,17 +454,14 @@ static inline hwaddr decode_basedisp_s(CPUS390XState 
> *env, uint32_t ipb,
>  #define decode_basedisp_rs decode_basedisp_s
>  
>  /* helper functions for run_on_cpu() */
> -static inline void s390_do_cpu_reset(void *arg)
> +static inline void s390_do_cpu_reset(CPUState *cs, void *arg)
>  {
> -    CPUState *cs = arg;
>      S390CPUClass *scc = S390_CPU_GET_CLASS(cs);
>  
>      scc->cpu_reset(cs);
>  }
> -static inline void s390_do_cpu_full_reset(void *arg)
> +static inline void s390_do_cpu_full_reset(CPUState *cs, void *arg)
>  {
> -    CPUState *cs = arg;
> -
>      cpu_reset(cs);
>  }

The run_on_cpu callers at target-s390x/misc_helper.c still pass
an unnecessary non-NULL void* argument, making the code
confusing.

-- 
Eduardo