Re: [RFC PATCH v1 04/10] arm/xen: move gic save and restore registers to gic driver

[Julien Grall <julien.grall@linaro.org>]

Hello Vijay,

Thanks for the patch.

On 03/19/2014 02:17 PM, vijay.kilari@gmail.com wrote:
> From: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
> 
> gic saved registers are moved to gic driver.
> This required structure is allocated at runtime
> and is saved & restored.
> 
> Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
> ---
>  xen/arch/arm/domain.c        |    3 +++
>  xen/arch/arm/gic.c           |   36 +++++++++++++++++++++++++++++-------
>  xen/include/asm-arm/domain.h |    3 +--
>  xen/include/asm-arm/gic.h    |    1 +
>  4 files changed, 34 insertions(+), 9 deletions(-)
> 
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 82a1e79..292716a 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -466,6 +466,9 @@ int vcpu_initialise(struct vcpu *v)
>      v->arch.saved_context.sp = (register_t)v->arch.cpu_info;
>      v->arch.saved_context.pc = (register_t)continue_new_vcpu;
>  
> +    if ( (rc = vcpu_gic_init(v)) != 0 )
> +        return rc;
> +
>      /* Idle VCPUs don't need the rest of this setup */
>      if ( is_idle_vcpu(v) )
>          return rc;
> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> index 4be0897..973fcf9 100644
> --- a/xen/arch/arm/gic.c
> +++ b/xen/arch/arm/gic.c
> @@ -41,6 +41,13 @@
>  #define GICH ((volatile uint32_t *) FIXMAP_ADDR(FIXMAP_GICH))
>  static void gic_restore_pending_irqs(struct vcpu *v);
>  
> +struct gic_state_data {
> +    uint32_t gic_hcr;
> +    uint32_t gic_vmcr;
> +    uint32_t gic_apr;
> +    uint32_t gic_lr[64];
> +};
> +

Can you move this structure in a gic_v2 header?

>  /* Global state */
>  static struct {
>      paddr_t dbase;       /* Address of distributor registers */
> @@ -98,6 +105,9 @@ irq_desc_t *__irq_to_desc(int irq)
>  void gic_save_state(struct vcpu *v)
>  {
>      int i;
> +    struct gic_state_data *d;
> +    d = (struct gic_state_data *)v->arch.gic_state;
> +

You don't need the cast. Can you also rename d in state? Using d is very
confusing as it's a common alias used for domain.

struct gic_state_data *d = v->arch.gic_state;

>      ASSERT(!local_irq_is_enabled());
>  
>      /* No need for spinlocks here because interrupts are disabled around
> @@ -105,10 +115,10 @@ void gic_save_state(struct vcpu *v)
>       * accessed simultaneously by another pCPU.
>       */
>      for ( i=0; i<nr_lrs; i++)
> -        v->arch.gic_lr[i] = GICH[GICH_LR + i];
> +        d->gic_lr[i] = GICH[GICH_LR + i];
>      v->arch.lr_mask = this_cpu(lr_mask);
> -    v->arch.gic_apr = GICH[GICH_APR];
> -    v->arch.gic_vmcr = GICH[GICH_VMCR];
> +    d->gic_apr = GICH[GICH_APR];
> +    d->gic_vmcr = GICH[GICH_VMCR];
>      /* Disable until next VCPU scheduled */
>      GICH[GICH_HCR] = 0;
>      isb();
> @@ -117,15 +127,17 @@ void gic_save_state(struct vcpu *v)
>  void gic_restore_state(struct vcpu *v)
>  {
>      int i;
> +    struct gic_state_data *d;
> +    d = (struct gic_state_data *)v->arch.gic_state;

Same comments here.

>  
>      if ( is_idle_vcpu(v) )
>          return;
>  
>      this_cpu(lr_mask) = v->arch.lr_mask;
>      for ( i=0; i<nr_lrs; i++)
> -        GICH[GICH_LR + i] = v->arch.gic_lr[i];
> -    GICH[GICH_APR] = v->arch.gic_apr;
> -    GICH[GICH_VMCR] = v->arch.gic_vmcr;
> +        GICH[GICH_LR + i] = d->gic_lr[i];
> +    GICH[GICH_APR] = d->gic_apr;
> +    GICH[GICH_VMCR] = d->gic_vmcr;
>      GICH[GICH_HCR] = GICH_HCR_EN;
>      isb();
>  
> @@ -877,6 +889,14 @@ void gic_interrupt(struct cpu_user_regs *regs, int is_fiq)
>      } while (1);
>  }
>  
> +int vcpu_gic_init(struct vcpu *v)
> +{
> +     v->arch.gic_state = xzalloc(struct gic_state_data);
> +     if(!v->arch.gic_state)

Coding style
if ( .. )

> +        return -ENOMEM;
> +     return 0;
> +}
> +

Where is the function to free v->arch.gic_state when the domain is
destroyed?

>  int gicv_setup(struct domain *d)
>  {
>      int ret;
> @@ -1001,6 +1021,8 @@ void gic_dump_info(struct vcpu *v)
>  {
>      int i;
>      struct pending_irq *p;
> +    struct gic_state_data *d;
> +    d = (struct gic_state_data *)v->arch.gic_state;

Don't need the cast and can you rename the d variable?

Regards,

-- 
Julien Grall