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Re: [Xen-devel] [PATCH v3] xen/arm: Deliver interrupts to vcpu specified in IROUTER



On Thu, 25 Sep 2014, vijay.kilari@xxxxxxxxx wrote:
> From: Vijaya Kumar K <Vijaya.Kumar@xxxxxxxxxxxxxxxxxx>
> 
> In GICv3 use IROUTER register contents to deliver irq to
> specified vcpu.
> 
> vgic irouter[irq] is used to represent vcpu number for which
> irq affinity is assigned. Bit[31] is used to store IROUTER
> bit[31] value to represent irq mode.
> 
> This patch is similar to Stefano's commit
> 5b3a817ea33b891caf7d7d788da9ce6deffa82a1 for GICv2
> 
> Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@xxxxxxxxxxxxxxxxxx>
> ---
> v3: -Removed assert and add check for irouter value in mmio write.
>     -Added back and used affinity value for vgic irouter[]
>      initialization.
> ---
>  xen/arch/arm/vgic-v3.c |  113 
> ++++++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 96 insertions(+), 17 deletions(-)
> 
> diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
> index dd70591..c9739f4 100644
> --- a/xen/arch/arm/vgic-v3.c
> +++ b/xen/arch/arm/vgic-v3.c
> @@ -45,10 +45,42 @@
>  #define GICV3_GICR_PIDR2  GICV3_GICD_PIDR2
>  #define GICV3_GICR_PIDR4  GICV3_GICD_PIDR4
>  
> +static struct vcpu *vgic_v3_irouter_to_vcpu(struct vcpu *v, uint64_t irouter)
> +{
> +    irouter &= ~(GICD_IROUTER_SPI_MODE_ANY);
> +    irouter = irouter & MPIDR_AFF0_MASK;
> +
> +    return v->domain->vcpu[irouter];
> +}
> +
> +static uint64_t vgic_v3_vcpu_to_irouter(struct vcpu *v,
> +                                        unsigned int vcpu_id)
> +{
> +    uint64_t irq_affinity;
> +    struct vcpu *v_target;
> +
> +    v_target = v->domain->vcpu[vcpu_id];
> +    irq_affinity = (MPIDR_AFFINITY_LEVEL(v_target->arch.vmpidr, 3) << 32 |
> +                    MPIDR_AFFINITY_LEVEL(v_target->arch.vmpidr, 2) << 16 |
> +                    MPIDR_AFFINITY_LEVEL(v_target->arch.vmpidr, 1) << 8  |
> +                    MPIDR_AFFINITY_LEVEL(v_target->arch.vmpidr, 0));
> +
> +    return irq_affinity;
> +}
> +
>  static struct vcpu *vgic_v3_get_target_vcpu(struct vcpu *v, unsigned int irq)
>  {
> -    /* TODO: Return vcpu0 always */
> -    return v->domain->vcpu[0];
> +    uint64_t target;
> +    struct vgic_irq_rank *rank = vgic_rank_irq(v, irq);
> +
> +    ASSERT(spin_is_locked(&rank->lock));
> +
> +    target = rank->v3.irouter[irq % 32];
> +    target &= ~(GICD_IROUTER_SPI_MODE_ANY);
> +    target &= MPIDR_AFF0_MASK;
> +    ASSERT(target >= 0 && target < v->domain->max_vcpus);
> +
> +    return v->domain->vcpu[target];
>  }
>  
>  static int __vgic_v3_rdistr_rd_mmio_read(struct vcpu *v, mmio_info_t *info,
> @@ -353,9 +385,9 @@ static int __vgic_v3_distr_common_mmio_write(struct vcpu 
> *v, mmio_info_t *info,
>          vgic_lock_rank(v, rank, flags);
>          tr = rank->ienable;
>          rank->ienable |= *r;
> -        vgic_unlock_rank(v, rank, flags);
>          /* The irq number is extracted from offset. so shift by register 
> size */
>          vgic_enable_irqs(v, (*r) & (~tr), (reg - GICD_ISENABLER) >> 
> DABT_WORD);
> +        vgic_unlock_rank(v, rank, flags);
>          return 1;
>      case GICD_ICENABLER ... GICD_ICENABLERN:
>          if ( dabt.size != DABT_WORD ) goto bad_width;
> @@ -364,9 +396,9 @@ static int __vgic_v3_distr_common_mmio_write(struct vcpu 
> *v, mmio_info_t *info,
>          vgic_lock_rank(v, rank, flags);
>          tr = rank->ienable;
>          rank->ienable &= ~*r;
> -        vgic_unlock_rank(v, rank, flags);
>          /* The irq number is extracted from offset. so shift by register 
> size */
>          vgic_disable_irqs(v, (*r) & tr, (reg - GICD_ICENABLER) >> DABT_WORD);
> +        vgic_unlock_rank(v, rank, flags);
>          return 1;
>      case GICD_ISPENDR ... GICD_ISPENDRN:
>          if ( dabt.size != DABT_WORD ) goto bad_width;
> @@ -620,6 +652,8 @@ static int vgic_v3_distr_mmio_read(struct vcpu *v, 
> mmio_info_t *info)
>      register_t *r = select_user_reg(regs, dabt.reg);
>      struct vgic_irq_rank *rank;
>      unsigned long flags;
> +    uint64_t irouter;
> +    unsigned int vcpu_id;
>      int gicd_reg = (int)(info->gpa - v->domain->arch.vgic.dbase);
>  
>      switch ( gicd_reg )
> @@ -673,8 +707,17 @@ static int vgic_v3_distr_mmio_read(struct vcpu *v, 
> mmio_info_t *info)
>                                  DABT_DOUBLE_WORD);
>          if ( rank == NULL ) goto read_as_zero;
>          vgic_lock_rank(v, rank, flags);
> -        *r = rank->v3.irouter[REG_RANK_INDEX(64,
> -                              (gicd_reg - GICD_IROUTER), DABT_DOUBLE_WORD)];
> +        irouter = rank->v3.irouter[REG_RANK_INDEX(64,
> +                                  (gicd_reg - GICD_IROUTER), 
> DABT_DOUBLE_WORD)];
> +        /* XXX: bit[31] stores IRQ mode. Just return */
> +        if ( irouter & GICD_IROUTER_SPI_MODE_ANY )
> +        {
> +            *r = GICD_IROUTER_SPI_MODE_ANY;
> +            vgic_unlock_rank(v, rank, flags);
> +            return 1;
> +        }
> +        vcpu_id = irouter & MPIDR_AFF0_MASK;

We should just set

vcpu_id = irouter;

as we already filtered by MPIDR_AFF0_MASK when writing to irouter.


> +        *r = vgic_v3_vcpu_to_irouter(v, vcpu_id);
>          vgic_unlock_rank(v, rank, flags);
>          return 1;
>      case GICD_NSACR ... GICD_NSACRN:
> @@ -755,6 +798,9 @@ static int vgic_v3_distr_mmio_write(struct vcpu *v, 
> mmio_info_t *info)
>      register_t *r = select_user_reg(regs, dabt.reg);
>      struct vgic_irq_rank *rank;
>      unsigned long flags;
> +    unsigned int new_target, old_target;
> +    uint64_t new_irouter, old_irouter;
> +    struct vcpu *old_vcpu, *new_vcpu;
>      int gicd_reg = (int)(info->gpa - v->domain->arch.vgic.dbase);
>  
>      switch ( gicd_reg )
> @@ -811,16 +857,43 @@ static int vgic_v3_distr_mmio_write(struct vcpu *v, 
> mmio_info_t *info)
>          rank = vgic_rank_offset(v, 64, gicd_reg - GICD_IROUTER,
>                                  DABT_DOUBLE_WORD);
>          if ( rank == NULL ) goto write_ignore_64;
> -        if ( *r )
> +        BUG_ON(v->domain->max_vcpus > 8);
> +        new_irouter = *r;
> +        vgic_lock_rank(v, rank, flags);
> +
> +        old_irouter = rank->v3.irouter[REG_RANK_INDEX(64,
> +                              (gicd_reg - GICD_IROUTER), DABT_DOUBLE_WORD)];
> +        old_irouter &= ~(GICD_IROUTER_SPI_MODE_ANY);
> +        old_target = old_irouter & MPIDR_AFF0_MASK;

for the same reasion we can just do

old_target = old_irouter

so we can just remove one of the two variables



> +        if ( new_irouter & GICD_IROUTER_SPI_MODE_ANY )
>          {
> -            /* TODO: Ignored. We don't support irq delivery for vcpu != 0 */
> -            gdprintk(XENLOG_DEBUG,
> -                     "SPI delivery to secondary cpus not supported\n");
> -            goto write_ignore_64;
> +            /*
> +             * IRQ routing mode set. Route any one processor in the entire
> +             * system. We chose vcpu 0 and set IRQ mode bit[31] in irouter.
> +             */
> +            new_target = 0;
> +            new_vcpu = v->domain->vcpu[0];
> +            new_irouter = GICD_IROUTER_SPI_MODE_ANY;
> +        }
> +        else
> +        {
> +            new_target = new_irouter & MPIDR_AFF0_MASK;
> +            if ( new_target >= v->domain->max_vcpus )
> +            {
> +                printk("vGICv3: vGICD: wrong irouter at offset %#08x\n",
> +                       gicd_reg);

You need to have:

vgic_unlock_rank(v, rank, flags);

before returning.
This is actually important, the other comments are just aesthetics.

> +                return 0;
> +            }
> +            new_vcpu = vgic_v3_irouter_to_vcpu(v, new_irouter);
> +        }
> +
> +        rank->v3.irouter[REG_RANK_INDEX(64, (gicd_reg - GICD_IROUTER),
> +                         DABT_DOUBLE_WORD)] = new_irouter;
> +        if ( old_target != new_target )
> +        {
> +            old_vcpu = v->domain->vcpu[old_target];
> +            vgic_migrate_irq(old_vcpu, new_vcpu, (gicd_reg - 
> GICD_IROUTER)/8);
>          }
> -        vgic_lock_rank(v, rank, flags);
> -        rank->v3.irouter[REG_RANK_INDEX(64,
> -                      (gicd_reg - GICD_IROUTER), DABT_DOUBLE_WORD)] = *r;
>          vgic_unlock_rank(v, rank, flags);
>          return 1;
>      case GICD_NSACR ... GICD_NSACRN:
> @@ -957,17 +1030,23 @@ static int vgic_v3_vcpu_init(struct vcpu *v)
>                  MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 2) << 16 |
>                  MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 1) << 8  |
>                  MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 0));
> -
> +    /* XXX: Store vcpu_id in AFF0 */
>      for ( i = 0 ; i < 32 ; i++ )
> -        v->arch.vgic.private_irqs->v3.irouter[i] = affinity;
> +        v->arch.vgic.private_irqs->v3.irouter[i] = affinity & 
> MPIDR_AFF0_MASK;


Here it is not useful to filter by MPIDR_AFF0_MASK yet again, correct?
Why not just leave it as it is or even better call vgic_v3_vcpu_to_irouter?


>      return 0;
>  }
>  
>  static int vgic_v3_domain_init(struct domain *d)
>  {
> -    int i;
> +    int i,idx;
>  
> +    /* By default deliver to CPU0 */
> +    for ( i = 0; i < DOMAIN_NR_RANKS(d); i++ )
> +    {
> +        for ( idx = 0; idx < 32; idx++ )
> +            d->arch.vgic.shared_irqs[i].v3.irouter[idx] = 0;
> +    }
>      /* We rely on gicv init to get dbase and size */
>      register_mmio_handler(d, &vgic_distr_mmio_handler, d->arch.vgic.dbase,
>                            d->arch.vgic.dbase_size);
> -- 
> 1.7.9.5
> 

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