Re: [Xen-devel] [PATCH v2 04/45] xen/arm: vgic: Override the group in lr everytime

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 15 Mar 2018, Andre Przywara wrote:
> From: Julien Grall <julien.grall@xxxxxxx>
> 
> At the moment, write_lr is assuming the caller will set correctly the
> group. However the group should always be 0 when the guest is using
> vGICv2 and 1 for vGICv3. As the caller should not care about the group,
> override it directly.
> 
> With that change, write_lr is now behaving like update_lr for the group.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> Changes:
> - Add Andre's reviewed-by
> 
>  xen/arch/arm/gic-v2.c     |  4 +---
>  xen/arch/arm/gic-v3.c     | 11 ++++++++---
>  xen/include/asm-arm/gic.h |  1 -
>  3 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/xen/arch/arm/gic-v2.c b/xen/arch/arm/gic-v2.c
> index f16e17c1a3..fc105c08b8 100644
> --- a/xen/arch/arm/gic-v2.c
> +++ b/xen/arch/arm/gic-v2.c
> @@ -469,7 +469,6 @@ static void gicv2_read_lr(int lr, struct gic_lr *lr_reg)
>      lr_reg->priority = (lrv >> GICH_V2_LR_PRIORITY_SHIFT) & 
> GICH_V2_LR_PRIORITY_MASK;
>      lr_reg->state     = (lrv >> GICH_V2_LR_STATE_SHIFT) & 
> GICH_V2_LR_STATE_MASK;
>      lr_reg->hw_status = (lrv >> GICH_V2_LR_HW_SHIFT) & GICH_V2_LR_HW_MASK;
> -    lr_reg->grp       = (lrv >> GICH_V2_LR_GRP_SHIFT) & GICH_V2_LR_GRP_MASK;
>  }
>  
>  static void gicv2_write_lr(int lr, const struct gic_lr *lr_reg)
> @@ -483,8 +482,7 @@ static void gicv2_write_lr(int lr, const struct gic_lr 
> *lr_reg)
>            ((uint32_t)(lr_reg->state & GICH_V2_LR_STATE_MASK)
>                                     << GICH_V2_LR_STATE_SHIFT) |
>            ((uint32_t)(lr_reg->hw_status & GICH_V2_LR_HW_MASK)
> -                                       << GICH_V2_LR_HW_SHIFT)  |
> -          ((uint32_t)(lr_reg->grp & GICH_V2_LR_GRP_MASK) << 
> GICH_V2_LR_GRP_SHIFT) );
> +                                       << GICH_V2_LR_HW_SHIFT));
>  
>      writel_gich(lrv, GICH_LR + lr * 4);
>  }
> diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
> index 09b49a07d5..0dfa1a1e08 100644
> --- a/xen/arch/arm/gic-v3.c
> +++ b/xen/arch/arm/gic-v3.c
> @@ -1012,7 +1012,6 @@ static void gicv3_read_lr(int lr, struct gic_lr *lr_reg)
>      lr_reg->priority  = (lrv >> ICH_LR_PRIORITY_SHIFT) & 
> ICH_LR_PRIORITY_MASK;
>      lr_reg->state     = (lrv >> ICH_LR_STATE_SHIFT) & ICH_LR_STATE_MASK;
>      lr_reg->hw_status = (lrv >> ICH_LR_HW_SHIFT) & ICH_LR_HW_MASK;
> -    lr_reg->grp       = (lrv >> ICH_LR_GRP_SHIFT) & ICH_LR_GRP_MASK;
>  }
>  
>  static void gicv3_write_lr(int lr_reg, const struct gic_lr *lr)
> @@ -1023,8 +1022,14 @@ static void gicv3_write_lr(int lr_reg, const struct 
> gic_lr *lr)
>          ((u64)(lr->virq & ICH_LR_VIRTUAL_MASK)  << ICH_LR_VIRTUAL_SHIFT) |
>          ((u64)(lr->priority & ICH_LR_PRIORITY_MASK) << 
> ICH_LR_PRIORITY_SHIFT)|
>          ((u64)(lr->state & ICH_LR_STATE_MASK) << ICH_LR_STATE_SHIFT) |
> -        ((u64)(lr->hw_status & ICH_LR_HW_MASK) << ICH_LR_HW_SHIFT)  |
> -        ((u64)(lr->grp & ICH_LR_GRP_MASK) << ICH_LR_GRP_SHIFT) );
> +        ((u64)(lr->hw_status & ICH_LR_HW_MASK) << ICH_LR_HW_SHIFT) );
> +
> +    /*
> +     * When the guest is using vGICv3, all the IRQs are Group 1. Group 0
> +     * would result in a FIQ, which will not be expected by the guest OS.
> +     */
> +    if ( current->domain->arch.vgic.version == GIC_V3 )
> +        lrv |= ICH_LR_GRP1;
>  
>      gicv3_ich_write_lr(lr_reg, lrv);
>  }
> diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h
> index 49cb94f792..1eb08b856e 100644
> --- a/xen/include/asm-arm/gic.h
> +++ b/xen/include/asm-arm/gic.h
> @@ -211,7 +211,6 @@ struct gic_lr {
>     uint8_t priority;
>     uint8_t state;
>     uint8_t hw_status;
> -   uint8_t grp;
>  };
>  
>  enum gic_version {
> -- 
> 2.14.1
> 

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