[PATCH v2] xen/arm: gic-v3: No need to sort the Redistributor regions

[PATCH v2] xen/arm: gic-v3: No need to sort the Redistributor regions

[Julien Grall]

The sorting was required by the vGIC emulation until commit
9b9d51e98edb8c5c731e2d06dfad3633053d88a4 "xen/arm: vgic-v3:
Correctly retrieve the vCPU associated to a re-distributor".

Furthermore, the code is buggy because both local variables 'l' and 'r'
point to the same region.

So drop the code which sort the Redistributors array.

Reported-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Julien Grall <julien.grall@arm.com>

---
    Changes in v2:
        - Fix compilation with ACPI
---
 xen/arch/arm/gic-v3.c | 14 --------------
 1 file changed, 14 deletions(-)

diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index dfc62e8..b8a4bde 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -1134,14 +1134,6 @@ static const hw_irq_controller gicv3_guest_irq_type = {
     .set_affinity = gicv3_irq_set_affinity,
 };
 
-static int __init cmp_rdist(const void *a, const void *b)
-{
-    const struct rdist_region *l = a, *r = a;
-
-    /* We assume that re-distributor regions can never overlap */
-    return ( l->base < r->base) ? -1 : 0;
-}
-
 static paddr_t __initdata dbase = INVALID_PADDR;
 static paddr_t __initdata vbase = INVALID_PADDR, vsize = 0;
 static paddr_t __initdata cbase = INVALID_PADDR, csize = 0;
@@ -1210,9 +1202,6 @@ static void __init gicv3_dt_init(void)
         rdist_regs[i].size = rdist_size;
     }
 
-    /* The vGIC code requires the region to be sorted */
-    sort(rdist_regs, gicv3.rdist_count, sizeof(*rdist_regs), cmp_rdist, NULL);
-
     if ( !dt_property_read_u32(node, "redistributor-stride", &gicv3.rdist_stride) )
         gicv3.rdist_stride = 0;
 
@@ -1455,9 +1444,6 @@ static void __init gicv3_acpi_init(void)
         rdist_regs[i].size = gic_rdist->length;
     }
 
-    /* The vGIC code requires the region to be sorted */
-    sort(rdist_regs, gicv3.rdist_count, sizeof(*rdist_regs), cmp_rdist, NULL);
-
     gicv3.rdist_regions= rdist_regs;
 
     /* Collect CPU base addresses */
-- 
1.9.1


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Re: [PATCH v2] xen/arm: gic-v3: No need to sort the Redistributor regions

[Stefano Stabellini]

On Tue, 28 Jun 2016, Julien Grall wrote:
> The sorting was required by the vGIC emulation until commit
> 9b9d51e98edb8c5c731e2d06dfad3633053d88a4 "xen/arm: vgic-v3:
> Correctly retrieve the vCPU associated to a re-distributor".
> 
> Furthermore, the code is buggy because both local variables 'l' and 'r'
> point to the same region.
> 
> So drop the code which sort the Redistributors array.
> 
> Reported-by: Shanker Donthineni <shankerd@codeaurora.org>
> Signed-off-by: Julien Grall <julien.grall@arm.com>

Acked-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
>     Changes in v2:
>         - Fix compilation with ACPI
> ---
>  xen/arch/arm/gic-v3.c | 14 --------------
>  1 file changed, 14 deletions(-)
> 
> diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
> index dfc62e8..b8a4bde 100644
> --- a/xen/arch/arm/gic-v3.c
> +++ b/xen/arch/arm/gic-v3.c
> @@ -1134,14 +1134,6 @@ static const hw_irq_controller gicv3_guest_irq_type = {
>      .set_affinity = gicv3_irq_set_affinity,
>  };
>  
> -static int __init cmp_rdist(const void *a, const void *b)
> -{
> -    const struct rdist_region *l = a, *r = a;
> -
> -    /* We assume that re-distributor regions can never overlap */
> -    return ( l->base < r->base) ? -1 : 0;
> -}
> -
>  static paddr_t __initdata dbase = INVALID_PADDR;
>  static paddr_t __initdata vbase = INVALID_PADDR, vsize = 0;
>  static paddr_t __initdata cbase = INVALID_PADDR, csize = 0;
> @@ -1210,9 +1202,6 @@ static void __init gicv3_dt_init(void)
>          rdist_regs[i].size = rdist_size;
>      }
>  
> -    /* The vGIC code requires the region to be sorted */
> -    sort(rdist_regs, gicv3.rdist_count, sizeof(*rdist_regs), cmp_rdist, NULL);
> -
>      if ( !dt_property_read_u32(node, "redistributor-stride", &gicv3.rdist_stride) )
>          gicv3.rdist_stride = 0;
>  
> @@ -1455,9 +1444,6 @@ static void __init gicv3_acpi_init(void)
>          rdist_regs[i].size = gic_rdist->length;
>      }
>  
> -    /* The vGIC code requires the region to be sorted */
> -    sort(rdist_regs, gicv3.rdist_count, sizeof(*rdist_regs), cmp_rdist, NULL);
> -
>      gicv3.rdist_regions= rdist_regs;
>  
>      /* Collect CPU base addresses */
> -- 
> 1.9.1
> 

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