Re: [Xen-devel] [PATCH V6 10/10] xen/arm64: increase MAX_VIRT_CPUS to 128 on arm64

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Mon, 2015-06-01 at 20:56 +0800, Chen Baozi wrote:
> From: Chen Baozi <baozich@xxxxxxxxx>
> 
> After we have increased the size of GICR in address space for guest
> and made use of both AFF0 and AFF1 in (v)MPIDR, we are now able to
> support up to 4096 vCPUs in theory. However, it will cost 512M
> address space for GICR region, which is not necessary big at the
> moment.

"which is unnecessarily big at the moment"

>  Considering the max CPU number that GIC-500 can support and
> the old value of MAX_VIRT_CPUS before commit aa25a61, we increase
> its value to 128.
> 
> Since the domain_max_vcpus has been changed to depends on vgic_ops,

"depend"

> we could have done more work in order to drop the definition of
> MAX_VIRT_CPUS. However, because it is still used for some conditional
> compilation in common code, I think that would be better done in a
> seperate cleanup patch series.

"separate"

(although, I think you could just omit the last paragraph from the
formal commit log and move it below the ---).

> 
> Signed-off-by: Chen Baozi <baozich@xxxxxxxxx>
> ---
>  xen/arch/arm/vgic-v3.c       | 1 -
>  xen/include/asm-arm/config.h | 4 ++++
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
> index 50dcfc9..2be9f81 100644
> --- a/xen/arch/arm/vgic-v3.c
> +++ b/xen/arch/arm/vgic-v3.c
> @@ -895,7 +895,6 @@ 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;
> -        BUG_ON(v->domain->max_vcpus > 8);
>          new_irouter = *r;
>          vgic_lock_rank(v, rank, flags);
>  
> diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
> index 3b23e05..817c216 100644
> --- a/xen/include/asm-arm/config.h
> +++ b/xen/include/asm-arm/config.h
> @@ -47,7 +47,11 @@
>  #define NR_CPUS 128
>  #endif
>  
> +#ifdef CONFIG_ARM_64
> +#define MAX_VIRT_CPUS 128
> +#else
>  #define MAX_VIRT_CPUS 8
> +#endif
>  
>  #define asmlinkage /* Nothing needed */
>  



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