Re: [Xen-devel] [PATCH 14/38] arm: do not set max_vcpus = 8 in arch_domain_create.

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Thu, 7 Jun 2012, Ian Campbell wrote:
> On Wed, 2012-06-06 at 16:26 +0100, Stefano Stabellini wrote:
> > On Fri, 1 Jun 2012, Ian Campbell wrote:
> > > XEN_DOMCTL_max_vcpus cannot reduce max_vcpus and therefore we can't 
> > > create a
> > > smaller guest.
> > > 
> > > The limit of 8 (due to GIC limits) should be expressed elsewhere, likely 
> > > in
> > > MAX_VIRT_CPUS -- but making that change caused:
> > 
> > Are you sure? I made that change and I didn't see the error.
> > I think this patch should set MAX_VIRT_CPUS to 8 as well as removing
> > max_vcpus = 8.
> 
> This was the same heap corruption again as seen in "[PATCH 16/38] arm:
> Add simple cpu_{sibling,core}_mask"  and having fixed that I don't see
> the crash with MAX_VIRT_CPUS == 8 any more...
> 
> The patch becomes:
> 
> From b68c4abe1dec44f3ed87a0d7ae98f4269043cce3 Mon Sep 17 00:00:00 2001
> From: Ian Campbell <ian.campbell@xxxxxxxxxx>
> Date: Thu, 7 Jun 2012 16:52:46 +0000
> Subject: [PATCH] arm: do not set max_vcpus = 8 in arch_domain_create.
> 
> XEN_DOMCTL_max_vcpus cannot reduce max_vcpus and therefore we can't create a
> smaller guest.
> 
> The limit of 8 (due to GIC limits) should be expressed in MAX_VIRT_CPUS.
> 
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>


Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

>  xen/arch/arm/domain.c        |    2 --
>  xen/include/asm-arm/config.h |    2 +-
>  2 files changed, 1 insertions(+), 3 deletions(-)
> 
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 1336dc4..040a2ce 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -338,8 +338,6 @@ int arch_domain_create(struct domain *d, unsigned int 
> domcr_flags)
>              goto fail;
>      }
>  
> -    d->max_vcpus = 8;
> -
>      if ( (rc = domain_vgic_init(d)) != 0 )
>          goto fail;
>  
> diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
> index 91e87e1..7d02cc7 100644
> --- a/xen/include/asm-arm/config.h
> +++ b/xen/include/asm-arm/config.h
> @@ -27,7 +27,7 @@
>  #define NR_CPUS 128
>  #endif
>  
> -#define MAX_VIRT_CPUS 128 /* XXX */
> +#define MAX_VIRT_CPUS 8
>  #define MAX_HVM_VCPUS MAX_VIRT_CPUS
>  
>  #define asmlinkage /* Nothing needed */
> -- 
> 1.7.9.1
> 
> 
> 
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel