Re: [Xen-devel] [PATCH v4 23/25] arm: vgic emulation

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2012-01-09 at 18:25 +0000, David Vrabel wrote:
> On 09/01/12 17:59, stefano.stabellini@xxxxxxxxxxxxx wrote:
> > 
> > +static int vgic_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
> > +{
> [...]
> > +    case GICD_ICFGR ... GICD_ICFGRN:
> > +        if ( dabt.size != 2 ) goto bad_width;
> > +        rank = vgic_irq_rank(v, 2, gicd_reg - GICD_ICFGR);
> > +        if ( rank == NULL) goto read_as_zero;
> > +        vgic_lock_rank(v, rank);
> > +        *r = rank->icfg[REG_RANK_INDEX(2, gicd_reg - GICD_ICFGR)];
> > +        vgic_unlock_rank(v, rank);
> > +        return 0;
> 
> This needs to return 1 or recent kernels will crash when they try and
> read these registers.
> 
> David
> 
> From 8c2377a9b4a10cba57fba9f8a19177ac73339d78 Mon Sep 17 00:00:00 2001
> From: David Vrabel <david.vrabel@xxxxxxxxxx>
> Date: Mon, 9 Jan 2012 15:17:22 +0000
> Subject: [PATCH] ARM: allow guest to read GICD_ICFGRn registers
> 
> Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

> ---
>  xen/arch/arm/vgic.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
> index 26eae55..584e682 100644
> --- a/xen/arch/arm/vgic.c
> +++ b/xen/arch/arm/vgic.c
> @@ -266,7 +266,7 @@ static int vgic_distr_mmio_read(struct vcpu *v,
> mmio_info_t *info)
>          vgic_lock_rank(v, rank);
>          *r = rank->icfg[REG_RANK_INDEX(2, gicd_reg - GICD_ICFGR)];
>          vgic_unlock_rank(v, rank);
> -        return 0;
> +        return 1;
> 
>      case GICD_NSACR ... GICD_NSACRN:
>          /* We do not implement securty extensions for guests, read zero */



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