From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@citrix.com>
Subject: Re: [PATCH] ignore writes to GICD_ICACTIVER ...
	GICD_ICACTIVERN
Date: Thu, 3 Dec 2015 11:25:21 +0000
Message-ID: <566026A1.9010608@citrix.com>
References: <alpine.DEB.2.02.1512031058001.11598@kaball.uk.xensource.com>
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To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>, xen-devel@lists.xensource.com
Cc: Ian Campbell <Ian.Campbell@citrix.com>
List-Id: xen-devel@lists.xenproject.org

Hi Stefano,

On 03/12/15 11:02, Stefano Stabellini wrote:
> Injecting a fault to the guest just because it is writing to one of the
> GICD_ICACTIVER registers, which are part of the GICv2 and GICv3 specs,
> is harsh. Additionally it causes recent linux kernels to fail to boot on
> Xen.
> 
> Ignore writes to GICD_ICACTIVER ... GICD_ICACTIVERN instead, to solve
> the boot issue and for backportability. However implementing the
> registers properly might a better long term solution.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

Please rebase this patch on top of staging.

Regards,

> 
> diff --git a/xen/arch/arm/vgic-v2.c b/xen/arch/arm/vgic-v2.c
> index b5a8f29..bf9f239 100644
> --- a/xen/arch/arm/vgic-v2.c
> +++ b/xen/arch/arm/vgic-v2.c
> @@ -315,11 +315,10 @@ static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
>          return 0;
>  
>      case GICD_ICACTIVER ... GICD_ICACTIVERN:
> -        if ( dabt.size != DABT_WORD ) goto bad_width;
> -        printk(XENLOG_G_ERR
> +        gdprintk(XENLOG_DEBUG,
>                 "%pv: vGICD: unhandled word write %#"PRIregister" to ICACTIVER%d\n",
>                 v, *r, gicd_reg - GICD_ICACTIVER);
> -        return 0;
> +        goto write_ignore_32;
>  
>      case GICD_ITARGETSR ... GICD_ITARGETSR + 7:
>          /* SGI/PPI target is read only */
> diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
> index 45a46c3..e115027 100644
> --- a/xen/arch/arm/vgic-v3.c
> +++ b/xen/arch/arm/vgic-v3.c
> @@ -412,11 +412,10 @@ static int __vgic_v3_distr_common_mmio_write(const char *name, struct vcpu *v,
>          return 0;
>  
>      case GICD_ICACTIVER ... GICD_ICACTIVERN:
> -        if ( dabt.size != DABT_WORD ) goto bad_width;
> -        printk(XENLOG_G_ERR
> +        gdprintk(XENLOG_DEBUG,
>                 "%pv: %s: unhandled word write %#"PRIregister" to ICACTIVER%d\n",
>                 v, name, *r, reg - GICD_ICACTIVER);
> -        return 0;
> +        goto write_ignore_32;
>  
>      case GICD_IPRIORITYR ... GICD_IPRIORITYRN:
>          if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
> 
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> 


-- 
Julien Grall