From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@citrix.com>
Subject: Re: [PATCH v2] ignore writes to GICD_ICACTIVER ...
	GICD_ICACTIVERN
Date: Fri, 4 Dec 2015 12:38:02 +0000
Message-ID: <5661892A.3020803@citrix.com>
References: <alpine.DEB.2.02.1512041233130.11598@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:

Can you please add xen/arm in the commit title?

On 04/12/2015 12:36, 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>
>
> ---
>
> Changes in v2:
> - rebase on staging
>
> diff --git a/xen/arch/arm/vgic-v2.c b/xen/arch/arm/vgic-v2.c
> index 2c73133..3079901 100644
> --- a/xen/arch/arm/vgic-v2.c
> +++ b/xen/arch/arm/vgic-v2.c
> @@ -494,11 +494,10 @@ static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info,
>           return 0;
>
>       case VRANGE32(GICD_ICACTIVER, GICD_ICACTIVERN):
> -        if ( dabt.size != DABT_WORD ) goto bad_width;
> -        printk(XENLOG_G_ERR
> +        gdprintk(XENLOG_DEBUG,

Why did you  move to gdprintk? The vCPU is already printed using %pv in 
the string.

>                  "%pv: vGICD: unhandled word write %#"PRIregister" to ICACTIVER%d\n",
>                  v, r, gicd_reg - GICD_ICACTIVER);
> -        return 0;
> +        goto write_ignore_32;
>
>       case VRANGE32(GICD_IPRIORITYR, GICD_IPRIORITYRN):
>       {
> diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
> index 985e866..6011e9e 100644
> --- a/xen/arch/arm/vgic-v3.c
> +++ b/xen/arch/arm/vgic-v3.c
> @@ -621,11 +621,10 @@ static int __vgic_v3_distr_common_mmio_write(const char *name, struct vcpu *v,
>           return 0;
>
>       case VRANGE32(GICD_ICACTIVER, GICD_ICACTIVERN):
> -        if ( dabt.size != DABT_WORD ) goto bad_width;
> -        printk(XENLOG_G_ERR
> +        gdprintk(XENLOG_DEBUG,

Ditto

>                  "%pv: %s: unhandled word write %#"PRIregister" to ICACTIVER%d\n",
>                  v, name, r, reg - GICD_ICACTIVER);
> -        return 0;
> +        goto write_ignore_32;
>
>       case VRANGE32(GICD_IPRIORITYR, GICD_IPRIORITYRN):
>       {
>

Regards,

-- 
Julien Grall