Re: [Xen-devel] [PATCH v2] ignore writes to GICD_ICACTIVER ... GICD_ICACTIVERN

[Julien Grall <julien.grall@xxxxxxxxxx>]

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@xxxxxxxxxxxxx>
>
> ---
>
> 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

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