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Date:   Wed, 05 Feb 2020 12:43:51 +0000
From:   Marc Zyngier <maz@kernel.org>
To:     Zenghui Yu <yuzenghui@huawei.com>
Cc:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        kvmarm@lists.cs.columbia.edu, tglx@linutronix.de,
        jason@lakedaemon.net, wanghaibin.wang@huawei.com
Subject: Re: [PATCH 1/5] irqchip/gic-v4.1: Fix programming of
 GICR_VPROPBASER_4_1_SIZE
In-Reply-To: <20200204090940.1225-2-yuzenghui@huawei.com>
References: <20200204090940.1225-1-yuzenghui@huawei.com>
 <20200204090940.1225-2-yuzenghui@huawei.com>
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On 2020-02-04 09:09, Zenghui Yu wrote:
> The Size field of GICv4.1 VPROPBASER register indicates number of
> pages minus one and together Page_Size and Size control the vPEID
> width. Let's respect this requirement of the architecture.
> 
> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
> ---
>  drivers/irqchip/irq-gic-v3-its.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/irqchip/irq-gic-v3-its.c 
> b/drivers/irqchip/irq-gic-v3-its.c
> index e5a25d97f8db..992bc72cab6f 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -2531,7 +2531,7 @@ static int allocate_vpe_l1_table(void)
>  		npg = 1;
>  	}
> 
> -	val |= FIELD_PREP(GICR_VPROPBASER_4_1_SIZE, npg);
> +	val |= FIELD_PREP(GICR_VPROPBASER_4_1_SIZE, npg - 1);
> 
>  	/* Right, that's the number of CPU pages we need for L1 */
>  	np = DIV_ROUND_UP(npg * psz, PAGE_SIZE);

Indeed, nice catch.

         M.
-- 
Jazz is not dead. It just smells funny...