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Subject: Re: [PATCH 1/2] xen-pciback: return proper values during BAR sizing
To: Jan Beulich <JBeulich@suse.com>, David Vrabel <david.vrabel@citrix.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Juergen Gross <JGross@suse.com>
References: <57554B8D02000078000F1DE4@prv-mh.provo.novell.com>
 <57554C5D02000078000F1DF1@prv-mh.provo.novell.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>, linux-kernel@vger.kernel.org
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Message-ID: <5755748D.6050900@oracle.com>
Date: Mon, 6 Jun 2016 09:03:09 -0400
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On 06/06/2016 04:11 AM, Jan Beulich wrote:
> @@ -225,38 +225,42 @@ static inline void read_dev_bar(struct p
>  			   (PCI_BASE_ADDRESS_SPACE_MEMORY |
>  				PCI_BASE_ADDRESS_MEM_TYPE_64))) {
>  			bar_info->val = res[pos - 1].start >> 32;
> -			bar_info->len_val = res[pos - 1].end >> 32;
> +			bar_info->len_val = -resource_size(&res[pos - 1]) >> 32;
>  			return;
>  		}
>  	}
>  
> +	if (!res[pos].flags ||
> +	    (res[pos].flags & (IORESOURCE_DISABLED | IORESOURCE_UNSET |
> +			       IORESOURCE_BUSY)))
> +		return;

Why are you not making this check first thing in the routine?

-boris