linux-kernel - Re: [PATCH 6/6] x86/xen: open code alloc_vm_area in arch_gnttab

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <0833b9a8-5096-d105-a850-1336150eada1@oracle.com>
Date:   Mon, 21 Sep 2020 16:44:10 -0400
From:   boris.ostrovsky@...cle.com
To:     Christoph Hellwig <hch@....de>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Juergen Gross <jgross@...e.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Minchan Kim <minchan@...nel.org>,
        Nitin Gupta <ngupta@...are.org>, x86@...nel.org,
        xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org,
        intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-mm@...ck.org
Subject: Re: [PATCH 6/6] x86/xen: open code alloc_vm_area in
 arch_gnttab_valloc


On 9/18/20 12:37 PM, Christoph Hellwig wrote:
>  
> +static int gnttab_apply(pte_t *pte, unsigned long addr, void *data)
> +{
> +	pte_t ***p = data;
> +
> +	**p = pte;
> +	(*p)++;
> +	return 0;
> +}
> +
>  static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
>  {
>  	area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL);
>  	if (area->ptes == NULL)
>  		return -ENOMEM;
> -
> -	area->area = alloc_vm_area(PAGE_SIZE * nr_frames, area->ptes);
> -	if (area->area == NULL) {
> -		kfree(area->ptes);
> -		return -ENOMEM;
> -	}
> -
> +	area->area = get_vm_area(PAGE_SIZE * nr_frames, VM_IOREMAP);
> +	if (!area->area)
> +		goto out_free_ptes;
> +	if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr,
> +			PAGE_SIZE * nr_frames, gnttab_apply, &area->ptes))


This will end up incrementing area->ptes pointer. So perhaps something like


pte_t **ptes = area->ptes;

if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr,
                        PAGE_SIZE * nr_frames, gnttab_apply, &ptes)) {

       ...

}


-boris