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Re: [PATCH v3 03/17] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn

From Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Newsgroups linux.kernel
Subject Re: [PATCH v3 03/17] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn
Date 2016-01-25 15:00 +0100
Message-ID <qUPQu-4Ie-23@gated-at.bofh.it> (permalink)
References <qTX3H-5bz-3@gated-at.bofh.it> <qTX3I-5bz-9@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Sat, 23 Jan 2016, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@linaro.org>
> 
> Use page_to_xen_pfn in case of 64KB page.
> 
> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>

Please update the commit message, something like:

"Make xen_xlate_map_ballooned_pages work with 64K pages. In that case
Kernel pages are 64K in size but Xen pages remain 4K in size. Xen pfns
refer to 4K pages."

Provided that you change the commit message:

Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>


>  drivers/xen/xlate_mmu.c | 26 ++++++++++++++++----------
>  1 file changed, 16 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
> index 9692656..28f728b 100644
> --- a/drivers/xen/xlate_mmu.c
> +++ b/drivers/xen/xlate_mmu.c
> @@ -207,9 +207,12 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
>  	void *vaddr;
>  	int rc;
>  	unsigned int i;
> +	unsigned long nr_pages;
> +	xen_pfn_t xen_pfn = 0;
>  
>  	BUG_ON(nr_grant_frames == 0);
> -	pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL);
> +	nr_pages = DIV_ROUND_UP(nr_grant_frames, XEN_PFN_PER_PAGE);
> +	pages = kcalloc(nr_pages, sizeof(pages[0]), GFP_KERNEL);
>  	if (!pages)
>  		return -ENOMEM;
>  
> @@ -218,22 +221,25 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
>  		kfree(pages);
>  		return -ENOMEM;
>  	}
> -	rc = alloc_xenballooned_pages(nr_grant_frames, pages);
> +	rc = alloc_xenballooned_pages(nr_pages, pages);
>  	if (rc) {
> -		pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", __func__,
> -			nr_grant_frames, rc);
> +		pr_warn("%s Couldn't balloon alloc %ld pages rc:%d\n", __func__,
> +			nr_pages, rc);
>  		kfree(pages);
>  		kfree(pfns);
>  		return rc;
>  	}
> -	for (i = 0; i < nr_grant_frames; i++)
> -		pfns[i] = page_to_pfn(pages[i]);
> +	for (i = 0; i < nr_grant_frames; i++) {
> +		if ((i % XEN_PFN_PER_PAGE) == 0)
> +			xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
> +		pfns[i] = pfn_to_gfn(xen_pfn++);
> +	}
>  
> -	vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL);
> +	vaddr = vmap(pages, nr_pages, 0, PAGE_KERNEL);
>  	if (!vaddr) {
> -		pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__,
> -			nr_grant_frames, rc);
> -		free_xenballooned_pages(nr_grant_frames, pages);
> +		pr_warn("%s Couldn't map %ld pages rc:%d\n", __func__,
> +			nr_pages, rc);
> +		free_xenballooned_pages(nr_pages, pages);
>  		kfree(pages);
>  		kfree(pfns);
>  		return -ENOMEM;
> -- 
> 2.0.4
> 
> 

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[PATCH v3 03/17] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn Shannon Zhao <zhaoshenglong@huawei.com> - 2016-01-23 04:30 +0100
  Re: [PATCH v3 03/17] Xen: xlate: Use page_to_xen_pfn instead of  page_to_pfn Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2016-01-25 15:00 +0100

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