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Groups > linux.kernel > #1309902 > unrolled thread

[PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn

Started byShannon Zhao <zhaoshenglong@huawei.com>
First post2016-01-15 08:00 +0100
Last post2016-01-19 16:20 +0100
Articles 5 — 3 participants

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  [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn Shannon Zhao <zhaoshenglong@huawei.com> - 2016-01-15 08:00 +0100
    Re: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn  instead of page_to_pfn Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2016-01-15 18:10 +0100
      Re: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn  instead of page_to_pfn Shannon Zhao <zhaoshenglong@huawei.com> - 2016-01-18 06:10 +0100
        Re: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn  instead of page_to_pfn Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2016-01-19 16:10 +0100
          Re: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn  instead of page_to_pfn Shannon Zhao <shannon.zhao@linaro.org> - 2016-01-19 16:20 +0100

#1309902 — [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn

FromShannon Zhao <zhaoshenglong@huawei.com>
Date2016-01-15 08:00 +0100
Subject[PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn
Message-ID<qR6wy-2kF-13@gated-at.bofh.it>
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>
---
 drivers/xen/xlate_mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
index 9692656..b9fcc2c 100644
--- a/drivers/xen/xlate_mmu.c
+++ b/drivers/xen/xlate_mmu.c
@@ -227,7 +227,7 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
 		return rc;
 	}
 	for (i = 0; i < nr_grant_frames; i++)
-		pfns[i] = page_to_pfn(pages[i]);
+		pfns[i] = page_to_xen_pfn(pages[i]);
 
 	vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL);
 	if (!vaddr) {
-- 
2.0.4

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#1310283 — Re: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn

FromStefano Stabellini <stefano.stabellini@eu.citrix.com>
Date2016-01-15 18:10 +0100
SubjectRe: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn
Message-ID<qRg2T-Ih-17@gated-at.bofh.it>
In reply to#1309902
On Fri, 15 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>
> ---
>  drivers/xen/xlate_mmu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
> index 9692656..b9fcc2c 100644
> --- a/drivers/xen/xlate_mmu.c
> +++ b/drivers/xen/xlate_mmu.c
> @@ -227,7 +227,7 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
>  		return rc;
>  	}
>  	for (i = 0; i < nr_grant_frames; i++)
> -		pfns[i] = page_to_pfn(pages[i]);
> +		pfns[i] = page_to_xen_pfn(pages[i]);

Shannon, thanks for the patch.

Keeping in mind that in the 64K case, kernel pages are 64K but xen pages
are still 4K, I think you also need to allocate
(nr_grant_frames/XEN_PFN_PER_PAGE) kernel pages (assuming that they are
allocated contiguously): nr_grant_frames refers to 4K pages, while
xen_xlate_map_ballooned_pages is allocating pages on a 64K granularity
(sizeof(pages[0]) == 64K).

Be careful that alloc_xenballooned_pages deals with 64K pages (because
it deals with kernel pages), while xen_pfn_t is always 4K based (because
it deals with Xen pfns).

Please test it with and without CONFIG_ARM64_64K_PAGES. Thanks!



>  	vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL);
>  	if (!vaddr) {
> -- 
> 2.0.4
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
>

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#1311318 — Re: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn

FromShannon Zhao <zhaoshenglong@huawei.com>
Date2016-01-18 06:10 +0100
SubjectRe: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn
Message-ID<qSaeK-4ni-3@gated-at.bofh.it>
In reply to#1310283

On 2016/1/16 1:08, Stefano Stabellini wrote:
> On Fri, 15 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>
>> ---
>>  drivers/xen/xlate_mmu.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
>> index 9692656..b9fcc2c 100644
>> --- a/drivers/xen/xlate_mmu.c
>> +++ b/drivers/xen/xlate_mmu.c
>> @@ -227,7 +227,7 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
>>  		return rc;
>>  	}
>>  	for (i = 0; i < nr_grant_frames; i++)
>> -		pfns[i] = page_to_pfn(pages[i]);
>> +		pfns[i] = page_to_xen_pfn(pages[i]);
> 
> Shannon, thanks for the patch.
> 
> Keeping in mind that in the 64K case, kernel pages are 64K but xen pages
> are still 4K, I think you also need to allocate
> (nr_grant_frames/XEN_PFN_PER_PAGE) kernel pages (assuming that they are
> allocated contiguously): nr_grant_frames refers to 4K pages, while
> xen_xlate_map_ballooned_pages is allocating pages on a 64K granularity
> (sizeof(pages[0]) == 64K).
> 
> Be careful that alloc_xenballooned_pages deals with 64K pages (because
> it deals with kernel pages), while xen_pfn_t is always 4K based (because
> it deals with Xen pfns).
> 
> Please test it with and without CONFIG_ARM64_64K_PAGES. Thanks!
> 
Stefano, thanks for your explanation. How about below patch?

diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
index 9692656..e1f7c95 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] = 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;

-- 
Shannon

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#1312316 — Re: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn

FromStefano Stabellini <stefano.stabellini@eu.citrix.com>
Date2016-01-19 16:10 +0100
SubjectRe: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn
Message-ID<qSG4W-18j-21@gated-at.bofh.it>
In reply to#1311318
On Mon, 18 Jan 2016, Shannon Zhao wrote:
> On 2016/1/16 1:08, Stefano Stabellini wrote:
> > On Fri, 15 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>
> >> ---
> >>  drivers/xen/xlate_mmu.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
> >> index 9692656..b9fcc2c 100644
> >> --- a/drivers/xen/xlate_mmu.c
> >> +++ b/drivers/xen/xlate_mmu.c
> >> @@ -227,7 +227,7 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
> >>  		return rc;
> >>  	}
> >>  	for (i = 0; i < nr_grant_frames; i++)
> >> -		pfns[i] = page_to_pfn(pages[i]);
> >> +		pfns[i] = page_to_xen_pfn(pages[i]);
> > 
> > Shannon, thanks for the patch.
> > 
> > Keeping in mind that in the 64K case, kernel pages are 64K but xen pages
> > are still 4K, I think you also need to allocate
> > (nr_grant_frames/XEN_PFN_PER_PAGE) kernel pages (assuming that they are
> > allocated contiguously): nr_grant_frames refers to 4K pages, while
> > xen_xlate_map_ballooned_pages is allocating pages on a 64K granularity
> > (sizeof(pages[0]) == 64K).
> > 
> > Be careful that alloc_xenballooned_pages deals with 64K pages (because
> > it deals with kernel pages), while xen_pfn_t is always 4K based (because
> > it deals with Xen pfns).
> > 
> > Please test it with and without CONFIG_ARM64_64K_PAGES. Thanks!
> > 
> Stefano, thanks for your explanation. How about below patch?

Good work, it looks like you covered all bases, I think it should work,
but I haven't tested it myself. Just one note below.


> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
> index 9692656..e1f7c95 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] = xen_pfn++;
> +       }

We might want to:

  pfns[i] = pfn_to_gfn(xen_pfn++);

for consistency, even though for autotranslate guests pfn_to_gfn always
returns 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;
> 
> -- 
> Shannon
>

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#1312323 — Re: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn

FromShannon Zhao <shannon.zhao@linaro.org>
Date2016-01-19 16:20 +0100
SubjectRe: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn
Message-ID<qSGeC-1c0-17@gated-at.bofh.it>
In reply to#1312316

On 2016/1/19 22:59, Stefano Stabellini wrote:
> On Mon, 18 Jan 2016, Shannon Zhao wrote:
>> On 2016/1/16 1:08, Stefano Stabellini wrote:
>>> On Fri, 15 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>
>>>> ---
>>>>   drivers/xen/xlate_mmu.c | 2 +-
>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
>>>> index 9692656..b9fcc2c 100644
>>>> --- a/drivers/xen/xlate_mmu.c
>>>> +++ b/drivers/xen/xlate_mmu.c
>>>> @@ -227,7 +227,7 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
>>>>   		return rc;
>>>>   	}
>>>>   	for (i = 0; i < nr_grant_frames; i++)
>>>> -		pfns[i] = page_to_pfn(pages[i]);
>>>> +		pfns[i] = page_to_xen_pfn(pages[i]);
>>>
>>> Shannon, thanks for the patch.
>>>
>>> Keeping in mind that in the 64K case, kernel pages are 64K but xen pages
>>> are still 4K, I think you also need to allocate
>>> (nr_grant_frames/XEN_PFN_PER_PAGE) kernel pages (assuming that they are
>>> allocated contiguously): nr_grant_frames refers to 4K pages, while
>>> xen_xlate_map_ballooned_pages is allocating pages on a 64K granularity
>>> (sizeof(pages[0]) == 64K).
>>>
>>> Be careful that alloc_xenballooned_pages deals with 64K pages (because
>>> it deals with kernel pages), while xen_pfn_t is always 4K based (because
>>> it deals with Xen pfns).
>>>
>>> Please test it with and without CONFIG_ARM64_64K_PAGES. Thanks!
>>>
>> Stefano, thanks for your explanation. How about below patch?
>
> Good work, it looks like you covered all bases, I think it should work,
> but I haven't tested it myself. Just one note below.
>
>
>> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
>> index 9692656..e1f7c95 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] = xen_pfn++;
>> +       }
>
> We might want to:
>
>    pfns[i] = pfn_to_gfn(xen_pfn++);
>
> for consistency, even though for autotranslate guests pfn_to_gfn always
> returns pfn.
>
Ok, will add. Thanks.

>
>> -       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;
>>
>> --
>> Shannon
>>

-- 
Shannon

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