From: Julien Grall <julien.grall@citrix.com>
To: David Vrabel <david.vrabel@citrix.com>, xen-devel@lists.xenproject.org
Cc: ian.campbell@citrix.com,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
stefano.stabellini@eu.citrix.com
Subject: Re: [PATCH v2 01/20] xen: Add Xen specific page definition
Date: Fri, 24 Jul 2015 14:03:14 +0100 [thread overview]
Message-ID: <55B23792.5090802__33954.7770949595$1437743215$gmane$org@citrix.com> (raw)
In-Reply-To: <55B214C5.3020501@citrix.com>
On 24/07/15 11:34, David Vrabel wrote:
> On 24/07/15 10:51, Julien Grall wrote:
>> On 24/07/15 10:48, David Vrabel wrote:
>>> On 24/07/15 10:39, Julien Grall wrote:
>>>> Hi David,
>>>>
>>>> On 24/07/15 10:28, David Vrabel wrote:
>>>>> On 09/07/15 21:42, Julien Grall wrote:
>>>>>> The Xen hypercall interface is always using 4K page granularity on ARM
>>>>>> and x86 architecture.
>>>>>>
>>>>>> With the incoming support of 64K page granularity for ARM64 guest, it
>>>>>> won't be possible to re-use the Linux page definition in Xen drivers.
>>>>>>
>>>>>> Introduce Xen page definition helpers based on the Linux page
>>>>>> definition. They have exactly the same name but prefixed with
>>>>>> XEN_/xen_ prefix.
>>>>>>
>>>>>> Also modify page_to_pfn to use new Xen page definition.
>>>>>>
>>>>>> Signed-off-by: Julien Grall <julien.grall@citrix.com>
>>>>>> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>>>>>> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>>>>> Cc: David Vrabel <david.vrabel@citrix.com>
>>>>>> ---
>>>>>> I'm wondering if we should drop page_to_pfn has the macro will likely
>>>>>> misuse when Linux is using 64KB page granularity.
>>>>>
>>>>> I think we want xen_gfn_to_page() and xen_page_to_gfn() and Xen
>>>>> front/back drivers never deal with PFNs only GFNs.
>>>>
>>>> What is xen_gfn_to_page and xen_page_to_gfn? Neither Linux, nor my
>>>> series have them.
>>>
>>> I suggesting that you introduce these.
>>
>> It's still not clear to me what you are suggesting here... Do you
>> suggest to rename xen_pfn_to_page and xen_page_to_pfn by xen_gfn_to_page
>> and xen_page_to_gfn?
>
> Effectively, yes but it would be better to think that:
>
> PFNs index guest-sized pages (which may be 64 KiB).
>
> GFNs index Xen-sized pages (which is always 4 KiB).
If I'm understanding correctly you mean:
#define xen_page_to_gfn(page) \
((page_to_pfn(page) << PAGE_SHIFT) >> XEN_PAGE_SHIFT))
static page_to_mfn(struct page *page)
{
return pfn_to_mfn(xen_page_to_gfn(page));
}
Although in some place you are suggesting to use:
xen_page_to_gfn(virt_to_page(info->intf)) (see patch #11) where it
suggests to rename page_to_mfn in xen_page_to_gfn.
I think it would make more sense to use the latter one. We would also
need to name to describe a PFN (pseudo-physical frame number based on
xen/include/xen/mm.h) but with 4K granularity and not the Linux granularity.
It's useful to have it in some place in order to iter on the 4K pfn (see
gnttab_foreach_grant and xen_apply_to_page). Maybe xpfn for Xen
pseudo-physical frame number?
I will preprend some patches into this serie to rename the function with
their correct naming.
I have in mind pfn_to_mfn which should be name into pfn_to_gfn given the
usage. Similarly, this function is mis-used on ARM because the function
may return an MFN where we expect a GFN.
Regards,
--
Julien Grall
next prev parent reply other threads:[~2015-07-24 13:04 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1436474552-31789-1-git-send-email-julien.grall@citrix.com>
2015-07-09 20:42 ` [PATCH v2 01/20] xen: Add Xen specific page definition Julien Grall
2015-07-16 14:19 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507161515420.17378@kaball.uk.xensource.com>
2015-07-16 14:52 ` Julien Grall
2015-07-24 9:28 ` David Vrabel
[not found] ` <55B20540.3020000@citrix.com>
2015-07-24 9:39 ` Julien Grall
[not found] ` <55B207C6.4020300@citrix.com>
2015-07-24 9:48 ` David Vrabel
[not found] ` <55B209D9.1080602@citrix.com>
2015-07-24 9:51 ` Julien Grall
[not found] ` <55B20ABE.7000609@citrix.com>
2015-07-24 10:34 ` David Vrabel
[not found] ` <55B214C5.3020501@citrix.com>
2015-07-24 10:43 ` Ian Campbell
2015-07-24 13:03 ` Julien Grall [this message]
2015-07-09 20:42 ` [PATCH v2 02/20] xen: Introduce a function to split a Linux page into Xen page Julien Grall
2015-07-16 14:23 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507161520330.17378@kaball.uk.xensource.com>
2015-07-16 14:54 ` Julien Grall
[not found] ` <55A7C5A1.7060006@citrix.com>
2015-07-16 15:19 ` Andrew Cooper
2015-07-16 16:09 ` Julien Grall
2015-07-16 16:13 ` Andrew Cooper
2015-07-24 9:31 ` David Vrabel
[not found] ` <55B205FB.5080209@citrix.com>
2015-07-24 9:54 ` Julien Grall
[not found] ` <55B20B56.7020605@citrix.com>
2015-07-24 10:10 ` David Vrabel
[not found] ` <55B20F1F.60902@citrix.com>
2015-07-24 10:20 ` Julien Grall
2015-08-05 14:30 ` Julien Grall
[not found] ` <55C21DF3.2090201@citrix.com>
2015-08-05 15:50 ` David Vrabel
[not found] ` <55C230C9.7060506@citrix.com>
2015-08-05 16:06 ` Julien Grall
2015-07-09 20:42 ` [PATCH v2 03/20] xen/grant: Introduce helpers to split a page into grant Julien Grall
2015-07-09 20:42 ` [PATCH v2 04/20] xen/grant: Add helper gnttab_page_grant_foreign_access_ref Julien Grall
2015-07-09 20:42 ` [PATCH v2 05/20] block/xen-blkfront: Split blkif_queue_request in 2 Julien Grall
2015-07-09 20:42 ` [PATCH v2 06/20] block/xen-blkfront: Store a page rather a pfn in the grant structure Julien Grall
2015-07-09 20:42 ` [PATCH v2 07/20] block/xen-blkfront: split get_grant in 2 Julien Grall
2015-07-09 20:42 ` [PATCH v2 08/20] net/xen-netback: xenvif_gop_frag_copy: move GSO check out of the loop Julien Grall
2015-07-09 20:42 ` [PATCH v2 09/20] xen/biomerge: Don't allow biovec to be merge when Linux is not using 4KB page Julien Grall
2015-07-10 19:12 ` Konrad Rzeszutek Wilk
[not found] ` <20150710191245.GA31063@l.oracle.com>
2015-07-15 8:56 ` Julien Grall
2015-07-16 15:33 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507161627010.17378@kaball.uk.xensource.com>
2015-07-16 16:15 ` Julien Grall
[not found] ` <55A7D8AD.1090102@citrix.com>
2015-07-16 18:30 ` Konrad Rzeszutek Wilk
2015-07-17 13:20 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507171418260.17378@kaball.uk.xensource.com>
2015-07-17 14:44 ` Julien Grall
[not found] ` <55A914D5.7080900@citrix.com>
2015-07-17 14:45 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507171545170.17378@kaball.uk.xensource.com>
2015-07-17 14:46 ` Julien Grall
2015-07-09 20:42 ` [PATCH v2 10/20] xen/xenbus: Use Xen page definition Julien Grall
2015-07-16 15:35 ` Stefano Stabellini
2015-07-24 9:49 ` David Vrabel
2015-07-09 20:42 ` [PATCH v2 11/20] tty/hvc: xen: Use xen " Julien Grall
2015-07-09 20:42 ` [PATCH v2 12/20] xen/balloon: Don't rely on the page granularity is the same for Xen and Linux Julien Grall
2015-07-17 14:03 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507161819200.17378@kaball.uk.xensource.com>
2015-07-17 14:32 ` Julien Grall
2015-07-09 20:42 ` [PATCH v2 13/20] xen/events: fifo: Make it running on 64KB granularity Julien Grall
2015-07-09 20:42 ` [PATCH v2 14/20] xen/grant-table: " Julien Grall
2015-07-09 20:42 ` [PATCH v2 15/20] block/xen-blkfront: Make it running on 64KB page granularity Julien Grall
2015-07-21 11:06 ` Roger Pau Monné
[not found] ` <55AE27C2.8090803@citrix.com>
2015-07-21 13:07 ` Julien Grall
2015-07-09 20:42 ` [PATCH v2 16/20] block/xen-blkback: " Julien Grall
2015-07-09 20:42 ` [PATCH v2 17/20] net/xen-netfront: " Julien Grall
2015-07-09 20:42 ` [PATCH v2 18/20] net/xen-netback: " Julien Grall
2015-07-09 20:42 ` [PATCH v2 19/20] xen/privcmd: Add support for Linux " Julien Grall
2015-07-09 20:42 ` [PATCH v2 20/20] arm/xen: Add support for " Julien Grall
[not found] ` <1436474552-31789-20-git-send-email-julien.grall@citrix.com>
2015-07-13 20:13 ` [PATCH v2 19/20] xen/privcmd: Add support for Linux " Boris Ostrovsky
[not found] ` <55A41BE4.3080104@oracle.com>
2015-07-13 22:05 ` Julien Grall
[not found] ` <55A43638.4030503@citrix.com>
2015-07-14 15:28 ` Boris Ostrovsky
[not found] ` <55A52A9E.2000400@oracle.com>
2015-07-14 15:37 ` Julien Grall
2015-07-16 17:12 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507161707300.17378@kaball.uk.xensource.com>
2015-07-16 17:16 ` Stefano Stabellini
2015-07-17 12:50 ` Julien Grall
[not found] ` <1436474552-31789-4-git-send-email-julien.grall@citrix.com>
2015-07-16 15:01 ` [PATCH v2 03/20] xen/grant: Introduce helpers to split a page into grant Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507161526030.17378@kaball.uk.xensource.com>
2015-07-16 16:07 ` Julien Grall
[not found] ` <55A7D6AC.5060004@citrix.com>
2015-07-17 13:10 ` Julien Grall
[not found] ` <1436474552-31789-5-git-send-email-julien.grall@citrix.com>
2015-07-16 15:05 ` [PATCH v2 04/20] xen/grant: Add helper gnttab_page_grant_foreign_access_ref Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507161603490.17378@kaball.uk.xensource.com>
2015-07-16 16:12 ` Julien Grall
2015-07-24 9:35 ` David Vrabel
[not found] ` <1436474552-31789-15-git-send-email-julien.grall@citrix.com>
2015-07-16 15:47 ` [PATCH v2 14/20] xen/grant-table: Make it running on 64KB granularity Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507161643380.17378@kaball.uk.xensource.com>
2015-07-16 16:23 ` Julien Grall
[not found] ` <55A7DA8F.2040805@citrix.com>
2015-07-17 13:37 ` Stefano Stabellini
[not found] ` <1436474552-31789-18-git-send-email-julien.grall@citrix.com>
2015-07-20 17:26 ` [PATCH v2 17/20] net/xen-netfront: Make it running on 64KB page granularity Julien Grall
2015-07-20 17:54 ` [PATCH v2 00/20] xen/arm64: Add support for 64KB page Julien Grall
[not found] ` <1436474552-31789-6-git-send-email-julien.grall@citrix.com>
2015-07-21 9:54 ` [PATCH v2 05/20] block/xen-blkfront: Split blkif_queue_request in 2 Roger Pau Monné
[not found] ` <55AE16EC.2020204@citrix.com>
2015-07-21 11:12 ` Julien Grall
[not found] ` <1436474552-31789-7-git-send-email-julien.grall@citrix.com>
2015-07-16 15:11 ` [PATCH v2 06/20] block/xen-blkfront: Store a page rather a pfn in the grant structure Stefano Stabellini
2015-07-21 10:16 ` Roger Pau Monné
[not found] ` <55AE1BE7.5030102@citrix.com>
2015-07-21 11:19 ` Julien Grall
[not found] ` <alpine.DEB.2.02.1507161610570.17378@kaball.uk.xensource.com>
2015-07-23 17:18 ` Julien Grall
[not found] ` <1436474552-31789-8-git-send-email-julien.grall@citrix.com>
2015-07-21 10:30 ` [PATCH v2 07/20] block/xen-blkfront: split get_grant in 2 Roger Pau Monné
[not found] ` <55AE1F2A.6010300@citrix.com>
2015-07-21 13:03 ` Julien Grall
[not found] ` <1436474552-31789-12-git-send-email-julien.grall@citrix.com>
2015-07-16 15:36 ` [PATCH v2 11/20] tty/hvc: xen: Use xen page definition Stefano Stabellini
2015-07-24 9:52 ` David Vrabel
[not found] ` <1436474552-31789-14-git-send-email-julien.grall@citrix.com>
2015-07-16 15:43 ` [PATCH v2 13/20] xen/events: fifo: Make it running on 64KB granularity Stefano Stabellini
[not found] ` <alpine.DEB.2.02.1507161642130.17378@kaball.uk.xensource.com>
2015-07-16 16:18 ` Julien Grall
[not found] ` <55A7D955.5090203@citrix.com>
2015-07-17 13:06 ` Stefano Stabellini
2015-07-24 10:36 ` David Vrabel
[not found] ` <55B21527.4010601@citrix.com>
2015-08-06 15:43 ` Julien Grall
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