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From: George Dunlap <dunlapg@umich.edu>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Julien Grall <julien.grall@arm.com>,
	Wei Liu <wei.liu2@citrix.com>, Jan Beulich <JBeulich@suse.com>,
	Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH v5 01/16] x86/mm: skip incrementing mfn if it is not a valid mfn
Date: Thu, 15 Mar 2018 16:06:59 +0000	[thread overview]
Message-ID: <CAFLBxZbtyMb3bmtBGUo98MM-rMMfpjd70bFub1zGqvyD=CaQRg@mail.gmail.com> (raw)
In-Reply-To: <6529a09f-93fd-474d-358a-064f8a0948ee@citrix.com>

On Thu, Mar 15, 2018 at 12:16 PM, Andrew Cooper
<andrew.cooper3@citrix.com> wrote:
> On 15/03/18 07:52, Jan Beulich wrote:
>>>>> On 14.03.18 at 19:31, <andrew.cooper3@citrix.com> wrote:
>>> On 14/03/18 18:19, julien.grall@arm.com wrote:
>>>> From: Wei Liu <wei.liu2@citrix.com>
>>>>
>>>> The function is called to fill in page table entries in
>>>> populate_pt_range. Skip incrementing mfn if it is invalid.
>>>>
>>>> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
>>> Remind me what the purpose of this patch is?
>> This is in preparation to switch callers to pass INVALID_MFN
>> instead of zero for non-present mappings. The incrementing
>> from zero was wrong here already (but couldn't be as easily
>> avoided, to not cause problems with possible legitimate uses of
>> MFN 0), but incrementing (and wrapping) from INVALID_MFN is
>> (imo) even worse, which is why I had asked the conversion to
>> INVALID_MFN to not be done without this change.
>
> Yes.  My reply was a (clearly too) thinly veiled hint that a sentence to
> this effect should be in the commit message.

You mean "a (clearly not thinly enough) veiled hint". :-)

I agree with Andy re both the code and the commit message.

 -George

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  reply	other threads:[~2018-03-15 16:06 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-14 18:19 [PATCH v5 00/16] xen: Convert page_to_mfn and mfn_to_page to use typesafe MFN julien.grall
2018-03-14 18:19 ` [PATCH v5 01/16] x86/mm: skip incrementing mfn if it is not a valid mfn julien.grall
2018-03-14 18:31   ` Andrew Cooper
2018-03-15  7:52     ` Jan Beulich
2018-03-15 12:16       ` Andrew Cooper
2018-03-15 16:06         ` George Dunlap [this message]
2018-03-15  7:49   ` Jan Beulich
2018-03-15 15:05     ` Julien Grall
2018-03-14 18:19 ` [PATCH v5 02/16] xen/arm: setup: use maddr_to_mfn rather than _mfn(paddr_to_pfn(...)) julien.grall
2018-03-15 16:10   ` George Dunlap
2018-03-14 18:19 ` [PATCH v5 03/16] xen/arm: mm: Use gaddr_to_gfn rather than _gfn(paddr_to_pfn(...)) julien.grall
2018-03-15 16:15   ` George Dunlap
2018-03-20  8:33     ` Julien Grall
2018-03-14 18:19 ` [PATCH v5 04/16] xen/arm: mm: Remove unused M2P code julien.grall
2018-03-15  7:20   ` Alan Robinson
2018-03-20  8:34     ` Julien Grall
2018-03-15 16:25   ` George Dunlap
2018-03-20  9:09     ` Julien Grall
2018-03-14 18:19 ` [PATCH v5 05/16] xen/arm: mm: Remove unused relinquish_shared_pages julien.grall
2018-03-15 16:28   ` George Dunlap
2018-03-14 18:19 ` [PATCH v5 06/16] xen/x86: Remove unused override of page_to_mfn/mfn_to_page julien.grall
2018-03-14 18:20 ` [PATCH v5 07/16] xen/x86: mm: Switch x86/mm.c to use typesafe for virt_to_mfn julien.grall
2018-03-15 16:36   ` George Dunlap
2018-03-20  9:12     ` Julien Grall
2018-03-14 18:20 ` [PATCH v5 08/16] xen/mm: Drop the parameter mfn from populate_pt_range julien.grall
2018-03-14 18:34   ` Andrew Cooper
2018-03-15 11:08   ` Wei Liu
2018-03-15 16:39   ` George Dunlap
2018-03-14 18:20 ` [PATCH v5 09/16] xen/pdx: Introduce helper to convert MFN <-> PDX julien.grall
2018-03-14 18:34   ` Andrew Cooper
2018-03-14 18:20 ` [PATCH v5 10/16] xen/mm: Switch map_pages_to_xen to use MFN typesafe julien.grall
2018-03-14 18:40   ` Andrew Cooper
2018-03-15 11:08   ` Wei Liu
2018-03-15 16:50   ` George Dunlap
2018-03-15 16:53     ` Julien Grall
2018-03-15 18:12       ` George Dunlap
2018-03-14 18:20 ` [PATCH v5 11/16] xen/mm: Switch some of page_alloc.c to typesafe MFN julien.grall
2018-03-15 17:02   ` George Dunlap
2018-03-15 18:07     ` Julien Grall
2018-03-14 18:20 ` [PATCH v5 12/16] xen/mm: Switch common/memory.c to use " julien.grall
2018-03-15  8:06   ` Jan Beulich
2018-03-15 15:03     ` Julien Grall
2018-03-15 15:51       ` Jan Beulich
2018-03-14 18:20 ` [PATCH v5 13/16] xen/grant: Switch {create, replace}_grant_p2m_mapping to " julien.grall
2018-03-14 18:20 ` [PATCH v5 14/16] xen/grant: Switch common/grant_table.c to use " julien.grall
2018-03-15  8:14   ` Jan Beulich
2018-03-20  9:30     ` Julien Grall
2018-03-15 11:09   ` Wei Liu
2018-03-14 18:20 ` [PATCH v5 15/16] xen/x86: Switch mfn_to_page in x86_64/mm.c " julien.grall
2018-03-15  8:15   ` Jan Beulich
2018-03-14 18:20 ` [PATCH v5 16/16] xen: Convert page_to_mfn and mfn_to_page " julien.grall
2018-03-15  8:18   ` Jan Beulich
2018-03-15 18:09   ` George Dunlap

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