From: Sergej Proskurin <proskurin@sec.in.tum.de>
To: Julien Grall <julien.grall@arm.com>, xen-devel@lists.xenproject.org
Cc: Stefano Stabellini <sstabellini@kernel.org>
Subject: Re: [PATCH 14/18] arm/altp2m: Add HVMOP_altp2m_set_mem_access.
Date: Tue, 5 Jul 2016 23:55:40 +0200 [thread overview]
Message-ID: <d6b2a611-7135-a8c9-3414-f1ffbfb98f35@sec.in.tum.de> (raw)
In-Reply-To: <577BACC2.3040607@arm.com>
Hello Julien,
On 07/05/2016 02:49 PM, Julien Grall wrote:
> Hello Sergej,
>
> On 04/07/16 12:45, Sergej Proskurin wrote:
>> +static inline
>> +int p2m_set_altp2m_mem_access(struct domain *d, struct p2m_domain *hp2m,
>> + struct p2m_domain *ap2m, p2m_access_t a,
>> + gfn_t gfn)
>> +{
>
> [...]
>
>> + /* Set mem access attributes - currently supporting only one (4K)
>> page. */
>> + mask = level_masks[3];
>> + return apply_p2m_changes(d, ap2m, INSERT,
>> + gpa & mask,
>> + (gpa + level_sizes[level]) & mask,
>> + maddr & mask, mattr, 0, p2mt, a);
>
> The operation INSERT will remove the previous mapping and decrease page
> reference for foreign mapping (see p2m_put_l3_page). So if you set the
> memory access for this kind of page, the reference count will be wrong
> afterward.
>
I see your point. As far as I understand, the purpose of the function
p2m_put_l3_page to simply decrement the ref count of the particular pte
and free the page if its' ref count reaches zero. Since p2m_put_l3_page
is called only twice in p2m.c, we could insert a check
(p2m_is_hostp2m/altp2m) making sure that the ref count is decremented
only if the p2m in question is the hostp2m. This will make sure that the
ref count is maintained correctly.
Thank you for pointing that out.
Cheers,
~Sergej
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next prev parent reply other threads:[~2016-07-05 21:51 UTC|newest]
Thread overview: 126+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-04 11:45 [PATCH 00/18] arm/altp2m: Introducing altp2m to ARM Sergej Proskurin
2016-07-04 11:45 ` [PATCH 01/18] arm/altp2m: Add cmd-line support for altp2m on ARM Sergej Proskurin
2016-07-04 12:15 ` Andrew Cooper
2016-07-04 13:02 ` Sergej Proskurin
2016-07-04 13:25 ` Julien Grall
2016-07-04 13:43 ` Sergej Proskurin
2016-07-04 17:42 ` Julien Grall
2016-07-04 17:56 ` Tamas K Lengyel
2016-07-04 21:08 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 02/18] arm/altp2m: Add first altp2m HVMOP stubs Sergej Proskurin
2016-07-04 13:36 ` Julien Grall
2016-07-04 13:51 ` Sergej Proskurin
2016-07-05 10:19 ` Julien Grall
2016-07-06 9:14 ` Sergej Proskurin
2016-07-06 13:43 ` Julien Grall
2016-07-06 15:23 ` Tamas K Lengyel
2016-07-06 15:54 ` Julien Grall
2016-07-06 16:05 ` Tamas K Lengyel
2016-07-06 16:29 ` Julien Grall
2016-07-06 16:35 ` Tamas K Lengyel
2016-07-06 18:35 ` Julien Grall
2016-07-07 9:14 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 03/18] arm/altp2m: Add HVMOP_altp2m_get_domain_state Sergej Proskurin
2016-07-04 11:45 ` [PATCH 04/18] arm/altp2m: Add altp2m init/teardown routines Sergej Proskurin
2016-07-04 15:17 ` Julien Grall
2016-07-04 16:40 ` Sergej Proskurin
2016-07-04 16:43 ` Andrew Cooper
2016-07-04 16:56 ` Sergej Proskurin
2016-07-04 17:44 ` Julien Grall
2016-07-04 21:19 ` Sergej Proskurin
2016-07-04 21:35 ` Julien Grall
2016-07-04 21:46 ` Sergej Proskurin
2016-07-04 18:18 ` Julien Grall
2016-07-04 21:37 ` Sergej Proskurin
2016-07-04 18:30 ` Julien Grall
2016-07-04 21:56 ` Sergej Proskurin
2016-07-04 16:15 ` Julien Grall
2016-07-04 16:51 ` Sergej Proskurin
2016-07-04 18:34 ` Julien Grall
2016-07-05 7:45 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 05/18] arm/altp2m: Add HVMOP_altp2m_set_domain_state Sergej Proskurin
2016-07-04 15:39 ` Julien Grall
2016-07-05 8:45 ` Sergej Proskurin
2016-07-05 10:11 ` Julien Grall
2016-07-05 12:05 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 06/18] arm/altp2m: Add a(p2m) table flushing routines Sergej Proskurin
2016-07-04 12:12 ` Sergej Proskurin
2016-07-04 15:42 ` Julien Grall
2016-07-05 8:52 ` Sergej Proskurin
2016-07-04 15:55 ` Julien Grall
2016-07-05 9:51 ` Sergej Proskurin
2016-07-04 16:20 ` Julien Grall
2016-07-05 9:57 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 07/18] arm/altp2m: Add HVMOP_altp2m_create_p2m Sergej Proskurin
2016-07-04 11:45 ` [PATCH 08/18] arm/altp2m: Add HVMOP_altp2m_destroy_p2m Sergej Proskurin
2016-07-04 16:32 ` Julien Grall
2016-07-05 11:37 ` Sergej Proskurin
2016-07-05 11:48 ` Julien Grall
2016-07-05 12:18 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 09/18] arm/altp2m: Add HVMOP_altp2m_switch_p2m Sergej Proskurin
2016-07-04 11:45 ` [PATCH 10/18] arm/altp2m: Renamed and extended p2m_alloc_table Sergej Proskurin
2016-07-04 18:43 ` Julien Grall
2016-07-05 13:56 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 11/18] arm/altp2m: Make flush_tlb_domain ready for altp2m Sergej Proskurin
2016-07-04 12:30 ` Sergej Proskurin
2016-07-04 20:32 ` Julien Grall
2016-07-05 14:48 ` Sergej Proskurin
2016-07-05 15:37 ` Julien Grall
2016-07-05 20:21 ` Sergej Proskurin
2016-07-06 14:28 ` Julien Grall
2016-07-06 14:39 ` Sergej Proskurin
2016-07-07 17:24 ` Julien Grall
2016-07-04 11:45 ` [PATCH 12/18] arm/altp2m: Cosmetic fixes - function prototypes Sergej Proskurin
2016-07-15 13:45 ` Julien Grall
2016-07-16 15:18 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 13/18] arm/altp2m: Make get_page_from_gva ready for altp2m Sergej Proskurin
2016-07-04 20:34 ` Julien Grall
2016-07-05 20:31 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 14/18] arm/altp2m: Add HVMOP_altp2m_set_mem_access Sergej Proskurin
2016-07-05 12:49 ` Julien Grall
2016-07-05 21:55 ` Sergej Proskurin [this message]
2016-07-06 14:32 ` Julien Grall
2016-07-06 16:12 ` Tamas K Lengyel
2016-07-06 16:59 ` Julien Grall
2016-07-06 17:03 ` Sergej Proskurin
2016-07-06 17:08 ` Julien Grall
2016-07-07 9:16 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 15/18] arm/altp2m: Add altp2m paging mechanism Sergej Proskurin
2016-07-04 20:53 ` Julien Grall
2016-07-06 8:33 ` Sergej Proskurin
2016-07-06 14:26 ` Julien Grall
2016-07-04 11:45 ` [PATCH 16/18] arm/altp2m: Extended libxl to activate altp2m on ARM Sergej Proskurin
2016-07-07 16:27 ` Wei Liu
2016-07-24 16:06 ` Sergej Proskurin
2016-07-25 8:32 ` Wei Liu
2016-07-25 9:04 ` Sergej Proskurin
2016-07-25 9:49 ` Julien Grall
2016-07-25 10:08 ` Wei Liu
2016-07-25 11:26 ` Sergej Proskurin
2016-07-25 11:37 ` Wei Liu
2016-07-04 11:45 ` [PATCH 17/18] arm/altp2m: Adjust debug information to altp2m Sergej Proskurin
2016-07-04 20:58 ` Julien Grall
2016-07-06 8:41 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 18/18] arm/altp2m: Extend xen-access for altp2m on ARM Sergej Proskurin
2016-07-04 13:38 ` Razvan Cojocaru
2016-07-06 8:44 ` Sergej Proskurin
2016-07-04 11:45 ` [PATCH 01/18] arm/altp2m: Add cmd-line support " Sergej Proskurin
2016-07-04 11:45 ` [PATCH 02/18] arm/altp2m: Add first altp2m HVMOP stubs Sergej Proskurin
2016-07-04 11:45 ` [PATCH 03/18] arm/altp2m: Add HVMOP_altp2m_get_domain_state Sergej Proskurin
2016-07-04 11:45 ` [PATCH 04/18] arm/altp2m: Add altp2m init/teardown routines Sergej Proskurin
2016-07-04 11:45 ` [PATCH 05/18] arm/altp2m: Add HVMOP_altp2m_set_domain_state Sergej Proskurin
2016-07-04 11:45 ` [PATCH 06/18] arm/altp2m: Add a(p2m) table flushing routines Sergej Proskurin
2016-07-04 11:45 ` [PATCH 07/18] arm/altp2m: Add HVMOP_altp2m_create_p2m Sergej Proskurin
2016-07-04 11:45 ` [PATCH 08/18] arm/altp2m: Add HVMOP_altp2m_destroy_p2m Sergej Proskurin
2016-07-04 11:45 ` [PATCH 09/18] arm/altp2m: Add HVMOP_altp2m_switch_p2m Sergej Proskurin
2016-07-04 11:45 ` [PATCH 10/18] arm/altp2m: Renamed and extended p2m_alloc_table Sergej Proskurin
2016-07-04 11:45 ` [PATCH 11/18] arm/altp2m: Make flush_tlb_domain ready for altp2m Sergej Proskurin
2016-07-04 11:45 ` [PATCH 12/18] arm/altp2m: Cosmetic fixes - function prototypes Sergej Proskurin
2016-07-04 11:46 ` [PATCH 13/18] arm/altp2m: Make get_page_from_gva ready for altp2m Sergej Proskurin
2016-07-04 11:46 ` [PATCH 14/18] arm/altp2m: Add HVMOP_altp2m_set_mem_access Sergej Proskurin
2016-07-04 11:46 ` [PATCH 15/18] arm/altp2m: Add altp2m paging mechanism Sergej Proskurin
2016-07-04 11:46 ` [PATCH 16/18] arm/altp2m: Extended libxl to activate altp2m on ARM Sergej Proskurin
2016-07-04 11:46 ` [PATCH 17/18] arm/altp2m: Adjust debug information to altp2m Sergej Proskurin
2016-07-04 11:46 ` [PATCH 18/18] arm/altp2m: Extend xen-access for altp2m on ARM Sergej Proskurin
2016-07-04 12:52 ` [PATCH 00/18] arm/altp2m: Introducing altp2m to ARM Andrew Cooper
2016-07-04 13:05 ` Sergej Proskurin
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