From: Julien Grall <julien.grall@arm.com>
To: Sergej Proskurin <proskurin@sec.in.tum.de>,
Andrew Cooper <andrew.cooper3@citrix.com>,
xen-devel@lists.xenproject.org
Cc: Stefano Stabellini <sstabellini@kernel.org>
Subject: Re: [PATCH 04/18] arm/altp2m: Add altp2m init/teardown routines.
Date: Mon, 4 Jul 2016 18:44:32 +0100 [thread overview]
Message-ID: <577AA080.9000004@arm.com> (raw)
In-Reply-To: <30edd21f-323b-9066-e2e2-5cd002b05b8b@sec.in.tum.de>
On 04/07/16 17:56, Sergej Proskurin wrote:
> Hi Andrew,
>
> On 07/04/2016 06:43 PM, Andrew Cooper wrote:
>> On 04/07/16 17:40, Sergej Proskurin wrote:
>>>
>>>>> {
>>>>> - struct p2m_domain *p2m = &d->arch.p2m;
>>>>> + int ret = 0;
>>>>> +
>>>>> + spin_lock_init(&p2m->lock);
>>>>> + INIT_PAGE_LIST_HEAD(&p2m->pages);
>>>>> +
>>>>> + spin_lock(&p2m->lock);
>>>>> +
>>>>> + p2m->domain = d;
>>>>> + p2m->access_required = false;
>>>>> + p2m->mem_access_enabled = false;
>>>>> + p2m->default_access = p2m_access_rwx;
>>>>> + p2m->p2m_class = p2m_host;
>>>>> + p2m->root = NULL;
>>>>> +
>>>>> + /* Adopt VMID of the associated domain */
>>>>> + p2m->vmid = d->arch.p2m.vmid;
>>>> It looks like to me that re-using the same VMID will require more TLB
>>>> flush (such as when a VCPU is migrated to another physical CPU). So
>>>> could you explain why you decided to re-use the same VMID?
>>>>
>>> Please correct me if I am wrong, but I associate a VMID with an entire
>>> domain. Since, the altp2m view still belongs to the same domain
>>> (p2m_init_one is called only from p2m_init_altp2m), the code re-uses the
>>> old VMID.
>>
>> (I am not an ARM expert but) looking into VMIDs from the last time, they
>> are the TLB tag for the address space in use.
>>
>> Does ARM have shared TLBs between multiple cores? If so, you must a
>> separate VMID, otherwise an ALT2PM used by one vcpu could cause a
>> separate vcpu with a different ALTP2M to reuse the wrong translation.
>>
>> ~Andrew
>>
>
> You're absolutely correct. However, on every VMENTRY Xen explicitly
> flushes the TLBs of the currently active domain (and with it, of the
> currently active (a)p2m table) and hence it should not result in an issue.
VMENTRY is x86 not ARM. So are you sure you looked at the correct code?
Regards,
--
Julien Grall
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next prev parent reply other threads:[~2016-07-04 17:44 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 [this message]
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
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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