From: Shannon Zhao <zhaoshenglong@huawei.com>
To: Wei Liu <wei.liu2@citrix.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
ian.jackson@eu.citrix.com, peter.huangpeng@huawei.com,
xen-devel@lists.xen.org, Julien Grall <julien.grall@arm.com>,
Shannon Zhao <shannon.zhao@linaro.org>
Subject: Re: [PATCH v2 16/17] libxc/xc_dom_arm: Copy ACPI tables to guest space
Date: Fri, 15 Jul 2016 17:39:32 +0800 [thread overview]
Message-ID: <5788AF54.1010500@huawei.com> (raw)
In-Reply-To: <20160714111523.GU31770@citrix.com>
On 2016/7/14 19:15, Wei Liu wrote:
> On Wed, Jul 13, 2016 at 01:08:57PM -0400, Boris Ostrovsky wrote:
>> On 07/13/2016 11:22 AM, Julien Grall wrote:
>>> Hello,
>>>
>>> On 12/07/2016 17:58, Boris Ostrovsky wrote:
>>>> On 07/12/2016 12:10 PM, Julien Grall wrote:
>>>>> On 12/07/2016 16:08, Boris Ostrovsky wrote:
>>>>>> On 07/12/2016 10:57 AM, Shannon Zhao wrote:
>>>>>>> On 2016年07月12日 22:50, Wei Liu wrote:
>>>>>>>> On Tue, Jul 12, 2016 at 10:42:07PM +0800, Shannon Zhao wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Does it mean we would need to update the slack
>>>>>>>>>>>>>>>>>>>>>>>>>>>> to take into account the ACPI
>>>>>>>>>>>>>>>>>>>>>>>>>>>> blob?
>>>>>>>>>>>>>>>>>>>> Yes, we need to take into account the ACPI blob.
>>>>>>>>>>>>>>>>>>>> Probably not in the
>>>>>>>>>>>>>>>>>>>> slack but directly in mam_memkb.
>>>>>>>>>>>>>>>> Sorry, I'm not sure understand this. I found the
>>>>>>>>>>>>>>>> b_info->max_memkb but
>>>>>>>>>>>>>>>> didn't find the slack you said. And how to fix this? Update
>>>>>>>>>>>>>>>> b_info->max_memkb or the slack?
>>>>>>>>>>>> Can you calculate the size of your payload and add that to
>>>>>>>>>>>> max_memkb?
>>>>>>>>>>>>
>>>>>>>>>> Yeah, but the size will be changed if we change the tables in the
>>>>>>>>>> future
>>>>>>>>>> and this also should consider x86, right?
>>>>>>>> That could easily be solved by introducing a function to
>>>>>>>> calculate the
>>>>>>>> size, right?
>>>>>>> Oh, I'm not familiar with this. Let's clarify on this. It can add the
>>>>>>> size to max_memkb after generating the ACPI tables and before loading
>>>>>>> the tables to guest space and it doesn't have to add the size at
>>>>>>> libxl__domain_build_info_setdefault(), right?
>>>>>>
>>>>>> This was discussed before: ACPI tables are part of RAM whose size is
>>>>>> specified by the config file (and is reflected in max_memkb I
>>>>>> believe).
>>>>>> It may not be presented to the guest as RAM (i.e. on x86 it is labeled
>>>>>> by BIOS (or whoever) as a dedicated type in e820) but it still resides
>>>>>> in DIMMs.
>>>>>
>>>>> I don't think this was the conclusion of the thread. IHMO, "maxmem" is
>>>>> the amount of RAM a guest could effectively use.
>>>>>
>>>>> Whilst the ACPI tables will be in the DIMM from the host point of
>>>>> view. From a guest point of view it will be a ROM.
>>>>
>>>> The config file specifies resources provided by the host. How the guest
>>>> views those resources is not important, I think.
>>>
>>> This would need to be clarified. For instance special pages (Xenstore,
>>> Console...) are RAM from the host point of view but not taken into
>>> account in the "maxmem" provided by the user. For my understanding,
>>> some kB of the slack is used for that.
>>
>>
>> Are these pages part of guest's address space?
>>
>>
>>>
>>>>
>>>>>
>>>>> It will affect some others part of the guest if we don't increment the
>>>>> "maxmem" requested by the user. For ARM the ACPI blob will be exposed
>>>>> at a specific address that is outside of the guest RAM (see the guest
>>>>> memory layout in public/arch-arm.h).
>>>>>
>>>>> We chose this solution over putting in the RAM because the ACPI tables
>>>>> are not easily relocatable (compare to the device tree, initrd and
>>>>> kernel) so we could not take advantage of superpage in both stage-2
>>>>> (hypervisor) and stage-1 (kernel) page table.
>>>>
>>>> Maybe this is something ARM-specific then. For x86 we will want to keep
>>>> maxmem unchanged.
>>>
>>> I don't think what I described in my previous mail is ARM-specific.
>>> The pressure will be more important on the TLBs, if Xen does not use
>>> superpage in the stage 2 page tables (i.e EPT for x86) no matter the
>>> architecture.
>>>
>>> IHMO, this seems to be a bigger drawback compare to add few more
>>> kilobytes to maxmem in the toolstack for the ACPI blob. You will loose
>>> them when creating the intermediate page table in any case.
>>
>>
>> Why not have the guest ask for more memory in the config file then?
>>
>> (OK, I can see that they can't ask for a few KB since we have MB
>> resolution but they can ask for an extra 1MB)
>>
>
> It would be trivial to have another option in xl.cfg to allow MB
> granularity. But I don't think that's a good idea. Asking for more
> memory when you don't really know how much is enough is not very useful.
> If an admin can know how much is needed, surely the library can be
> taught to obtain that knowledge, too.
>
> We need to decide which model we should go with. And, if we decide to
> diverge, document the difference between x86 and ARM model.
>
Hi Wei,
Do you decide how to add the size of ACPI blob to max_memkb?
Thanks,
--
Shannon
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next prev parent reply other threads:[~2016-07-15 9:39 UTC|newest]
Thread overview: 130+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-23 3:16 [PATCH v2 00/17] Xen ARM DomU ACPI support Shannon Zhao
2016-06-23 3:16 ` [PATCH v2 01/17] libxl/arm: Factor out codes for generating DTB Shannon Zhao
2016-06-23 3:16 ` [PATCH v2 02/17] libxc: Add placeholders for ACPI tables blob and size Shannon Zhao
2016-06-23 3:16 ` [PATCH v2 03/17] libxl/arm: Add a configuration option for ARM DomU ACPI Shannon Zhao
2016-06-23 13:39 ` Stefano Stabellini
2016-06-23 14:34 ` Shannon Zhao
2016-06-27 10:40 ` Julien Grall
2016-07-07 15:30 ` Wei Liu
2016-07-12 3:40 ` Shannon Zhao
2016-07-12 9:22 ` Julien Grall
2016-07-12 11:33 ` Wei Liu
2016-07-12 14:17 ` Shannon Zhao
2016-07-12 14:33 ` Wei Liu
2016-07-12 14:45 ` Shannon Zhao
2016-07-13 7:54 ` Shannon Zhao
2016-07-13 9:20 ` Julien Grall
2016-07-13 9:48 ` Shannon Zhao
2016-07-13 10:03 ` Julien Grall
2016-07-15 8:00 ` Shannon Zhao
2016-07-15 8:07 ` Shannon Zhao
2016-07-18 19:40 ` Stefano Stabellini
2016-07-19 10:40 ` Wei Liu
2016-07-19 10:44 ` Ian Jackson
2016-06-23 15:53 ` Julien Grall
2016-06-23 3:16 ` [PATCH v2 04/17] libxl/arm: prepare for constructing ACPI tables Shannon Zhao
2016-06-23 13:37 ` Stefano Stabellini
2016-06-23 14:23 ` Shannon Zhao
2016-06-23 14:27 ` Stefano Stabellini
2016-06-23 16:18 ` Julien Grall
2016-06-23 3:16 ` [PATCH v2 05/17] libxl/arm: Construct ACPI RSDP table Shannon Zhao
2016-06-23 3:16 ` [PATCH v2 06/17] libxl/arm: Construct ACPI XSDT table Shannon Zhao
2016-06-23 3:16 ` [PATCH v2 07/17] libxl/arm: Construct ACPI GTDT table Shannon Zhao
2016-06-23 15:00 ` Stefano Stabellini
2016-06-23 16:19 ` Julien Grall
2016-06-23 16:26 ` Julien Grall
2016-06-23 16:58 ` Julien Grall
2016-06-27 1:44 ` Shannon Zhao
2016-06-27 10:17 ` Julien Grall
2016-06-29 9:29 ` Shannon Zhao
2016-06-29 9:42 ` Julien Grall
2016-06-29 13:41 ` Shannon Zhao
2016-07-05 16:42 ` Stefano Stabellini
2016-07-06 9:50 ` Julien Grall
2016-07-06 10:16 ` Stefano Stabellini
2016-06-23 3:16 ` [PATCH v2 08/17] libxl/arm: Factor MPIDR computing codes out as a helper Shannon Zhao
2016-06-23 16:29 ` Julien Grall
2016-06-23 3:16 ` [PATCH v2 09/17] libxl/arm: Construct ACPI MADT table Shannon Zhao
2016-06-23 16:36 ` Julien Grall
2016-06-23 3:16 ` [PATCH v2 10/17] libxl/arm: Construct ACPI FADT table Shannon Zhao
2016-06-23 3:16 ` [PATCH v2 11/17] libxl/arm: Construct ACPI DSDT table Shannon Zhao
2016-06-23 14:50 ` Stefano Stabellini
2016-06-23 16:42 ` Julien Grall
2016-06-27 1:50 ` Shannon Zhao
2016-06-23 17:03 ` Julien Grall
2016-06-27 6:01 ` Shannon Zhao
2016-06-27 10:29 ` Julien Grall
2016-06-27 12:05 ` Boris Ostrovsky
2016-06-28 11:03 ` Shannon Zhao
2016-06-28 13:41 ` Boris Ostrovsky
2016-06-29 18:58 ` Boris Ostrovsky
2016-07-01 7:58 ` Shannon Zhao
2016-07-01 10:18 ` Julien Grall
2016-07-01 14:42 ` Boris Ostrovsky
2016-07-01 15:14 ` Julien Grall
2016-06-23 3:16 ` [PATCH v2 12/17] libxl/arm: Add a helper to calculate the ACPI table checksum Shannon Zhao
2016-06-23 17:05 ` Julien Grall
2016-06-23 3:17 ` [PATCH v2 13/17] libxl/arm: Link all ACPI tables into one buffer Shannon Zhao
2016-06-23 17:10 ` Julien Grall
2016-06-23 3:17 ` [PATCH v2 14/17] libxl/arm: Factor finalise_one_memory_node as a gerneric function Shannon Zhao
2016-06-23 3:17 ` [PATCH v2 15/17] libxl/arm: Add ACPI module Shannon Zhao
2016-06-23 18:35 ` Julien Grall
2016-06-25 3:22 ` Shannon Zhao
2016-06-27 9:48 ` Julien Grall
2016-06-23 3:17 ` [PATCH v2 16/17] libxc/xc_dom_arm: Copy ACPI tables to guest space Shannon Zhao
2016-06-23 18:46 ` Julien Grall
2016-06-27 6:25 ` Shannon Zhao
2016-06-27 10:49 ` Julien Grall
2016-06-27 12:11 ` Boris Ostrovsky
2016-07-05 17:13 ` Stefano Stabellini
2016-07-06 9:46 ` Julien Grall
2016-07-06 10:12 ` Stefano Stabellini
2016-07-12 3:47 ` Shannon Zhao
2016-07-12 9:25 ` Julien Grall
2016-07-12 11:35 ` Wei Liu
2016-07-12 14:42 ` Shannon Zhao
2016-07-12 14:50 ` Wei Liu
2016-07-12 14:57 ` Shannon Zhao
2016-07-12 15:08 ` Boris Ostrovsky
2016-07-12 15:13 ` Wei Liu
2016-07-12 15:21 ` Boris Ostrovsky
2016-07-12 16:05 ` Wei Liu
2016-07-12 16:10 ` Julien Grall
2016-07-12 16:58 ` Boris Ostrovsky
2016-07-13 15:22 ` Julien Grall
2016-07-13 17:08 ` Boris Ostrovsky
2016-07-14 11:15 ` Wei Liu
2016-07-15 9:39 ` Shannon Zhao [this message]
2016-07-19 10:38 ` Wei Liu
2016-07-20 6:52 ` Shannon Zhao
2016-07-20 9:32 ` Wei Liu
2016-07-25 7:56 ` Shannon Zhao
2016-07-28 11:10 ` Julien Grall
2016-07-14 11:29 ` Julien Grall
2016-07-14 13:37 ` Stefano Stabellini
2016-07-20 12:33 ` Julien Grall
2016-07-20 13:33 ` Boris Ostrovsky
2016-07-20 13:41 ` Julien Grall
2016-07-20 14:09 ` Boris Ostrovsky
2016-07-20 17:28 ` Stefano Stabellini
2016-07-20 19:51 ` Boris Ostrovsky
2016-07-21 17:53 ` Stefano Stabellini
2016-07-21 18:23 ` Julien Grall
2016-07-21 18:54 ` Stefano Stabellini
2016-07-21 19:14 ` Julien Grall
2016-07-21 21:15 ` Stefano Stabellini
2016-07-25 8:38 ` George Dunlap
2016-07-25 9:46 ` Julien Grall
2016-07-25 22:06 ` Stefano Stabellini
2016-07-25 22:46 ` Boris Ostrovsky
2016-07-25 23:40 ` Stefano Stabellini
2016-07-26 1:17 ` Boris Ostrovsky
2016-07-28 11:06 ` Julien Grall
2016-07-28 12:42 ` Shannon Zhao
2016-08-02 11:01 ` Wei Liu
2016-08-03 19:20 ` Julien Grall
2016-08-04 10:17 ` Wei Liu
2016-08-02 11:01 ` Wei Liu
2016-07-07 15:35 ` Wei Liu
2016-06-23 3:17 ` [PATCH v2 17/17] libxl/arm: Initialize domain param HVM_PARAM_CALLBACK_IRQ Shannon Zhao
2016-06-23 18:48 ` Julien Grall
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