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From: Julien Grall <julien@xen.org>
To: Michal Orzel <michal.orzel@arm.com>, Ian Jackson <iwj@xenproject.org>
Cc: Bertrand Marquis <Bertrand.Marquis@arm.com>,
	xen-devel@lists.xenproject.org, Rahul Singh <rahul.singh@arm.com>,
	Wei Liu <wl@xen.org>, Anthony PERARD <anthony.perard@citrix.com>,
	Juergen Gross <jgross@suse.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
	Andre Przywara <Andre.Przywara@arm.com>
Subject: Re: [PATCH v6 3/3] arm/libxl: Emulated PCI device tree node in libxl [and 1 more messages]
Date: Fri, 15 Oct 2021 13:10:47 +0100	[thread overview]
Message-ID: <76897e97-8f44-d1c5-f108-045ea48442e5@xen.org> (raw)
In-Reply-To: <6e29d836-918c-3b15-7608-342b2e4f8475@arm.com>

Hi Michal,

On 15/10/2021 12:53, Michal Orzel wrote:
> 
> 
> On 15.10.2021 13:46, Ian Jackson wrote:
>> Michal Orzel writes ("Re: [PATCH v6 3/3] arm/libxl: Emulated PCI device tree node in libxl [and 1 more messages]"):
>>> On 15.10.2021 12:02, Ian Jackson wrote:
>>>> Can you leave a comment somewhere (near where c_info.passthrough is
>>>> set) pointing to this use of num_pcidevs ?  That might save someone
>>>> some future confusion.
>>>
>>> Here, c_info->passthrough is set to enabled if either d_config->num_pcidevs or
>>> d_config->num_dtdevs is set. Do you think we need to add there additional comment?
>>> If so can you please help with what should I write there?
>>>
>>> BTW. None of the patch I'm preparing with regards to this discussion modifies libxl_create
>>> where c_info.passthrough i set. Do you still want me to add some comment there?
>>
>> Yes, I think so.  I won't insisting on it if you feel it doesn't make
>> sense.
>>
>> Maybe something like
>>
>>    // NB, on ARM, libxl__arch_blah directly examines num_pcidevs to
>>    // decide whether to enable vpci, rather than using c_info->passthrough.
>>    // This will be insufficient if and when ARM does PCI hotplug.
>>
> Well we are not enabling vpci. We are creating a DT node for it.
> So either I will write:
> /*
>   * Note: libxl_arm directly examines num_pcidevs to decide whether
>   * to create a vPCI DT node, rather than using c_info->passthrough.
>   * This will be insufficient if and when ARM does PCI hotplug.
>   */
> 
> or I will not add any comment (it can be add in the future when "enabling" vpci).
> @Julien?

I would prefer if we had a comment. Your proposal makes more sense as we 
only create the DT.

Long term, I would expect a similar check to be necessary to set the 
vCPI flag at the domain creation. So it would be best to introduce an 
internal field 'vpci' to avoid duplicating that check. (Note I am not 
requesting this change for Xen 4.16).

Cheers,

-- 
Julien Grall


  reply	other threads:[~2021-10-15 12:11 UTC|newest]

Thread overview: 190+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-06 17:40 [PATCH v5 00/11] PCI devices passthrough on Arm Rahul Singh
2021-10-06 17:40 ` [PATCH v5 01/11] xen/arm: xc_domain_ioport_permission(..) not supported on ARM Rahul Singh
2021-10-11 11:47   ` Roger Pau Monné
2021-10-11 12:11     ` Bertrand Marquis
2021-10-11 13:20       ` Roger Pau Monné
2021-10-11 13:40         ` Bertrand Marquis
2021-10-11 13:57           ` Roger Pau Monné
2021-10-11 14:16             ` Bertrand Marquis
2021-10-11 16:32               ` Roger Pau Monné
2021-10-11 17:11                 ` Bertrand Marquis
2021-10-12  8:29                   ` Jan Beulich
2021-10-12  8:41                     ` Bertrand Marquis
2021-10-12  9:32                       ` Jan Beulich
2021-10-12  9:38                         ` Oleksandr Andrushchenko
2021-10-12 10:01                           ` Jan Beulich
2021-10-12 10:06                             ` Oleksandr Andrushchenko
2021-10-12 10:20                               ` Jan Beulich
2021-10-12 10:41                                 ` Bertrand Marquis
2021-10-12 10:44                                   ` Jan Beulich
2021-10-12 14:53                                   ` Ian Jackson
2021-10-12 16:15                                     ` Bertrand Marquis
2021-10-12 16:29                                       ` Ian Jackson
2021-10-12 20:42                                         ` Stefano Stabellini
2021-10-13  8:07                                           ` Roger Pau Monné
2021-10-13 11:52                                             ` Ian Jackson
2021-10-13  8:02                                       ` Roger Pau Monné
2021-10-13 12:02                                         ` Ian Jackson
2021-10-12  9:40                         ` Bertrand Marquis
2021-10-12 10:03                           ` Jan Beulich
2021-10-11 14:16           ` Oleksandr Andrushchenko
2021-10-06 17:40 ` [PATCH v5 02/11] xen/arm: Add PHYSDEVOP_pci_device_(*add/remove) support for ARM Rahul Singh
2021-10-07  0:05   ` Stefano Stabellini
2021-10-07 12:58     ` Jan Beulich
2021-10-21  9:28   ` xen/arm: Missing appropriate locking for the IOMMU (WAS Re: [PATCH v5 02/11] xen/arm: Add PHYSDEVOP_pci_device_(*add/remove) support for ARM) Julien Grall
2021-10-21 13:15     ` Bertrand Marquis
2021-10-21 13:47       ` Julien Grall
2021-10-21 13:52         ` Bertrand Marquis
2021-10-06 17:40 ` [PATCH v5 03/11] xen/arm: Add cmdline boot option "pci-passthrough = <boolean>" Rahul Singh
2021-10-07  8:27   ` Jan Beulich
2021-10-07  8:32     ` Rahul Singh
2021-10-07 12:59   ` Jan Beulich
2021-10-06 17:40 ` [PATCH v5 04/11] xen/arm: PCI host bridge discovery within XEN on ARM Rahul Singh
2021-10-06 17:40 ` [PATCH v5 05/11] xen/arm: Add support for Xilinx ZynqMP PCI host controller Rahul Singh
2021-10-06 17:40 ` [PATCH v5 06/11] xen/arm: Implement pci access functions Rahul Singh
2021-10-06 17:40 ` [PATCH v5 07/11] xen/domctl: Introduce XEN_DOMCTL_CDF_vpci flag Rahul Singh
2021-10-07 13:08   ` Jan Beulich
2021-10-08 18:06   ` Andrew Cooper
2021-10-08 21:12     ` Julien Grall
2021-10-08 21:46       ` Stefano Stabellini
2021-10-11  9:24         ` Julien Grall
2021-10-11 11:29         ` Michal Orzel
2021-10-11 11:35           ` Jan Beulich
2021-10-11 13:17             ` Roger Pau Monné
2021-10-11  9:48     ` Ian Jackson
2021-10-11  9:27   ` Roger Pau Monné
2021-10-11 12:06     ` Michal Orzel
2021-10-12 10:38     ` Michal Orzel
2021-10-13  8:30       ` Roger Pau Monné
2021-10-13  9:36         ` Bertrand Marquis
2021-10-13 10:56           ` Roger Pau Monné
2021-10-13 12:11             ` Bertrand Marquis
2021-10-13 12:57               ` Jan Beulich
2021-10-13 20:41                 ` Stefano Stabellini
2021-10-14  6:23                   ` Jan Beulich
2021-10-14  7:53                     ` Bertrand Marquis
2021-10-13 14:28               ` Roger Pau Monné
2021-10-13 20:53             ` Stefano Stabellini
2021-10-13 23:21               ` Stefano Stabellini
2021-10-12 21:48     ` Stefano Stabellini
2021-10-13  6:18       ` Jan Beulich
2021-10-13  7:11         ` Michal Orzel
2021-10-06 17:40 ` [PATCH v5 08/11] xen/arm: Enable the existing x86 virtual PCI support for ARM Rahul Singh
2021-10-07 13:43   ` Jan Beulich
2021-10-11 12:41     ` Bertrand Marquis
2021-10-11 13:09       ` Jan Beulich
2021-10-11 13:34         ` Bertrand Marquis
2021-10-11 14:10           ` Jan Beulich
2021-10-11 14:52             ` Bertrand Marquis
2021-10-11 18:18             ` Stefano Stabellini
2021-10-12  8:04               ` Jan Beulich
2021-10-12 21:37                 ` Stefano Stabellini
2021-10-13  6:10                   ` Jan Beulich
2021-10-13 10:02                     ` Bertrand Marquis
2021-10-13 12:21                       ` Jan Beulich
2021-10-12 15:04       ` Julien Grall
2021-10-12 16:12         ` Bertrand Marquis
2021-10-12 16:20           ` Julien Grall
2021-10-12 17:50             ` Bertrand Marquis
2021-10-11 10:51   ` Roger Pau Monné
2021-10-11 16:12     ` Bertrand Marquis
2021-10-11 16:20       ` Oleksandr Andrushchenko
2021-10-11 16:43         ` Roger Pau Monné
2021-10-11 17:15           ` Bertrand Marquis
2021-10-11 18:30             ` Oleksandr Andrushchenko
2021-10-11 19:27               ` Stefano Stabellini
2021-10-12  5:34                 ` Oleksandr Andrushchenko
2021-10-12  7:44                 ` Bertrand Marquis
2021-10-12 14:32   ` Julien Grall
2021-10-12 14:34     ` Bertrand Marquis
2021-10-13  8:45   ` Roger Pau Monné
2021-10-13  9:48     ` Bertrand Marquis
2021-10-13 10:33       ` Roger Pau Monné
2021-10-13 13:00     ` Jan Beulich
2021-10-13 14:51       ` Oleksandr Andrushchenko
2021-10-13 15:15         ` Jan Beulich
2021-10-13 19:27           ` Stefano Stabellini
2021-10-14  6:33             ` Jan Beulich
2021-10-14  7:53               ` Bertrand Marquis
2021-10-14  9:03               ` Bertrand Marquis
2021-10-14  9:24                 ` Jan Beulich
2021-10-06 17:40 ` [PATCH v5 09/11] xen/arm: Transitional change to build HAS_VPCI on ARM Rahul Singh
2021-10-11 11:43   ` Roger Pau Monné
2021-10-11 12:15     ` Bertrand Marquis
2021-10-12  1:32       ` Stefano Stabellini
2021-10-06 17:40 ` [PATCH v5 10/11] arm/libxl: Emulated PCI device tree node in libxl Rahul Singh
2021-10-06 18:01   ` Julien Grall
2021-10-07  0:26     ` Stefano Stabellini
2021-10-07 15:31       ` Rahul Singh
2021-10-07 10:53     ` Ian Jackson
2021-10-07 15:29       ` Rahul Singh
2021-10-07 16:11         ` Ian Jackson
2021-10-11 13:46           ` Roger Pau Monné
2021-10-14 17:16           ` Bertrand Marquis
2021-10-14 14:49             ` [PATCH v6 0/3] PCI devices passthrough on Arm Bertrand Marquis
2021-10-14 14:49               ` [PATCH v6 1/3] xen/vpci: Move ecam access functions to common code Bertrand Marquis
2021-10-14 16:06                 ` Jan Beulich
2021-10-14 17:09                   ` Bertrand Marquis
2021-10-15  6:29                     ` Jan Beulich
2021-10-15  7:37                       ` Bertrand Marquis
2021-10-15  8:13                         ` Jan Beulich
2021-10-15  8:20                           ` Bertrand Marquis
2021-10-15  8:24                             ` Jan Beulich
2021-10-15  9:49                           ` Roger Pau Monné
2021-10-14 23:47                 ` Stefano Stabellini
2021-10-15  7:44                 ` Roger Pau Monné
2021-10-15  7:53                   ` Bertrand Marquis
2021-10-15  9:53                     ` Roger Pau Monné
2021-10-15 10:12                       ` Bertrand Marquis
2021-10-15 10:14                       ` Jan Beulich
2021-10-14 14:49               ` [PATCH v6 2/3] xen/arm: Enable the existing x86 virtual PCI support for ARM Bertrand Marquis
2021-10-14 23:49                 ` Stefano Stabellini
2021-10-15  6:40                   ` Jan Beulich
2021-10-15  9:59                     ` Ian Jackson
2021-10-15 10:10                   ` Bertrand Marquis
2021-10-15  8:00                 ` Jan Beulich
2021-10-15 10:09                   ` Bertrand Marquis
2021-10-15 10:14                     ` Ian Jackson
2021-10-15 10:18                       ` Jan Beulich
2021-10-15 11:35                         ` Roger Pau Monné
2021-10-15 12:13                           ` Bertrand Marquis
2021-10-15 12:18                             ` Jan Beulich
2021-10-15 12:28                               ` Bertrand Marquis
2021-10-15 13:00                                 ` Jan Beulich
2021-10-15 13:10                                   ` Bertrand Marquis
2021-10-15 10:38                     ` Jan Beulich
2021-10-15  8:32                 ` Roger Pau Monné
2021-10-15  8:42                   ` Michal Orzel
2021-10-15  9:52                   ` Bertrand Marquis
2021-10-15 10:13                     ` Luca Fancellu
2021-10-15 10:17                       ` Bertrand Marquis
2021-10-15 10:19                     ` Roger Pau Monné
2021-10-15 10:31                       ` Bertrand Marquis
2021-10-15 10:24                     ` Jan Beulich
2021-10-15 10:33                       ` Bertrand Marquis
2021-10-15 10:41                         ` Jan Beulich
2021-10-15 10:48                           ` Bertrand Marquis
2021-10-15 10:51                             ` Jan Beulich
2021-10-15 11:08                               ` Bertrand Marquis
2021-10-15 13:47                             ` Roger Pau Monné
2021-10-15 14:00                               ` Luca Fancellu
2021-10-15 14:32                                 ` Roger Pau Monné
2021-10-14 14:49               ` [PATCH v6 3/3] arm/libxl: Emulated PCI device tree node in libxl Bertrand Marquis
2021-10-14 17:54                 ` [PATCH v6 3/3] arm/libxl: Emulated PCI device tree node in libxl [and 1 more messages] Ian Jackson
2021-10-14 23:50                   ` Stefano Stabellini
2021-10-15  7:28                   ` Julien Grall
2021-10-15  7:41                     ` Michal Orzel
2021-10-15  9:01                       ` Julien Grall
2021-10-15 10:02                     ` Ian Jackson
2021-10-15 10:58                       ` Michal Orzel
2021-10-15 11:04                         ` Michal Orzel
2021-10-15 11:46                         ` Ian Jackson
2021-10-15 11:53                           ` Michal Orzel
2021-10-15 12:10                             ` Julien Grall [this message]
2021-10-15 12:14                               ` Ian Jackson
2021-10-15 12:13                             ` Ian Jackson
2021-10-12 15:03   ` [PATCH v5 10/11] arm/libxl: Emulated PCI device tree node in libxl Ian Jackson
2021-10-06 17:40 ` [PATCH v5 11/11] xen/arm: Add linux,pci-domain property for hwdom if not available Rahul Singh
2021-10-13 20:54   ` Stefano Stabellini
2021-10-07 19:54 ` [PATCH v5 00/11] PCI devices passthrough on Arm Stefano Stabellini
2021-10-07 21:29   ` Rahul Singh

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