From: Bertrand Marquis <Bertrand.Marquis@arm.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>,
"Ian Jackson" <iwj@xenproject.org>,
"Rahul Singh" <Rahul.Singh@arm.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Julien Grall" <julien@xen.org>,
"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Wei Liu" <wl@xen.org>, "Paul Durrant" <paul@xen.org>,
"Oleksandr Andrushchenko" <Oleksandr_Andrushchenko@epam.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH v6 2/3] xen/arm: Enable the existing x86 virtual PCI support for ARM.
Date: Fri, 15 Oct 2021 10:33:54 +0000 [thread overview]
Message-ID: <BFC005A8-4C72-41C5-93F4-98BB9CBAB198@arm.com> (raw)
In-Reply-To: <1c298c02-5791-8935-f996-516da2409f24@suse.com>
> On 15 Oct 2021, at 11:24, Jan Beulich <jbeulich@suse.com> wrote:
>
> On 15.10.2021 11:52, Bertrand Marquis wrote:
>>> On 15 Oct 2021, at 09:32, Roger Pau Monné <roger.pau@citrix.com> wrote:
>>> On Thu, Oct 14, 2021 at 03:49:50PM +0100, Bertrand Marquis wrote:
>>>> @@ -752,6 +752,19 @@ int pci_add_device(u16 seg, u8 bus, u8 devfn,
>>>>
>>>> check_pdev(pdev);
>>>>
>>>> +#ifdef CONFIG_ARM
>>>> + /*
>>>> + * On ARM PCI devices discovery will be done by Dom0. Add vpci handler when
>>>> + * Dom0 inform XEN to add the PCI devices in XEN.
>>>> + */
>>>> + ret = vpci_add_handlers(pdev);
>>>> + if ( ret )
>>>> + {
>>>> + printk(XENLOG_ERR "Setup of vPCI failed: %d\n", ret);
>>>> + goto out;
>>>> + }
>>>> +#endif
>>>
>>> I think vpci_add_handlers should be called after checking that
>>> pdev->domain is != NULL, so I would move this chunk a bit below.
>>
>> On arm this would prevent the dom0less use case or to have the PCI
>> bus enumerated from an other domain.
>> @oleksandr: can you comment on this one, you might have a better
>> answer than me on this ?
>
> Well, without Xen doing the enumeration, some other entity would need
> to do so, including the reporting to Xen. Obviously without a Dom0 it
> would be ambiguous which domain to assign the device to; perhaps it
> should be the caller in this case? That would make that caller domain
> a pseudo-hwdom though, as far as PCI is concerned, which may not be
> desirable according to my (limited) understanding of dom0less.
This is not really related to this patch but the plan is the following:
- enumeration would have to be done by the firmware or boot loader before
- xen will have some code to detect PCI devices
- dom0less can be used to assign PCI devices to guest
Anyway does not change the fact that this must be called when domain is not NULL and I will fix that.
>
>>>> @@ -784,6 +797,9 @@ out:
>>>> &PCI_SBDF(seg, bus, slot, func));
>>>> }
>>>> }
>>>> + else if ( pdev )
>>>> + pci_cleanup_msi(pdev);
>>>
>>> I'm slightly lost at why you add this chunk, is this strictly related
>>> to the patch?
>>
>> This was discussed a lot in previous version of the patch and
>> requested by Stefano. The idea here is that as soon as handlers
>> are added some bits might be modified in the PCI config space
>> leading possibly to msi interrupts. So it is safer to cleanup on the
>> error path. For references please see discussion on v4 and v5 where
>> this was actually added (to much references as the discussion was
>> long so here [1] and [2] are the patchwork thread).
>>
>> [1] https://patchwork.kernel.org/project/xen-devel/patch/9bdca2cda5d2e83f94dc2423e55714273539760a.1633540842.git.rahul.singh@arm.com/
>> [2] https://patchwork.kernel.org/project/xen-devel/patch/f093de681c2560a7196895bcd666ef8840885c1d.1633340795.git.rahul.singh@arm.com/
>
> The addition of this call has repeatedly raised questions. This is a
> good indication that sufficient discussion thereof has been lacking
> from the patch description.
Yes and I will remove it as it only impacts x86 right now.
If this is needed, we will have to do it while adding MSI support on Arm.
Regards
Bertrand
>
> Jan
>
next prev parent reply other threads:[~2021-10-15 10:34 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 [this message]
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
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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