From: Oleksandr Andrushchenko <Oleksandr_Andrushchenko@epam.com>
To: Jan Beulich <jbeulich@suse.com>,
Bertrand Marquis <bertrand.marquis@arm.com>
Cc: "Rahul Singh" <rahul.singh@arm.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"Andre Przywara" <Andre.Przywara@arm.com>,
"Ian Jackson" <iwj@xenproject.org>, "Wei Liu" <wl@xen.org>,
"Juergen Gross" <jgross@suse.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Roger Pau Monné" <roger.pau@citrix.com>,
"Oleksandr Andrushchenko" <Oleksandr_Andrushchenko@epam.com>
Subject: Re: [PATCH v5 01/11] xen/arm: xc_domain_ioport_permission(..) not supported on ARM.
Date: Tue, 12 Oct 2021 09:38:29 +0000 [thread overview]
Message-ID: <c3952fd5-b893-4cb6-a9bc-325a89e859db@epam.com> (raw)
In-Reply-To: <0744b957-1832-dff2-9ae2-b8e8534f501b@suse.com>
On 12.10.21 12:32, Jan Beulich wrote:
> On 12.10.2021 10:41, Bertrand Marquis wrote:
>> Hi Jan,
>>
>>> On 12 Oct 2021, at 09:29, Jan Beulich <jbeulich@suse.com> wrote:
>>>
>>> On 11.10.2021 19:11, Bertrand Marquis wrote:
>>>>> On 11 Oct 2021, at 17:32, Roger Pau Monné <roger.pau@citrix.com> wrote:
>>>>> On Mon, Oct 11, 2021 at 02:16:19PM +0000, Bertrand Marquis wrote:
>>>>>>> On 11 Oct 2021, at 14:57, Roger Pau Monné <roger.pau@citrix.com> wrote:
>>>>>>> I think the commit message needs to at least be expanded in order to
>>>>>>> contain the information provided here. It might also be helpful to
>>>>>>> figure out whether we would have to handle IO port accesses in the
>>>>>>> future on Arm, or if it's fine to just ignore them.
>>>>>> All our investigations and tests have been done without supporting it
>>>>>> without any issues so this is not a critical feature (most devices can
>>>>>> be operated without using the I/O ports).
>>>>> IMO we should let the users know they attempted to use a device with
>>>>> BARs in the IO space, and that those BARs won't be accessible which
>>>>> could make the device not function as expected.
>>>>>
>>>>> Do you think it would be reasonable to attempt the hypercall on Arm
>>>>> also, and in case of error (on Arm) just print a warning message and
>>>>> continue operations as normal?
>>>> I think this would lead to a warning printed on lots of devices where in
>>>> fact there would be no issues.
>>>>
>>>> If this is an issue for a device driver because it cannot operate without
>>>> I/O ports, this will be raised by the driver inside the guest.
>>> On what basis would the driver complain? The kernel might know of
>>> the MMIO equivalent for ports, and hence might allow the driver
>>> to properly obtain whatever is needed to later access the ports.
>>> Just that the port accesses then wouldn't work (possibly crashing
>>> the guest, or making it otherwise misbehave).
>> As ECAM and Arm does not support I/O ports, a driver requesting access
>> to them would get an error back.
>> So in practice it is not possible to try to access the ioports as there is no
>> way on arm to use them (no instructions).
>>
>> A driver could misbehave by ignoring the fact that ioports are not there but
>> I am not quite sure how we could solve that as it would be a bug in the driver.
> The minimal thing I'd suggest (or maybe you're doing this already)
> would be to expose such BARs to the guest as r/o zero, rather than
> letting their port nature "shine through".
If we have the same, but baremetal then which entity disallows
those BARs to shine? I mean that if guest wants to crash... why
should we stop it and try emulating something special for it?
>
> Jan
>
next prev parent reply other threads:[~2021-10-12 9:39 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 [this message]
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
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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