From: Julien Grall <julien@xen.org>
To: "Alex Bennée" <alex.bennee@linaro.org>,
"Oleksandr Tyshchenko" <olekstysh@gmail.com>
Cc: "Oleksandr Tyshchenko" <oleksandr_tyshchenko@epam.com>,
"Paul Durrant" <paul@xen.org>, "Jan Beulich" <jbeulich@suse.com>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Julien Grall" <julien.grall@arm.com>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH V4 05/24] xen/ioreq: Make x86's hvm_ioreq_needs_completion() common
Date: Wed, 20 Jan 2021 09:31:38 +0000 [thread overview]
Message-ID: <7c05fcd2-f85b-5f5a-1be9-237d8fdc715f@xen.org> (raw)
In-Reply-To: <87v9bst29r.fsf@linaro.org>
Hi Alex,
On 20/01/2021 08:48, Alex Bennée wrote:
>
> Oleksandr Tyshchenko <olekstysh@gmail.com> writes:
>
>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>
>> The IOREQ is a common feature now and this helper will be used
>> on Arm as is. Move it to xen/ioreq.h and remove "hvm" prefix.
>>
>> Although PIO handling on Arm is not introduced with the current series
>> (it will be implemented when we add support for vPCI), technically
>> the PIOs exist on Arm (however they are accessed the same way as MMIO)
>> and it would be better not to diverge now.
>
> I find this description a little confusing. When you say PIO do you mean
> using instructions like in/out on the x86? If so then AFAIK it's a
> legacy feature of x86 as everything I've come across since just does
> MMIO, including PCI.
Stefano and I had quite a long discussion about this a few months ago
(see [1]).
From my understanding, while Arm will access the PCI I/O BAR via MMIO,
the BAR itself will be configured using an offset from a fixed I/O
window base address. IOW, we don't configure the BAR with a full MMIO
address.
In the case the hostbridge is emulated in Xen, I would like to re-use
the TYPE_PIO for such access because it makes the device model
arch-agnostic.
I believe this would behave the same way as a real PCI device card: you
can plug it anywhere without having to understand the underlying
architecture.
If we were going to use the MMIO type, then we would need:
1) Inform each device model where is the I/O Window (necessary to be
able to know we are accessing the I/O BAR)
2) Have arch boiler plate in the device model
>
> The code changes look fine to me though:
>
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
>
Cheers,
[1] <4cbe37bd-abd2-3d02-535e-cca6f7497ef2@xen.org>
--
Julien Grall
next prev parent reply other threads:[~2021-01-20 9:31 UTC|newest]
Thread overview: 144+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-12 21:52 [PATCH V4 00/24] IOREQ feature (+ virtio-mmio) on Arm Oleksandr Tyshchenko
2021-01-12 21:52 ` [PATCH V4 01/24] x86/ioreq: Prepare IOREQ feature for making it common Oleksandr Tyshchenko
2021-01-15 15:16 ` Julien Grall
2021-01-15 16:41 ` Jan Beulich
2021-01-16 9:48 ` Oleksandr
2021-01-18 8:22 ` Paul Durrant
2021-01-12 21:52 ` [PATCH V4 02/24] x86/ioreq: Add IOREQ_STATUS_* #define-s and update code for moving Oleksandr Tyshchenko
2021-01-15 15:17 ` Julien Grall
2021-01-18 8:24 ` Paul Durrant
2021-01-12 21:52 ` [PATCH V4 03/24] x86/ioreq: Provide out-of-line wrapper for the handle_mmio() Oleksandr Tyshchenko
2021-01-15 14:48 ` Alex Bennée
2021-01-15 15:19 ` Julien Grall
2021-01-18 8:29 ` Paul Durrant
2021-01-12 21:52 ` [PATCH V4 04/24] xen/ioreq: Make x86's IOREQ feature common Oleksandr Tyshchenko
2021-01-15 14:55 ` Alex Bennée
2021-01-15 15:23 ` Julien Grall
2021-01-18 8:48 ` Paul Durrant
2021-01-12 21:52 ` [PATCH V4 05/24] xen/ioreq: Make x86's hvm_ioreq_needs_completion() common Oleksandr Tyshchenko
2021-01-15 15:25 ` Julien Grall
2021-01-20 8:48 ` Alex Bennée
2021-01-20 9:31 ` Julien Grall [this message]
2021-01-12 21:52 ` [PATCH V4 06/24] xen/ioreq: Make x86's hvm_mmio_first(last)_byte() common Oleksandr Tyshchenko
2021-01-15 15:34 ` Julien Grall
2021-01-20 8:57 ` Alex Bennée
2021-01-20 16:15 ` Jan Beulich
2021-01-20 20:47 ` Oleksandr
2021-01-12 21:52 ` [PATCH V4 07/24] xen/ioreq: Make x86's hvm_ioreq_(page/vcpu/server) structs common Oleksandr Tyshchenko
2021-01-15 15:36 ` Julien Grall
2021-01-18 8:59 ` Paul Durrant
2021-01-20 8:58 ` Alex Bennée
2021-01-12 21:52 ` [PATCH V4 08/24] xen/ioreq: Move x86's ioreq_server to struct domain Oleksandr Tyshchenko
2021-01-15 15:44 ` Julien Grall
2021-01-18 9:09 ` Paul Durrant
2021-01-20 9:00 ` Alex Bennée
2021-01-12 21:52 ` [PATCH V4 09/24] xen/ioreq: Make x86's IOREQ related dm-op handling common Oleksandr Tyshchenko
2021-01-18 9:17 ` Paul Durrant
2021-01-18 10:19 ` Oleksandr
2021-01-18 10:34 ` Paul Durrant
2021-01-20 16:21 ` Jan Beulich
2021-01-21 10:23 ` Oleksandr
2021-01-21 10:27 ` Jan Beulich
2021-01-21 11:13 ` Oleksandr
2021-01-12 21:52 ` [PATCH V4 10/24] xen/ioreq: Move x86's io_completion/io_req fields to struct vcpu Oleksandr Tyshchenko
2021-01-15 19:34 ` Julien Grall
2021-01-18 9:35 ` Paul Durrant
2021-01-20 16:24 ` Jan Beulich
2021-01-12 21:52 ` [PATCH V4 11/24] xen/mm: Make x86's XENMEM_resource_ioreq_server handling common Oleksandr Tyshchenko
2021-01-14 3:58 ` Wei Chen
2021-01-14 15:31 ` Oleksandr
2021-01-15 14:35 ` Alex Bennée
2021-01-18 17:42 ` Oleksandr
2021-01-18 9:38 ` Paul Durrant
2021-01-12 21:52 ` [PATCH V4 12/24] xen/ioreq: Remove "hvm" prefixes from involved function names Oleksandr Tyshchenko
2021-01-18 9:55 ` Paul Durrant
2021-01-12 21:52 ` [PATCH V4 13/24] xen/ioreq: Use guest_cmpxchg64() instead of cmpxchg() Oleksandr Tyshchenko
2021-01-15 19:37 ` Julien Grall
2021-01-17 11:32 ` Oleksandr
2021-01-18 10:00 ` Paul Durrant
2021-01-12 21:52 ` [PATCH V4 14/24] arm/ioreq: Introduce arch specific bits for IOREQ/DM features Oleksandr Tyshchenko
2021-01-15 0:55 ` Stefano Stabellini
2021-01-17 12:45 ` Oleksandr
2021-01-20 0:23 ` Stefano Stabellini
2021-01-21 9:51 ` Oleksandr
2021-01-15 20:26 ` Julien Grall
2021-01-17 17:11 ` Oleksandr
2021-01-17 18:07 ` Julien Grall
2021-01-17 18:52 ` Oleksandr
2021-01-18 19:17 ` Julien Grall
2021-01-19 15:20 ` Oleksandr
2021-01-20 0:50 ` Stefano Stabellini
2021-01-20 15:57 ` Julien Grall
2021-01-20 19:47 ` Stefano Stabellini
2021-01-21 9:31 ` Oleksandr
2021-01-21 21:34 ` Stefano Stabellini
2021-01-20 15:50 ` Julien Grall
2021-01-21 8:50 ` Oleksandr
2021-01-27 10:24 ` Jan Beulich
2021-01-27 12:22 ` Oleksandr
2021-01-27 12:52 ` Jan Beulich
2021-01-18 10:44 ` Jan Beulich
2021-01-18 15:52 ` Oleksandr
2021-01-18 16:00 ` Jan Beulich
2021-01-18 16:29 ` Oleksandr
2021-01-12 21:52 ` [PATCH V4 15/24] xen/arm: Stick around in leave_hypervisor_to_guest until I/O has completed Oleksandr Tyshchenko
2021-01-15 1:12 ` Stefano Stabellini
2021-01-15 20:55 ` Julien Grall
2021-01-17 20:23 ` Oleksandr
2021-01-18 10:57 ` Julien Grall
2021-01-18 13:23 ` Oleksandr
2021-01-12 21:52 ` [PATCH V4 16/24] xen/mm: Handle properly reference in set_foreign_p2m_entry() on Arm Oleksandr Tyshchenko
2021-01-15 1:19 ` Stefano Stabellini
2021-01-15 20:59 ` Julien Grall
2021-01-21 13:57 ` Jan Beulich
2021-01-21 18:42 ` Oleksandr
2021-01-12 21:52 ` [PATCH V4 17/24] xen/ioreq: Introduce domain_has_ioreq_server() Oleksandr Tyshchenko
2021-01-15 1:24 ` Stefano Stabellini
2021-01-18 10:23 ` Paul Durrant
2021-01-12 21:52 ` [PATCH V4 18/24] xen/dm: Introduce xendevicemodel_set_irq_level DM op Oleksandr Tyshchenko
2021-01-15 1:32 ` Stefano Stabellini
2021-01-12 21:52 ` [PATCH V4 19/24] xen/arm: io: Abstract sign-extension Oleksandr Tyshchenko
2021-01-15 1:35 ` Stefano Stabellini
2021-01-12 21:52 ` [PATCH V4 20/24] xen/arm: io: Harden sign extension check Oleksandr Tyshchenko
2021-01-15 1:48 ` Stefano Stabellini
2021-01-22 10:15 ` Volodymyr Babchuk
2021-01-12 21:52 ` [PATCH V4 21/24] xen/ioreq: Make x86's send_invalidate_req() common Oleksandr Tyshchenko
2021-01-18 10:31 ` Paul Durrant
2021-01-21 14:02 ` Jan Beulich
2021-01-12 21:52 ` [PATCH V4 22/24] xen/arm: Add mapcache invalidation handling Oleksandr Tyshchenko
2021-01-15 2:11 ` Stefano Stabellini
2021-01-21 19:47 ` Oleksandr
2021-01-12 21:52 ` [PATCH V4 23/24] libxl: Introduce basic virtio-mmio support on Arm Oleksandr Tyshchenko
2021-01-15 21:30 ` Julien Grall
2021-01-17 22:22 ` Oleksandr
2021-01-20 16:40 ` Julien Grall
2021-01-20 20:35 ` Stefano Stabellini
2021-02-09 21:04 ` Oleksandr
2021-01-12 21:52 ` [PATCH V4 24/24] [RFC] libxl: Add support for virtio-disk configuration Oleksandr Tyshchenko
2021-01-14 17:20 ` Ian Jackson
2021-01-16 9:05 ` Oleksandr
2021-01-15 22:01 ` Julien Grall
2021-01-18 8:32 ` Oleksandr
2021-01-20 17:05 ` Julien Grall
2021-02-10 9:02 ` Oleksandr
2021-03-06 19:52 ` Julien Grall
2021-01-14 3:55 ` [PATCH V4 00/24] IOREQ feature (+ virtio-mmio) on Arm Wei Chen
2021-01-14 15:23 ` Oleksandr
2021-01-07 14:35 ` [ANNOUNCE] Xen 4.15 release schedule and feature tracking Ian Jackson
2021-01-07 15:45 ` Oleksandr
2021-01-14 16:11 ` [PATCH V4 00/24] IOREQ feature (+ virtio-mmio) on Arm Ian Jackson
2021-01-14 18:41 ` Oleksandr
2021-01-14 16:06 ` [ANNOUNCE] Xen 4.15 release schedule and feature tracking Ian Jackson
2021-01-14 19:02 ` Andrew Cooper
2021-01-15 9:57 ` Jan Beulich
2021-01-15 10:00 ` Julien Grall
2021-01-15 10:52 ` Andrew Cooper
2021-01-15 10:59 ` Andrew Cooper
2021-01-15 11:08 ` Jan Beulich
2021-01-15 10:43 ` Bertrand Marquis
2021-01-15 15:14 ` Lengyel, Tamas
2021-01-28 22:55 ` Dario Faggioli
2021-01-28 18:26 ` Dario Faggioli
2021-01-28 22:15 ` Dario Faggioli
2021-01-29 8:38 ` Jan Beulich
2021-01-29 9:22 ` Dario Faggioli
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