From: Jan Beulich <jbeulich@suse.com>
To: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien@xen.org>, Wei Liu <wl@xen.org>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Oleksandr Tyshchenko <olekstysh@gmail.com>,
Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>,
Julien Grall <julien.grall@arm.com>,
xen-devel@lists.xenproject.org,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
Subject: Re: [RFC PATCH V1 05/12] hvm/dm: Introduce xendevicemodel_set_irq_level DM op
Date: Fri, 7 Aug 2020 10:43:20 +0200 [thread overview]
Message-ID: <d8aa0f36-d3c4-011a-9ec1-32c1e3118112@suse.com> (raw)
In-Reply-To: <alpine.DEB.2.21.2008061422300.16004@sstabellini-ThinkPad-T480s>
On 07.08.2020 01:49, Stefano Stabellini wrote:
> On Thu, 6 Aug 2020, Julien Grall wrote:
>> On 06/08/2020 01:37, Stefano Stabellini wrote:
>>> On Wed, 5 Aug 2020, Julien Grall wrote:
>>>> On 05/08/2020 00:22, Stefano Stabellini wrote:
>>>>> On Mon, 3 Aug 2020, Oleksandr Tyshchenko wrote:
>>>>>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>>>>>
>>>>>> This patch adds ability to the device emulator to notify otherend
>>>>>> (some entity running in the guest) using a SPI and implements Arm
>>>>>> specific bits for it. Proposed interface allows emulator to set
>>>>>> the logical level of a one of a domain's IRQ lines.
>>>>>>
>>>>>> Please note, this is a split/cleanup of Julien's PoC:
>>>>>> "Add support for Guest IO forwarding to a device emulator"
>>>>>>
>>>>>> Signed-off-by: Julien Grall <julien.grall@arm.com>
>>>>>> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
>>>>>> ---
>>>>>> tools/libs/devicemodel/core.c | 18
>>>>>> ++++++++++++++++++
>>>>>> tools/libs/devicemodel/include/xendevicemodel.h | 4 ++++
>>>>>> tools/libs/devicemodel/libxendevicemodel.map | 1 +
>>>>>> xen/arch/arm/dm.c | 22
>>>>>> +++++++++++++++++++++-
>>>>>> xen/common/hvm/dm.c | 1 +
>>>>>> xen/include/public/hvm/dm_op.h | 15
>>>>>> +++++++++++++++
>>>>>> 6 files changed, 60 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/tools/libs/devicemodel/core.c
>>>>>> b/tools/libs/devicemodel/core.c
>>>>>> index 4d40639..30bd79f 100644
>>>>>> --- a/tools/libs/devicemodel/core.c
>>>>>> +++ b/tools/libs/devicemodel/core.c
>>>>>> @@ -430,6 +430,24 @@ int xendevicemodel_set_isa_irq_level(
>>>>>> return xendevicemodel_op(dmod, domid, 1, &op, sizeof(op));
>>>>>> }
>>>>>> +int xendevicemodel_set_irq_level(
>>>>>> + xendevicemodel_handle *dmod, domid_t domid, uint32_t irq,
>>>>>> + unsigned int level)
>>>>>
>>>>> It is a pity that having xen_dm_op_set_pci_intx_level and
>>>>> xen_dm_op_set_isa_irq_level already we need to add a third one, but from
>>>>> the names alone I don't think we can reuse either of them.
>>>>
>>>> The problem is not the name...
>>>>
>>>>>
>>>>> It is very similar to set_isa_irq_level. We could almost rename
>>>>> xendevicemodel_set_isa_irq_level to xendevicemodel_set_irq_level or,
>>>>> better, just add an alias to it so that xendevicemodel_set_irq_level is
>>>>> implemented by calling xendevicemodel_set_isa_irq_level. Honestly I am
>>>>> not sure if it is worth doing it though. Any other opinions?
>>>>
>>>> ... the problem is the interrupt field is only 8-bit. So we would only be
>>>> able
>>>> to cover IRQ 0 - 255.
>>>
>>> Argh, that's not going to work :-( I wasn't sure if it was a good idea
>>> anyway.
>>>
>>>
>>>> It is not entirely clear how the existing subop could be extended without
>>>> breaking existing callers.
>>>>
>>>>> But I think we should plan for not needing two calls (one to set level
>>>>> to 1, and one to set it to 0):
>>>>> https://marc.info/?l=xen-devel&m=159535112027405
>>>>
>>>> I am not sure to understand your suggestion here? Are you suggesting to
>>>> remove
>>>> the 'level' parameter?
>>>
>>> My hope was to make it optional to call the hypercall with level = 0,
>>> not necessarily to remove 'level' from the struct.
>>
>> From my understanding, the hypercall is meant to represent the status of the
>> line between the device and the interrupt controller (either low or high).
>>
>> This is then up to the interrupt controller to decide when the interrupt is
>> going to be fired:
>> - For edge interrupt, this will fire when the line move from low to high (or
>> vice versa).
>> - For level interrupt, this will fire when line is high (assuming level
>> trigger high) and will keeping firing until the device decided to lower the
>> line.
>>
>> For a device, it is common to keep the line high until an OS wrote to a
>> specific register.
>>
>> Furthermore, technically, the guest OS is in charge to configure how an
>> interrupt is triggered. Admittely this information is part of the DT, but
>> nothing prevent a guest to change it.
>>
>> As side note, we have a workaround in Xen for some buggy DT (see the arch
>> timer) exposing the wrong trigger type.
>>
>> Because of that, I don't really see a way to make optional. Maybe you have
>> something different in mind?
>
> For level, we need the level parameter. For edge, we are only interested
> in the "edge", right?
I don't think so, unless Arm has special restrictions. Edges can be
both rising and falling ones.
Jan
next prev parent reply other threads:[~2020-08-07 8:43 UTC|newest]
Thread overview: 140+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-03 18:21 [RFC PATCH V1 00/12] IOREQ feature (+ virtio-mmio) on Arm Oleksandr Tyshchenko
2020-08-03 18:21 ` [RFC PATCH V1 01/12] hvm/ioreq: Make x86's IOREQ feature common Oleksandr Tyshchenko
2020-08-04 7:45 ` Paul Durrant
2020-08-04 11:10 ` Oleksandr
2020-08-04 11:23 ` Paul Durrant
2020-08-04 11:51 ` Oleksandr
2020-08-04 13:18 ` Paul Durrant
2020-08-04 13:52 ` Julien Grall
2020-08-04 15:41 ` Jan Beulich
2020-08-04 19:11 ` Stefano Stabellini
2020-08-05 7:01 ` Jan Beulich
2020-08-06 0:37 ` Stefano Stabellini
2020-08-06 6:59 ` Jan Beulich
2020-08-06 20:32 ` Stefano Stabellini
2020-08-07 13:19 ` Oleksandr
2020-08-07 16:45 ` Oleksandr
2020-08-07 21:50 ` Stefano Stabellini
2020-08-07 22:19 ` Oleksandr
2020-08-10 13:41 ` Oleksandr
2020-08-10 23:34 ` Stefano Stabellini
2020-08-11 9:19 ` Julien Grall
2020-08-11 10:10 ` Oleksandr
2020-08-11 22:47 ` Stefano Stabellini
2020-08-12 14:35 ` Oleksandr
2020-08-12 23:08 ` Stefano Stabellini
2020-08-13 20:16 ` Julien Grall
2020-08-07 23:45 ` Oleksandr
2020-08-10 23:34 ` Stefano Stabellini
2020-08-05 8:33 ` Julien Grall
2020-08-06 0:37 ` Stefano Stabellini
2020-08-06 9:45 ` Julien Grall
2020-08-06 23:48 ` Stefano Stabellini
2020-08-10 19:20 ` Julien Grall
2020-08-10 23:34 ` Stefano Stabellini
2020-08-11 11:28 ` Julien Grall
2020-08-11 22:48 ` Stefano Stabellini
2020-08-12 8:19 ` Julien Grall
2020-08-20 19:14 ` Oleksandr
2020-08-21 0:53 ` Stefano Stabellini
2020-08-21 18:54 ` Julien Grall
2020-08-05 13:30 ` Julien Grall
2020-08-06 11:37 ` Oleksandr
2020-08-10 16:29 ` Julien Grall
2020-08-10 17:28 ` Oleksandr
2020-08-05 16:15 ` Andrew Cooper
2020-08-06 8:20 ` Oleksandr
2020-08-15 17:30 ` Julien Grall
2020-08-16 19:37 ` Oleksandr
2020-08-03 18:21 ` [RFC PATCH V1 02/12] hvm/dm: Make x86's DM " Oleksandr Tyshchenko
2020-08-03 18:21 ` [RFC PATCH V1 03/12] xen/mm: Make x86's XENMEM_resource_ioreq_server handling common Oleksandr Tyshchenko
2020-08-03 18:21 ` [RFC PATCH V1 04/12] xen/arm: Introduce arch specific bits for IOREQ/DM features Oleksandr Tyshchenko
2020-08-04 7:49 ` Paul Durrant
2020-08-04 14:01 ` Julien Grall
2020-08-04 23:22 ` Stefano Stabellini
2020-08-15 17:56 ` Julien Grall
2020-08-17 14:36 ` Oleksandr
2020-08-04 23:22 ` Stefano Stabellini
2020-08-05 7:05 ` Jan Beulich
2020-08-05 16:41 ` Stefano Stabellini
2020-08-05 19:45 ` Oleksandr
2020-08-05 9:32 ` Julien Grall
2020-08-05 15:41 ` Oleksandr
2020-08-06 10:19 ` Julien Grall
2020-08-10 18:09 ` Oleksandr
2020-08-10 18:21 ` Oleksandr
2020-08-10 19:00 ` Julien Grall
2020-08-10 20:29 ` Oleksandr
2020-08-10 22:37 ` Julien Grall
2020-08-11 6:13 ` Oleksandr
2020-08-12 15:08 ` Oleksandr
2020-08-11 17:09 ` Oleksandr
2020-08-11 17:50 ` Julien Grall
2020-08-13 18:41 ` Oleksandr
2020-08-13 20:36 ` Julien Grall
2020-08-13 21:49 ` Oleksandr
2020-08-13 20:39 ` Oleksandr Tyshchenko
2020-08-13 22:14 ` Julien Grall
2020-08-14 12:08 ` Oleksandr
2020-08-05 14:12 ` Julien Grall
2020-08-05 14:45 ` Jan Beulich
2020-08-05 19:30 ` Oleksandr
2020-08-06 11:08 ` Julien Grall
2020-08-06 11:29 ` Jan Beulich
2020-08-20 18:30 ` Oleksandr
2020-08-21 6:16 ` Jan Beulich
2020-08-21 11:13 ` Oleksandr
2020-08-06 13:27 ` Oleksandr
2020-08-10 18:25 ` Julien Grall
2020-08-10 19:58 ` Oleksandr
2020-08-05 16:13 ` Jan Beulich
2020-08-05 19:47 ` Oleksandr
2020-08-03 18:21 ` [RFC PATCH V1 05/12] hvm/dm: Introduce xendevicemodel_set_irq_level DM op Oleksandr Tyshchenko
2020-08-04 23:22 ` Stefano Stabellini
2020-08-05 9:39 ` Julien Grall
2020-08-06 0:37 ` Stefano Stabellini
2020-08-06 11:32 ` Julien Grall
2020-08-06 23:49 ` Stefano Stabellini
2020-08-07 8:43 ` Jan Beulich [this message]
2020-08-07 21:50 ` Stefano Stabellini
2020-08-08 9:27 ` Julien Grall
2020-08-08 9:28 ` Julien Grall
2020-08-10 23:34 ` Stefano Stabellini
2020-08-11 13:04 ` Julien Grall
2020-08-11 22:48 ` Stefano Stabellini
2020-08-18 9:31 ` Julien Grall
2020-08-21 0:53 ` Stefano Stabellini
2020-08-17 15:23 ` Jan Beulich
2020-08-17 22:56 ` Stefano Stabellini
2020-08-18 8:03 ` Jan Beulich
2020-08-05 16:15 ` Jan Beulich
2020-08-05 22:12 ` Oleksandr
2020-08-03 18:21 ` [RFC PATCH V1 06/12] libxl: Introduce basic virtio-mmio support on Arm Oleksandr Tyshchenko
2020-08-03 18:21 ` [RFC PATCH V1 07/12] A collection of tweaks to be able to run emulator in driver domain Oleksandr Tyshchenko
2020-08-05 16:19 ` Jan Beulich
2020-08-05 16:40 ` Paul Durrant
2020-08-06 9:22 ` Oleksandr
2020-08-06 9:27 ` Jan Beulich
2020-08-14 16:30 ` Oleksandr
2020-08-16 15:36 ` Julien Grall
2020-08-17 15:07 ` Oleksandr
2020-08-03 18:21 ` [RFC PATCH V1 08/12] xen/arm: Invalidate qemu mapcache on XENMEM_decrease_reservation Oleksandr Tyshchenko
2020-08-05 16:21 ` Jan Beulich
2020-08-06 11:35 ` Julien Grall
2020-08-06 11:50 ` Jan Beulich
2020-08-06 14:28 ` Oleksandr
2020-08-06 16:33 ` Jan Beulich
2020-08-06 16:57 ` Oleksandr
2020-08-03 18:21 ` [RFC PATCH V1 09/12] libxl: Handle virtio-mmio irq in more correct way Oleksandr Tyshchenko
2020-08-04 23:22 ` Stefano Stabellini
2020-08-05 20:51 ` Oleksandr
2020-08-03 18:21 ` [RFC PATCH V1 10/12] libxl: Add support for virtio-disk configuration Oleksandr Tyshchenko
2020-08-04 23:23 ` Stefano Stabellini
2020-08-05 21:12 ` Oleksandr
2020-08-06 0:37 ` Stefano Stabellini
2020-08-03 18:21 ` [RFC PATCH V1 11/12] libxl: Insert "dma-coherent" property into virtio-mmio device node Oleksandr Tyshchenko
2020-08-04 23:23 ` Stefano Stabellini
2020-08-05 20:35 ` Oleksandr
2020-08-03 18:21 ` [RFC PATCH V1 12/12] libxl: Fix duplicate memory node in DT Oleksandr Tyshchenko
2020-08-15 17:24 ` [RFC PATCH V1 00/12] IOREQ feature (+ virtio-mmio) on Arm Julien Grall
2020-08-16 19:34 ` Oleksandr
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=d8aa0f36-d3c4-011a-9ec1-32c1e3118112@suse.com \
--to=jbeulich@suse.com \
--cc=Volodymyr_Babchuk@epam.com \
--cc=andrew.cooper3@citrix.com \
--cc=george.dunlap@citrix.com \
--cc=ian.jackson@eu.citrix.com \
--cc=julien.grall@arm.com \
--cc=julien@xen.org \
--cc=oleksandr_tyshchenko@epam.com \
--cc=olekstysh@gmail.com \
--cc=sstabellini@kernel.org \
--cc=wl@xen.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).