From: Oleksandr Andrushchenko <andr2000@gmail.com>
To: Stefano Stabellini <sstabellini@kernel.org>
Cc: Julien Grall <julien.grall@arm.com>,
xen-devel@lists.xenproject.org, joculator@gmail.com,
al1img@gmail.com, vlad.babchuk@gmail.com,
andrii.anisov@gmail.com, olekstysh@gmail.com,
konrad.wilk@oracle.com, lars.kurth@citrix.com,
linux-kernel@vger.kernel.org,
Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>,
Oleksandr Grytsov <oleksandr_grytsov@epam.com>
Subject: Re: [For Linux 4/4] xen/displif: add ABI for para-virtual display
Date: Fri, 7 Apr 2017 20:51:42 +0300 [thread overview]
Message-ID: <b87d169c-8463-f93d-4733-f1c2451be931@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.10.1704071050020.2759@sstabellini-ThinkPad-X260>
On 04/07/2017 08:50 PM, Stefano Stabellini wrote:
> On Fri, 7 Apr 2017, Oleksandr Andrushchenko wrote:
>> On 04/07/2017 07:36 PM, Stefano Stabellini wrote:
>>> On Fri, 7 Apr 2017, Oleksandr Andrushchenko wrote:
>>>> Hi, Julien!
>>>>
>>>> On 04/07/2017 04:50 PM, Julien Grall wrote:
>>>>> Hi Oleksandr,
>>>>>
>>>>> On 07/04/17 09:30, Oleksandr Andrushchenko wrote:
>>>>>> +/*
>>>>>> +
>>>>>> ******************************************************************************
>>>>>> + * Back to front events delivery
>>>>>> +
>>>>>> ******************************************************************************
>>>>>> + * In order to deliver asynchronous events from back to front a
>>>>>> shared
>>>>>> page is
>>>>>> + * allocated by front and its granted reference propagated to back
>>>>>> via
>>>>>> + * XenStore entries (evt-ring-ref/evt-event-channel).
>>>>>> + * This page has a common header used by both front and back to
>>>>>> synchronize
>>>>>> + * access and control event's ring buffer, while back being a
>>>>>> producer of
>>>>>> the
>>>>>> + * events and front being a consumer. The rest of the page after the
>>>>>> header
>>>>>> + * is used for event packets.
>>>>>> + *
>>>>>> + * Upon reception of an event(s) front may confirm its reception
>>>>>> + * for either each event, group of events or none.
>>>>>> + */
>>>>>> +
>>>>>> +struct xendispl_event_page {
>>>>>> + uint32_t in_cons;
>>>>>> + uint32_t in_prod;
>>>>>> + uint8_t reserved[56];
>>>>>> +};
>>>>>> +
>>>>>> +#define XENDISPL_EVENT_PAGE_SIZE 4096
>>>>> This will be always the size of a grant (e.g xen page size), right? If
>>>>> so, I
>>>>> would prefer if you use XEN_PAGE_SIZE to so we can easily update Linux
>>>>> in
>>>>> the case Xen is using a different page size.
>>>>>
>>>>> Note that the Front-end, Backend and Xen may use different page size, so
>>>>> your drivers would need to cope with that. The current approach is to
>>>>> always
>>>>> use the page granularity of Xen.
>>>>>
>>>> Will the following satisfy the requirement?
>>>> #define XENDISPL_EVENT_PAGE_SIZE XEN_PAGE_SIZE
>>> It is already defined in include/xen/page.h
>> Thank you, Stefano, but I meant if the change below
>> will fit the requirement, e.g. what Julien means is:
>> -#define XENDISPL_EVENT_PAGE_SIZE 4096
>> +#define XENDISPL_EVENT_PAGE_SIZE XEN_PAGE_SIZE
>> Julien, does this change work for you?
> Sure, I think that would be OK. Also using XEN_PAGE_SIZE directly would
> be OK.
>
Great, thanks
>>>>>> +#define XENDISPL_IN_RING_OFFS (sizeof(struct xendispl_event_page))
>>>>>> +#define XENDISPL_IN_RING_SIZE (XENDISPL_EVENT_PAGE_SIZE -
>>>>>> XENDISPL_IN_RING_OFFS)
>>>>>> +#define XENDISPL_IN_RING_LEN (XENDISPL_IN_RING_SIZE / sizeof(struct
>>>>>> xendispl_evt))
>>>>>> +#define XENDISPL_IN_RING(page) \
>>>>>> + ((struct xendispl_evt *)((char *)(page) + XENDISPL_IN_RING_OFFS))
>>>>>> +#define XENDISPL_IN_RING_REF(page, idx) \
>>>>>> + (XENDISPL_IN_RING((page))[(idx) % XENDISPL_IN_RING_LEN])
>>>>>> +
>>>>>> +#endif /* __XEN_PUBLIC_IO_DISPLIF_H__ */
>>>>>> +
>>>>>> +/*
>>>>>> + * Local variables:
>>>>>> + * mode: C
>>>>>> + * c-file-style: "BSD"
>>>>>> + * c-basic-offset: 4
>>>>>> + * tab-width: 4
>>>>>> + * indent-tabs-mode: nil
>>>>>> + * End:
>>>>>> + */
>>>>>>
>>>>> Cheers,
>>>>>
>>>> Thank you,
>>>> Oleksandr
>>>>
>> Thank you,
>> Oleksandr
>>
next prev parent reply other threads:[~2017-04-07 17:51 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-07 8:30 [For Linux 0/4] PV protocol headers for Linux Kernel Oleksandr Andrushchenko
2017-04-07 8:30 ` [For Linux 1/4] xen/kbdif: update protocol description Oleksandr Andrushchenko
2017-04-07 11:29 ` [Xen-devel] " Juergen Gross
2017-04-07 12:45 ` Konrad Rzeszutek Wilk
2017-04-07 12:58 ` Oleksandr Andrushchenko
2017-04-07 8:30 ` [For Linux 2/4] xen/kbdif: add multi-touch support Oleksandr Andrushchenko
2017-04-07 11:30 ` [Xen-devel] " Juergen Gross
2017-04-07 8:30 ` [For Linux 3/4] xen/sndif: add sound-device ABI Oleksandr Andrushchenko
2017-04-07 11:31 ` [Xen-devel] " Juergen Gross
2017-04-07 8:30 ` [For Linux 4/4] xen/displif: add ABI for para-virtual display Oleksandr Andrushchenko
2017-04-07 11:31 ` [Xen-devel] " Juergen Gross
2017-04-07 13:50 ` Julien Grall
2017-04-07 14:02 ` Oleksandr Andrushchenko
2017-04-07 16:36 ` Stefano Stabellini
2017-04-07 17:43 ` Oleksandr Andrushchenko
2017-04-07 17:50 ` Stefano Stabellini
2017-04-07 17:51 ` Oleksandr Andrushchenko [this message]
2017-04-10 6:03 ` Juergen Gross
2017-04-10 6:06 ` Oleksandr Andrushchenko
2017-04-10 6:07 ` Juergen Gross
2017-04-07 8:47 ` [For Linux 0/4] PV protocol headers for Linux Kernel Oleksandr Andrushchenko
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