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Re: [Xen-devel] [For Linux 4/4] xen/displif: add ABI for para-virtual display
- To: Juergen Gross <jgross@xxxxxxxx>, Julien Grall <julien.grall@xxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
- From: Oleksandr Andrushchenko <andr2000@xxxxxxxxx>
- Date: Mon, 10 Apr 2017 09:06:41 +0300
- Cc: lars.kurth@xxxxxxxxxx, sstabellini@xxxxxxxxxx, vlad.babchuk@xxxxxxxxx, Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, andrii.anisov@xxxxxxxxx, olekstysh@xxxxxxxxx, al1img@xxxxxxxxx, Oleksandr Grytsov <oleksandr_grytsov@xxxxxxxx>, joculator@xxxxxxxxx
- Delivery-date: Mon, 10 Apr 2017 06:06:49 +0000
- List-id: Xen developer discussion <xen-devel.lists.xen.org>
On 04/10/2017 09:03 AM, Juergen Gross wrote:
On 07/04/17 16:02, 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
+#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:
+ */
I believe you'll send V2 due to the XEN_PAGE_SIZE usage?
yes
Can you then please remove the editor mode settings block in each
header, too? Those are disliked in the Linux tree.
sure, I will
Juergen
Do you mind if I keep your acks for V2 with these changes?
Thank you,
Oleksandr
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