xen/kbdif: Add frontend's virtual device options
PATCH 1/1 xen/kbdif: Add frontend's virtual device options
From: Oleksandr Andrushchenko <[email protected]>
It is now not possible to control if and which virtual devices are created by the frontend, e.g. keyboard and pointer devices are always created and multi-touch device is created if the backend advertises multi-touch support. In some cases this behavior is not desirable and better control over the frontend's configuration is required.
Add new frontend options, so it is possible to individually control set of exposed virtual devices for each guest OS:
- set opt-no-pointer if no pointer device needs to be created
- set opt-no-keyboard if no keyboard device needs to be created
- set opt-no-multi-touch if no multi-touch device needs to be created
Keep old behavior by default.
--- xen/include/public/io/kbdif.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)
xen/include/public/io/kbdif.h +26 -0
@@ -132,6 +132,29 @@* OBSOLETE, not recommended for use. * PFN of the shared page. * +*--------------------------- Frontend Options ------------------------------- +* +* For the below options if corresponding XenStore entry omitted, +* then the value must be treated as set to 0. +* +* opt-no-pointer +* Values: <uint> +* +* If no virtual pointer device to be exposed by the frontend then +* this must be set to 1. +* +* opt-no-keyboard +* Values: <uint> +* +* If no virtual keyboard device to be exposed by the frontend then +* this must be set to 1. +* +* opt-no-multi-touch +* Values: <uint> +* +* If no virtual multi-touch device to be exposed by the frontend then +* this must be set to 1. +* *----------------------- Multi-touch Device Parameters ----------------------- * * multi-touch-num-contacts
@@ -181,6 +204,9 @@#define XENKBD_FIELD_FEAT_MTOUCH "feature-multi-touch"#define XENKBD_FIELD_REQ_ABS_POINTER "request-abs-pointer"#define XENKBD_FIELD_REQ_MTOUCH "request-multi-touch" +#define XENKBD_FIELD_OPT_NO_PTR "opt-no-pointer" +#define XENKBD_FIELD_OPT_NO_KBD "opt-no-keyboard" +#define XENKBD_FIELD_OPT_NO_MTOUCH "opt-no-multi-touch"#define XENKBD_FIELD_RING_GREF "page-gref"#define XENKBD_FIELD_EVT_CHANNEL "event-channel"#define XENKBD_FIELD_WIDTH "width"
Signature · 7 lines
2.17.0 _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
Hi Oleksandr,
Quoted 57 lines · Oleksandr Andrushchenko
From: Oleksandr Andrushchenko <[email protected]>
It is now not possible to control if and which virtual devices are created by the frontend, e.g. keyboard and pointer devices are always created and multi-touch device is created if the backend advertises multi-touch support. In some cases this behavior is not desirable and better control over the frontend's configuration is required.
Add new frontend options, so it is possible to individually control set of exposed virtual devices for each guest OS:
- set opt-no-pointer if no pointer device needs to be created
- set opt-no-keyboard if no keyboard device needs to be created
- set opt-no-multi-touch if no multi-touch device needs to be createdKeep old behavior by default.
Signed-off-by Oleksandr Andrushchenko <[email protected]>--- xen/include/public/io/kbdif.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)xen/include/public/io/kbdif.h +23
-0@@ -132,6 +132,29 @@* OBSOLETE, not recommended for use. * PFN of the shared page. * +*--------------------------- Frontend Options ------------------------------- +* +* For the below options if corresponding XenStore entry omitted, +* then the value must be treated as set to 0. +* +* opt-no-pointer +* Values: <uint> +* +* If no virtual pointer device to be exposed by the frontend then +* this must be set to 1. +* +* opt-no-keyboard +* Values: <uint> +* +* If no virtual keyboard device to be exposed by the frontend then +* this must be set to 1. +* +* opt-no-multi-touch +* Values: <uint> +* +* If no virtual multi-touch device to be exposed by the frontend then +* this must be set to 1. +* *----------------------- Multi-touch Device Parameters ----------------------- * * multi-touch-num-contacts
xen/include/public/io/kbdif.h line 209
Quoted 6 lines
xen/include/public/io/kbdif.h +3
-0@@ -181,6 +204,9 @@#define XENKBD_FIELD_FEAT_MTOUCH "feature-multi-touch"#define XENKBD_FIELD_REQ_ABS_POINTER "request-abs-pointer"#define XENKBD_FIELD_REQ_MTOUCH "request-multi-touch" +#define XENKBD_FIELD_OPT_NO_PTR "opt-no-pointer" +#define XENKBD_FIELD_OPT_NO_KBD "opt-no-keyboard" +#define XENKBD_FIELD_OPT_NO_MTOUCH "opt-no-multi-touch"
So we have "feature-multi-touch" and "opt-no-multi-touch". What is the difference between feature and option?
Also, for the pointer and keyboard, if we decide that features and options can be merged, can we keep them positive (i.e. "feature-keyboard" or "feature-rel-pointer") and mention in the protocol spec that they are assumed to be present by default?
Quoted 6 lines
xen/include/public/io/kbdif.h +0
-0#define XENKBD_FIELD_RING_GREF "page-gref"#define XENKBD_FIELD_EVT_CHANNEL "event-channel"#define XENKBD_FIELD_WIDTH "width"Signature · 1 line
2.17.0
Thanks.
Signature · 6 lines
Dmitry _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
Quoted 60 lines · Dmitry Torokhov
Hi Oleksandr,
Quoted 57 lines · Oleksandr Andrushchenko
From: Oleksandr Andrushchenko <[email protected]>
It is now not possible to control if and which virtual devices are created by the frontend, e.g. keyboard and pointer devices are always created and multi-touch device is created if the backend advertises multi-touch support. In some cases this behavior is not desirable and better control over the frontend's configuration is required.
Add new frontend options, so it is possible to individually control set of exposed virtual devices for each guest OS:
- set opt-no-pointer if no pointer device needs to be created
- set opt-no-keyboard if no keyboard device needs to be created
- set opt-no-multi-touch if no multi-touch device needs to be createdKeep old behavior by default.
Signed-off-by Oleksandr Andrushchenko <[email protected]>--- xen/include/public/io/kbdif.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)xen/include/public/io/kbdif.h +23
-0@@ -132,6 +132,29 @@* OBSOLETE, not recommended for use. * PFN of the shared page. * +*--------------------------- Frontend Options ------------------------------- +* +* For the below options if corresponding XenStore entry omitted, +* then the value must be treated as set to 0. +* +* opt-no-pointer +* Values: <uint> +* +* If no virtual pointer device to be exposed by the frontend then +* this must be set to 1. +* +* opt-no-keyboard +* Values: <uint> +* +* If no virtual keyboard device to be exposed by the frontend then +* this must be set to 1. +* +* opt-no-multi-touch +* Values: <uint> +* +* If no virtual multi-touch device to be exposed by the frontend then +* this must be set to 1. +* *----------------------- Multi-touch Device Parameters ----------------------- * * multi-touch-num-contacts @@ -181,6 +204,9 @@
Quoted 8 lines
xen/include/public/io/kbdif.h line 209
Quoted 6 lines
xen/include/public/io/kbdif.h +3
-0#define XENKBD_FIELD_FEAT_MTOUCH "feature-multi-touch"#define XENKBD_FIELD_REQ_ABS_POINTER "request-abs-pointer"#define XENKBD_FIELD_REQ_MTOUCH "request-multi-touch" +#define XENKBD_FIELD_OPT_NO_PTR "opt-no-pointer" +#define XENKBD_FIELD_OPT_NO_KBD "opt-no-keyboard" +#define XENKBD_FIELD_OPT_NO_MTOUCH "opt-no-multi-touch"So we have "feature-multi-touch" and "opt-no-multi-touch". What is the difference between feature and option?
Indeed, it can be made simpler.
This is how it looks in XenStore for a given frontend:
/local/domain/2/device/vkbd/0/feature-multi-touch = "1" /local/domain/2/device/vkbd/0/request-multi-touch = "1"
Thus, feature-multi-touch field already controls if multi-touch device is created *per frontend*, so the multi-touch control is already there. (request-multi-touch field is set by the frontend to request multi-touch events to be sent by the backend, e.g. this is sort of negotiation that backend offers multi-touch to frontend and if frontend is capable and willing to support that it then replies by setting this field).
So, "opt-no-multi-touch" will be removed from the protocol.
Quoted 5 lines
Also, for the pointer and keyboard, if we decide that features and options can be merged, can we keep them positive (i.e. "feature-keyboard" or "feature-rel-pointer") and mention in the protocol spec that they are assumed to be present by default?
As Dmitry suggested at [1]:
"I think you can have them as "feature-pointer" and "feature-keyboard" (no negation), but assume not present considered enabled. I.e.
kbd = xenbus_read_unsigned(..., XENKBD_FIELD_FEAT_KEYBOARD, 1); if (kbd) {
...
}
"
So, I'll add *per frontend* features:
- feature-keyboard
- feature-pointer (without "rel", we just need to enable the pointer device which is by default "rel": there is a dedicated feature for "abs" - feature-abs-pointer).
/local/domain/2/device/vkbd/0/feature-keyboard = "1" /local/domain/2/device/vkbd/0/feature-pointer = "1"
For backward compatibility the default will be "1" if the field is not present. opt-no-keyboard and opt-no-pointer will be removed.
I will send v1 with the changes above.
Quoted 9 lines
Quoted 7 lines
xen/include/public/io/kbdif.h +0
-0#define XENKBD_FIELD_RING_GREF "page-gref"#define XENKBD_FIELD_EVT_CHANNEL "event-channel"#define XENKBD_FIELD_WIDTH "width"Signature · 1 line
2.17.0Thanks.
Thank you,
Oleksandr
[1] https://lkml.org/lkml/2018/4/26/865
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