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xen/events: Add the hypervisor interface for the FIFO-based event channels

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Add the hypercall sub-ops and the structures for the shared data used
in the FIFO-based event channel ABI.

The design document for this new ABI is available here:

    http://xenbits.xen.org/people/dvrabel/event-channels-H.pdf

In summary, events are reported using a per-domain shared event array
of event words.  Each event word has PENDING, LINKED and MASKED bits
and a LINK field for pointing to the next event in the event queue.

There are 16 event queues (with different priorities) per-VCPU.

Key advantages of this new ABI include:

- Support for over 100,000 events (2^17).
- 16 different event priorities.
- Improved fairness in event latency through the use of FIFOs.

The ABI is available in Xen 4.4 and later.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This commit is contained in:
David Vrabel
2013-03-15 10:55:41 +00:00
committed by Konrad Rzeszutek Wilk
parent 0dc0064add
commit bf2bbe07f1
3 changed files with 72 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/xen/interface/event_channel.h
+68
View File
@@ -190,6 +190,39 @@ struct evtchn_reset {
};
typedef struct evtchn_reset evtchn_reset_t;
/*
* EVTCHNOP_init_control: initialize the control block for the FIFO ABI.
*/
#define EVTCHNOP_init_control 11
struct evtchn_init_control {
/* IN parameters. */
uint64_t control_gfn;
uint32_t offset;
uint32_t vcpu;
/* OUT parameters. */
uint8_t link_bits;
uint8_t _pad[7];
};
/*
* EVTCHNOP_expand_array: add an additional page to the event array.
*/
#define EVTCHNOP_expand_array 12
struct evtchn_expand_array {
/* IN parameters. */
uint64_t array_gfn;
};
/*
* EVTCHNOP_set_priority: set the priority for an event channel.
*/
#define EVTCHNOP_set_priority 13
struct evtchn_set_priority {
/* IN parameters. */
uint32_t port;
uint32_t priority;
};
struct evtchn_op {
uint32_t cmd; /* EVTCHNOP_* */
union {
@@ -207,4 +240,39 @@ struct evtchn_op {
};
DEFINE_GUEST_HANDLE_STRUCT(evtchn_op);
/*
* 2-level ABI
*/
#define EVTCHN_2L_NR_CHANNELS (sizeof(xen_ulong_t) * sizeof(xen_ulong_t) * 64)
/*
* FIFO ABI
*/
/* Events may have priorities from 0 (highest) to 15 (lowest). */
#define EVTCHN_FIFO_PRIORITY_MAX 0
#define EVTCHN_FIFO_PRIORITY_DEFAULT 7
#define EVTCHN_FIFO_PRIORITY_MIN 15
#define EVTCHN_FIFO_MAX_QUEUES (EVTCHN_FIFO_PRIORITY_MIN + 1)
typedef uint32_t event_word_t;
#define EVTCHN_FIFO_PENDING 31
#define EVTCHN_FIFO_MASKED 30
#define EVTCHN_FIFO_LINKED 29
#define EVTCHN_FIFO_BUSY 28
#define EVTCHN_FIFO_LINK_BITS 17
#define EVTCHN_FIFO_LINK_MASK ((1 << EVTCHN_FIFO_LINK_BITS) - 1)
#define EVTCHN_FIFO_NR_CHANNELS (1 << EVTCHN_FIFO_LINK_BITS)
struct evtchn_fifo_control_block {
uint32_t ready;
uint32_t _rsvd;
event_word_t head[EVTCHN_FIFO_MAX_QUEUES];
};
#endif /* __XEN_PUBLIC_EVENT_CHANNEL_H__ */
include/xen/interface/xen.h
-6
View File
@@ -281,12 +281,6 @@ struct multicall_entry {
};
DEFINE_GUEST_HANDLE_STRUCT(multicall_entry);
/*
* Event channel endpoints per domain:
* 1024 if a long is 32 bits; 4096 if a long is 64 bits.
*/
#define NR_EVENT_CHANNELS (sizeof(xen_ulong_t) * sizeof(xen_ulong_t) * 64)
struct vcpu_time_info {
/*
* Updates to the following values are preceded and followed