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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/xen/events/events_2l.c
View File

@ -38,12 +38,12 @@
/* Find the first set bit in a evtchn mask */
#define EVTCHN_FIRST_BIT(w) find_first_bit(BM(&(w)), BITS_PER_EVTCHN_WORD)
static DEFINE_PER_CPU(xen_ulong_t [NR_EVENT_CHANNELS/BITS_PER_EVTCHN_WORD],
static DEFINE_PER_CPU(xen_ulong_t [EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD],
cpu_evtchn_mask);
static unsigned evtchn_2l_max_channels(void)
{
return NR_EVENT_CHANNELS;
return EVTCHN_2L_NR_CHANNELS;
}
static void evtchn_2l_bind_to_cpu(struct irq_info *info, unsigned cpu)
@ -316,7 +316,7 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
i % 8 == 0 ? "\n " : " ");
printk("\nlocal cpu%d mask:\n ", cpu);
for (i = (NR_EVENT_CHANNELS/BITS_PER_EVTCHN_WORD)-1; i >= 0; i--)
for (i = (EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD)-1; i >= 0; i--)
printk("%0*"PRI_xen_ulong"%s", (int)(sizeof(cpu_evtchn[0])*2),
cpu_evtchn[i],
i % 8 == 0 ? "\n " : " ");
@ -332,7 +332,7 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
}
printk("\npending list:\n");
for (i = 0; i < NR_EVENT_CHANNELS; i++) {
for (i = 0; i < EVTCHN_2L_NR_CHANNELS; i++) {
if (sync_test_bit(i, BM(sh->evtchn_pending))) {
int word_idx = i / BITS_PER_EVTCHN_WORD;
printk(" %d: event %d -> irq %d%s%s%s\n",

68
include/xen/interface/event_channel.h
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__ */

6
include/xen/interface/xen.h
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