From bf2bbe07f13846a90d4447521d87566d6f87bc0e Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Fri, 15 Mar 2013 10:55:41 +0000 Subject: [PATCH] xen/events: Add the hypervisor interface for the FIFO-based event channels 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 Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Boris Ostrovsky --- drivers/xen/events/events_2l.c | 8 ++-- include/xen/interface/event_channel.h | 68 +++++++++++++++++++++++++++ include/xen/interface/xen.h | 6 --- 3 files changed, 72 insertions(+), 10 deletions(-) diff --git a/drivers/xen/events/events_2l.c b/drivers/xen/events/events_2l.c index ecb402a149e3..d7ff91757307 100644 --- a/drivers/xen/events/events_2l.c +++ b/drivers/xen/events/events_2l.c @@ -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", diff --git a/include/xen/interface/event_channel.h b/include/xen/interface/event_channel.h index f4942921e202..7e6acef5415b 100644 --- a/include/xen/interface/event_channel.h +++ b/include/xen/interface/event_channel.h @@ -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__ */ diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h index 53ec4167bd0b..0cd5ca333fac 100644 --- a/include/xen/interface/xen.h +++ b/include/xen/interface/xen.h @@ -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 -- 2.20.1