From fda1f7684935ae7290c8a31e3ba9fdb30eead4ed Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Fri, 13 Apr 2012 17:46:01 +0000 Subject: xen: introduce an event channel for buffered io event notifications Use the newly introduced HVM_PARAM_BUFIOREQ_EVTCHN to receive notifications for buffered io events. After the first notification is received leave the event channel masked and setup a timer to process the rest of the batch. Once we have completed processing the batch, unmask the event channel and delete the timer. Signed-off-by: Stefano Stabellini --- xen-all.c | 45 +++++++++++++++++++++++++++++++++++++++------ 1 file changed, 39 insertions(+), 6 deletions(-) (limited to 'xen-all.c') diff --git a/xen-all.c b/xen-all.c index abd2b2d..a08eec0 100644 --- a/xen-all.c +++ b/xen-all.c @@ -59,6 +59,9 @@ static inline ioreq_t *xen_vcpu_ioreq(shared_iopage_t *shared_page, int vcpu) } # define FMT_ioreq_size "u" #endif +#ifndef HVM_PARAM_BUFIOREQ_EVTCHN +#define HVM_PARAM_BUFIOREQ_EVTCHN 26 +#endif #define BUFFER_IO_MAX_DELAY 100 @@ -77,6 +80,8 @@ typedef struct XenIOState { QEMUTimer *buffered_io_timer; /* the evtchn port for polling the notification, */ evtchn_port_t *ioreq_local_port; + /* evtchn local port for buffered io */ + evtchn_port_t bufioreq_local_port; /* the evtchn fd for polling */ XenEvtchn xce_handle; /* which vcpu we are serving */ @@ -629,6 +634,12 @@ static ioreq_t *cpu_get_ioreq(XenIOState *state) evtchn_port_t port; port = xc_evtchn_pending(state->xce_handle); + if (port == state->bufioreq_local_port) { + qemu_mod_timer(state->buffered_io_timer, + BUFFER_IO_MAX_DELAY + qemu_get_clock_ms(rt_clock)); + return NULL; + } + if (port != -1) { for (i = 0; i < smp_cpus; i++) { if (state->ioreq_local_port[i] == port) { @@ -777,16 +788,18 @@ static void handle_ioreq(ioreq_t *req) } } -static void handle_buffered_iopage(XenIOState *state) +static int handle_buffered_iopage(XenIOState *state) { buf_ioreq_t *buf_req = NULL; ioreq_t req; int qw; if (!state->buffered_io_page) { - return; + return 0; } + memset(&req, 0x00, sizeof(req)); + while (state->buffered_io_page->read_pointer != state->buffered_io_page->write_pointer) { buf_req = &state->buffered_io_page->buf_ioreq[ state->buffered_io_page->read_pointer % IOREQ_BUFFER_SLOT_NUM]; @@ -811,15 +824,21 @@ static void handle_buffered_iopage(XenIOState *state) xen_mb(); state->buffered_io_page->read_pointer += qw ? 2 : 1; } + + return req.count; } static void handle_buffered_io(void *opaque) { XenIOState *state = opaque; - handle_buffered_iopage(state); - qemu_mod_timer(state->buffered_io_timer, - BUFFER_IO_MAX_DELAY + qemu_get_clock_ms(rt_clock)); + if (handle_buffered_iopage(state)) { + qemu_mod_timer(state->buffered_io_timer, + BUFFER_IO_MAX_DELAY + qemu_get_clock_ms(rt_clock)); + } else { + qemu_del_timer(state->buffered_io_timer); + xc_evtchn_unmask(state->xce_handle, state->bufioreq_local_port); + } } static void cpu_handle_ioreq(void *opaque) @@ -949,7 +968,6 @@ static void xen_main_loop_prepare(XenIOState *state) state->buffered_io_timer = qemu_new_timer_ms(rt_clock, handle_buffered_io, state); - qemu_mod_timer(state->buffered_io_timer, qemu_get_clock_ms(rt_clock)); if (evtchn_fd != -1) { qemu_set_fd_handler(evtchn_fd, cpu_handle_ioreq, NULL, state); @@ -1050,6 +1068,7 @@ int xen_hvm_init(void) { int i, rc; unsigned long ioreq_pfn; + unsigned long bufioreq_evtchn; XenIOState *state; state = g_malloc0(sizeof (XenIOState)); @@ -1102,6 +1121,20 @@ int xen_hvm_init(void) state->ioreq_local_port[i] = rc; } + rc = xc_get_hvm_param(xen_xc, xen_domid, HVM_PARAM_BUFIOREQ_EVTCHN, + &bufioreq_evtchn); + if (rc < 0) { + fprintf(stderr, "failed to get HVM_PARAM_BUFIOREQ_EVTCHN\n"); + return -1; + } + rc = xc_evtchn_bind_interdomain(state->xce_handle, xen_domid, + (uint32_t)bufioreq_evtchn); + if (rc == -1) { + fprintf(stderr, "bind interdomain ioctl error %d\n", errno); + return -1; + } + state->bufioreq_local_port = rc; + /* Init RAM management */ xen_map_cache_init(xen_phys_offset_to_gaddr, state); xen_ram_init(ram_size); -- cgit v1.1