On Tue, 2011-11-15 at 14:51 +0000, stefano.stabellini@xxxxxxxxxxxxx
wrote:
> From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
>
> 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 <stefano.stabellini@xxxxxxxxxxxxx>
> ---
> xen-all.c | 38 ++++++++++++++++++++++++++++++++------
> 1 files changed, 32 insertions(+), 6 deletions(-)
>
> diff --git a/xen-all.c b/xen-all.c
> index b5e28ab..b28d7e7 100644
> --- a/xen-all.c
> +++ b/xen-all.c
> @@ -70,6 +70,8 @@ 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 */
> @@ -516,6 +518,12 @@ 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) {
> @@ -664,16 +672,18 @@ 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];
> @@ -698,15 +708,21 @@ 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)
> @@ -836,7 +852,6 @@ 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);
> @@ -888,6 +903,7 @@ int xen_hvm_init(void)
> {
> int i, rc;
> unsigned long ioreq_pfn;
> + unsigned long bufioreq_evtchn;
> XenIOState *state;
>
> state = g_malloc0(sizeof (XenIOState));
> @@ -937,6 +953,16 @@ int xen_hvm_init(void)
> state->ioreq_local_port[i] = rc;
> }
>
> + xc_get_hvm_param(xen_xc, xen_domid, HVM_PARAM_BUFIOREQ_EVTCHN,
> + &bufioreq_evtchn);
> + 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;
Does this fallback gracefully on hypervisors which don't have this new
hvm param? It doesn't look like it but perhaps I'm missing something.
> +
> /* Init RAM management */
> xen_map_cache_init();
> xen_ram_init(ram_size);
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