[PATCH v4 05/10] hyper-v: use fast hypercall for HVCALL_SIGNAL_EVENT

Vitaly Kuznetsov
2017-05-24T12:04:47Z

We need to pass only 8 bytes of input for HvSignalEvent which makes it a
perfect fit for fast hypercall. hv_input_signal_event_buffer is not needed
any more and hv_input_signal_event is converted to union for convenience.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Simon Xiao <sixiao@microsoft.com>
Tested-by: Srikanth Myakam <v-srm@microsoft.com>
---
drivers/hv/channel_mgmt.c | 15 +++++----------
drivers/hv/connection.c | 3 ++-
include/linux/hyperv.h | 19 ++++++++-----------
3 files changed, 15 insertions(+), 22 deletions(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 0fabd41..ee2a8dd 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -806,20 +806,15 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
/*
* Setup state for signalling the host.
*/
- newchannel->sig_event = (struct hv_input_signal_event *)
- (ALIGN((unsigned long)
- &newchannel->sig_buf,
- HV_HYPERCALL_PARAM_ALIGN));
-
- newchannel->sig_event->connectionid.asu32 = 0;
- newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
- newchannel->sig_event->flag_number = 0;
- newchannel->sig_event->rsvdz = 0;
+ newchannel->sig_event.connectionid.asu32 = 0;
+ newchannel->sig_event.connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
+ newchannel->sig_event.flag_number = 0;
+ newchannel->sig_event.rsvdz = 0;

if (vmbus_proto_version != VERSION_WS2008) {
newchannel->is_dedicated_interrupt =
(offer->is_dedicated_interrupt != 0);
- newchannel->sig_event->connectionid.u.id =
+ newchannel->sig_event.connectionid.u.id =
offer->connection_id;
}

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 4a0a9f6..51f8cb2 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -408,6 +408,7 @@ void vmbus_set_event(struct vmbus_channel *channel)
if (!channel->is_dedicated_interrupt)
vmbus_send_interrupt(child_relid);

- hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL);
+ hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT,
+ channel->sig_event.as_uint64);
}
EXPORT_SYMBOL_GPL(vmbus_set_event);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index d1ae02d..68a5772 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -678,15 +678,13 @@ union hv_connection_id {
};

/* Definition of the hv_signal_event hypercall input structure. */
-struct hv_input_signal_event {
- union hv_connection_id connectionid;
- u16 flag_number;
- u16 rsvdz;
-};
-
-struct hv_input_signal_event_buffer {
- u64 align8;
- struct hv_input_signal_event event;
+union hv_input_signal_event {
+ u64 as_uint64;
+ struct {
+ union hv_connection_id connectionid;
+ u16 flag_number;
+ u16 rsvdz;
+ };
};

enum hv_numa_policy {
@@ -771,8 +769,7 @@ struct vmbus_channel {
} callback_mode;

bool is_dedicated_interrupt;
- struct hv_input_signal_event_buffer sig_buf;
- struct hv_input_signal_event *sig_event;
+ union hv_input_signal_event sig_event;

/*
* Starting with win8, this field will be used to specify
--
2.9.4