[tip:x86/platform] hyper-v: Use fast hypercall for HVCALL_SIGNAL_EVENT

[tip-bot for Vitaly Kuznetsov <tipbot@zytor.com>]

Commit-ID:  057841713cfff62b4485cdd2b245f05b7ea3ba16
Gitweb:     http://git.kernel.org/tip/057841713cfff62b4485cdd2b245f05b7ea3ba16
Author:     Vitaly Kuznetsov <vkuznets@redhat.com>
AuthorDate: Wed, 2 Aug 2017 18:09:16 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 10 Aug 2017 16:50:22 +0200

hyper-v: Use fast hypercall for HVCALL_SIGNAL_EVENT

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>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: devel@linuxdriverproject.org
Link: http://lkml.kernel.org/r/20170802160921.21791-5-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 drivers/hv/channel_mgmt.c | 13 ++-----------
 drivers/hv/connection.c   |  2 +-
 include/linux/hyperv.h    | 15 +--------------
 3 files changed, 4 insertions(+), 26 deletions(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 4bbb8de..fd2b6c6 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -805,21 +805,12 @@ 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 = VMBUS_EVENT_CONNECTION_ID;
 
 	if (vmbus_proto_version != VERSION_WS2008) {
 		newchannel->is_dedicated_interrupt =
 				(offer->is_dedicated_interrupt != 0);
-		newchannel->sig_event->connectionid.u.id =
-				offer->connection_id;
+		newchannel->sig_event = offer->connection_id;
 	}
 
 	memcpy(&newchannel->offermsg, offer,
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 45e806e..37ecf51 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -408,6 +408,6 @@ 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);
 }
 EXPORT_SYMBOL_GPL(vmbus_set_event);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 6608a71..c472bd4 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -677,18 +677,6 @@ union hv_connection_id {
 	} u;
 };
 
-/* 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;
-};
-
 enum hv_numa_policy {
 	HV_BALANCED = 0,
 	HV_LOCALIZED,
@@ -770,8 +758,7 @@ struct vmbus_channel {
 	} callback_mode;
 
 	bool is_dedicated_interrupt;
-	struct hv_input_signal_event_buffer sig_buf;
-	struct hv_input_signal_event *sig_event;
+	u64 sig_event;
 
 	/*
 	 * Starting with win8, this field will be used to specify