From: Roman Kagan <rkagan@virtuozzo.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, <x86@kernel.org>,
        Haiyang Zhang <haiyangz@microsoft.com>, <kvm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <devel@linuxdriverproject.org>,
        "Denis V . Lunev" <den@openvz.org>, Roman Kagan <rkagan@virtuozzo.com>
Subject: [PATCH 02/15] hyperv: uapi-fy synic event flags definitions
Date: Tue, 20 Dec 2016 18:55:49 +0300
Message-ID: <20161220155602.6298-3-rkagan@virtuozzo.com>
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Move definitions related to the Hyper-V SynIC event flags to a header
where they can be consumed by userspace.

While doing so, also clean up their use by switching to standard bitops
and struct-based dereferencing.  The latter is also done for message
pages.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
---
 arch/x86/include/uapi/asm/hyperv.h | 13 +++++++++
 drivers/hv/hyperv_vmbus.h          | 24 ++--------------
 drivers/hv/channel_mgmt.c          | 10 +++----
 drivers/hv/connection.c            | 47 ++++++++++---------------------
 drivers/hv/vmbus_drv.c             | 57 ++++++++++++++------------------------
 5 files changed, 54 insertions(+), 97 deletions(-)

diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
index 6098ab5..af542a3 100644
--- a/arch/x86/include/uapi/asm/hyperv.h
+++ b/arch/x86/include/uapi/asm/hyperv.h
@@ -363,4 +363,17 @@ struct hv_timer_message_payload {
 #define HV_STIMER_AUTOENABLE		(1ULL << 3)
 #define HV_STIMER_SINT(config)		(__u8)(((config) >> 16) & 0x0F)
 
+/* Define synthetic interrupt controller flag constants. */
+#define HV_EVENT_FLAGS_COUNT		(256 * 8)
+
+/* Define the synthetic interrupt controller event flags format. */
+struct hv_synic_event_flags {
+	__u64 flags[HV_EVENT_FLAGS_COUNT / 64];
+};
+
+/* Define the synthetic interrupt flags page layout. */
+struct hv_synic_event_flags_page {
+	struct hv_synic_event_flags sintevent_flags[HV_SYNIC_SINT_COUNT];
+};
+
 #endif
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 4516498..4fab154 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -26,7 +26,6 @@
 #define _HYPERV_VMBUS_H
 
 #include <linux/list.h>
-#include <asm/sync_bitops.h>
 #include <linux/atomic.h>
 #include <linux/hyperv.h>
 
@@ -75,11 +74,6 @@ enum hv_cpuid_function {
 
 #define HV_ANY_VP			(0xFFFFFFFF)
 
-/* Define synthetic interrupt controller flag constants. */
-#define HV_EVENT_FLAGS_COUNT		(256 * 8)
-#define HV_EVENT_FLAGS_BYTE_COUNT	(256)
-#define HV_EVENT_FLAGS_DWORD_COUNT	(256 / sizeof(u32))
-
 /* Define invalid partition identifier. */
 #define HV_PARTITION_ID_INVALID		((u64)0x0)
 
@@ -146,20 +140,6 @@ union hv_timer_config {
 	};
 };
 
-/* Define the number of message buffers associated with each port. */
-#define HV_PORT_MESSAGE_BUFFER_COUNT	(16)
-
-/* Define the synthetic interrupt controller event flags format. */
-union hv_synic_event_flags {
-	u8 flags8[HV_EVENT_FLAGS_BYTE_COUNT];
-	u32 flags32[HV_EVENT_FLAGS_DWORD_COUNT];
-};
-
-/* Define the synthetic interrupt flags page layout. */
-struct hv_synic_event_flags_page {
-	union hv_synic_event_flags sintevent_flags[HV_SYNIC_SINT_COUNT];
-};
-
 /* Define SynIC control register. */
 union hv_synic_scontrol {
 	u64 as_uint64;
@@ -434,8 +414,8 @@ struct hv_context {
 
 	bool synic_initialized;
 
-	void *synic_message_page[NR_CPUS];
-	void *synic_event_page[NR_CPUS];
+	struct hv_message_page *synic_message_page[NR_CPUS];
+	struct hv_synic_event_flags_page *synic_event_page[NR_CPUS];
 	/*
 	 * Hypervisor's notion of virtual processor ID is different from
 	 * Linux' notion of CPU ID. This information can only be retrieved
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 26b4192..49eaae2 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -654,7 +654,6 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 static void vmbus_wait_for_unload(void)
 {
 	int cpu;
-	void *page_addr;
 	struct hv_message *msg;
 	struct vmbus_channel_message_header *hdr;
 	u32 message_type;
@@ -673,9 +672,8 @@ static void vmbus_wait_for_unload(void)
 			break;
 
 		for_each_online_cpu(cpu) {
-			page_addr = hv_context.synic_message_page[cpu];
-			msg = (struct hv_message *)page_addr +
-				VMBUS_MESSAGE_SINT;
+			msg = &hv_context.synic_message_page[cpu]->
+					sint_message[VMBUS_MESSAGE_SINT];
 
 			message_type = READ_ONCE(msg->header.message_type);
 			if (message_type == HVMSG_NONE)
@@ -699,8 +697,8 @@ static void vmbus_wait_for_unload(void)
 	 * messages after we reconnect.
 	 */
 	for_each_online_cpu(cpu) {
-		page_addr = hv_context.synic_message_page[cpu];
-		msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
+		msg = &hv_context.synic_message_page[cpu]->
+				sint_message[VMBUS_MESSAGE_SINT];
 		msg->header.message_type = HVMSG_NONE;
 	}
 }
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 6ce8b87..aaa2103 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -381,17 +381,12 @@ static void process_chn_event(u32 relid)
  */
 void vmbus_on_event(unsigned long data)
 {
-	u32 dword;
-	u32 maxdword;
-	int bit;
-	u32 relid;
-	u32 *recv_int_page = NULL;
-	void *page_addr;
+	u32 relid, max_relid;
+	unsigned long *recv_int_page;
 	int cpu = smp_processor_id();
-	union hv_synic_event_flags *event;
 
 	if (vmbus_proto_version < VERSION_WIN8) {
-		maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
+		max_relid = MAX_NUM_CHANNELS_SUPPORTED;
 		recv_int_page = vmbus_connection.recv_int_page;
 	} else {
 		/*
@@ -399,36 +394,22 @@ void vmbus_on_event(unsigned long data)
 		 * can be directly checked to get the id of the channel
 		 * that has the interrupt pending.
 		 */
-		maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
-		page_addr = hv_context.synic_event_page[cpu];
-		event = (union hv_synic_event_flags *)page_addr +
-						 VMBUS_MESSAGE_SINT;
-		recv_int_page = event->flags32;
+		struct hv_synic_event_flags *event =
+			&hv_context.synic_event_page[cpu]->
+				sintevent_flags[VMBUS_MESSAGE_SINT];
+		max_relid = HV_EVENT_FLAGS_COUNT;
+		recv_int_page = (unsigned long *)event->flags;
 	}
 
-
-
 	/* Check events */
 	if (!recv_int_page)
 		return;
-	for (dword = 0; dword < maxdword; dword++) {
-		if (!recv_int_page[dword])
-			continue;
-		for (bit = 0; bit < 32; bit++) {
-			if (sync_test_and_clear_bit(bit,
-				(unsigned long *)&recv_int_page[dword])) {
-				relid = (dword << 5) + bit;
-
-				if (relid == 0)
-					/*
-					 * Special case - vmbus
-					 * channel protocol msg
-					 */
-					continue;
-
-				process_chn_event(relid);
-			}
-		}
+
+	/* relid == 0 is vmbus channel protocol msg */
+	relid = 1;
+	for_each_set_bit_from(relid, recv_int_page, max_relid) {
+		clear_bit(relid, recv_int_page);
+		process_chn_event(relid);
 	}
 }
 
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 230c62e..13dd210 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -872,9 +872,8 @@ static void hv_process_timer_expiration(struct hv_message *msg, int cpu)
 void vmbus_on_msg_dpc(unsigned long data)
 {
 	int cpu = smp_processor_id();
-	void *page_addr = hv_context.synic_message_page[cpu];
-	struct hv_message *msg = (struct hv_message *)page_addr +
-				  VMBUS_MESSAGE_SINT;
+	struct hv_message *msg = &hv_context.synic_message_page[cpu]->
+					sint_message[VMBUS_MESSAGE_SINT];
 	struct vmbus_channel_message_header *hdr;
 	struct vmbus_channel_message_table_entry *entry;
 	struct onmessage_work_context *ctx;
@@ -911,54 +910,40 @@ void vmbus_on_msg_dpc(unsigned long data)
 static void vmbus_isr(void)
 {
 	int cpu = smp_processor_id();
-	void *page_addr;
 	struct hv_message *msg;
-	union hv_synic_event_flags *event;
-	bool handled = false;
+	struct hv_synic_event_flags *event;
 
-	page_addr = hv_context.synic_event_page[cpu];
-	if (page_addr == NULL)
+	if (!hv_context.synic_event_page[cpu])
 		return;
 
-	event = (union hv_synic_event_flags *)page_addr +
-					 VMBUS_MESSAGE_SINT;
+	event = &hv_context.synic_event_page[cpu]->
+			sintevent_flags[VMBUS_MESSAGE_SINT];
 	/*
 	 * Check for events before checking for messages. This is the order
 	 * in which events and messages are checked in Windows guests on
 	 * Hyper-V, and the Windows team suggested we do the same.
 	 */
 
-	if ((vmbus_proto_version == VERSION_WS2008) ||
-		(vmbus_proto_version == VERSION_WIN7)) {
-
+	/* On win8 and above the channel interrupts are signaled directly in
+	 * the event page and will be checked in the .event_dpc
+	 */
+	if (vmbus_proto_version >= VERSION_WIN8 ||
 		/* Since we are a child, we only need to check bit 0 */
-		if (sync_test_and_clear_bit(0,
-			(unsigned long *) &event->flags32[0])) {
-			handled = true;
-		}
-	} else {
-		/*
-		 * Our host is win8 or above. The signaling mechanism
-		 * has changed and we can directly look at the event page.
-		 * If bit n is set then we have an interrup on the channel
-		 * whose id is n.
-		 */
-		handled = true;
-	}
-
-	if (handled)
+	    test_and_clear_bit(0, (unsigned long *)event->flags))
 		tasklet_schedule(hv_context.event_dpc[cpu]);
 
-
-	page_addr = hv_context.synic_message_page[cpu];
-	msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
+	msg = &hv_context.synic_message_page[cpu]->
+			sint_message[VMBUS_MESSAGE_SINT];
 
 	/* Check if there are actual msgs to be processed */
-	if (msg->header.message_type != HVMSG_NONE) {
-		if (msg->header.message_type == HVMSG_TIMER_EXPIRED)
-			hv_process_timer_expiration(msg, cpu);
-		else
-			tasklet_schedule(hv_context.msg_dpc[cpu]);
+	switch (READ_ONCE(msg->header.message_type)) {
+	case HVMSG_NONE:
+		break;
+	case HVMSG_TIMER_EXPIRED:
+		hv_process_timer_expiration(msg, cpu);
+		break;
+	default:
+		tasklet_schedule(hv_context.msg_dpc[cpu]);
 	}
 
 	add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0);
-- 
2.9.3