Linux Virtualization - Nov 2010 - [PATCH 2/3]: An Implementation of HyperV KVP functionality

The hv_utils module will be composed of more than one file;
rename hv_utils.c to accommodate this without changing the module name.

Signed-off-by: K. Y. Srinivasan <ksrinivasan at novell.com>


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Hi.

I will ack connector part of course, but this hunk is actually quite
bad.

> +static void shutdown_onchannelcallback(void *context)
> +{
> +	struct vmbus_channel *channel = context;
> +	u8 *buf;
> +	u32 buflen, recvlen;
> +	u64 requestid;
> +	u8  execute_shutdown = false;
> +
> +	struct shutdown_msg_data *shutdown_msg;
> +
> +	struct icmsg_hdr *icmsghdrp;
> +	struct icmsg_negotiate *negop = NULL;
> +
> +	buflen = PAGE_SIZE;
> +	buf = kmalloc(buflen, GFP_ATOMIC);
> +
> +	vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);
Boom. I did not read further, since this function returns void and thus
can not propagate error, which is likely not a good idea.

-- 
	Evgeniy Polyakov

>>> On 11/24/2010 at  9:56 AM, in message <20101124145617.GA11133 at
ioremap.net>,
Evgeniy Polyakov <zbr at ioremap.net> wrote: 
> Hi.
> 
> I will ack connector part of course, but this hunk is actually quite
Thank you.
> bad.
> 
> 
>> +static void shutdown_onchannelcallback(void *context)
>> +{
>> +	struct vmbus_channel *channel = context;
>> +	u8 *buf;
>> +	u32 buflen, recvlen;
>> +	u64 requestid;
>> +	u8  execute_shutdown = false;
>> +
>> +	struct shutdown_msg_data *shutdown_msg;
>> +
>> +	struct icmsg_hdr *icmsghdrp;
>> +	struct icmsg_negotiate *negop = NULL;
>> +
>> +	buflen = PAGE_SIZE;
>> +	buf = kmalloc(buflen, GFP_ATOMIC);
>> +
>> +	vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);
> 
> Boom. I did not read further, since this function returns void and thus
> can not propagate error, which is likely not a good idea.
Hank and Haiyang (both copied here) are the authors of this code. My
contribution to this code (in this patch) has been to change the name of the
file! I will let Hank and Haiyang comment on your feedback.

Regards,

K. Y

This patch is re-based on the latest linux-next tree.

From: K. Y. Srinivasan <ksrinivasan at novell.com>

Subject: The hv_utils module will be composed of more than one file;
rename hv_utils.c to accommodate this without changing the module name.

Signed-off-by: K. Y. Srinivasan <ksrinivasan at novell.com>

Index: linux.trees.git/drivers/staging/hv/Makefile
==================================================================---
linux.trees.git.orig/drivers/staging/hv/Makefile	2010-12-07 07:04:41.000000000
-0500
+++ linux.trees.git/drivers/staging/hv/Makefile	2010-12-07 08:00:10.000000000
-0500
@@ -10,3 +10,4 @@ hv_vmbus-y := vmbus_drv.o osd.o \
 hv_storvsc-y := storvsc_drv.o storvsc.o
 hv_blkvsc-y := blkvsc_drv.o blkvsc.o
 hv_netvsc-y := netvsc_drv.o netvsc.o rndis_filter.o
+hv_utils-y := hv_util.o
Index: linux.trees.git/drivers/staging/hv/hv_util.c
==================================================================--- /dev/null
1970-01-01 00:00:00.000000000 +0000
+++ linux.trees.git/drivers/staging/hv/hv_util.c	2010-12-07 08:00:10.000000000
-0500
@@ -0,0 +1,308 @@
+/*
+ * Copyright (c) 2010, Microsoft Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Authors:
+ *   Haiyang Zhang <haiyangz at microsoft.com>
+ *   Hank Janssen  <hjanssen at microsoft.com>
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/reboot.h>
+#include <linux/dmi.h>
+#include <linux/pci.h>
+
+#include "logging.h"
+#include "osd.h"
+#include "vmbus.h"
+#include "vmbus_packet_format.h"
+#include "vmbus_channel_interface.h"
+#include "version_info.h"
+#include "channel.h"
+#include "vmbus_private.h"
+#include "vmbus_api.h"
+#include "utils.h"
+
+
+static void shutdown_onchannelcallback(void *context)
+{
+	struct vmbus_channel *channel = context;
+	u8 *buf;
+	u32 buflen, recvlen;
+	u64 requestid;
+	u8  execute_shutdown = false;
+
+	struct shutdown_msg_data *shutdown_msg;
+
+	struct icmsg_hdr *icmsghdrp;
+	struct icmsg_negotiate *negop = NULL;
+
+	buflen = PAGE_SIZE;
+	buf = kmalloc(buflen, GFP_ATOMIC);
+
+	vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);
+
+	if (recvlen > 0) {
+		DPRINT_DBG(VMBUS, "shutdown packet: len=%d, requestid=%lld",
+			   recvlen, requestid);
+
+		icmsghdrp = (struct icmsg_hdr *)&buf[
+			sizeof(struct vmbuspipe_hdr)];
+
+		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+			prep_negotiate_resp(icmsghdrp, negop, buf);
+		} else {
+			shutdown_msg = (struct shutdown_msg_data *)&buf[
+				sizeof(struct vmbuspipe_hdr) +
+				sizeof(struct icmsg_hdr)];
+
+			switch (shutdown_msg->flags) {
+			case 0:
+			case 1:
+				icmsghdrp->status = HV_S_OK;
+				execute_shutdown = true;
+
+				DPRINT_INFO(VMBUS, "Shutdown request received -"
+					    " gracefull shutdown initiated");
+				break;
+			default:
+				icmsghdrp->status = HV_E_FAIL;
+				execute_shutdown = false;
+
+				DPRINT_INFO(VMBUS, "Shutdown request received -"
+					    " Invalid request");
+				break;
+			};
+		}
+
+		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
+			| ICMSGHDRFLAG_RESPONSE;
+
+		vmbus_sendpacket(channel, buf,
+				       recvlen, requestid,
+				       VmbusPacketTypeDataInBand, 0);
+	}
+
+	kfree(buf);
+
+	if (execute_shutdown == true)
+		orderly_poweroff(false);
+}
+
+/*
+ * Set guest time to host UTC time.
+ */
+static inline void do_adj_guesttime(u64 hosttime)
+{
+	s64 host_tns;
+	struct timespec host_ts;
+
+	host_tns = (hosttime - WLTIMEDELTA) * 100;
+	host_ts = ns_to_timespec(host_tns);
+
+	do_settimeofday(&host_ts);
+}
+
+/*
+ * Synchronize time with host after reboot, restore, etc.
+ *
+ * ICTIMESYNCFLAG_SYNC flag bit indicates reboot, restore events of the VM.
+ * After reboot the flag ICTIMESYNCFLAG_SYNC is included in the first time
+ * message after the timesync channel is opened. Since the hv_utils module is
+ * loaded after hv_vmbus, the first message is usually missed. The other
+ * thing is, systime is automatically set to emulated hardware clock which may
+ * not be UTC time or in the same time zone. So, to override these effects, we
+ * use the first 50 time samples for initial system time setting.
+ */
+static inline void adj_guesttime(u64 hosttime, u8 flags)
+{
+	static s32 scnt = 50;
+
+	if ((flags & ICTIMESYNCFLAG_SYNC) != 0) {
+		do_adj_guesttime(hosttime);
+		return;
+	}
+
+	if ((flags & ICTIMESYNCFLAG_SAMPLE) != 0 && scnt > 0) {
+		scnt--;
+		do_adj_guesttime(hosttime);
+	}
+}
+
+/*
+ * Time Sync Channel message handler.
+ */
+static void timesync_onchannelcallback(void *context)
+{
+	struct vmbus_channel *channel = context;
+	u8 *buf;
+	u32 buflen, recvlen;
+	u64 requestid;
+	struct icmsg_hdr *icmsghdrp;
+	struct ictimesync_data *timedatap;
+
+	buflen = PAGE_SIZE;
+	buf = kmalloc(buflen, GFP_ATOMIC);
+
+	vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);
+
+	if (recvlen > 0) {
+		DPRINT_DBG(VMBUS, "timesync packet: recvlen=%d, requestid=%lld",
+			recvlen, requestid);
+
+		icmsghdrp = (struct icmsg_hdr *)&buf[
+				sizeof(struct vmbuspipe_hdr)];
+
+		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+			prep_negotiate_resp(icmsghdrp, NULL, buf);
+		} else {
+			timedatap = (struct ictimesync_data *)&buf[
+				sizeof(struct vmbuspipe_hdr) +
+				sizeof(struct icmsg_hdr)];
+			adj_guesttime(timedatap->parenttime, timedatap->flags);
+		}
+
+		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
+			| ICMSGHDRFLAG_RESPONSE;
+
+		vmbus_sendpacket(channel, buf,
+				recvlen, requestid,
+				VmbusPacketTypeDataInBand, 0);
+	}
+
+	kfree(buf);
+}
+
+/*
+ * Heartbeat functionality.
+ * Every two seconds, Hyper-V send us a heartbeat request message.
+ * we respond to this message, and Hyper-V knows we are alive.
+ */
+static void heartbeat_onchannelcallback(void *context)
+{
+	struct vmbus_channel *channel = context;
+	u8 *buf;
+	u32 buflen, recvlen;
+	u64 requestid;
+	struct icmsg_hdr *icmsghdrp;
+	struct heartbeat_msg_data *heartbeat_msg;
+
+	buflen = PAGE_SIZE;
+	buf = kmalloc(buflen, GFP_ATOMIC);
+
+	vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);
+
+	if (recvlen > 0) {
+		DPRINT_DBG(VMBUS, "heartbeat packet: len=%d, requestid=%lld",
+			   recvlen, requestid);
+
+		icmsghdrp = (struct icmsg_hdr *)&buf[
+				sizeof(struct vmbuspipe_hdr)];
+
+		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+			prep_negotiate_resp(icmsghdrp, NULL, buf);
+		} else {
+			heartbeat_msg = (struct heartbeat_msg_data *)&buf[
+				sizeof(struct vmbuspipe_hdr) +
+				sizeof(struct icmsg_hdr)];
+
+			DPRINT_DBG(VMBUS, "heartbeat seq = %lld",
+				   heartbeat_msg->seq_num);
+
+			heartbeat_msg->seq_num += 1;
+		}
+
+		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
+			| ICMSGHDRFLAG_RESPONSE;
+
+		vmbus_sendpacket(channel, buf,
+				       recvlen, requestid,
+				       VmbusPacketTypeDataInBand, 0);
+	}
+
+	kfree(buf);
+}
+
+static const struct pci_device_id __initconst
+hv_utils_pci_table[] __maybe_unused = {
+	{ PCI_DEVICE(0x1414, 0x5353) }, /* Hyper-V emulated VGA controller */
+	{ 0 }
+};
+MODULE_DEVICE_TABLE(pci, hv_utils_pci_table);
+
+
+static const struct dmi_system_id __initconst
+hv_utils_dmi_table[] __maybe_unused  = {
+	{
+		.ident = "Hyper-V",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Virtual Machine"),
+			DMI_MATCH(DMI_BOARD_NAME, "Virtual Machine"),
+		},
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(dmi, hv_utils_dmi_table);
+
+
+static int __init init_hyperv_utils(void)
+{
+	printk(KERN_INFO "Registering HyperV Utility Driver\n");
+
+	if (!dmi_check_system(hv_utils_dmi_table))
+		return -ENODEV;
+
+	hv_cb_utils[HV_SHUTDOWN_MSG].channel->onchannel_callback +	
&shutdown_onchannelcallback;
+	hv_cb_utils[HV_SHUTDOWN_MSG].callback = &shutdown_onchannelcallback;
+
+	hv_cb_utils[HV_TIMESYNC_MSG].channel->onchannel_callback +	
&timesync_onchannelcallback;
+	hv_cb_utils[HV_TIMESYNC_MSG].callback = &timesync_onchannelcallback;
+
+	hv_cb_utils[HV_HEARTBEAT_MSG].channel->onchannel_callback +	
&heartbeat_onchannelcallback;
+	hv_cb_utils[HV_HEARTBEAT_MSG].callback = &heartbeat_onchannelcallback;
+
+	return 0;
+}
+
+static void exit_hyperv_utils(void)
+{
+	printk(KERN_INFO "De-Registered HyperV Utility Driver\n");
+
+	hv_cb_utils[HV_SHUTDOWN_MSG].channel->onchannel_callback +	
&chn_cb_negotiate;
+	hv_cb_utils[HV_SHUTDOWN_MSG].callback = &chn_cb_negotiate;
+
+	hv_cb_utils[HV_TIMESYNC_MSG].channel->onchannel_callback +	
&chn_cb_negotiate;
+	hv_cb_utils[HV_TIMESYNC_MSG].callback = &chn_cb_negotiate;
+
+	hv_cb_utils[HV_HEARTBEAT_MSG].channel->onchannel_callback +	
&chn_cb_negotiate;
+	hv_cb_utils[HV_HEARTBEAT_MSG].callback = &chn_cb_negotiate;
+}
+
+module_init(init_hyperv_utils);
+module_exit(exit_hyperv_utils);
+
+MODULE_DESCRIPTION("Hyper-V Utilities");
+MODULE_VERSION(HV_DRV_VERSION);
+MODULE_LICENSE("GPL");
Index: linux.trees.git/drivers/staging/hv/hv_utils.c
==================================================================---
linux.trees.git.orig/drivers/staging/hv/hv_utils.c	2010-12-07 07:04:41.000000000
-0500
+++ /dev/null	1970-01-01 00:00:00.000000000 +0000
@@ -1,308 +0,0 @@
-/*
- * Copyright (c) 2010, Microsoft Corporation.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms and conditions of the GNU General Public License,
- * version 2, as published by the Free Software Foundation.
- *
- * This program is distributed in the hope it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
- * Place - Suite 330, Boston, MA 02111-1307 USA.
- *
- * Authors:
- *   Haiyang Zhang <haiyangz at microsoft.com>
- *   Hank Janssen  <hjanssen at microsoft.com>
- */
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/sysctl.h>
-#include <linux/reboot.h>
-#include <linux/dmi.h>
-#include <linux/pci.h>
-
-#include "logging.h"
-#include "osd.h"
-#include "vmbus.h"
-#include "vmbus_packet_format.h"
-#include "vmbus_channel_interface.h"
-#include "version_info.h"
-#include "channel.h"
-#include "vmbus_private.h"
-#include "vmbus_api.h"
-#include "utils.h"
-
-
-static void shutdown_onchannelcallback(void *context)
-{
-	struct vmbus_channel *channel = context;
-	u8 *buf;
-	u32 buflen, recvlen;
-	u64 requestid;
-	u8  execute_shutdown = false;
-
-	struct shutdown_msg_data *shutdown_msg;
-
-	struct icmsg_hdr *icmsghdrp;
-	struct icmsg_negotiate *negop = NULL;
-
-	buflen = PAGE_SIZE;
-	buf = kmalloc(buflen, GFP_ATOMIC);
-
-	vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);
-
-	if (recvlen > 0) {
-		DPRINT_DBG(VMBUS, "shutdown packet: len=%d, requestid=%lld",
-			   recvlen, requestid);
-
-		icmsghdrp = (struct icmsg_hdr *)&buf[
-			sizeof(struct vmbuspipe_hdr)];
-
-		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
-			prep_negotiate_resp(icmsghdrp, negop, buf);
-		} else {
-			shutdown_msg = (struct shutdown_msg_data *)&buf[
-				sizeof(struct vmbuspipe_hdr) +
-				sizeof(struct icmsg_hdr)];
-
-			switch (shutdown_msg->flags) {
-			case 0:
-			case 1:
-				icmsghdrp->status = HV_S_OK;
-				execute_shutdown = true;
-
-				DPRINT_INFO(VMBUS, "Shutdown request received -"
-					    " gracefull shutdown initiated");
-				break;
-			default:
-				icmsghdrp->status = HV_E_FAIL;
-				execute_shutdown = false;
-
-				DPRINT_INFO(VMBUS, "Shutdown request received -"
-					    " Invalid request");
-				break;
-			};
-		}
-
-		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
-			| ICMSGHDRFLAG_RESPONSE;
-
-		vmbus_sendpacket(channel, buf,
-				       recvlen, requestid,
-				       VmbusPacketTypeDataInBand, 0);
-	}
-
-	kfree(buf);
-
-	if (execute_shutdown == true)
-		orderly_poweroff(false);
-}
-
-/*
- * Set guest time to host UTC time.
- */
-static inline void do_adj_guesttime(u64 hosttime)
-{
-	s64 host_tns;
-	struct timespec host_ts;
-
-	host_tns = (hosttime - WLTIMEDELTA) * 100;
-	host_ts = ns_to_timespec(host_tns);
-
-	do_settimeofday(&host_ts);
-}
-
-/*
- * Synchronize time with host after reboot, restore, etc.
- *
- * ICTIMESYNCFLAG_SYNC flag bit indicates reboot, restore events of the VM.
- * After reboot the flag ICTIMESYNCFLAG_SYNC is included in the first time
- * message after the timesync channel is opened. Since the hv_utils module is
- * loaded after hv_vmbus, the first message is usually missed. The other
- * thing is, systime is automatically set to emulated hardware clock which may
- * not be UTC time or in the same time zone. So, to override these effects, we
- * use the first 50 time samples for initial system time setting.
- */
-static inline void adj_guesttime(u64 hosttime, u8 flags)
-{
-	static s32 scnt = 50;
-
-	if ((flags & ICTIMESYNCFLAG_SYNC) != 0) {
-		do_adj_guesttime(hosttime);
-		return;
-	}
-
-	if ((flags & ICTIMESYNCFLAG_SAMPLE) != 0 && scnt > 0) {
-		scnt--;
-		do_adj_guesttime(hosttime);
-	}
-}
-
-/*
- * Time Sync Channel message handler.
- */
-static void timesync_onchannelcallback(void *context)
-{
-	struct vmbus_channel *channel = context;
-	u8 *buf;
-	u32 buflen, recvlen;
-	u64 requestid;
-	struct icmsg_hdr *icmsghdrp;
-	struct ictimesync_data *timedatap;
-
-	buflen = PAGE_SIZE;
-	buf = kmalloc(buflen, GFP_ATOMIC);
-
-	vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);
-
-	if (recvlen > 0) {
-		DPRINT_DBG(VMBUS, "timesync packet: recvlen=%d, requestid=%lld",
-			recvlen, requestid);
-
-		icmsghdrp = (struct icmsg_hdr *)&buf[
-				sizeof(struct vmbuspipe_hdr)];
-
-		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
-			prep_negotiate_resp(icmsghdrp, NULL, buf);
-		} else {
-			timedatap = (struct ictimesync_data *)&buf[
-				sizeof(struct vmbuspipe_hdr) +
-				sizeof(struct icmsg_hdr)];
-			adj_guesttime(timedatap->parenttime, timedatap->flags);
-		}
-
-		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
-			| ICMSGHDRFLAG_RESPONSE;
-
-		vmbus_sendpacket(channel, buf,
-				recvlen, requestid,
-				VmbusPacketTypeDataInBand, 0);
-	}
-
-	kfree(buf);
-}
-
-/*
- * Heartbeat functionality.
- * Every two seconds, Hyper-V send us a heartbeat request message.
- * we respond to this message, and Hyper-V knows we are alive.
- */
-static void heartbeat_onchannelcallback(void *context)
-{
-	struct vmbus_channel *channel = context;
-	u8 *buf;
-	u32 buflen, recvlen;
-	u64 requestid;
-	struct icmsg_hdr *icmsghdrp;
-	struct heartbeat_msg_data *heartbeat_msg;
-
-	buflen = PAGE_SIZE;
-	buf = kmalloc(buflen, GFP_ATOMIC);
-
-	vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);
-
-	if (recvlen > 0) {
-		DPRINT_DBG(VMBUS, "heartbeat packet: len=%d, requestid=%lld",
-			   recvlen, requestid);
-
-		icmsghdrp = (struct icmsg_hdr *)&buf[
-				sizeof(struct vmbuspipe_hdr)];
-
-		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
-			prep_negotiate_resp(icmsghdrp, NULL, buf);
-		} else {
-			heartbeat_msg = (struct heartbeat_msg_data *)&buf[
-				sizeof(struct vmbuspipe_hdr) +
-				sizeof(struct icmsg_hdr)];
-
-			DPRINT_DBG(VMBUS, "heartbeat seq = %lld",
-				   heartbeat_msg->seq_num);
-
-			heartbeat_msg->seq_num += 1;
-		}
-
-		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
-			| ICMSGHDRFLAG_RESPONSE;
-
-		vmbus_sendpacket(channel, buf,
-				       recvlen, requestid,
-				       VmbusPacketTypeDataInBand, 0);
-	}
-
-	kfree(buf);
-}
-
-static const struct pci_device_id __initconst
-hv_utils_pci_table[] __maybe_unused = {
-	{ PCI_DEVICE(0x1414, 0x5353) }, /* Hyper-V emulated VGA controller */
-	{ 0 }
-};
-MODULE_DEVICE_TABLE(pci, hv_utils_pci_table);
-
-
-static const struct dmi_system_id __initconst
-hv_utils_dmi_table[] __maybe_unused  = {
-	{
-		.ident = "Hyper-V",
-		.matches = {
-			DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
-			DMI_MATCH(DMI_PRODUCT_NAME, "Virtual Machine"),
-			DMI_MATCH(DMI_BOARD_NAME, "Virtual Machine"),
-		},
-	},
-	{ },
-};
-MODULE_DEVICE_TABLE(dmi, hv_utils_dmi_table);
-
-
-static int __init init_hyperv_utils(void)
-{
-	printk(KERN_INFO "Registering HyperV Utility Driver\n");
-
-	if (!dmi_check_system(hv_utils_dmi_table))
-		return -ENODEV;
-
-	hv_cb_utils[HV_SHUTDOWN_MSG].channel->onchannel_callback -	
&shutdown_onchannelcallback;
-	hv_cb_utils[HV_SHUTDOWN_MSG].callback = &shutdown_onchannelcallback;
-
-	hv_cb_utils[HV_TIMESYNC_MSG].channel->onchannel_callback -	
&timesync_onchannelcallback;
-	hv_cb_utils[HV_TIMESYNC_MSG].callback = &timesync_onchannelcallback;
-
-	hv_cb_utils[HV_HEARTBEAT_MSG].channel->onchannel_callback -	
&heartbeat_onchannelcallback;
-	hv_cb_utils[HV_HEARTBEAT_MSG].callback = &heartbeat_onchannelcallback;
-
-	return 0;
-}
-
-static void exit_hyperv_utils(void)
-{
-	printk(KERN_INFO "De-Registered HyperV Utility Driver\n");
-
-	hv_cb_utils[HV_SHUTDOWN_MSG].channel->onchannel_callback -	
&chn_cb_negotiate;
-	hv_cb_utils[HV_SHUTDOWN_MSG].callback = &chn_cb_negotiate;
-
-	hv_cb_utils[HV_TIMESYNC_MSG].channel->onchannel_callback -	
&chn_cb_negotiate;
-	hv_cb_utils[HV_TIMESYNC_MSG].callback = &chn_cb_negotiate;
-
-	hv_cb_utils[HV_HEARTBEAT_MSG].channel->onchannel_callback -	
&chn_cb_negotiate;
-	hv_cb_utils[HV_HEARTBEAT_MSG].callback = &chn_cb_negotiate;
-}
-
-module_init(init_hyperv_utils);
-module_exit(exit_hyperv_utils);
-
-MODULE_DESCRIPTION("Hyper-V Utilities");
-MODULE_VERSION(HV_DRV_VERSION);
-MODULE_LICENSE("GPL");

On Tue, Dec 07, 2010 at 03:25:56PM -0700, Ky Srinivasan (ksrinivasan at
novell.com) wrote:
> +static void shutdown_onchannelcallback(void *context)
> +{
> +	struct vmbus_channel *channel = context;
> +	u8 *buf;
> +	u32 buflen, recvlen;
> +	u64 requestid;
> +	u8  execute_shutdown = false;
> +
> +	struct shutdown_msg_data *shutdown_msg;
> +
> +	struct icmsg_hdr *icmsghdrp;
> +	struct icmsg_negotiate *negop = NULL;
> +
> +	buflen = PAGE_SIZE;
> +	buf = kmalloc(buflen, GFP_ATOMIC);
> +
> +	vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);
This did not change since previous review and this is wrong.
It is the right way to crash kernel.

I did not read further since this is a show-stopper imo.

-- 
	Evgeniy Polyakov

>>> On 12/7/2010 at  5:29 PM, in message <20101207222933.GA10431 at
ioremap.net>,
Evgeniy Polyakov <zbr at ioremap.net> wrote: 
> On Tue, Dec 07, 2010 at 03:25:56PM -0700, Ky Srinivasan 
> (ksrinivasan at novell.com) wrote:
>> +static void shutdown_onchannelcallback(void *context)
>> +{
>> +	struct vmbus_channel *channel = context;
>> +	u8 *buf;
>> +	u32 buflen, recvlen;
>> +	u64 requestid;
>> +	u8  execute_shutdown = false;
>> +
>> +	struct shutdown_msg_data *shutdown_msg;
>> +
>> +	struct icmsg_hdr *icmsghdrp;
>> +	struct icmsg_negotiate *negop = NULL;
>> +
>> +	buflen = PAGE_SIZE;
>> +	buf = kmalloc(buflen, GFP_ATOMIC);
>> +
>> +	vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid);
> 
> This did not change since previous review and this is wrong.
> It is the right way to crash kernel.
> 
> I did not read further since this is a show-stopper imo.
Hank, do you want to respond to this comment.

Regards,

K. Y

> From: Ky Srinivasan [mailto:ksrinivasan at novell.com]
> Sent: Tuesday, December 07, 2010 3:19 PM
> >>> On 12/7/2010 at  5:29 PM, in message
> <20101207222933.GA10431 at ioremap.net>,
> Evgeniy Polyakov <zbr at ioremap.net> wrote:
> > On Tue, Dec 07, 2010 at 03:25:56PM -0700, Ky Srinivasan
> > (ksrinivasan at novell.com) wrote:
> >> +static void shutdown_onchannelcallback(void *context)
> >> +{
> >> +	struct vmbus_channel *channel = context;
> >> +	u8 *buf;
> >> +	u32 buflen, recvlen;
> >> +	u64 requestid;
> >> +	u8  execute_shutdown = false;
> >> +
> >> +	struct shutdown_msg_data *shutdown_msg;
> >> +
> >> +	struct icmsg_hdr *icmsghdrp;
> >> +	struct icmsg_negotiate *negop = NULL;
> >> +
> >> +	buflen = PAGE_SIZE;
> >> +	buf = kmalloc(buflen, GFP_ATOMIC);
> >> +
> >> +	vmbus_recvpacket(channel, buf, buflen, &recvlen,
&requestid);
> >
> > This did not change since previous review and this is wrong.
> > It is the right way to crash kernel.
> >
> > I did not read further since this is a show-stopper imo.
> Hank, do you want to respond to this comment.
> 
I will submit a patch for hv_utils.c to check the return value from
kmalloc and vmbus_recvpacket and return if either one of them fail.

The function is a void because they are treated here as fire and
Forget. But it comment about what would happen if kmalloc or 
Vmbus_recvpacket fails is correct. We could cause a crash.

So I will correct that part.

Hank.