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Drivers: hv: vmbus: Support a vmbus API for efficiently sending page arrays

PATCH In review K. Y. Srinivasan 2 participants 3 messages Dec 15, 2014 Hyper-V/Azure core and drivers

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K. Y. Srinivasan

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#0 lore raw

PATCH 1/1 Drivers: hv: vmbus: Support a vmbus API for efficiently sending page arrays

Currently, the API for sending a multi-page buffer over VMBUS is limited to a maximum pfn array of MAX_MULTIPAGE_BUFFER_COUNT. This limitation is not imposed by the host and unnecessarily limits the maximum payload that can be sent. Implement an API that does not have this restriction.

Signed-off-by K. Y. Srinivasan <[email protected]>
---
 drivers/hv/channel.c   |   44 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/hyperv.h |   31 +++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 0 deletions(-)
drivers/hv/channel.c +44 -0
index c76ffbe..18c4f23 100644
@@ -686,6 +686,50 @@ EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 /*
  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
  * using a GPADL Direct packet type.
+ * The buffer includes the vmbus descriptor.
+ */
+int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
+			      struct vmbus_packet_mpb_array *desc,
+			      u32 desc_size,
+			      void *buffer, u32 bufferlen, u64 requestid)
+{
+	int ret;
+	u32 packetlen;
+	u32 packetlen_aligned;
+	struct kvec bufferlist[3];
+	u64 aligned_data = 0;
+	bool signal = false;
+
+	packetlen = desc_size + bufferlen;
+	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
+
+	/* Setup the descriptor */
+	desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
+	desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
+	desc->dataoffset8 = desc_size >> 3; /* in 8-bytes grandularity */
+	desc->length8 = (u16)(packetlen_aligned >> 3);
+	desc->transactionid = requestid;
+	desc->rangecount = 1;
+
+	bufferlist[0].iov_base = desc;
+	bufferlist[0].iov_len = desc_size;
+	bufferlist[1].iov_base = buffer;
+	bufferlist[1].iov_len = bufferlen;
+	bufferlist[2].iov_base = &aligned_data;
+	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
+
+	ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
+
+	if (ret == 0 && signal)
+		vmbus_setevent(channel);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
+
+/*
+ * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
+ * using a GPADL Direct packet type.
  */
 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 				struct hv_multipage_buffer *multi_pagebuffer,
include/linux/hyperv.h +31 -0
index 08cfaff..8615b0d 100644
@@ -57,6 +57,18 @@ struct hv_multipage_buffer {
 	u64 pfn_array[MAX_MULTIPAGE_BUFFER_COUNT];
 };
 
+/*
+ * Multiple-page buffer array; the pfn array is variable size:
+ * The number of entries in the PFN array is determined by
+ * "len" and "offset".
+ */
+struct hv_mpb_array {
+	/* Length and Offset determines the # of pfns in the array */
+	u32 len;
+	u32 offset;
+	u64 pfn_array[];
+};
+
 /* 0x18 includes the proprietary packet header */
 #define MAX_PAGE_BUFFER_PACKET		(0x18 +			\
 					(sizeof(struct hv_page_buffer) * \

@@ -812,6 +824,18 @@ struct vmbus_channel_packet_multipage_buffer {
 	struct hv_multipage_buffer range;
 } __packed;
 
+/* The format must be the same as struct vmdata_gpa_direct */
+struct vmbus_packet_mpb_array {
+	u16 type;
+	u16 dataoffset8;
+	u16 length8;
+	u16 flags;
+	u64 transactionid;
+	u32 reserved;
+	u32 rangecount;         /* Always 1 in this case */
+	struct hv_mpb_array range;
+} __packed;
+
 
 extern int vmbus_open(struct vmbus_channel *channel,
 			    u32 send_ringbuffersize,

@@ -843,6 +867,13 @@ extern int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 					u32 bufferlen,
 					u64 requestid);
 
+extern int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
+				     struct vmbus_packet_mpb_array *mpb,
+				     u32 desc_size,
+				     void *buffer,
+				     u32 bufferlen,
+				     u64 requestid);
+
 extern int vmbus_establish_gpadl(struct vmbus_channel *channel,
 				      void *kbuffer,
 				      u32 size,
Signature · 1 line
1.7.4.1
#1 lore raw
Quoted 75 lines · K. Y. Srinivasan

Currently, the API for sending a multi-page buffer over VMBUS is limited to a maximum pfn array of MAX_MULTIPAGE_BUFFER_COUNT. This limitation is not imposed by the host and unnecessarily limits the maximum payload that can be sent. Implement an API that does not have this restriction.

Signed-off-by K. Y. Srinivasan <[email protected]>
---
 drivers/hv/channel.c   |   44 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/hyperv.h |   31 +++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 0 deletions(-)
drivers/hv/channel.c +44 -0
index c76ffbe..18c4f23 100644
@@ -686,6 +686,50 @@ EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 /*
  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
  * using a GPADL Direct packet type.
+ * The buffer includes the vmbus descriptor.
+ */
+int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
+			      struct vmbus_packet_mpb_array *desc,
+			      u32 desc_size,
+			      void *buffer, u32 bufferlen, u64 requestid)
+{
+	int ret;
+	u32 packetlen;
+	u32 packetlen_aligned;
+	struct kvec bufferlist[3];
+	u64 aligned_data = 0;
+	bool signal = false;
+
+	packetlen = desc_size + bufferlen;
+	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
+
+	/* Setup the descriptor */
+	desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
+	desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
+	desc->dataoffset8 = desc_size >> 3; /* in 8-bytes grandularity */
+	desc->length8 = (u16)(packetlen_aligned >> 3);
+	desc->transactionid = requestid;
+	desc->rangecount = 1;
+
+	bufferlist[0].iov_base = desc;
+	bufferlist[0].iov_len = desc_size;
+	bufferlist[1].iov_base = buffer;
+	bufferlist[1].iov_len = bufferlen;
+	bufferlist[2].iov_base = &aligned_data;
+	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
+
+	ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
+
+	if (ret == 0 && signal)
+		vmbus_setevent(channel);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
+
+/*
+ * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
+ * using a GPADL Direct packet type.
  */
 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 				struct hv_multipage_buffer *multi_pagebuffer,
include/linux/hyperv.h +1 -0
index 08cfaff..8615b0d 100644
@@ -57,6 +57,18 @@ struct hv_multipage_buffer {
 	u64 pfn_array[MAX_MULTIPAGE_BUFFER_COUNT];
 };
 
+/*

include/linux/hyperv.h struct hv_multipage_buffer { · line 70

Quoted 10 lines
include/linux/hyperv.h +10 -0
+ * Multiple-page buffer array; the pfn array is variable size:
+ * The number of entries in the PFN array is determined by
+ * "len" and "offset".
+ */
+struct hv_mpb_array {
+	/* Length and Offset determines the # of pfns in the array */
+	u32 len;
+	u32 offset;
+	u64 pfn_array[];
+};

Does this cross the user/kernel boundry? If so, they need to be __u32 and __u64 variables.

Quoted 9 lines
include/linux/hyperv.h +2 -0
+
 /* 0x18 includes the proprietary packet header */
 #define MAX_PAGE_BUFFER_PACKET		(0x18 +			\
 					(sizeof(struct hv_page_buffer) * \

@@ -812,6 +824,18 @@ struct vmbus_channel_packet_multipage_buffer {
 	struct hv_multipage_buffer range;
 } __packed;
 
+/* The format must be the same as struct vmdata_gpa_direct */

include/linux/hyperv.h struct vmbus_channel_packet_multipage_buffer { · line 837

Quoted 10 lines
include/linux/hyperv.h +10 -0
+struct vmbus_packet_mpb_array {
+	u16 type;
+	u16 dataoffset8;
+	u16 length8;
+	u16 flags;
+	u64 transactionid;
+	u32 reserved;
+	u32 rangecount;         /* Always 1 in this case */
+	struct hv_mpb_array range;
+} __packed;

Same here.

thanks,

greg k-h

author
#2 lore raw
Quoted 92 lines

-----Original Message-----
From: Greg KH [mailto:[email protected]]
Sent: Monday, December 15, 2014 11:34 AM
To: KY Srinivasan
Cc: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
Subject: Re: [PATCH 1/1] Drivers: hv: vmbus: Support a vmbus API for efficiently sending page arrays

Quoted 2 lines · K. Y. Srinivasan

Currently, the API for sending a multi-page buffer over VMBUS is limited to a maximum pfn array of MAX_MULTIPAGE_BUFFER_COUNT.

This

Quoted 2 lines

limitation is not imposed by the host and unnecessarily limits the maximum payload that can be sent. Implement an API that does not have

this restriction.

Quoted 4 lines
Signed-off-by K. Y. Srinivasan <[email protected]>
---
 drivers/hv/channel.c   |   44

++++++++++++++++++++++++++++++++++++++++++++

drivers/hv/channel.c

Quoted 8 lines
 include/linux/hyperv.h |   31 +++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 0 deletions(-)
drivers/hv/channel.c index renamed from drivers/hv/channel.c +0 -0

c76ffbe..18c4f23 100644

drivers/hv/channel.c +0 -0
@@ -686,6 +686,50 @@

EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);

Quoted 12 lines
drivers/hv/channel.c +9 -0
 /*
  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
  * using a GPADL Direct packet type.
+ * The buffer includes the vmbus descriptor.
+ */
+int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
+			      struct vmbus_packet_mpb_array *desc,
+			      u32 desc_size,
+			      void *buffer, u32 bufferlen, u64 requestid) {
+	int ret;
+	u32 packetlen;
+	u32 packetlen_aligned;

drivers/hv/channel.c EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);

Quoted 10 lines
drivers/hv/channel.c +10 -0
+	struct kvec bufferlist[3];
+	u64 aligned_data = 0;
+	bool signal = false;
+
+	packetlen = desc_size + bufferlen;
+	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
+
+	/* Setup the descriptor */
+	desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
+	desc->flags =

VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;

Quoted 18 lines
drivers/hv/channel.c +18 -0
+	desc->dataoffset8 = desc_size >> 3; /* in 8-bytes grandularity */
+	desc->length8 = (u16)(packetlen_aligned >> 3);
+	desc->transactionid = requestid;
+	desc->rangecount = 1;
+
+	bufferlist[0].iov_base = desc;
+	bufferlist[0].iov_len = desc_size;
+	bufferlist[1].iov_base = buffer;
+	bufferlist[1].iov_len = bufferlen;
+	bufferlist[2].iov_base = &aligned_data;
+	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
+
+	ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3,
+&signal);
+
+	if (ret == 0 && signal)
+		vmbus_setevent(channel);
+

drivers/hv/channel.c EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);

Quoted 10 lines
drivers/hv/channel.c +7 -0
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
+
+/*
+ * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
+ * using a GPADL Direct packet type.
  */
 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 				struct hv_multipage_buffer

*multi_pagebuffer, diff --git

Quoted 8 lines

a/include/linux/hyperv.h b/include/linux/hyperv.h index 08cfaff..8615b0d 100644

include/linux/hyperv.h +0 -0
@@ -57,6 +57,18 @@ struct hv_multipage_buffer {
 	u64 pfn_array[MAX_MULTIPAGE_BUFFER_COUNT];
 };
Quoted 14 lines

include/linux/hyperv.h struct hv_multipage_buffer { · line 70

Quoted 11 lines
include/linux/hyperv.h +11 -0
+/*
+ * Multiple-page buffer array; the pfn array is variable size:
+ * The number of entries in the PFN array is determined by
+ * "len" and "offset".
+ */
+struct hv_mpb_array {
+	/* Length and Offset determines the # of pfns in the array */
+	u32 len;
+	u32 offset;
+	u64 pfn_array[];
+};

Does this cross the user/kernel boundry? If so, they need to be __u32 and __u64 variables.

This does not cross user/kernel boundry.

Quoted 11 lines

include/linux/hyperv.h struct hv_multipage_buffer {

Quoted 4 lines
include/linux/hyperv.h +1 -0
+
 /* 0x18 includes the proprietary packet header */
 #define MAX_PAGE_BUFFER_PACKET		(0x18 +

	\
Quoted 1 line
include/linux/hyperv.h +0 -0
 					(sizeof(struct hv_page_buffer) * \
(quoted diff) +0 -0
@@ -812,6 +824,18 @@ struct
 > vmbus_channel_packet_multipage_buffer {
 >  	struct hv_multipage_buffer range;
 >  } __packed;
Quoted 1 line
Quoted 13 lines

include/linux/hyperv.h struct vmbus_channel_packet_multipage_buffer { · line 837

Quoted 11 lines
include/linux/hyperv.h +11 -0
+/* The format must be the same as struct vmdata_gpa_direct */ struct
+vmbus_packet_mpb_array {
+	u16 type;
+	u16 dataoffset8;
+	u16 length8;
+	u16 flags;
+	u64 transactionid;
+	u32 reserved;
+	u32 rangecount;         /* Always 1 in this case */
+	struct hv_mpb_array range;
+} __packed;

Same here.

This is completely internal to the kernel.

Regards,

K. Y

Quoted 4 lines

thanks,

greg k-h