Commit d61031ee authored by K. Y. Srinivasan's avatar K. Y. Srinivasan Committed by Greg Kroah-Hartman
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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: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9f52a163

drivers/hv/channel.c

+44 −0
Original line number Diff line number Diff line
@@ -683,6 +683,50 @@ int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel, 
}

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.

include/linux/hyperv.h

+31 −0
Original line number Diff line number Diff line
@@ -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) * \
@@ -814,6 +826,18 @@ 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,
@@ -845,6 +869,13 @@ 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,

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