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 <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index c76ffbe..18c4f23 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -686,6 +686,50 @@
/*
* 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,