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 <k...@microsoft.com>
---
drivers/hv/channel.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/hyperv.h | 31 +++++++++++++++++++++++++++++++
2 files changed, 75 insertions(+), 0 deletions(-)
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 @@ 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,
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 08cfaff..8615b0d 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -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,
--
1.7.4.1
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