To get the payload of hvsock, we need raw=0 to skip the level-1 header
(i.e., struct vmpacket_descriptor desc) and we also need to skip the
level-2 header (i.e., struct vmpipe_proto_header pipe_hdr).
NB: if the length of the hvsock payload is not aligned with the 8-byte
boundeary, at most 7 padding bytes are appended, so the real hvsock
payload's length must be retrieved by the pipe_hdr.data_size field.
I 'upgrade' the 'raw' parameter of hv_ringbuffer_read() to a
'read_flags', trying to share the logic of the function.
This patch is required by the next patch, which will introduce the hvsock
send/recv APIs.
Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
drivers/hv/channel.c | 10 +++++----
drivers/hv/hyperv_vmbus.h | 13 +++++++++++-
drivers/hv/ring_buffer.c | 54 ++++++++++++++++++++++++++++++++++++-----------
include/linux/hyperv.h | 12 +++++++++++
4 files changed, 72 insertions(+), 17 deletions(-)
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index eaaa066..cc49966 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -940,13 +940,14 @@ EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
static inline int
__vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
- bool raw)
+ u32 read_flags)
{
int ret;
bool signal = false;
ret = hv_ringbuffer_read(&channel->inbound, buffer, bufferlen,
- buffer_actual_len, requestid, &signal, raw);
+ buffer_actual_len, requestid, &signal,
+ read_flags);
if (signal)
vmbus_setevent(channel);
@@ -959,7 +960,7 @@ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
u64 *requestid)
{
return __vmbus_recvpacket(channel, buffer, bufferlen,
- buffer_actual_len, requestid, false);
+ buffer_actual_len, requestid, 0);
}
EXPORT_SYMBOL(vmbus_recvpacket);
@@ -971,6 +972,7 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
u64 *requestid)
{
return __vmbus_recvpacket(channel, buffer, bufferlen,
- buffer_actual_len, requestid, true);
+ buffer_actual_len, requestid,
+ HV_RINGBUFFER_READ_FLAG_RAW);
}
EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 0411b7b..46206b6 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -619,9 +619,20 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *ring_info,
struct kvec *kv_list,
u32 kv_count, bool *signal);
+/*
+ * By default, a read_flags of 0 means: the payload offset is
+ * sizeof(struct vmpacket_descriptor).
+ *
+ * If HV_RINGBUFFER_READ_FLAG_RAW is used, the payload offset is 0.
+ *
+ * If HV_RINGBUFFER_READ_FLAG_HVSOCK is used, the payload offset is
+ * sizeof(struct vmpacket_descriptor) + sizeof(struct vmpipe_proto_header).
+ */
+#define HV_RINGBUFFER_READ_FLAG_RAW (1 << 0)
+#define HV_RINGBUFFER_READ_FLAG_HVSOCK (1 << 1)
int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
void *buffer, u32 buflen, u32 *buffer_actual_len,
- u64 *requestid, bool *signal, bool raw);
+ u64 *requestid, bool *signal, u32 read_flags);
void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
struct hv_ring_buffer_debug_info *debug_info);
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index b53702c..03a509c 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -382,32 +382,43 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
void *buffer, u32 buflen, u32 *buffer_actual_len,
- u64 *requestid, bool *signal, bool raw)
+ u64 *requestid, bool *signal, u32 read_flags)
{
+ bool raw = !!(read_flags & HV_RINGBUFFER_READ_FLAG_RAW);
+ bool hvsock = !!(read_flags & HV_RINGBUFFER_READ_FLAG_HVSOCK);
+
u32 bytes_avail_towrite;
u32 bytes_avail_toread;
u32 next_read_location = 0;
u64 prev_indices = 0;
unsigned long flags;
- struct vmpacket_descriptor desc;
+ struct vmpipe_proto_header *pipe_hdr;
+ struct vmpacket_descriptor *desc;
u32 offset;
- u32 packetlen;
+ u32 packetlen, tot_hdrlen;
int ret = 0;
if (buflen <= 0)
return -EINVAL;
+ tot_hdrlen = sizeof(*desc);
+ if (hvsock)
+ tot_hdrlen += sizeof(*pipe_hdr);
+
spin_lock_irqsave(&inring_info->ring_lock, flags);
*buffer_actual_len = 0;
- *requestid = 0;
+
+ /* If some driver doesn't need the info, a NULL is passed in. */
+ if (requestid)
+ *requestid = 0;
hv_get_ringbuffer_availbytes(inring_info,
&bytes_avail_toread,
&bytes_avail_towrite);
/* Make sure there is something to read */
- if (bytes_avail_toread < sizeof(desc)) {
+ if (bytes_avail_toread < tot_hdrlen) {
/*
* No error is set when there is even no header, drivers are
* supposed to analyze buffer_actual_len.
@@ -415,17 +426,26 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
goto out_unlock;
}
+ if (tot_hdrlen > buflen) {
+ ret = -ENOBUFS;
+ goto out_unlock;
+ }
+
+ desc = (struct vmpacket_descriptor *)buffer;
+
next_read_location = hv_get_next_read_location(inring_info);
- next_read_location = hv_copyfrom_ringbuffer(inring_info, &desc,
- sizeof(desc),
+ next_read_location = hv_copyfrom_ringbuffer(inring_info, desc,
+ tot_hdrlen,
next_read_location);
+ offset = 0;
+ if (!raw)
+ offset += (desc->offset8 << 3);
+ if (hvsock)
+ offset += sizeof(*pipe_hdr);
- offset = raw ? 0 : (desc.offset8 << 3);
- packetlen = (desc.len8 << 3) - offset;
- *buffer_actual_len = packetlen;
- *requestid = desc.trans_id;
+ packetlen = (desc->len8 << 3) - offset;
- if (bytes_avail_toread < packetlen + offset) {
+ if (bytes_avail_toread < (desc->len8 << 3)) {
ret = -EAGAIN;
goto out_unlock;
}
@@ -435,6 +455,16 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
goto out_unlock;
}
+ if (requestid)
+ *requestid = desc->trans_id;
+
+ if (!hvsock)
+ *buffer_actual_len = packetlen;
+ else {
+ pipe_hdr = (struct vmpipe_proto_header *)(desc + 1);
+ *buffer_actual_len = pipe_hdr->data_size;
+ }
+
next_read_location =
hv_get_next_readlocation_withoffset(inring_info, offset);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index b835d80..e005223 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1268,4 +1268,16 @@ extern __u32 vmbus_proto_version;
int vmbus_send_tl_connect_request(const uuid_le *shv_guest_servie_id,
const uuid_le *shv_host_servie_id);
+struct vmpipe_proto_header {
+ u32 pkt_type;
+
+ union {
+ u32 data_size;
+ struct {
+ u16 data_size;
+ u16 offset;
+ } partial;
+ };
+} __packed;
+
#endif /* _HYPERV_H */
--
2.1.4
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