diff options
| author | Yanming Liu <yanminglr@gmail.com> | 2022-01-20 04:20:52 +0800 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2022-01-23 22:31:23 +0000 |
| commit | 96d9d1fa5cd505078534113308ced0aa56d8da58 (patch) | |
| tree | 748c037da2bc41d3c5b8b555297c950f2f12b472 | |
| parent | e783362eb54cd99b2cac8b3a9aeac942e6f6ac07 (diff) | |
Drivers: hv: balloon: account for vmbus packet header in max_pkt_size
Commit adae1e931acd ("Drivers: hv: vmbus: Copy packets sent by Hyper-V
out of the ring buffer") introduced a notion of maximum packet size in
vmbus channel and used that size to initialize a buffer holding all
incoming packet along with their vmbus packet header. hv_balloon uses
the default maximum packet size VMBUS_DEFAULT_MAX_PKT_SIZE which matches
its maximum message size, however vmbus_open expects this size to also
include vmbus packet header. This leads to 4096 bytes
dm_unballoon_request messages being truncated to 4080 bytes. When the
driver tries to read next packet it starts from a wrong read_index,
receives garbage and prints a lot of "Unhandled message: type:
<garbage>" in dmesg.
Allocate the buffer with HV_HYP_PAGE_SIZE more bytes to make room for
the header.
Fixes: adae1e931acd ("Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer")
Suggested-by: Michael Kelley (LINUX) <mikelley@microsoft.com>
Suggested-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Signed-off-by: Yanming Liu <yanminglr@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20220119202052.3006981-1-yanminglr@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
| -rw-r--r-- | drivers/hv/hv_balloon.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index ca873a3b98db..f2d05bff4245 100644 --- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -1660,6 +1660,13 @@ static int balloon_connect_vsp(struct hv_device *dev) unsigned long t; int ret; + /* + * max_pkt_size should be large enough for one vmbus packet header plus + * our receive buffer size. Hyper-V sends messages up to + * HV_HYP_PAGE_SIZE bytes long on balloon channel. + */ + dev->channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2; + ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0, balloon_onchannelcallback, dev); if (ret) |