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authorYanming Liu <yanminglr@gmail.com>2022-01-20 04:20:52 +0800
committerWei Liu <wei.liu@kernel.org>2022-01-23 22:31:23 +0000
commit96d9d1fa5cd505078534113308ced0aa56d8da58 (patch)
tree748c037da2bc41d3c5b8b555297c950f2f12b472 /drivers/hv
parente783362eb54cd99b2cac8b3a9aeac942e6f6ac07 (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>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/hv_balloon.c7
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)