diff options
Diffstat (limited to 'drivers/hv/channel.c')
| -rw-r--r-- | drivers/hv/channel.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index 16f91c8490fe..5e482d7f60cb 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -676,10 +676,18 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer, * NOTE: in this case, the hvsock channel is an exception, because * it looks the host side's hvsock implementation has a throttling * mechanism which can hurt the performance otherwise. + * + * KYS: Oct. 30, 2016: + * It looks like Windows hosts have logic to deal with DOS attacks that + * can be triggered if it receives interrupts when it is not expecting + * the interrupt. The host expects interrupts only when the ring + * transitions from empty to non-empty (or full to non full on the guest + * to host ring). + * So, base the signaling decision solely on the ring state until the + * host logic is fixed. */ - if (((ret == 0) && kick_q && signal) || - (ret && !is_hvsock_channel(channel))) + if (((ret == 0) && signal)) vmbus_setevent(channel); return ret; @@ -786,9 +794,18 @@ int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel, * If we cannot write to the ring-buffer; signal the host * even if we may not have written anything. This is a rare * enough condition that it should not matter. + * + * KYS: Oct. 30, 2016: + * It looks like Windows hosts have logic to deal with DOS attacks that + * can be triggered if it receives interrupts when it is not expecting + * the interrupt. The host expects interrupts only when the ring + * transitions from empty to non-empty (or full to non full on the guest + * to host ring). + * So, base the signaling decision solely on the ring state until the + * host logic is fixed. */ - if (((ret == 0) && kick_q && signal) || (ret)) + if (((ret == 0) && signal)) vmbus_setevent(channel); return ret; |