diff options
Diffstat (limited to 'drivers/hv')
| -rw-r--r-- | drivers/hv/channel.c | 99 | ||||
| -rw-r--r-- | drivers/hv/hyperv_vmbus.h | 6 | ||||
| -rw-r--r-- | drivers/hv/ring_buffer.c | 30 |
3 files changed, 34 insertions, 101 deletions
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index 5e482d7f60cb..8a8148f7b842 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -39,7 +39,7 @@ * vmbus_setevent- Trigger an event notification on the specified * channel. */ -static void vmbus_setevent(struct vmbus_channel *channel) +void vmbus_setevent(struct vmbus_channel *channel) { struct hv_monitor_page *monitorpage; @@ -65,6 +65,7 @@ static void vmbus_setevent(struct vmbus_channel *channel) vmbus_set_event(channel); } } +EXPORT_SYMBOL_GPL(vmbus_setevent); /* * vmbus_open - Open the specified channel. @@ -635,8 +636,6 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer, u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64)); struct kvec bufferlist[3]; u64 aligned_data = 0; - int ret; - bool signal = false; bool lock = channel->acquire_ring_lock; int num_vecs = ((bufferlen != 0) ? 3 : 1); @@ -656,41 +655,9 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer, bufferlist[2].iov_base = &aligned_data; bufferlist[2].iov_len = (packetlen_aligned - packetlen); - ret = hv_ringbuffer_write(&channel->outbound, bufferlist, num_vecs, - &signal, lock, channel->signal_policy); - - /* - * Signalling the host is conditional on many factors: - * 1. The ring state changed from being empty to non-empty. - * This is tracked by the variable "signal". - * 2. The variable kick_q tracks if more data will be placed - * on the ring. We will not signal if more data is - * to be placed. - * - * Based on the channel signal state, we will decide - * which signaling policy will be applied. - * - * 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. - * 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) && signal)) - vmbus_setevent(channel); + return hv_ringbuffer_write(channel, bufferlist, num_vecs, + lock, kick_q); - return ret; } EXPORT_SYMBOL(vmbus_sendpacket_ctl); @@ -731,7 +698,6 @@ int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel, u32 flags, bool kick_q) { - int ret; int i; struct vmbus_channel_packet_page_buffer desc; u32 descsize; @@ -739,7 +705,6 @@ int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel, u32 packetlen_aligned; struct kvec bufferlist[3]; u64 aligned_data = 0; - bool signal = false; bool lock = channel->acquire_ring_lock; if (pagecount > MAX_PAGE_BUFFER_COUNT) @@ -777,38 +742,8 @@ int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel, bufferlist[2].iov_base = &aligned_data; bufferlist[2].iov_len = (packetlen_aligned - packetlen); - ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, - &signal, lock, channel->signal_policy); - - /* - * Signalling the host is conditional on many factors: - * 1. The ring state changed from being empty to non-empty. - * This is tracked by the variable "signal". - * 2. The variable kick_q tracks if more data will be placed - * on the ring. We will not signal if more data is - * to be placed. - * - * Based on the channel signal state, we will decide - * which signaling policy will be applied. - * - * 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) && signal)) - vmbus_setevent(channel); - - return ret; + return hv_ringbuffer_write(channel, bufferlist, 3, + lock, kick_q); } EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer_ctl); @@ -839,12 +774,10 @@ int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel, 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; bool lock = channel->acquire_ring_lock; packetlen = desc_size + bufferlen; @@ -865,13 +798,8 @@ int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel, bufferlist[2].iov_base = &aligned_data; bufferlist[2].iov_len = (packetlen_aligned - packetlen); - ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, - &signal, lock, channel->signal_policy); - - if (ret == 0 && signal) - vmbus_setevent(channel); - - return ret; + return hv_ringbuffer_write(channel, bufferlist, 3, + lock, true); } EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc); @@ -883,14 +811,12 @@ int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel, struct hv_multipage_buffer *multi_pagebuffer, void *buffer, u32 bufferlen, u64 requestid) { - int ret; struct vmbus_channel_packet_multipage_buffer desc; u32 descsize; u32 packetlen; u32 packetlen_aligned; struct kvec bufferlist[3]; u64 aligned_data = 0; - bool signal = false; bool lock = channel->acquire_ring_lock; u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset, multi_pagebuffer->len); @@ -930,13 +856,8 @@ int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel, bufferlist[2].iov_base = &aligned_data; bufferlist[2].iov_len = (packetlen_aligned - packetlen); - ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, - &signal, lock, channel->signal_policy); - - if (ret == 0 && signal) - vmbus_setevent(channel); - - return ret; + return hv_ringbuffer_write(channel, bufferlist, 3, + lock, true); } EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer); diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index a5b4442433c8..fa782e13c8da 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -527,10 +527,10 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info); -int hv_ringbuffer_write(struct hv_ring_buffer_info *ring_info, +int hv_ringbuffer_write(struct vmbus_channel *channel, struct kvec *kv_list, - u32 kv_count, bool *signal, bool lock, - enum hv_signal_policy policy); + u32 kv_count, bool lock, + bool kick_q); int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, u32 buflen, u32 *buffer_actual_len, diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 5d11d93eedf4..4af71306d0ff 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -66,14 +66,25 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi) * once the ring buffer is empty, it will clear the * interrupt_mask and re-check to see if new data has * arrived. + * + * 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. */ -static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi, - enum hv_signal_policy policy) +static void hv_signal_on_write(u32 old_write, struct vmbus_channel *channel, + bool kick_q) { + struct hv_ring_buffer_info *rbi = &channel->outbound; + virt_mb(); if (READ_ONCE(rbi->ring_buffer->interrupt_mask)) - return false; + return; /* check interrupt_mask before read_index */ virt_rmb(); @@ -82,9 +93,9 @@ static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi, * ring transitions from being empty to non-empty. */ if (old_write == READ_ONCE(rbi->ring_buffer->read_index)) - return true; + vmbus_setevent(channel); - return false; + return; } /* Get the next write location for the specified ring buffer. */ @@ -273,9 +284,9 @@ void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info) } /* Write to the ring buffer. */ -int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, - struct kvec *kv_list, u32 kv_count, bool *signal, bool lock, - enum hv_signal_policy policy) +int hv_ringbuffer_write(struct vmbus_channel *channel, + struct kvec *kv_list, u32 kv_count, bool lock, + bool kick_q) { int i = 0; u32 bytes_avail_towrite; @@ -285,6 +296,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, u32 old_write; u64 prev_indices = 0; unsigned long flags = 0; + struct hv_ring_buffer_info *outring_info = &channel->outbound; for (i = 0; i < kv_count; i++) totalbytes_towrite += kv_list[i].iov_len; @@ -337,7 +349,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, if (lock) spin_unlock_irqrestore(&outring_info->ring_lock, flags); - *signal = hv_need_to_signal(old_write, outring_info, policy); + hv_signal_on_write(old_write, channel, kick_q); return 0; } |