system/freebsd-src
system/freebsd-src
1
0
Fork 0
mirror of https://github.com/freebsd/freebsd-src synced 2024-09-06 09:10:28 +00:00
Code Issues Packages Projects Releases Wiki Activity

Hyper-V: vmbus: check if signaling host is needed in vmbus_rxbr_read

Browse source 
It is observed that netvsc's send rings could stall on the latest
Azure Boost platforms. This is due to vmbus_rxbr_read() routine
doesn't check if host is waiting for more room to put data, which
leads to host side sleeping forever on this vmbus channel. The
problem was only observed on the latest platform because the host
requests larger buffer ring room to be available, which causes
the issue to happen much more easily.

Fix this by adding check in the vmbus_rxbr_read call and signaling
the host in the callers if check returns positively.

Reported by:	NetApp
Tested by:	whu
MFC after:	3 days
Sponsored by:	Microsoft
This commit is contained in:
Wei Hu 2023-10-20 08:58:20 +00:00
parent c1146e6ad6
commit 49fa9a6437
3 changed files with 19 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
sys/dev/hyperv/vmbus/vmbus_br.c
View file

@ -684,7 +684,8 @@ vmbus_rxbr_idxadv(struct vmbus_rxbr *rbr, uint32_t idx_adv,
* We assume (dlen + skip) == sizeof(channel packet).
*/
int
vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen, uint32_t skip)
vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen, uint32_t skip,
boolean_t *need_sig)
{
uint32_t rindex, br_dsize = rbr->rxbr_dsize;
@ -717,5 +718,11 @@ vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen, uint32_t skip)
mtx_unlock_spin(&rbr->rxbr_lock);
if (need_sig) {
*need_sig =
vmbus_rxbr_need_signal(rbr,
dlen + skip + sizeof(uint64_t));
}
return (0);
}

2
sys/dev/hyperv/vmbus/vmbus_brvar.h
View file

@ -129,7 +129,7 @@ void vmbus_rxbr_deinit(struct vmbus_rxbr *rbr);
void vmbus_rxbr_setup(struct vmbus_rxbr *rbr, void *buf, int blen);
int vmbus_rxbr_peek(struct vmbus_rxbr *rbr, void *data, int dlen);
int vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen,
uint32_t skip);
uint32_t skip, boolean_t *need_sig);
int vmbus_rxbr_idxadv(struct vmbus_rxbr *rbr, uint32_t idx_adv,
boolean_t *need_sig);
int vmbus_rxbr_idxadv_peek(struct vmbus_rxbr *rbr, void *data,

12
sys/dev/hyperv/vmbus/vmbus_chan.c
View file

@ -1205,6 +1205,7 @@ vmbus_chan_recv(struct vmbus_channel *chan, void *data, int *dlen0,
{
struct vmbus_chanpkt_hdr pkt;
int error, dlen, hlen;
boolean_t sig_event;
error = vmbus_rxbr_peek(&chan->ch_rxbr, &pkt, sizeof(pkt));
if (error)
@ -1235,9 +1236,12 @@ vmbus_chan_recv(struct vmbus_channel *chan, void *data, int *dlen0,
*dlen0 = dlen;
/* Skip packet header */
error = vmbus_rxbr_read(&chan->ch_rxbr, data, dlen, hlen);
error = vmbus_rxbr_read(&chan->ch_rxbr, data, dlen, hlen, &sig_event);
KASSERT(!error, ("vmbus_rxbr_read failed"));
if (!error && sig_event)
vmbus_chan_signal_rx(chan);
return (0);
}
@ -1246,6 +1250,7 @@ vmbus_chan_recv_pkt(struct vmbus_channel *chan,
struct vmbus_chanpkt_hdr *pkt, int *pktlen0)
{
int error, pktlen, pkt_hlen;
boolean_t sig_event;
pkt_hlen = sizeof(*pkt);
error = vmbus_rxbr_peek(&chan->ch_rxbr, pkt, pkt_hlen);
@ -1277,9 +1282,12 @@ vmbus_chan_recv_pkt(struct vmbus_channel *chan,
* by the above vmbus_rxbr_peek().
*/
error = vmbus_rxbr_read(&chan->ch_rxbr, pkt + 1,
pktlen - pkt_hlen, pkt_hlen);
pktlen - pkt_hlen, pkt_hlen, &sig_event);
KASSERT(!error, ("vmbus_rxbr_read failed"));
if (!error && sig_event)
vmbus_chan_signal_rx(chan);
return (0);
}