On Fri, Jul 31, 2026 at 06:23:20PM +0200, Laurent Vivier wrote:
Convert the global pool_tap4 and pool_tap6 packet pools from single pools to arrays of pools, one for each queue pair. This change is necessary to support multiqueue operation in vhost-user mode, where multiple queue pairs may be processing packets concurrently.
The pool storage structures (pool_tap4_storage and pool_tap6_storage) are now arrays of VHOST_USER_MAX_VQS/2 elements, with corresponding pointer arrays (pool_tap4 and pool_tap6) for accessing them.
Add a qpair parameter to tap_flush_pools() so it flushes the correct pool. tap4_handler() and tap6_handler() now use the qpair they already receive to index into the pool arrays. Add bounds checking assertions in tap_handler() and tap_add_packet().
In passt and pasta modes, all operations use QPAIR_DEFAULT. In vhost-user mode, the queue pair is derived from the virtqueue index via QPAIR_FROM_QUEUE().
All pools within the array share the same buffer pointer: - In vhost-user mode: Points to the vhost-user memory structure, which is safe as packet data remains in guest memory and pools only track iovecs - In passt/pasta mode: Points to pkt_buf, which is safe as only queue pair 0 is used
Signed-off-by: Laurent Vivier
Reviewed-by: David Gibson
--- tap.c | 77 ++++++++++++++++++++++++++++++----------------------- tap.h | 2 +- vu_common.c | 2 +- 3 files changed, 46 insertions(+), 35 deletions(-)
diff --git a/tap.c b/tap.c index 029888e32db5..6bba436f148f 100644 --- a/tap.c +++ b/tap.c @@ -94,9 +94,13 @@ CHECK_FRAME_LEN(L2_MAX_LEN_VU); DIV_ROUND_UP(sizeof(pkt_buf), \ ETH_HLEN + sizeof(struct ipv6hdr) + sizeof(struct udphdr))
-/* IPv4 (plus ARP) and IPv6 message batches from tap/guest to IP handlers */ -static PACKET_POOL_NOINIT(pool_tap4, TAP_MSGS_IP4); -static PACKET_POOL_NOINIT(pool_tap6, TAP_MSGS_IP6); +/* IPv4 (plus ARP) and IPv6 message batches from tap/guest to IP handlers + * One pool per queue pair for multiqueue support + */ +static PACKET_POOL_DECL(pool_tap4, TAP_MSGS_IP4) pool_tap4_storage[VHOST_USER_MAX_VQS / 2]; +static struct pool *pool_tap4[VHOST_USER_MAX_VQS / 2]; +static PACKET_POOL_DECL(pool_tap6, TAP_MSGS_IP6) pool_tap6_storage[VHOST_USER_MAX_VQS / 2]; +static struct pool *pool_tap6[VHOST_USER_MAX_VQS / 2];
#define TAP_SEQS 128 /* Different L4 tuples in one batch */
@@ -702,12 +706,12 @@ static int tap4_handler(struct ctx *c, unsigned int qpair, unsigned int i, j, seq_count; struct tap4_l4_t *seq;
- if (!c->ifi4 || !pool_tap4->count) - return pool_tap4->count; + if (!c->ifi4 || !pool_tap4[qpair]->count) + return pool_tap4[qpair]->count;
i = 0; resume: - for (seq_count = 0, seq = NULL; i < pool_tap4->count; i++) { + for (seq_count = 0, seq = NULL; i < pool_tap4[qpair]->count; i++) { struct iovec trim_iov[UIO_MAXIOV]; size_t l3len, hlen, l4len, check; struct ethhdr eh_storage; @@ -718,7 +722,7 @@ resume: struct iov_tail data; struct iphdr *iph;
- if (!packet_get(pool_tap4, i, &data)) + if (!packet_get(pool_tap4[qpair], i, &data)) continue;
eh = IOV_PEEK_HEADER(&data, eh_storage); @@ -801,7 +805,7 @@ resume: if (iph->protocol == IPPROTO_UDP) { struct iov_tail eh_data;
- packet_get(pool_tap4, i, &eh_data); + packet_get(pool_tap4[qpair], i, &eh_data); if (dhcp(c, qpair, &eh_data)) continue; } @@ -832,7 +836,7 @@ resume: goto append;
if (seq_count == TAP_SEQS) - break; /* Resume after flushing if i < pool_tap4->count */ + break; /* Resume after flushing if i < pool_tap4[qpair]->count */
for (seq = tap4_l4 + seq_count - 1; seq >= tap4_l4; seq--) { if (L4_MATCH(iph, uh, seq)) { @@ -878,10 +882,10 @@ append: } }
- if (i < pool_tap4->count) + if (i < pool_tap4[qpair]->count) goto resume;
- return pool_tap4->count; + return pool_tap4[qpair]->count; }
#define IPV6_NH_OPT(nh) \ @@ -950,12 +954,12 @@ static int tap6_handler(struct ctx *c, unsigned int qpair, unsigned int i, j, seq_count = 0; struct tap6_l4_t *seq;
- if (!c->ifi6 || !pool_tap6->count) - return pool_tap6->count; + if (!c->ifi6 || !pool_tap6[qpair]->count) + return pool_tap6[qpair]->count;
i = 0; resume: - for (seq_count = 0, seq = NULL; i < pool_tap6->count; i++) { + for (seq_count = 0, seq = NULL; i < pool_tap6[qpair]->count; i++) { size_t l4len, plen, check; struct in6_addr *saddr, *daddr; struct ipv6hdr ip6h_storage; @@ -967,7 +971,7 @@ resume: struct ipv6hdr *ip6h; uint8_t proto;
- if (!packet_get(pool_tap6, i, &data)) + if (!packet_get(pool_tap6[qpair], i, &data)) return -1;
eh = IOV_REMOVE_HEADER(&data, eh_storage); @@ -1082,7 +1086,7 @@ resume: goto append;
if (seq_count == TAP_SEQS) - break; /* Resume after flushing if i < pool_tap6->count */ + break; /* Resume after flushing if i < pool_tap6[qpair]->count */
for (seq = tap6_l4 + seq_count - 1; seq >= tap6_l4; seq--) { if (L4_MATCH(ip6h, proto, uh, seq)) { @@ -1129,19 +1133,19 @@ append: } }
- if (i < pool_tap6->count) + if (i < pool_tap6[qpair]->count) goto resume;
- return pool_tap6->count; + return pool_tap6[qpair]->count; }
/** - * tap_flush_pools() - Flush both IPv4 and IPv6 packet pools + * tap_flush_pools() - Flush both IPv4 and IPv6 packet pools for a given qpair */ -void tap_flush_pools(void) +void tap_flush_pools(unsigned int qpair) { - pool_flush(pool_tap4); - pool_flush(pool_tap6); + pool_flush(pool_tap4[qpair]); + pool_flush(pool_tap6[qpair]); }
/** @@ -1152,6 +1156,7 @@ void tap_flush_pools(void) */ void tap_handler(struct ctx *c, unsigned int qpair, const struct timespec *now) { + assert(qpair < VHOST_USER_MAX_VQS / 2); tap4_handler(c, qpair, now); tap6_handler(c, qpair, now); } @@ -1186,21 +1191,23 @@ void tap_add_packet(struct ctx *c, unsigned int qpair, struct iov_tail *data, proto_update_l2_buf(c->guest_mac); }
+ assert(qpair < VHOST_USER_MAX_VQS / 2); + switch (ntohs(eh->h_proto)) { case ETH_P_ARP: case ETH_P_IP: - if (!pool_can_fit(pool_tap4, data)) { + if (!pool_can_fit(pool_tap4[qpair], data)) { tap4_handler(c, qpair, now); - pool_flush(pool_tap4); + pool_flush(pool_tap4[qpair]); } - packet_add(pool_tap4, data); + packet_add(pool_tap4[qpair], data); break; case ETH_P_IPV6: - if (!pool_can_fit(pool_tap6, data)) { + if (!pool_can_fit(pool_tap6[qpair], data)) { tap6_handler(c, qpair, now); - pool_flush(pool_tap6); + pool_flush(pool_tap6[qpair]); } - packet_add(pool_tap6, data); + packet_add(pool_tap6[qpair], data); break; default: break; @@ -1238,7 +1245,7 @@ static void tap_passt_input(struct ctx *c, const struct timespec *now) ssize_t n; char *p;
- tap_flush_pools(); + tap_flush_pools(QPAIR_DEFAULT);
if (partial_len) { /* We have a partial frame from an earlier pass. Move it to the @@ -1321,7 +1328,7 @@ static void tap_pasta_input(struct ctx *c, const struct timespec *now) { ssize_t n, len;
- tap_flush_pools(); + tap_flush_pools(QPAIR_DEFAULT);
for (n = 0; n <= (ssize_t)(sizeof(pkt_buf) - L2_MAX_LEN_PASTA); @@ -1586,10 +1593,14 @@ static void tap_sock_tun_init(struct ctx *c) */ static void tap_sock_update_pool(void *base, size_t size) { - int i; + unsigned int i;
- pool_tap4_storage = PACKET_INIT(pool_tap4, TAP_MSGS_IP4, base, size); - pool_tap6_storage = PACKET_INIT(pool_tap6, TAP_MSGS_IP6, base, size); + for (i = 0; i < VHOST_USER_MAX_VQS / 2; i++) { + pool_tap4_storage[i] = PACKET_INIT(pool_tap4, TAP_MSGS_IP4, base, size); + pool_tap4[i] = (struct pool *)&pool_tap4_storage[i]; + pool_tap6_storage[i] = PACKET_INIT(pool_tap6, TAP_MSGS_IP6, base, size); + pool_tap6[i] = (struct pool *)&pool_tap6_storage[i]; + }
for (i = 0; i < TAP_SEQS; i++) { tap4_l4[i].p = PACKET_INIT(pool_l4, UIO_MAXIOV, base, size); diff --git a/tap.h b/tap.h index 0f8e98fc5f84..7d77e071ba49 100644 --- a/tap.h +++ b/tap.h @@ -121,7 +121,7 @@ void tap_handler_passt(struct ctx *c, uint32_t events, int tap_sock_unix_open(char *sock_path); void tap_sock_reset(struct ctx *c); void tap_backend_init(struct ctx *c); -void tap_flush_pools(void); +void tap_flush_pools(unsigned int qpair); void tap_handler(struct ctx *c, unsigned int qpair, const struct timespec *now); void tap_add_packet(struct ctx *c, unsigned int qpair, struct iov_tail *data, const struct timespec *now); diff --git a/vu_common.c b/vu_common.c index 7239cb42f38b..0cd19b36737d 100644 --- a/vu_common.c +++ b/vu_common.c @@ -177,7 +177,7 @@ static void vu_handle_tx(struct vu_dev *vdev, int index,
assert(QPAIR_IS_FROMGUEST(index));
- tap_flush_pools(); + tap_flush_pools(QPAIR_DEFAULT);
count = 0; out_sg_count = 0; -- 2.54.0
-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson