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List: openbsd-tech
Subject: vmd(8) vionet: adapt zero-copy approach from vioblk
From: Dave Voutila <dv () sisu ! io>
Date: 2023-10-29 14:04:44
Message-ID: 87o7gh30z1.fsf () mars ! sisu ! io
[Download RAW message or body]
Recently, I rewrote parts of the emulated virtio block device in vmd(8)
to fix issues found bringing up NetBSD as a guest. In the process, the
rewrite introduced the chance to do zero-copy transfers for raw block
devices. The diff below brings that design to the virtio network device.
In summary:
- flips the logic to only read from the tap(4) when there's space in
the rx virtqueue instead of just when the tap is readable
- uses readv/writev when not needing to enforce locked lladdr or do
local interface packet inspection for DHCP intercept
- redesigns packet injection for DHCP replies by using a pipe,
allowing it to be handled by the rx event path
- puts the device into "needs reset" state under error conditions so
the driver will know something is borked
- drops the include of sys/param.h as it switches the static rx buffer
to be based on maximum tx size and not PAGE_SIZE
Don't expect throughput increases, but you may notice improved tail
latency and decreased cpu utilization under networking load, especially
if you're not using vmd(8)'s "local" interfaces.
ok's, feedback?
-dv
diffstat refs/heads/master refs/heads/vmd-vionet-rewrite
M usr.sbin/vmd/vionet.c | 445+ 301-
M usr.sbin/vmd/virtio.h | 0+ 7-
2 files changed, 445 insertions(+), 308 deletions(-)
diff refs/heads/master refs/heads/vmd-vionet-rewrite
commit - dae64e9e225d0c4320fe266e6b924a1630222416
commit + 7743ecfaef9332d7e7df5932ff472c6a00225414
blob - 740296a125e15f905e370e84ecf07163c58e2c99
blob + e08383130c5f19a25dcc3620cb31f4e5bab09b0d
--- usr.sbin/vmd/vionet.c
+++ usr.sbin/vmd/vionet.c
@@ -16,9 +16,8 @@
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
-#include <sys/mman.h>
-#include <sys/param.h> /* PAGE_SIZE */
#include <sys/socket.h>
+#include <sys/types.h>
#include <dev/pci/virtio_pcireg.h>
#include <dev/pv/virtioreg.h>
@@ -26,7 +25,6 @@
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
-#include <netinet/ip.h>
#include <errno.h>
#include <event.h>
@@ -36,7 +34,6 @@
#include <unistd.h>
#include "atomicio.h"
-#include "pci.h"
#include "virtio.h"
#include "vmd.h"
@@ -47,20 +44,36 @@
extern char *__progname;
extern struct vmd_vm *current_vm;
-/* Device Globals */
-struct event ev_tap;
+struct packet {
+ uint8_t *buf;
+ size_t len;
+};
-static int vionet_rx(struct vionet_dev *);
+static int vionet_rx(struct vionet_dev *, int);
+static ssize_t vionet_rx_copy(struct vionet_dev *, int, const struct iovec *,
+ int, size_t);
+static ssize_t vionet_rx_zerocopy(struct vionet_dev *, int,
+ const struct iovec *, int);
static void vionet_rx_event(int, short, void *);
static uint32_t handle_io_read(struct viodev_msg *, struct virtio_dev *,
int8_t *);
static int handle_io_write(struct viodev_msg *, struct virtio_dev *);
-void vionet_notify_rx(struct virtio_dev *);
-int vionet_notifyq(struct virtio_dev *);
+static int vionet_notify_tx(struct virtio_dev *);
+static int vionet_notifyq(struct virtio_dev *);
static void dev_dispatch_vm(int, short, void *);
static void handle_sync_io(int, short, void *);
+/* Device Globals */
+struct event ev_tap;
+struct event ev_inject;
+int pipe_inject[2];
+#define READ 0
+#define WRITE 1
+struct iovec iov_rx[VIONET_QUEUE_SIZE];
+struct iovec iov_tx[VIONET_QUEUE_SIZE];
+
+
__dead void
vionet_main(int fd, int fd_vmm)
{
@@ -79,6 +92,10 @@ vionet_main(int fd, int fd_vmm)
if (pledge("stdio vmm proc", NULL) == -1)
fatal("pledge");
+ /* Initialize iovec arrays. */
+ memset(iov_rx, 0, sizeof(iov_rx));
+ memset(iov_tx, 0, sizeof(iov_tx));
+
/* Receive our vionet_dev, mostly preconfigured. */
sz = atomicio(read, fd, &dev, sizeof(dev));
if (sz != sizeof(dev)) {
@@ -153,6 +170,12 @@ vionet_main(int fd, int fd_vmm)
}
}
+ /* Initialize our packet injection pipe. */
+ if (pipe2(pipe_inject, O_NONBLOCK) == -1) {
+ log_warn("%s: injection pipe", __func__);
+ goto fail;
+ }
+
/* Initialize libevent so we can start wiring event handlers. */
event_init();
@@ -171,6 +194,12 @@ vionet_main(int fd, int fd_vmm)
event_set(&ev_tap, vionet->data_fd, EV_READ | EV_PERSIST,
vionet_rx_event, &dev);
+ /* Add an event for injected packets. */
+ log_debug("%s: wiring in packet injection handler (fd=%d)", __func__,
+ pipe_inject[READ]);
+ event_set(&ev_inject, pipe_inject[READ], EV_READ | EV_PERSIST,
+ vionet_rx_event, &dev);
+
/* Configure our sync channel event handler. */
log_debug("%s: wiring in sync channel handler (fd=%d)", __func__,
dev.sync_fd);
@@ -209,6 +238,8 @@ vionet_main(int fd, int fd_vmm)
close_fd(dev.sync_fd);
close_fd(dev.async_fd);
close_fd(vionet->data_fd);
+ close_fd(pipe_inject[READ]);
+ close_fd(pipe_inject[WRITE]);
_exit(ret);
/* NOTREACHED */
}
@@ -223,6 +254,8 @@ fail:
close_fd(dev.sync_fd);
close_fd(dev.async_fd);
+ close_fd(pipe_inject[READ]);
+ close_fd(pipe_inject[WRITE]);
if (vionet != NULL)
close_fd(vionet->data_fd);
@@ -232,7 +265,7 @@ fail:
/*
* Update the gpa and hva of the virtqueue.
*/
-void
+static void
vionet_update_qa(struct vionet_dev *dev)
{
struct virtio_vq_info *vq_info;
@@ -259,7 +292,7 @@ vionet_update_qa(struct vionet_dev *dev)
/*
* Update the queue size.
*/
-void
+static void
vionet_update_qs(struct vionet_dev *dev)
{
struct virtio_vq_info *vq_info;
@@ -280,34 +313,28 @@ vionet_update_qs(struct vionet_dev *dev)
}
/*
- * vionet_enq_rx
+ * vionet_rx
*
- * Take a given packet from the host-side tap and copy it into the guest's
- * buffers utilizing the rx virtio ring. If the packet length is invalid
- * (too small or too large) or if there are not enough buffers available,
- * the packet is dropped.
+ * Pull packet from the provided fd and fill the receive-side virtqueue. We
+ * selectively use zero-copy approaches when possible.
+ *
+ * Returns 1 if guest notification is needed. Otherwise, returns -1 on failure
+ * or 0 if no notification is needed.
*/
-int
-vionet_enq_rx(struct vionet_dev *dev, char *pkt, size_t sz, int *spc)
+static int
+vionet_rx(struct vionet_dev *dev, int fd)
{
- uint16_t dxx, idx, hdr_desc_idx, chain_hdr_idx;
+ uint16_t idx, hdr_idx;
char *vr = NULL;
- size_t bufsz = 0, off = 0, pkt_offset = 0, chunk_size = 0;
- size_t chain_len = 0;
- struct vring_desc *desc, *pkt_desc, *hdr_desc;
+ size_t chain_len = 0, iov_cnt;
+ struct vring_desc *desc, *table;
struct vring_avail *avail;
struct vring_used *used;
struct virtio_vq_info *vq_info;
- struct virtio_net_hdr hdr;
- size_t hdr_sz;
+ struct iovec *iov;
+ int notify = 0;
+ ssize_t sz;
- if (sz < VIONET_MIN_TXLEN || sz > VIONET_MAX_TXLEN) {
- log_warnx("%s: invalid packet size", __func__);
- return (0);
- }
-
- hdr_sz = sizeof(hdr);
-
if (!(dev->cfg.device_status
& VIRTIO_CONFIG_DEVICE_STATUS_DRIVER_OK)) {
log_warnx("%s: driver not ready", __func__);
@@ -315,178 +342,287 @@ vionet_enq_rx(struct vionet_dev *dev, char *pkt, size_
}
vq_info = &dev->vq[RXQ];
+ idx = vq_info->last_avail;
vr = vq_info->q_hva;
if (vr == NULL)
fatalx("%s: vr == NULL", __func__);
-
/* Compute offsets in ring of descriptors, avail ring, and used ring */
- desc = (struct vring_desc *)(vr);
+ table = (struct vring_desc *)(vr);
avail = (struct vring_avail *)(vr + vq_info->vq_availoffset);
used = (struct vring_used *)(vr + vq_info->vq_usedoffset);
+ used->flags |= VRING_USED_F_NO_NOTIFY;
- idx = vq_info->last_avail & VIONET_QUEUE_MASK;
- if ((vq_info->notified_avail & VIONET_QUEUE_MASK) == idx) {
- log_debug("%s: insufficient available buffer capacity, "
- "dropping packet.", __func__);
- return (0);
- }
+ while (idx != avail->idx) {
+ hdr_idx = avail->ring[idx & VIONET_QUEUE_MASK];
+ desc = &table[hdr_idx & VIONET_QUEUE_MASK];
+ if (!DESC_WRITABLE(desc)) {
+ log_warnx("%s: invalid descriptor state", __func__);
+ goto reset;
+ }
- hdr_desc_idx = avail->ring[idx] & VIONET_QUEUE_MASK;
- hdr_desc = &desc[hdr_desc_idx];
+ iov = &iov_rx[0];
+ iov_cnt = 1;
- dxx = hdr_desc_idx;
- chain_hdr_idx = dxx;
- chain_len = 0;
+ /*
+ * First descriptor should be at least as large as the
+ * virtio_net_hdr. It's not technically required, but in
+ * legacy devices it should be safe to assume.
+ */
+ iov->iov_len = desc->len;
+ if (iov->iov_len < sizeof(struct virtio_net_hdr)) {
+ log_warnx("%s: invalid descriptor length", __func__);
+ goto reset;
+ }
- /* Process the descriptor and walk any potential chain. */
- do {
- off = 0;
- pkt_desc = &desc[dxx];
- if (!(pkt_desc->flags & VRING_DESC_F_WRITE)) {
- log_warnx("%s: invalid descriptor, not writable",
+ /*
+ * Insert the virtio_net_hdr and adjust len/base. We do the
+ * pointer math here before it's a void*.
+ */
+ iov->iov_base = hvaddr_mem(desc->addr, iov->iov_len);
+ if (iov->iov_base == NULL)
+ goto reset;
+ memset(iov->iov_base, 0, sizeof(struct virtio_net_hdr));
+
+ /* Tweak the iovec to account for the virtio_net_hdr. */
+ iov->iov_len -= sizeof(struct virtio_net_hdr);
+ iov->iov_base = hvaddr_mem(desc->addr +
+ sizeof(struct virtio_net_hdr), iov->iov_len);
+ if (iov->iov_base == NULL)
+ goto reset;
+ chain_len = iov->iov_len;
+
+ /*
+ * Walk the remaining chain and collect remaining addresses
+ * and lengths.
+ */
+ while (desc->flags & VRING_DESC_F_NEXT) {
+ desc = &table[desc->next & VIONET_QUEUE_MASK];
+ if (!DESC_WRITABLE(desc)) {
+ log_warnx("%s: invalid descriptor state",
+ __func__);
+ goto reset;
+ }
+
+ /* Collect our IO information. Translate gpa's. */
+ iov = &iov_rx[iov_cnt];
+ iov->iov_len = desc->len;
+ iov->iov_base = hvaddr_mem(desc->addr, iov->iov_len);
+ if (iov->iov_base == NULL)
+ goto reset;
+ chain_len += iov->iov_len;
+
+ /* Guard against infinitely looping chains. */
+ if (++iov_cnt >= nitems(iov_rx)) {
+ log_warnx("%s: infinite chain detected",
+ __func__);
+ goto reset;
+ }
+ }
+
+ /* Make sure the driver gave us the bare minimum buffers. */
+ if (chain_len < VIONET_MIN_TXLEN) {
+ log_warnx("%s: insufficient buffers provided",
__func__);
- return (0);
+ goto reset;
}
- /* How much data do we get to write? */
- if (sz - bufsz > pkt_desc->len)
- chunk_size = pkt_desc->len;
+ /*
+ * If we're enforcing hardware address or handling an injected
+ * packet, we need to use a copy-based approach.
+ */
+ if (dev->lockedmac || fd != dev->data_fd)
+ sz = vionet_rx_copy(dev, fd, iov_rx, iov_cnt,
+ chain_len);
else
- chunk_size = sz - bufsz;
-
- if (chain_len == 0) {
- off = hdr_sz;
- if (chunk_size == pkt_desc->len)
- chunk_size -= off;
- }
-
- /* Write a chunk of data if we need to */
- if (chunk_size && write_mem(pkt_desc->addr + off,
- pkt + pkt_offset, chunk_size)) {
- log_warnx("%s: failed to write to buffer 0x%llx",
- __func__, pkt_desc->addr);
- return (0);
- }
-
- chain_len += chunk_size + off;
- bufsz += chunk_size;
- pkt_offset += chunk_size;
-
- dxx = pkt_desc->next & VIONET_QUEUE_MASK;
- } while (bufsz < sz && pkt_desc->flags & VRING_DESC_F_NEXT);
-
- /* Move our marker in the ring...*/
- vq_info->last_avail = (vq_info->last_avail + 1) &
- VIONET_QUEUE_MASK;
-
- /* Prepend the virtio net header in the first buffer. */
- memset(&hdr, 0, sizeof(hdr));
- hdr.hdr_len = hdr_sz;
- if (write_mem(hdr_desc->addr, &hdr, hdr_sz)) {
- log_warnx("vionet: rx enq header write_mem error @ 0x%llx",
- hdr_desc->addr);
- return (0);
- }
-
- /* Update the index field in the used ring. This must be done last. */
- dev->cfg.isr_status = 1;
- *spc = (vq_info->notified_avail - vq_info->last_avail)
- & VIONET_QUEUE_MASK;
-
- /* Update the list of used buffers. */
- used->ring[used->idx & VIONET_QUEUE_MASK].id = chain_hdr_idx;
- used->ring[used->idx & VIONET_QUEUE_MASK].len = chain_len;
- __sync_synchronize();
- used->idx++;
-
- return (1);
-}
-
-/*
- * vionet_rx
- *
- * Enqueue data that was received on a tap file descriptor
- * to the vionet device queue.
- */
-static int
-vionet_rx(struct vionet_dev *dev)
-{
- char buf[PAGE_SIZE];
- int num_enq = 0, spc = 0;
- struct ether_header *eh;
- ssize_t sz;
-
- do {
- sz = read(dev->data_fd, buf, sizeof(buf));
- if (sz == -1) {
- /*
- * If we get EAGAIN, No data is currently available.
- * Do not treat this as an error.
- */
- if (errno != EAGAIN)
- log_warn("%s: read error", __func__);
- } else if (sz > 0) {
- eh = (struct ether_header *)buf;
- if (!dev->lockedmac ||
- ETHER_IS_MULTICAST(eh->ether_dhost) ||
- memcmp(eh->ether_dhost, dev->mac,
- sizeof(eh->ether_dhost)) == 0)
- num_enq += vionet_enq_rx(dev, buf, sz, &spc);
- } else if (sz == 0) {
- log_debug("%s: no data", __func__);
+ sz = vionet_rx_zerocopy(dev, fd, iov_rx, iov_cnt);
+ if (sz == -1)
+ goto reset;
+ if (sz == 0) /* No packets, so bail out for now. */
break;
+
+ /*
+ * Account for the prefixed header since it wasn't included
+ * in the copy or zerocopy operations.
+ */
+ sz += sizeof(struct virtio_net_hdr);
+
+ /* Mark our buffers as used. */
+ used->ring[used->idx & VIONET_QUEUE_MASK].id = hdr_idx;
+ used->ring[used->idx & VIONET_QUEUE_MASK].len = sz;
+ __sync_synchronize();
+ used->idx++;
+ idx++;
+ }
+
+ if (idx != vq_info->last_avail &&
+ !(avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) {
+ notify = 1;
+ dev->cfg.isr_status |= 1;
+ }
+
+ vq_info->last_avail = idx;
+ return (notify);
+reset:
+ log_warnx("%s: requesting device reset", __func__);
+ dev->cfg.device_status |= DEVICE_NEEDS_RESET;
+ dev->cfg.isr_status |= VIRTIO_CONFIG_ISR_CONFIG_CHANGE;
+ return (1);
+}
+
+/*
+ * vionet_rx_copy
+ *
+ * Read a packet off the provided file descriptor, validating packet
+ * characteristics, and copy into the provided buffers in the iovec array.
+ *
+ * It's assumed that the provided iovec array contains validated host virtual
+ * address translations and not guest physical addreses.
+ *
+ * Returns number of bytes copied on success, 0 if packet is dropped, and
+ * -1 on an error.
+ */
+ssize_t
+vionet_rx_copy(struct vionet_dev *dev, int fd, const struct iovec *iov,
+ int iov_cnt, size_t chain_len)
+{
+ static uint8_t buf[VIONET_HARD_MTU];
+ struct packet *pkt = NULL;
+ struct ether_header *eh = NULL;
+ uint8_t *payload = buf;
+ size_t i, chunk, nbytes, copied = 0;
+ ssize_t sz;
+
+ /* If reading from the tap(4), try to right-size the read. */
+ if (fd == dev->data_fd)
+ nbytes = MIN(chain_len, VIONET_HARD_MTU);
+ else if (fd == pipe_inject[READ])
+ nbytes = sizeof(struct packet);
+ else {
+ log_warnx("%s: invalid fd: %d", __func__, fd);
+ return (-1);
+ }
+
+ /*
+ * Try to pull a packet. The fd should be non-blocking and we don't
+ * care if we under-read (i.e. sz != nbytes) as we may not have a
+ * packet large enough to fill the buffer.
+ */
+ sz = read(fd, buf, nbytes);
+ if (sz == -1) {
+ if (errno != EAGAIN) {
+ log_warn("%s: error reading packet", __func__);
+ return (-1);
}
- } while (spc > 0 && sz > 0);
+ return (0);
+ } else if (fd == dev->data_fd && sz < VIONET_MIN_TXLEN) {
+ /* If reading the tap(4), we should get valid ethernet. */
+ log_warnx("%s: invalid packet size", __func__);
+ return (0);
+ } else if (sz != sizeof(struct packet)) {
+ log_warnx("%s: invalid injected packet object", __func__);
+ return (0);
+ }
- return (num_enq);
+ /* Decompose an injected packet, if that's what we're working with. */
+ if (fd == pipe_inject[READ]) {
+ pkt = (struct packet *)buf;
+ if (pkt->buf == NULL) {
+ log_warnx("%s: invalid injected packet, no buffer",
+ __func__);
+ return (0);
+ }
+ if (sz < VIONET_MIN_TXLEN || sz > VIONET_MAX_TXLEN) {
+ log_warnx("%s: invalid injected packet size", __func__);
+ goto drop;
+ }
+ payload = pkt->buf;
+ sz = (ssize_t)pkt->len;
+ }
+
+ /* Validate the ethernet header, if required. */
+ if (dev->lockedmac) {
+ eh = (struct ether_header *)(payload);
+ if (!ETHER_IS_MULTICAST(eh->ether_dhost) &&
+ memcmp(eh->ether_dhost, dev->mac,
+ sizeof(eh->ether_dhost)) != 0)
+ goto drop;
+ }
+
+ /* Truncate one last time to the chain length, if shorter. */
+ sz = MIN(chain_len, (size_t)sz);
+
+ /*
+ * Copy the packet into the provided buffers. We can use memcpy(3)
+ * here as the gpa was validated and translated to an hva previously.
+ */
+ for (i = 0; (int)i < iov_cnt && (size_t)sz > copied; i++) {
+ chunk = MIN(iov[i].iov_len, (size_t)(sz - copied));
+ memcpy(iov[i].iov_base, payload + copied, chunk);
+ copied += chunk;
+ }
+
+drop:
+ /* Free any injected packet buffer. */
+ if (pkt != NULL)
+ free(pkt->buf);
+
+ return (copied);
}
/*
+ * vionet_rx_zerocopy
+ *
+ * Perform a vectorized read from the given fd into the guest physical memory
+ * pointed to by iovecs.
+ *
+ * Returns number of bytes read on success, -1 on error, or 0 if EAGAIN was
+ * returned by readv.
+ *
+ */
+static ssize_t
+vionet_rx_zerocopy(struct vionet_dev *dev, int fd, const struct iovec *iov,
+ int iov_cnt)
+{
+ ssize_t sz;
+
+ if (dev->lockedmac) {
+ log_warnx("%s: zerocopy not available for locked lladdr",
+ __func__);
+ return (-1);
+ }
+
+ sz = readv(fd, iov, iov_cnt);
+ if (sz == -1 && errno == EAGAIN)
+ return (0);
+ return (sz);
+}
+
+
+/*
* vionet_rx_event
*
* Called when new data can be received on the tap fd of a vionet device.
*/
static void
-vionet_rx_event(int fd, short kind, void *arg)
+vionet_rx_event(int fd, short event, void *arg)
{
struct virtio_dev *dev = (struct virtio_dev *)arg;
- if (vionet_rx(&dev->vionet) > 0)
+ if (!(event & EV_READ))
+ fatalx("%s: invalid event type", __func__);
+
+ if (vionet_rx(&dev->vionet, fd) > 0)
virtio_assert_pic_irq(dev, 0);
}
-void
-vionet_notify_rx(struct virtio_dev *dev)
-{
- struct vionet_dev *vionet = &dev->vionet;
- struct vring_avail *avail;
- struct virtio_vq_info *vq_info;
- char *vr;
-
- vq_info = &vionet->vq[RXQ];
- vr = vq_info->q_hva;
- if (vr == NULL)
- fatalx("%s: vr == NULL", __func__);
-
- /* Compute offset into avail ring */
- avail = (struct vring_avail *)(vr + vq_info->vq_availoffset);
- vq_info->notified_avail = avail->idx - 1;
-}
-
-int
+static int
vionet_notifyq(struct virtio_dev *dev)
{
struct vionet_dev *vionet = &dev->vionet;
- int ret = 0;
switch (vionet->cfg.queue_notify) {
- case RXQ:
- vionet_notify_rx(dev);
- break;
- case TXQ:
- ret = vionet_notify_tx(dev);
- break;
+ case TXQ: return vionet_notify_tx(dev);
default:
/*
* Catch the unimplemented queue ID 2 (control queue) as
@@ -497,23 +633,25 @@ vionet_notifyq(struct virtio_dev *dev)
break;
}
- return (ret);
+ return (0);
}
-int
+static int
vionet_notify_tx(struct virtio_dev *dev)
{
- uint16_t idx, pkt_desc_idx, hdr_desc_idx, dxx, cnt;
- size_t pktsz, chunk_size = 0;
- ssize_t dhcpsz = 0;
- int num_enq, ofs, spc = 0;
- char *vr = NULL, *pkt = NULL, *dhcppkt = NULL;
+ uint16_t idx, hdr_idx;
+ size_t chain_len, iov_cnt;
+ ssize_t dhcpsz = 0, sz;
+ int notify = 0;
+ char *vr = NULL, *dhcppkt = NULL;
struct vionet_dev *vionet = &dev->vionet;
- struct vring_desc *desc, *pkt_desc, *hdr_desc;
+ struct vring_desc *desc, *table;
struct vring_avail *avail;
struct vring_used *used;
struct virtio_vq_info *vq_info;
struct ether_header *eh;
+ struct iovec *iov;
+ struct packet pkt;
if (!(vionet->cfg.device_status
& VIRTIO_CONFIG_DEVICE_STATUS_DRIVER_OK)) {
@@ -522,159 +660,161 @@ vionet_notify_tx(struct virtio_dev *dev)
}
vq_info = &vionet->vq[TXQ];
+ idx = vq_info->last_avail;
vr = vq_info->q_hva;
if (vr == NULL)
fatalx("%s: vr == NULL", __func__);
/* Compute offsets in ring of descriptors, avail ring, and used ring */
- desc = (struct vring_desc *)(vr);
+ table = (struct vring_desc *)(vr);
avail = (struct vring_avail *)(vr + vq_info->vq_availoffset);
used = (struct vring_used *)(vr + vq_info->vq_usedoffset);
- num_enq = 0;
+ while (idx != avail->idx) {
+ hdr_idx = avail->ring[idx & VIONET_QUEUE_MASK];
+ desc = &table[hdr_idx & VIONET_QUEUE_MASK];
+ if (DESC_WRITABLE(desc)) {
+ log_warnx("%s: invalid descriptor state", __func__);
+ goto reset;
+ }
- idx = vq_info->last_avail & VIONET_QUEUE_MASK;
+ iov = &iov_tx[0];
+ iov_cnt = 0;
+ chain_len = 0;
- if ((avail->idx & VIONET_QUEUE_MASK) == idx)
- return (0);
+ /*
+ * As a legacy device, we most likely will receive a lead
+ * descriptor sized to the virtio_net_hdr. However, the framing
+ * is not guaranteed, so check for packet data.
+ */
+ iov->iov_len = desc->len;
+ if (iov->iov_len < sizeof(struct virtio_net_hdr)) {
+ log_warnx("%s: invalid descriptor length", __func__);
+ goto reset;
+ } else if (iov->iov_len > sizeof(struct virtio_net_hdr)) {
+ /* Chop off the virtio header, leaving packet data. */
+ iov->iov_len -= sizeof(struct virtio_net_hdr);
+ chain_len += iov->iov_len;
+ iov->iov_base = hvaddr_mem(desc->addr +
+ sizeof(struct virtio_net_hdr), iov->iov_len);
+ if (iov->iov_base == NULL)
+ goto reset;
+ iov_cnt++;
+ }
- while ((avail->idx & VIONET_QUEUE_MASK) != idx) {
- hdr_desc_idx = avail->ring[idx] & VIONET_QUEUE_MASK;
- hdr_desc = &desc[hdr_desc_idx];
- pktsz = 0;
-
- cnt = 0;
- dxx = hdr_desc_idx;
- do {
- pktsz += desc[dxx].len;
- dxx = desc[dxx].next & VIONET_QUEUE_MASK;
-
- /*
- * Virtio 1.0, cs04, section 2.4.5:
- * "The number of descriptors in the table is defined
- * by the queue size for this virtqueue: this is the
- * maximum possible descriptor chain length."
- */
- if (++cnt >= VIONET_QUEUE_SIZE) {
- log_warnx("%s: descriptor table invalid",
+ /*
+ * Walk the chain and collect remaining addresses and lengths.
+ */
+ while (desc->flags & VRING_DESC_F_NEXT) {
+ desc = &table[desc->next & VIONET_QUEUE_MASK];
+ if (DESC_WRITABLE(desc)) {
+ log_warnx("%s: invalid descriptor state",
__func__);
- goto out;
+ goto reset;
}
- } while (desc[dxx].flags & VRING_DESC_F_NEXT);
- pktsz += desc[dxx].len;
+ /* Collect our IO information, translating gpa's. */
+ iov = &iov_tx[iov_cnt];
+ iov->iov_len = desc->len;
+ iov->iov_base = hvaddr_mem(desc->addr, iov->iov_len);
+ if (iov->iov_base == NULL)
+ goto reset;
+ chain_len += iov->iov_len;
- /* Remove virtio header descriptor len */
- pktsz -= hdr_desc->len;
-
- /* Drop packets violating device MTU-based limits */
- if (pktsz < VIONET_MIN_TXLEN || pktsz > VIONET_MAX_TXLEN) {
- log_warnx("%s: invalid packet size %lu", __func__,
- pktsz);
- goto drop_packet;
- }
- pkt = malloc(pktsz);
- if (pkt == NULL) {
- log_warn("malloc error alloc packet buf");
- goto out;
- }
-
- ofs = 0;
- pkt_desc_idx = hdr_desc->next & VIONET_QUEUE_MASK;
- pkt_desc = &desc[pkt_desc_idx];
-
- while (pkt_desc->flags & VRING_DESC_F_NEXT) {
- /* must be not writable */
- if (pkt_desc->flags & VRING_DESC_F_WRITE) {
- log_warnx("unexpected writable tx desc "
- "%d", pkt_desc_idx);
- goto out;
- }
-
- /* Check we don't read beyond allocated pktsz */
- if (pkt_desc->len > pktsz - ofs) {
- log_warnx("%s: descriptor len past pkt len",
+ /* Guard against infinitely looping chains. */
+ if (++iov_cnt >= nitems(iov_tx)) {
+ log_warnx("%s: infinite chain detected",
__func__);
- chunk_size = pktsz - ofs;
- } else
- chunk_size = pkt_desc->len;
-
- /* Read packet from descriptor ring */
- if (read_mem(pkt_desc->addr, pkt + ofs, chunk_size)) {
- log_warnx("vionet: packet read_mem error "
- "@ 0x%llx", pkt_desc->addr);
- goto out;
+ goto reset;
}
-
- ofs += pkt_desc->len;
- pkt_desc_idx = pkt_desc->next & VIONET_QUEUE_MASK;
- pkt_desc = &desc[pkt_desc_idx];
}
- /* Now handle tail descriptor - must be not writable */
- if (pkt_desc->flags & VRING_DESC_F_WRITE) {
- log_warnx("unexpected writable tx descriptor %d",
- pkt_desc_idx);
- goto out;
+ /* Check if we've got a minimum viable amount of data. */
+ if (chain_len < VIONET_MIN_TXLEN) {
+ sz = chain_len;
+ goto drop;
}
- /* Check we don't read beyond allocated pktsz */
- if (pkt_desc->len > pktsz - ofs) {
- log_warnx("%s: descriptor len past pkt len", __func__);
- chunk_size = pktsz - ofs - pkt_desc->len;
- } else
- chunk_size = pkt_desc->len;
-
- /* Read packet from descriptor ring */
- if (read_mem(pkt_desc->addr, pkt + ofs, chunk_size)) {
- log_warnx("vionet: packet read_mem error @ "
- "0x%llx", pkt_desc->addr);
- goto out;
+ /*
+ * Packet inspection for ethernet header (if using a "local"
+ * interface) for possibility of a DHCP packet or (if using
+ * locked lladdr) for validating ethernet header.
+ *
+ * To help preserve zero-copy semantics, we require the first
+ * descriptor with packet data contains a large enough buffer
+ * for this inspection.
+ */
+ iov = &iov_tx[0];
+ if (vionet->lockedmac) {
+ if (iov->iov_len < ETHER_HDR_LEN) {
+ log_warnx("%s: insufficient header data",
+ __func__);
+ goto drop;
+ }
+ eh = (struct ether_header *)iov->iov_base;
+ if (memcmp(eh->ether_shost, vionet->mac,
+ sizeof(eh->ether_shost)) != 0) {
+ log_warnx("%s: bad source address %s",
+ __func__, ether_ntoa((struct ether_addr *)
+ eh->ether_shost));
+ sz = chain_len;
+ goto drop;
+ }
}
-
- /* reject other source addresses */
- if (vionet->lockedmac && pktsz >= ETHER_HDR_LEN &&
- (eh = (struct ether_header *)pkt) &&
- memcmp(eh->ether_shost, vionet->mac,
- sizeof(eh->ether_shost)) != 0)
- log_debug("vionet: wrong source address %s for vm %d",
- ether_ntoa((struct ether_addr *)
- eh->ether_shost), dev->vm_id);
- else if (vionet->local &&
- (dhcpsz = dhcp_request(dev, pkt, pktsz, &dhcppkt)) != -1) {
- log_debug("vionet: dhcp request,"
- " local response size %zd", dhcpsz);
-
- /* XXX signed vs unsigned here, funky cast */
- } else if (write(vionet->data_fd, pkt, pktsz) != (int)pktsz) {
- log_warnx("vionet: tx failed writing to tap: "
- "%d", errno);
- goto out;
+ if (vionet->local) {
+ dhcpsz = dhcp_request(dev, iov->iov_base, iov->iov_len,
+ &dhcppkt);
+ log_debug("%s: detected dhcp request of %zu bytes",
+ __func__, dhcpsz);
}
- drop_packet:
- vionet->cfg.isr_status = 1;
- used->ring[used->idx & VIONET_QUEUE_MASK].id = hdr_desc_idx;
- used->ring[used->idx & VIONET_QUEUE_MASK].len = hdr_desc->len;
+ /* Write our packet to the tap(4). */
+ sz = writev(vionet->data_fd, iov_tx, iov_cnt);
+ if (sz == -1 && errno != ENOBUFS) {
+ log_warn("%s", __func__);
+ goto reset;
+ }
+ sz += sizeof(struct virtio_net_hdr);
+drop:
+ used->ring[used->idx & VIONET_QUEUE_MASK].id = hdr_idx;
+ used->ring[used->idx & VIONET_QUEUE_MASK].len = sz;
__sync_synchronize();
used->idx++;
+ idx++;
- vq_info->last_avail = avail->idx & VIONET_QUEUE_MASK;
- idx = (idx + 1) & VIONET_QUEUE_MASK;
+ /* Facilitate DHCP reply injection, if needed. */
+ if (dhcpsz > 0) {
+ pkt.buf = dhcppkt;
+ pkt.len = dhcpsz;
+ sz = write(pipe_inject[WRITE], &pkt, sizeof(pkt));
+ if (sz == -1 && errno != EAGAIN) {
+ log_warn("%s: packet injection", __func__);
+ free(pkt.buf);
+ } else if (sz == -1 && errno == EAGAIN) {
+ log_debug("%s: dropping dhcp reply", __func__);
+ free(pkt.buf);
+ } else if (sz != sizeof(pkt)) {
+ log_warnx("%s: failed packet injection",
+ __func__);
+ free(pkt.buf);
+ }
+ log_debug("%s: injected dhcp reply with %ld bytes",
+ __func__, sz);
+ }
+ }
- num_enq++;
-
- free(pkt);
- pkt = NULL;
+ if (idx != vq_info->last_avail &&
+ !(avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) {
+ notify = 1;
+ vionet->cfg.isr_status |= 1;
}
- if (dhcpsz > 0)
- vionet_enq_rx(vionet, dhcppkt, dhcpsz, &spc);
-
-out:
- free(pkt);
- free(dhcppkt);
-
+ vq_info->last_avail = idx;
+ return (notify);
+reset:
+ log_warnx("%s: requesting device reset", __func__);
+ vionet->cfg.device_status |= DEVICE_NEEDS_RESET;
+ vionet->cfg.isr_status |= VIRTIO_CONFIG_ISR_CONFIG_CHANGE;
return (1);
}
@@ -732,12 +872,15 @@ dev_dispatch_vm(int fd, short event, void *arg)
case IMSG_VMDOP_PAUSE_VM:
log_debug("%s: pausing", __func__);
event_del(&ev_tap);
+ event_del(&ev_inject);
break;
case IMSG_VMDOP_UNPAUSE_VM:
log_debug("%s: unpausing", __func__);
if (vionet->cfg.device_status
- & VIRTIO_CONFIG_DEVICE_STATUS_DRIVER_OK)
+ & VIRTIO_CONFIG_DEVICE_STATUS_DRIVER_OK) {
event_add(&ev_tap, NULL);
+ event_add(&ev_inject, NULL);
+ }
break;
case IMSG_CTL_VERBOSE:
IMSG_SIZE_CHECK(&imsg, &verbose);
@@ -825,6 +968,7 @@ handle_sync_io(int fd, short event, void *arg)
case VIODEV_MSG_SHUTDOWN:
event_del(&dev->sync_iev.ev);
event_del(&ev_tap);
+ event_del(&ev_inject);
event_loopbreak();
return;
default:
@@ -885,11 +1029,11 @@ handle_io_write(struct viodev_msg *msg, struct virtio_
virtio_deassert_pic_irq(dev, msg->vcpu);
}
event_del(&ev_tap);
+ event_del(&ev_inject);
if (vionet->cfg.device_status
& VIRTIO_CONFIG_DEVICE_STATUS_DRIVER_OK) {
- if (event_add(&ev_tap, NULL))
- log_warn("%s: could not initialize virtio tap "
- "event handler", __func__);
+ event_add(&ev_tap, NULL);
+ event_add(&ev_inject, NULL);
}
break;
default:
blob - 23608635c85d151186c39ea3c72e75f8a9eb7f68
blob + 2593643d6fdbc9109c8462ef661169b6a245a46e
--- usr.sbin/vmd/virtio.h
+++ usr.sbin/vmd/virtio.h
@@ -366,13 +366,6 @@ int vioblk_restore(int, struct vmd_vm *, int[][VM_MAX_
int vionet_dump(int);
int vionet_restore(int, struct vmd_vm *, int *);
-void vionet_update_qs(struct vionet_dev *);
-void vionet_update_qa(struct vionet_dev *);
-int vionet_notifyq(struct virtio_dev *);
-void vionet_notify_rx(struct virtio_dev *);
-int vionet_notify_tx(struct virtio_dev *);
-void vionet_process_rx(uint32_t);
-int vionet_enq_rx(struct vionet_dev *, char *, size_t, int *);
void vionet_set_hostmac(struct vmd_vm *, unsigned int, uint8_t *);
int vmmci_io(int, uint16_t, uint32_t *, uint8_t *, void *, uint8_t);
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