On Tue, Jul 19, 2022 at 7:42 AM Eugenio Perez Martin
<epere...@redhat.com> wrote:
>
> On Tue, Jul 19, 2022 at 4:39 AM Jason Wang <jasow...@redhat.com> wrote:
> >
> >
> > 在 2022/7/18 18:29, Eugenio Pérez 写道:
> > > Introduce the control virtqueue support for vDPA shadow virtqueue. This
> > > is needed for advanced networking features like rx filtering.
> > >
> > > Virtio-net control VQ copies the descriptors to qemu's VA, so we avoid
> > > TOCTOU with the guest's or device's memory every time there is a device
> > > model change. Otherwise, the guest could change the memory content in
> > > the time between qemu and the device read it.
> > >
> > > To demonstrate command handling, VIRTIO_NET_F_CTRL_MACADDR is
> > > implemented. If the virtio-net driver changes MAC the virtio-net device
> > > model will be updated with the new one, and a rx filtering change event
> > > will be raised.
> > >
> > > More cvq commands could be added here straightforwardly but they have
> > > not been tested.
> > >
> > > Signed-off-by: Eugenio Pérez <epere...@redhat.com>
> > > ---
> > > net/vhost-vdpa.c | 211 +++++++++++++++++++++++++++++++++++++++++++++--
> > > 1 file changed, 204 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> > > index 2e3b6b10d8..3915b148c4 100644
> > > --- a/net/vhost-vdpa.c
> > > +++ b/net/vhost-vdpa.c
> > > @@ -33,6 +33,9 @@ typedef struct VhostVDPAState {
> > > NetClientState nc;
> > > struct vhost_vdpa vhost_vdpa;
> > > VHostNetState *vhost_net;
> > > +
> > > + /* Control commands shadow buffers */
> > > + void *cvq_cmd_out_buffer, *cvq_cmd_in_buffer;
> > > bool started;
> > > } VhostVDPAState;
> > >
> > > @@ -131,6 +134,8 @@ static void vhost_vdpa_cleanup(NetClientState *nc)
> > > {
> > > VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
> > >
> > > + qemu_vfree(s->cvq_cmd_out_buffer);
> > > + qemu_vfree(s->cvq_cmd_in_buffer);
> > > if (s->vhost_net) {
> > > vhost_net_cleanup(s->vhost_net);
> > > g_free(s->vhost_net);
> > > @@ -190,24 +195,191 @@ static NetClientInfo net_vhost_vdpa_info = {
> > > .check_peer_type = vhost_vdpa_check_peer_type,
> > > };
> > >
> > > +static void vhost_vdpa_cvq_unmap_buf(struct vhost_vdpa *v, void *addr)
> > > +{
> > > + VhostIOVATree *tree = v->iova_tree;
> > > + DMAMap needle = {
> > > + /*
> > > + * No need to specify size or to look for more translations since
> > > + * this contiguous chunk was allocated by us.
> > > + */
> > > + .translated_addr = (hwaddr)(uintptr_t)addr,
> > > + };
> > > + const DMAMap *map = vhost_iova_tree_find_iova(tree, &needle);
> > > + int r;
> > > +
> > > + if (unlikely(!map)) {
> > > + error_report("Cannot locate expected map");
> > > + return;
> > > + }
> > > +
> > > + r = vhost_vdpa_dma_unmap(v, map->iova, map->size + 1);
> > > + if (unlikely(r != 0)) {
> > > + error_report("Device cannot unmap: %s(%d)", g_strerror(r), r);
> > > + }
> > > +
> > > + vhost_iova_tree_remove(tree, map);
> > > +}
> > > +
> > > +static size_t vhost_vdpa_net_cvq_cmd_len(void)
> > > +{
> > > + /*
> > > + * MAC_TABLE_SET is the ctrl command that produces the longer out
> > > buffer.
> > > + * In buffer is always 1 byte, so it should fit here
> > > + */
> > > + return sizeof(struct virtio_net_ctrl_hdr) +
> > > + 2 * sizeof(struct virtio_net_ctrl_mac) +
> > > + MAC_TABLE_ENTRIES * ETH_ALEN;
> > > +}
> > > +
> > > +static size_t vhost_vdpa_net_cvq_cmd_page_len(void)
> > > +{
> > > + return ROUND_UP(vhost_vdpa_net_cvq_cmd_len(),
> > > qemu_real_host_page_size());
> > > +}
> > > +
> > > +/** Copy and map a guest buffer. */
> > > +static bool vhost_vdpa_cvq_map_buf(struct vhost_vdpa *v,
> > > + const struct iovec *out_data,
> > > + size_t out_num, size_t data_len, void
> > > *buf,
> > > + size_t *written, bool write)
> > > +{
> > > + DMAMap map = {};
> > > + int r;
> > > +
> > > + if (unlikely(!data_len)) {
> > > + qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid legnth of %s
> > > buffer\n",
> > > + __func__, write ? "in" : "out");
> > > + return false;
> > > + }
> > > +
> > > + *written = iov_to_buf(out_data, out_num, 0, buf, data_len);
> > > + map.translated_addr = (hwaddr)(uintptr_t)buf;
> > > + map.size = vhost_vdpa_net_cvq_cmd_page_len() - 1;
> > > + map.perm = write ? IOMMU_RW : IOMMU_RO,
> > > + r = vhost_iova_tree_map_alloc(v->iova_tree, &map);
> > > + if (unlikely(r != IOVA_OK)) {
> > > + error_report("Cannot map injected element");
> > > + return false;
> > > + }
> > > +
> > > + r = vhost_vdpa_dma_map(v, map.iova,
> > > vhost_vdpa_net_cvq_cmd_page_len(), buf,
> > > + !write);
> > > + if (unlikely(r < 0)) {
> > > + goto dma_map_err;
> > > + }
> > > +
> > > + return true;
> > > +
> > > +dma_map_err:
> > > + vhost_iova_tree_remove(v->iova_tree, &map);
> > > + return false;
> > > +}
> > > +
> > > /**
> > > - * Forward buffer for the moment.
> > > + * Copy the guest element into a dedicated buffer suitable to be sent to
> > > NIC
> > > + *
> > > + * @iov: [0] is the out buffer, [1] is the in one
> > > + */
> > > +static bool vhost_vdpa_net_cvq_map_elem(VhostVDPAState *s,
> > > + VirtQueueElement *elem,
> > > + struct iovec *iov)
> > > +{
> > > + size_t in_copied;
> > > + bool ok;
> > > +
> > > + iov[0].iov_base = s->cvq_cmd_out_buffer;
> > > + ok = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, elem->out_sg,
> > > elem->out_num,
> > > + vhost_vdpa_net_cvq_cmd_len(),
> > > iov[0].iov_base,
> > > + &iov[0].iov_len, false);
> > > + if (unlikely(!ok)) {
> > > + return false;
> > > + }
> > > +
> > > + iov[1].iov_base = s->cvq_cmd_in_buffer;
> > > + ok = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, NULL, 0,
> > > + sizeof(virtio_net_ctrl_ack),
> > > iov[1].iov_base,
> > > + &in_copied, true);
> > > + if (unlikely(!ok)) {
> > > + vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer);
> > > + return false;
> > > + }
> > > +
> > > + iov[1].iov_len = sizeof(virtio_net_ctrl_ack);
> > > + return true;
> > > +}
> > > +
> > > +/**
> > > + * Do not forward commands not supported by SVQ. Otherwise, the device
> > > could
> > > + * accept it and qemu would not know how to update the device model.
> > > + */
> > > +static bool vhost_vdpa_net_cvq_validate_cmd(const struct iovec *out,
> > > + size_t out_num)
> > > +{
> > > + struct virtio_net_ctrl_hdr ctrl;
> > > + size_t n;
> > > +
> > > + n = iov_to_buf(out, out_num, 0, &ctrl, sizeof(ctrl));
> > > + if (unlikely(n < sizeof(ctrl))) {
> > > + qemu_log_mask(LOG_GUEST_ERROR,
> > > + "%s: invalid legnth of out buffer %zu\n",
> > > __func__, n);
> > > + return false;
> > > + }
> > > +
> > > + switch (ctrl.class) {
> > > + case VIRTIO_NET_CTRL_MAC:
> > > + switch (ctrl.cmd) {
> > > + case VIRTIO_NET_CTRL_MAC_ADDR_SET:
> > > + return true;
> > > + default:
> > > + qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid mac cmd %u\n",
> > > + __func__, ctrl.cmd);
> > > + };
> > > + break;
> > > + default:
> > > + qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid control class %u\n",
> > > + __func__, ctrl.class);
> > > + };
> > > +
> > > + return false;
> > > +}
> > > +
> > > +/**
> > > + * Validate and copy control virtqueue commands.
> > > + *
> > > + * Following QEMU guidelines, we offer a copy of the buffers to the
> > > device to
> > > + * prevent TOCTOU bugs.
> > > */
> > > static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
> > > VirtQueueElement *elem,
> > > void *opaque)
> > > {
> > > - unsigned int n = elem->out_num + elem->in_num;
> > > - g_autofree struct iovec *dev_buffers = g_new(struct iovec, n);
> > > + VhostVDPAState *s = opaque;
> > > size_t in_len, dev_written;
> > > virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
> > > + /* out and in buffers sent to the device */
> > > + struct iovec dev_buffers[2] = {
> > > + { .iov_base = s->cvq_cmd_out_buffer },
> > > + { .iov_base = s->cvq_cmd_in_buffer },
> > > + };
> > > + /* in buffer used for device model */
> > > + const struct iovec in = {
> > > + .iov_base = &status,
> > > + .iov_len = sizeof(status),
> > > + };
> > > int r;
> >
> >
> > I got this:
> >
> > FAILED: libcommon.fa.p/net_vhost-vdpa.c.o
> > cc -m64 -mcx16 -Ilibcommon.fa.p -I../dtc/libfdt -I../slirp
> > -I../slirp/src -I/usr/include/capstone -I/usr/include/pixman-1
> > -I/usr/include/libpng16 -I/usr/include/libmount -I/usr/include/blkid
> > -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include
> > -I/usr/include/gio-unix-2.0 -fdiagnostics-color=auto -Wall -Winvalid-pch
> > -Werror -std=gnu11 -O2 -g -isystem /home/devel/git/qemu/linux-headers
> > -isystem linux-headers -iquote . -iquote /home/devel/git/qemu -iquote
> > /home/devel/git/qemu/include -iquote /home/devel/git/qemu/tcg/i386
> > -pthread -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE
> > -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes
> > -Wredundant-decls -Wundef -Wwrite-strings -Wmissing-prototypes
> > -fno-strict-aliasing -fno-common -fwrapv -Wold-style-declaration
> > -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k
> > -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs
> > -Wendif-labels -Wexpansion-to-defined -Wimplicit-fallthrough=2
> > -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-psabi
> > -fstack-protector-strong -fPIE -D_DEFAULT_SOURCE -D_XOPEN_SOURCE=600
> > -DNCURSES_WIDECHAR=1 -MD -MQ libcommon.fa.p/net_vhost-vdpa.c.o -MF
> > libcommon.fa.p/net_vhost-vdpa.c.o.d -o libcommon.fa.p/net_vhost-vdpa.c.o
> > -c ../net/vhost-vdpa.c
> > ../net/vhost-vdpa.c: In function ‘vhost_vdpa_net_handle_ctrl_avail’:
> > ../net/vhost-vdpa.c:427:12: error: ‘r’ may be used uninitialized in this
> > function [-Werror=maybe-uninitialized]
> > 427 | return r;
> > | ^
> > cc1: all warnings being treated as errors
> >
>
> Sorry, I rebase with these applied (or half applied) [1].
>
> I'll send a new version based on the current master in a moment.
>
So that was not the issue. With --enable-debug, the optimization
prevents that analysis from running in my compiler.
However, if I enable it there are other areas using uninitialized variables:
../tests/fp/berkeley-testfloat-3/source/slowfloat.c:1016:14: error:
'uiZ' may be used uninitialized in this function
[-Werror=maybe-uninitialized]
return uZ.f;
I'll send a new version. I'll add a warning in the cover letter for
these unmerged fixes anyway.
Thanks!
> Thanks!
>
> [1] https://lists.nongnu.org/archive/html/qemu-devel/2022-07/msg01986.html
>
> >
> > > + bool ok;
> > >
> > > - memcpy(dev_buffers, elem->out_sg, elem->out_num);
> > > - memcpy(dev_buffers + elem->out_num, elem->in_sg, elem->in_num);
> > > + ok = vhost_vdpa_net_cvq_map_elem(s, elem, dev_buffers);
> >
> >
> > I think it's good idea to let this function return int instead of a boolean.
> >
> > Thanks
> >
> >
> > > + if (unlikely(!ok)) {
> > > + goto out;
> > > + }
> > >
> > > - r = vhost_svq_add(svq, &dev_buffers[0], elem->out_num,
> > > &dev_buffers[1],
> > > - elem->in_num, elem);
> > > + ok = vhost_vdpa_net_cvq_validate_cmd(&dev_buffers[0], 1);
> > > + if (unlikely(!ok)) {
> > > + goto out;
> > > + }
> > > +
> > > + r = vhost_svq_add(svq, &dev_buffers[0], 1, &dev_buffers[1], 1, elem);
> > > if (unlikely(r != 0)) {
> > > if (unlikely(r == -ENOSPC)) {
> > > qemu_log_mask(LOG_GUEST_ERROR, "%s: No space on device
> > > queue\n",
> > > @@ -224,6 +396,18 @@ static int
> > > vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
> > > dev_written = vhost_svq_poll(svq);
> > > if (unlikely(dev_written < sizeof(status))) {
> > > error_report("Insufficient written data (%zu)", dev_written);
> > > + goto out;
> > > + }
> > > +
> > > + memcpy(&status, dev_buffers[1].iov_base, sizeof(status));
> > > + if (status != VIRTIO_NET_OK) {
> > > + goto out;
> > > + }
> > > +
> > > + status = VIRTIO_NET_ERR;
> > > + virtio_net_handle_ctrl_iov(svq->vdev, &in, 1, dev_buffers, 1);
> > > + if (status != VIRTIO_NET_OK) {
> > > + error_report("Bad CVQ processing in model");
> > > }
> > >
> > > out:
> > > @@ -234,6 +418,12 @@ out:
> > > }
> > > vhost_svq_push_elem(svq, elem, MIN(in_len, sizeof(status)));
> > > g_free(elem);
> > > + if (dev_buffers[0].iov_base) {
> > > + vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa,
> > > dev_buffers[0].iov_base);
> > > + }
> > > + if (dev_buffers[1].iov_base) {
> > > + vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa,
> > > dev_buffers[1].iov_base);
> > > + }
> > > return r;
> > > }
> > >
> > > @@ -266,6 +456,13 @@ static NetClientState
> > > *net_vhost_vdpa_init(NetClientState *peer,
> > > s->vhost_vdpa.device_fd = vdpa_device_fd;
> > > s->vhost_vdpa.index = queue_pair_index;
> > > if (!is_datapath) {
> > > + s->cvq_cmd_out_buffer = qemu_memalign(qemu_real_host_page_size(),
> > > +
> > > vhost_vdpa_net_cvq_cmd_page_len());
> > > + memset(s->cvq_cmd_out_buffer, 0,
> > > vhost_vdpa_net_cvq_cmd_page_len());
> > > + s->cvq_cmd_in_buffer = qemu_memalign(qemu_real_host_page_size(),
> > > +
> > > vhost_vdpa_net_cvq_cmd_page_len());
> > > + memset(s->cvq_cmd_in_buffer, 0,
> > > vhost_vdpa_net_cvq_cmd_page_len());
> > > +
> > > s->vhost_vdpa.shadow_vq_ops = &vhost_vdpa_net_svq_ops;
> > > s->vhost_vdpa.shadow_vq_ops_opaque = s;
> > > }
> >
