Hi,
> -----Original Message-----
> From: Xia, Chenbo <chenbo....@intel.com>
> Sent: Monday, July 27, 2020 9:14 PM
> To: Fu, Patrick <patrick...@intel.com>; dev@dpdk.org;
> maxime.coque...@redhat.com
> Subject: RE: [PATCH v3] vhost: fix async copy fail on multi-page buffers
>
> Hi Patrick,
>
> > -----Original Message-----
> > From: Fu, Patrick <patrick...@intel.com>
> > Sent: Monday, July 27, 2020 2:33 PM
> > To: dev@dpdk.org; maxime.coque...@redhat.com; Xia, Chenbo
> > <chenbo....@intel.com>
> > Cc: Fu, Patrick <patrick...@intel.com>
> > Subject: [PATCH v3] vhost: fix async copy fail on multi-page buffers
> >
> > lib/librte_vhost/vhost.h | 50 +++++++++++++++++++++++++++++++++++
> > lib/librte_vhost/virtio_net.c | 40 +++++++++++++++++-----------
> > 2 files changed, 75 insertions(+), 15 deletions(-)
> >
> > + } else {
> > + for (i = 0; i < dev->nr_guest_pages; i++) {
> > + page = &dev->guest_pages[i];
> > +
> > + if (gpa >= page->guest_phys_addr) {
> > + if (gpa + gpa_size <
>
> Should the '<' be '<=' here?
>
Yes, it should be. Will update in v4 patch
> > static __rte_always_inline uint64_t
> > hva_to_gpa(struct virtio_net *dev, uint64_t vva, uint64_t len) {
> > diff --git a/lib/librte_vhost/virtio_net.c
> > b/lib/librte_vhost/virtio_net.c index
> > 95a0bc19f..124a33a10 100644
> > --- a/lib/librte_vhost/virtio_net.c
> > +++ b/lib/librte_vhost/virtio_net.c
> > @@ -980,6 +980,7 @@ async_mbuf_to_desc(struct virtio_net *dev, struct
> > vhost_virtqueue *vq,
> > struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
> > struct virtio_net_hdr_mrg_rxbuf tmp_hdr, *hdr = NULL;
> > int error = 0;
> > + uint64_t mapped_len;
> >
> > uint32_t tlen = 0;
> > int tvec_idx = 0;
> > @@ -1072,24 +1073,31 @@ async_mbuf_to_desc(struct virtio_net *dev,
> > struct vhost_virtqueue *vq,
> >
> > cpy_len = RTE_MIN(buf_avail, mbuf_avail);
> >
> > - if (unlikely(cpy_len >= cpy_threshold)) {
> > - hpa = (void *)(uintptr_t)gpa_to_hpa(dev,
> > - buf_iova + buf_offset, cpy_len);
> > + while (unlikely(cpy_len && cpy_len >= cpy_threshold)) {
> > + hpa = (void *)(uintptr_t)gpa_to_first_hpa(dev,
> > + buf_iova + buf_offset,
> > + cpy_len, &mapped_len);
> >
> > - if (unlikely(!hpa)) {
> > - error = -1;
> > - goto out;
> > - }
> > + if (unlikely(!hpa || mapped_len < cpy_threshold))
> > + break;
> >
> > async_fill_vec(src_iovec + tvec_idx,
> > (void *)(uintptr_t)rte_pktmbuf_iova_offset(m,
> > - mbuf_offset), cpy_len);
> > + mbuf_offset), (size_t)mapped_len);
> >
> > - async_fill_vec(dst_iovec + tvec_idx, hpa, cpy_len);
> > + async_fill_vec(dst_iovec + tvec_idx,
> > + hpa, (size_t)mapped_len);
> >
> > - tlen += cpy_len;
> > + tlen += (uint32_t)mapped_len;
> > + cpy_len -= (uint32_t)mapped_len;
> > + mbuf_avail -= (uint32_t)mapped_len;
> > + mbuf_offset += (uint32_t)mapped_len;
> > + buf_avail -= (uint32_t)mapped_len;
> > + buf_offset += (uint32_t)mapped_len;
>
> Will it be ok we just transform the uint64_t to uint32_t here?
> What if mapped_len > MAX uint32_t ?
>
"mapped_len" could not exceed "cpy_len" (according to the gpa_to_first_hpa()
logic). As cpy_len is uint32, mapped_len is safe to down casting.
Thanks,
Patrick
