[v5] vhost: fix async copy fail on multi-page buffers
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Commit Message
Async copy fails when single ring buffer vector is splited on multiple
physical pages. This happens because current hpa address translation
function doesn't handle multi-page buffers. A new gpa to hpa address
conversion function, which returns the hpa on the first hitting host
pages, is implemented in this patch. Async data path recursively calls
this new function to construct a multi-segments async copy descriptor
for ring buffers crossing physical page boundaries.
Fixes: cd6760da1076 ("vhost: introduce async enqueue for split ring")
Signed-off-by: Patrick Fu <patrick.fu@intel.com>
---
v2:
- change commit message and title
- v1 patch used CPU to copy multi-page buffers; v2 patch split the
copy into multiple async copy segments whenever possible
v3:
- added fixline
v4:
- fix miss translation of the gpa which is the same length with host
page size
v5:
- combine redundant "if" statement in async_mbuf_to_desc()
lib/librte_vhost/vhost.h | 50 +++++++++++++++++++++++++++++++++++
lib/librte_vhost/virtio_net.c | 39 ++++++++++++++++-----------
2 files changed, 74 insertions(+), 15 deletions(-)
Comments
On 7/29/20 4:04 AM, Patrick Fu wrote:
> Async copy fails when single ring buffer vector is splited on multiple
> physical pages. This happens because current hpa address translation
> function doesn't handle multi-page buffers. A new gpa to hpa address
> conversion function, which returns the hpa on the first hitting host
> pages, is implemented in this patch. Async data path recursively calls
> this new function to construct a multi-segments async copy descriptor
> for ring buffers crossing physical page boundaries.
>
> Fixes: cd6760da1076 ("vhost: introduce async enqueue for split ring")
>
> Signed-off-by: Patrick Fu <patrick.fu@intel.com>
> ---
> v2:
> - change commit message and title
> - v1 patch used CPU to copy multi-page buffers; v2 patch split the
> copy into multiple async copy segments whenever possible
>
> v3:
> - added fixline
>
> v4:
> - fix miss translation of the gpa which is the same length with host
> page size
> v5:
> - combine redundant "if" statement in async_mbuf_to_desc()
>
> lib/librte_vhost/vhost.h | 50 +++++++++++++++++++++++++++++++++++
> lib/librte_vhost/virtio_net.c | 39 ++++++++++++++++-----------
> 2 files changed, 74 insertions(+), 15 deletions(-)
Thanks Patrick, it looks better to me now:
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Maxime
On 7/29/20 4:04 AM, Patrick Fu wrote:
> Async copy fails when single ring buffer vector is splited on multiple
> physical pages. This happens because current hpa address translation
> function doesn't handle multi-page buffers. A new gpa to hpa address
> conversion function, which returns the hpa on the first hitting host
> pages, is implemented in this patch. Async data path recursively calls
> this new function to construct a multi-segments async copy descriptor
> for ring buffers crossing physical page boundaries.
>
> Fixes: cd6760da1076 ("vhost: introduce async enqueue for split ring")
>
> Signed-off-by: Patrick Fu <patrick.fu@intel.com>
> ---
> v2:
> - change commit message and title
> - v1 patch used CPU to copy multi-page buffers; v2 patch split the
> copy into multiple async copy segments whenever possible
>
> v3:
> - added fixline
>
> v4:
> - fix miss translation of the gpa which is the same length with host
> page size
> v5:
> - combine redundant "if" statement in async_mbuf_to_desc()
>
> lib/librte_vhost/vhost.h | 50 +++++++++++++++++++++++++++++++++++
> lib/librte_vhost/virtio_net.c | 39 ++++++++++++++++-----------
> 2 files changed, 74 insertions(+), 15 deletions(-)
Applied to dpdk-next-virtio/master.
Thanks,
Maxime
@@ -616,6 +616,56 @@ gpa_to_hpa(struct virtio_net *dev, uint64_t gpa, uint64_t size)
return 0;
}
+static __rte_always_inline rte_iova_t
+gpa_to_first_hpa(struct virtio_net *dev, uint64_t gpa,
+ uint64_t gpa_size, uint64_t *hpa_size)
+{
+ uint32_t i;
+ struct guest_page *page;
+ struct guest_page key;
+
+ *hpa_size = gpa_size;
+ if (dev->nr_guest_pages >= VHOST_BINARY_SEARCH_THRESH) {
+ key.guest_phys_addr = gpa & ~(dev->guest_pages[0].size - 1);
+ page = bsearch(&key, dev->guest_pages, dev->nr_guest_pages,
+ sizeof(struct guest_page), guest_page_addrcmp);
+ if (page) {
+ if (gpa + gpa_size <=
+ page->guest_phys_addr + page->size) {
+ return gpa - page->guest_phys_addr +
+ page->host_phys_addr;
+ } else if (gpa < page->guest_phys_addr +
+ page->size) {
+ *hpa_size = page->guest_phys_addr +
+ page->size - gpa;
+ return gpa - page->guest_phys_addr +
+ page->host_phys_addr;
+ }
+ }
+ } 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 <=
+ page->guest_phys_addr + page->size) {
+ return gpa - page->guest_phys_addr +
+ page->host_phys_addr;
+ } else if (gpa < page->guest_phys_addr +
+ page->size) {
+ *hpa_size = page->guest_phys_addr +
+ page->size - gpa;
+ return gpa - page->guest_phys_addr +
+ page->host_phys_addr;
+ }
+ }
+ }
+ }
+
+ *hpa_size = 0;
+ return 0;
+}
+
static __rte_always_inline uint64_t
hva_to_gpa(struct virtio_net *dev, uint64_t vva, uint64_t len)
{
@@ -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;
tvec_idx++;
- } else {
+ }
+
+ if (likely(cpy_len)) {
if (unlikely(vq->batch_copy_nb_elems >= vq->size)) {
rte_memcpy(
(void *)((uintptr_t)(buf_addr + buf_offset)),
@@ -1110,12 +1118,13 @@ async_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
cpy_len;
vq->batch_copy_nb_elems++;
}
+
+ mbuf_avail -= cpy_len;
+ mbuf_offset += cpy_len;
+ buf_avail -= cpy_len;
+ buf_offset += cpy_len;
}
- mbuf_avail -= cpy_len;
- mbuf_offset += cpy_len;
- buf_avail -= cpy_len;
- buf_offset += cpy_len;
}
out: