[dpdk-dev] [RFC PATCH v2] kni: properly translate pa2va for cloned mbuf
Junxiao Shi
git at mail1.yoursunny.com
Tue Jan 28 17:16:44 CET 2020
Previously, KNI kernel module uses the difference between m->buf_addr
and m->buf_iova to calculate userspace virtual address from physical
address. This works for direct mbufs, but does not work for indirect
(cloned) mbufs that come from another mempool. Transmitting a cloned
mbuf may cause segmentation fault in userspace.
Now, userspace KNI library writes the virtual address of each mbuf
in m->userdata field, and KNI kernel module uses this field to restore
virtual address before putting mbuf into free_q. This approach works
for both direct and indirect mbufs.
NOTE TO REVIEWER - DO NOT MERGE
The idea of this change is at https://bugs.dpdk.org/show_bug.cgi?id=183#c4
Test case is at https://bugs.dpdk.org/show_bug.cgi?id=183#c5
I only modified kni_net_rx_normal function.
If this approach is acceptable, I will modify kni_net_rx_lo_fifo,
kni_net_rx_lo_fifo_skb, and kni_fifo_trans_pa2va(rx_q) as well.
Bugzilla ID: 183
Signed-off-by: Junxiao Shi <git at mail1.yoursunny.com>
---
kernel/linux/kni/kni_net.c | 4 ++--
lib/librte_eal/linux/eal/include/rte_kni_common.h | 3 ++-
lib/librte_kni/rte_kni.c | 8 ++++++--
3 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/kernel/linux/kni/kni_net.c b/kernel/linux/kni/kni_net.c
index 97fe85b..d783545 100644
--- a/kernel/linux/kni/kni_net.c
+++ b/kernel/linux/kni/kni_net.c
@@ -377,7 +377,7 @@ kni_net_rx_normal(struct kni_dev *kni)
kva = get_kva(kni, kni->pa[i]);
len = kva->pkt_len;
data_kva = get_data_kva(kni, kva);
- kni->va[i] = pa2va(kni->pa[i], kva);
+ kni->va[i] = kva->va;
skb = netdev_alloc_skb(dev, len);
if (!skb) {
@@ -403,7 +403,7 @@ kni_net_rx_normal(struct kni_dev *kni)
kva = pa2kva(kva->next);
data_kva = kva2data_kva(kva);
/* Convert physical address to virtual address */
- prev_kva->next = pa2va(prev_kva->next, kva);
+ prev_kva->next = kva->va;
}
}
diff --git a/lib/librte_eal/linux/eal/include/rte_kni_common.h b/lib/librte_eal/linux/eal/include/rte_kni_common.h
index 7313ef5..c694a1d 100644
--- a/lib/librte_eal/linux/eal/include/rte_kni_common.h
+++ b/lib/librte_eal/linux/eal/include/rte_kni_common.h
@@ -86,7 +86,8 @@ struct rte_kni_mbuf {
uint16_t data_len; /**< Amount of data in segment buffer. */
/* fields on second cache line */
- char pad3[8] __attribute__((__aligned__(RTE_CACHE_LINE_MIN_SIZE)));
+ void *va __attribute__((__aligned__(RTE_CACHE_LINE_MIN_SIZE)));
+ /**< Virtual address of this mbuf in userspace (overwrites userdata). */
void *pool;
void *next; /**< Physical address of next mbuf in kernel. */
};
diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
index e388751..463485f 100644
--- a/lib/librte_kni/rte_kni.c
+++ b/lib/librte_kni/rte_kni.c
@@ -359,13 +359,15 @@ va2pa(struct rte_mbuf *m)
static void *
va2pa_all(struct rte_mbuf *mbuf)
{
- void *phy_mbuf = va2pa(mbuf);
+ void *phy_mbuf = (void*)rte_mempool_virt2iova(mbuf);
struct rte_mbuf *next = mbuf->next;
while (next) {
- mbuf->next = va2pa(next);
+ mbuf->userdata = mbuf;
+ mbuf->next = (void*)rte_mempool_virt2iova(next);
mbuf = next;
next = mbuf->next;
}
+ mbuf->userdata = mbuf;
return phy_mbuf;
}
@@ -652,6 +654,8 @@ kni_allocate_mbufs(struct rte_kni *kni)
offsetof(struct rte_kni_mbuf, buf_addr));
RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, next) !=
offsetof(struct rte_kni_mbuf, next));
+ RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, userdata) !=
+ offsetof(struct rte_kni_mbuf, va));
RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, data_off) !=
offsetof(struct rte_kni_mbuf, data_off));
RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, data_len) !=
--
2.7.4
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