Tested-by: Mei,JianweiX < jianweix....@intel.com>
-----Original Message-----
From: dev <dev-boun...@dpdk.org> On Behalf Of Anatoly Burakov
Sent: Wednesday, September 16, 2020 7:26 PM
To: dev@dpdk.org
Cc: sta...@dpdk.org
Subject: [dpdk-dev] [PATCH 18.11] vfio: map contiguous areas in one go
Currently, when we are creating DMA mappings for memory that's either external
or is backed by hugepages in IOVA as PA mode, we assume that each page is
necessarily discontiguous. This may not actually be the case, especially for
external memory, where the user is able to create their own IOVA table and make
it contiguous. This is a problem because VFIO has a limited number of DMA
mappings, and it does not appear to concatenate them and treats each mapping as
separate, even when they cover adjacent areas.
Fix this so that we always map contiguous memory in a single chunk, as opposed
to mapping each segment separately.
Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com>
---
Notes:
Resend for stable as original patch [1] no longer applies
[1] http://patches.dpdk.org/patch/66041/
lib/librte_eal/linuxapp/eal/eal_vfio.c | 59 ++++++++++++++++++++++----
1 file changed, 51 insertions(+), 8 deletions(-)
diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c
b/lib/librte_eal/linuxapp/eal/eal_vfio.c
index 2f84e0f215..be969bbaac 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
@@ -510,9 +510,11 @@ static void
vfio_mem_event_callback(enum rte_mem_event type, const void *addr, size_t len,
void *arg __rte_unused)
{
+ rte_iova_t iova_start, iova_expected;
struct rte_memseg_list *msl;
struct rte_memseg *ms;
size_t cur_len = 0;
+ uint64_t va_start;
msl = rte_mem_virt2memseg_list(addr);
@@ -530,22 +532,63 @@ vfio_mem_event_callback(enum rte_mem_event type, const
void *addr, size_t len,
/* memsegs are contiguous in memory */
ms = rte_mem_virt2memseg(addr, msl);
+
+ /*
+ * This memory is not guaranteed to be contiguous, but it still could
+ * be, or it could have some small contiguous chunks. Since the number
+ * of VFIO mappings is limited, and VFIO appears to not concatenate
+ * adjacent mappings, we have to do this ourselves.
+ *
+ * So, find contiguous chunks, then map them.
+ */
+ va_start = ms->addr_64;
+ iova_start = iova_expected = ms->iova;
while (cur_len < len) {
+ bool new_contig_area = ms->iova != iova_expected;
+ bool last_seg = (len - cur_len) == ms->len;
+ bool skip_last = false;
+
+ /* only do mappings when current contiguous area ends */
+ if (new_contig_area) {
+ if (type == RTE_MEM_EVENT_ALLOC)
+ vfio_dma_mem_map(default_vfio_cfg, va_start,
+ iova_start,
+ iova_expected - iova_start, 1);
+ else
+ vfio_dma_mem_map(default_vfio_cfg, va_start,
+ iova_start,
+ iova_expected - iova_start, 0);
+ va_start = ms->addr_64;
+ iova_start = ms->iova;
+ }
/* some memory segments may have invalid IOVA */
if (ms->iova == RTE_BAD_IOVA) {
RTE_LOG(DEBUG, EAL, "Memory segment at %p has bad IOVA,
skipping\n",
ms->addr);
- goto next;
+ skip_last = true;
}
- if (type == RTE_MEM_EVENT_ALLOC)
- vfio_dma_mem_map(default_vfio_cfg, ms->addr_64,
- ms->iova, ms->len, 1);
- else
- vfio_dma_mem_map(default_vfio_cfg, ms->addr_64,
- ms->iova, ms->len, 0);
-next:
+ iova_expected = ms->iova + ms->len;
cur_len += ms->len;
++ms;
+
+ /*
+ * don't count previous segment, and don't attempt to
+ * dereference a potentially invalid pointer.
+ */
+ if (skip_last && !last_seg) {
+ iova_expected = iova_start = ms->iova;
+ va_start = ms->addr_64;
+ } else if (!skip_last && last_seg) {
+ /* this is the last segment and we're not skipping */
+ if (type == RTE_MEM_EVENT_ALLOC)
+ vfio_dma_mem_map(default_vfio_cfg, va_start,
+ iova_start,
+ iova_expected - iova_start, 1);
+ else
+ vfio_dma_mem_map(default_vfio_cfg, va_start,
+ iova_start,
+ iova_expected - iova_start, 0);
+ }
}
}
--
2.17.1
