[dpdk-dev] [PATCH 19.11] vfio: fix DMA mapping of externally allocated heaps

[Anatoly Burakov <anatoly.burakov@intel.com>]

Currently, externally created heaps are supposed to be automatically
mapped for VFIO DMA by EAL, however they only do so if, at the time of
heap creation, VFIO is initialized and has at least one device
available. If no devices are available at the time of heap creation (or
if devices were available, but were since hot-unplugged, thus dropping
all VFIO container mappings), then VFIO mapping code would have skipped
over externally allocated heaps.

The fix is two-fold. First, we allow externally allocated memory
segments to be marked as "heap" segments. This allows us to distinguish
between external memory segments that were created via heap API, from
those that were created via rte_extmem_register() API.

Then, we fix the VFIO code to only skip non-heap external segments.
Also, since external heaps are not guaranteed to have valid IOVA
addresses, we will skip those which have invalid IOVA addresses as well.

Fixes: 0f526d674f8e ("malloc: separate creating memseg list and malloc heap")

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
---

Notes:
    This cannot be backported to older releases as it breaks the
    API and ABI. A separate fix is in the works for stable.

 lib/librte_eal/common/include/rte_memory.h |  1 +
 lib/librte_eal/common/rte_malloc.c         |  1 +
 lib/librte_eal/freebsd/eal/eal_memory.c    |  1 +
 lib/librte_eal/linux/eal/eal_memory.c      |  3 ++
 lib/librte_eal/linux/eal/eal_vfio.c        | 46 +++++++++++++++++++---
 5 files changed, 47 insertions(+), 5 deletions(-)

diff --git a/lib/librte_eal/common/include/rte_memory.h b/lib/librte_eal/common/include/rte_memory.h
index 38e00e382c..bf81a2faa8 100644
--- a/lib/librte_eal/common/include/rte_memory.h
+++ b/lib/librte_eal/common/include/rte_memory.h
@@ -81,6 +81,7 @@ struct rte_memseg_list {
 	volatile uint32_t version; /**< version number for multiprocess sync. */
 	size_t len; /**< Length of memory area covered by this memseg list. */
 	unsigned int external; /**< 1 if this list points to external memory */
+	unsigned int heap; /**< 1 if this list points to a heap */
 	struct rte_fbarray memseg_arr;
 };
 
diff --git a/lib/librte_eal/common/rte_malloc.c b/lib/librte_eal/common/rte_malloc.c
index 044d3a9078..413e4aa004 100644
--- a/lib/librte_eal/common/rte_malloc.c
+++ b/lib/librte_eal/common/rte_malloc.c
@@ -396,6 +396,7 @@ rte_malloc_heap_memory_add(const char *heap_name, void *va_addr, size_t len,
 
 	rte_spinlock_lock(&heap->lock);
 	ret = malloc_heap_add_external_memory(heap, msl);
+	msl->heap = 1; /* mark it as heap segment */
 	rte_spinlock_unlock(&heap->lock);
 
 unlock:
diff --git a/lib/librte_eal/freebsd/eal/eal_memory.c b/lib/librte_eal/freebsd/eal/eal_memory.c
index 7fe3178898..a97d8f0f0c 100644
--- a/lib/librte_eal/freebsd/eal/eal_memory.c
+++ b/lib/librte_eal/freebsd/eal/eal_memory.c
@@ -93,6 +93,7 @@ rte_eal_hugepage_init(void)
 		msl->page_sz = page_sz;
 		msl->len = internal_config.memory;
 		msl->socket_id = 0;
+		msl->heap = 1;
 
 		/* populate memsegs. each memseg is 1 page long */
 		for (cur_seg = 0; cur_seg < n_segs; cur_seg++) {
diff --git a/lib/librte_eal/linux/eal/eal_memory.c b/lib/librte_eal/linux/eal/eal_memory.c
index accfd2e232..43e4ffc757 100644
--- a/lib/librte_eal/linux/eal/eal_memory.c
+++ b/lib/librte_eal/linux/eal/eal_memory.c
@@ -831,6 +831,7 @@ alloc_memseg_list(struct rte_memseg_list *msl, uint64_t page_sz,
 	msl->page_sz = page_sz;
 	msl->socket_id = socket_id;
 	msl->base_va = NULL;
+	msl->heap = 1; /* mark it as a heap segment */
 
 	RTE_LOG(DEBUG, EAL, "Memseg list allocated: 0x%zxkB at socket %i\n",
 			(size_t)page_sz >> 10, socket_id);
@@ -1405,6 +1406,7 @@ eal_legacy_hugepage_init(void)
 		msl->page_sz = page_sz;
 		msl->socket_id = 0;
 		msl->len = internal_config.memory;
+		msl->heap = 1;
 
 		/* we're in single-file segments mode, so only the segment list
 		 * fd needs to be set up.
@@ -1677,6 +1679,7 @@ eal_legacy_hugepage_init(void)
 		mem_sz = msl->len;
 		munmap(msl->base_va, mem_sz);
 		msl->base_va = NULL;
+		msl->heap = 0;
 
 		/* destroy backing fbarray */
 		rte_fbarray_destroy(&msl->memseg_arr);
diff --git a/lib/librte_eal/linux/eal/eal_vfio.c b/lib/librte_eal/linux/eal/eal_vfio.c
index d9541b1220..d5a2bbea0d 100644
--- a/lib/librte_eal/linux/eal/eal_vfio.c
+++ b/lib/librte_eal/linux/eal/eal_vfio.c
@@ -1250,7 +1250,16 @@ type1_map(const struct rte_memseg_list *msl, const struct rte_memseg *ms,
 {
 	int *vfio_container_fd = arg;
 
-	if (msl->external)
+	/* skip external memory that isn't a heap */
+	if (msl->external && !msl->heap)
+		return 0;
+
+	/* skip any segments with invalid IOVA addresses */
+	if (ms->iova == RTE_BAD_IOVA)
+		return 0;
+
+	/* if IOVA mode is VA, we've already mapped the internal segments */
+	if (!msl->external && rte_eal_iova_mode() == RTE_IOVA_VA)
 		return 0;
 
 	return vfio_type1_dma_mem_map(*vfio_container_fd, ms->addr_64, ms->iova,
@@ -1313,12 +1322,18 @@ vfio_type1_dma_mem_map(int vfio_container_fd, uint64_t vaddr, uint64_t iova,
 static int
 vfio_type1_dma_map(int vfio_container_fd)
 {
+	int ret;
 	if (rte_eal_iova_mode() == RTE_IOVA_VA) {
 		/* with IOVA as VA mode, we can get away with mapping contiguous
 		 * chunks rather than going page-by-page.
 		 */
-		return rte_memseg_contig_walk(type1_map_contig,
+		ret = rte_memseg_contig_walk(type1_map_contig,
 				&vfio_container_fd);
+		if (ret)
+			return ret;
+		/* we have to continue the walk because we've skipped the
+		 * external segments during the config walk.
+		 */
 	}
 	return rte_memseg_walk(type1_map, &vfio_container_fd);
 }
@@ -1410,7 +1425,15 @@ vfio_spapr_map_walk(const struct rte_memseg_list *msl,
 {
 	struct spapr_remap_walk_param *param = arg;
 
-	if (msl->external || ms->addr_64 == param->addr_64)
+	/* skip external memory that isn't a heap */
+	if (msl->external && !msl->heap)
+		return 0;
+
+	/* skip any segments with invalid IOVA addresses */
+	if (ms->iova == RTE_BAD_IOVA)
+		return 0;
+
+	if (ms->addr_64 == param->addr_64)
 		return 0;
 
 	return vfio_spapr_dma_do_map(param->vfio_container_fd, ms->addr_64, ms->iova,
@@ -1423,7 +1446,15 @@ vfio_spapr_unmap_walk(const struct rte_memseg_list *msl,
 {
 	struct spapr_remap_walk_param *param = arg;
 
-	if (msl->external || ms->addr_64 == param->addr_64)
+	/* skip external memory that isn't a heap */
+	if (msl->external && !msl->heap)
+		return 0;
+
+	/* skip any segments with invalid IOVA addresses */
+	if (ms->iova == RTE_BAD_IOVA)
+		return 0;
+
+	if (ms->addr_64 == param->addr_64)
 		return 0;
 
 	return vfio_spapr_dma_do_map(param->vfio_container_fd, ms->addr_64, ms->iova,
@@ -1443,7 +1474,12 @@ vfio_spapr_window_size_walk(const struct rte_memseg_list *msl,
 	struct spapr_walk_param *param = arg;
 	uint64_t max = ms->iova + ms->len;
 
-	if (msl->external)
+	/* skip external memory that isn't a heap */
+	if (msl->external && !msl->heap)
+		return 0;
+
+	/* skip any segments with invalid IOVA addresses */
+	if (ms->iova == RTE_BAD_IOVA)
 		return 0;
 
 	/* do not iterate ms we haven't mapped yet  */
-- 
2.17.1