[dpdk-dev] [PATCH v2] eal: don't advertise a physical address when no hugepages

[Olivier Matz <olivier.matz@6wind.com>]

When populating a mempool with a virtual memory area, the mempool
library expects to be able to get the physical address of each page.

When started with --no-huge, the physical addresses may not be available
because the pages are not locked in memory. It sometimes returns
RTE_BAD_PHYS_ADDR, which makes the mempool_populate() function to fail.

This was working before the commit cdc242f260e7 ("eal/linux: support
running as unprivileged user"), because rte_mem_virt2phy() was returning
0 instead of RTE_BAD_PHYS_ADDR, which was seen as a valid physical
address.

Since --no-huge is a debug function that breaks the support of physical
drivers, always set physical addresses to RTE_BAD_PHYS_ADDR in memzones
or in rte_mem_virt2phy(), and ensure that mempool won't complain in that
case.

Fixes: cdc242f260e7 ("eal/linux: support running as unprivileged user")

CC: stable@dpdk.org
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---

v1 -> v2:
- initialize memory segments (rte_memseg) with RTE_BAD_PHYS_ADDR
  if started with --no-huge
- return RTE_BAD_PHYS_ADDR when rte_malloc_virt2phy() if the
  memory segment has no physical address
- drop change in eal_common_memzone.c: the physical address is
  now set to RTE_BAD_PHYS_ADDR as per return value of
  rte_malloc_virt2phy()


 lib/librte_eal/common/include/rte_malloc.h | 2 +-
 lib/librte_eal/common/rte_malloc.c         | 4 +++-
 lib/librte_eal/linuxapp/eal/eal_memory.c   | 9 ++++++++-
 lib/librte_mempool/rte_mempool.c           | 2 +-
 4 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eal/common/include/rte_malloc.h b/lib/librte_eal/common/include/rte_malloc.h
index 61aac322b..3d37f79b8 100644
--- a/lib/librte_eal/common/include/rte_malloc.h
+++ b/lib/librte_eal/common/include/rte_malloc.h
@@ -329,7 +329,7 @@ rte_malloc_set_limit(const char *type, size_t max);
  * @param addr
  *   Address obtained from a previous rte_malloc call
  * @return
- *   NULL on error
+ *   RTE_BAD_PHYS_ADDR on error
  *   otherwise return physical address of the buffer
  */
 phys_addr_t
diff --git a/lib/librte_eal/common/rte_malloc.c b/lib/librte_eal/common/rte_malloc.c
index f4a883529..5c0627bf4 100644
--- a/lib/librte_eal/common/rte_malloc.c
+++ b/lib/librte_eal/common/rte_malloc.c
@@ -253,6 +253,8 @@ rte_malloc_virt2phy(const void *addr)
 {
 	const struct malloc_elem *elem = malloc_elem_from_data(addr);
 	if (elem == NULL)
-		return 0;
+		return RTE_BAD_PHYS_ADDR;
+	if (elem->ms->phys_addr == RTE_BAD_PHYS_ADDR)
+		return RTE_BAD_PHYS_ADDR;
 	return elem->ms->phys_addr + ((uintptr_t)addr - (uintptr_t)elem->ms->addr);
 }
diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
index 647d89c58..040f24a43 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -112,6 +112,13 @@ test_phys_addrs_available(void)
 	if (rte_xen_dom0_supported())
 		return;
 
+	if (!rte_eal_has_hugepages()) {
+		RTE_LOG(ERR, EAL,
+			"Started without hugepages support, physical addresses not available\n");
+		phys_addrs_available = false;
+		return;
+	}
+
 	physaddr = rte_mem_virt2phy(&tmp);
 	if (physaddr == RTE_BAD_PHYS_ADDR) {
 		RTE_LOG(ERR, EAL,
@@ -1054,7 +1061,7 @@ rte_eal_hugepage_init(void)
 					strerror(errno));
 			return -1;
 		}
-		mcfg->memseg[0].phys_addr = (phys_addr_t)(uintptr_t)addr;
+		mcfg->memseg[0].phys_addr = RTE_BAD_PHYS_ADDR;
 		mcfg->memseg[0].addr = addr;
 		mcfg->memseg[0].hugepage_sz = RTE_PGSIZE_4K;
 		mcfg->memseg[0].len = internal_config.memory;
diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index f65310f60..6fc3c9c7c 100644
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -476,7 +476,7 @@ rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
 		/* required for xen_dom0 to get the machine address */
 		paddr = rte_mem_phy2mch(-1, paddr);
 
-		if (paddr == RTE_BAD_PHYS_ADDR) {
+		if (paddr == RTE_BAD_PHYS_ADDR && rte_eal_has_hugepages()) {
 			ret = -EINVAL;
 			goto fail;
 		}
-- 
2.11.0