On 5/6/2025 7:40 PM, Jake Freeland wrote:
When mapping PCI resources in secondary processes, use the
RTE_MAP_FORCE_ADDRESS_NOREPLACE flag to indicate that the
mapping must be made at the provided address.
Without this flag, the kernel might return a different address for
the mapping, even if the requested region was available.
Signed-off-by: Jake Freeland <jf...@freebsd.org>
---
drivers/bus/pci/pci_common_uio.c | 4 +++-
lib/eal/common/eal_private.h | 7 ++++++-
lib/eal/include/rte_eal_paging.h | 7 ++++++-
lib/eal/unix/eal_unix_memory.c | 8 +++++++-
4 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/bus/pci/pci_common_uio.c b/drivers/bus/pci/pci_common_uio.c
index 30503bd23a..71974e9f56 100644
--- a/drivers/bus/pci/pci_common_uio.c
+++ b/drivers/bus/pci/pci_common_uio.c
@@ -10,6 +10,7 @@
#include <sys/mman.h>
#include <rte_eal.h>
+#include <rte_eal_paging.h>
#include <rte_pci.h>
#include <rte_bus_pci.h>
#include <rte_tailq.h>
@@ -58,7 +59,8 @@ pci_uio_map_secondary(struct rte_pci_device *dev)
void *mapaddr = pci_map_resource(uio_res->maps[i].addr,
fd, (off_t)uio_res->maps[i].offset,
- (size_t)uio_res->maps[i].size, 0);
+ (size_t)uio_res->maps[i].size,
+ RTE_MAP_FORCE_ADDRESS_NOREPLACE);
/* fd is not needed in secondary process, close it */
close(fd);
diff --git a/lib/eal/common/eal_private.h b/lib/eal/common/eal_private.h
index 04ba8ddb86..aaeb140eaf 100644
--- a/lib/eal/common/eal_private.h
+++ b/lib/eal/common/eal_private.h
@@ -211,7 +211,12 @@ enum eal_mem_reserve_flags {
* @see RTE_MAP_FORCE_ADDRESS for description of possible consequences
* (although implementations are not required to use it).
*/
- EAL_RESERVE_FORCE_ADDRESS = 1 << 1
+ EAL_RESERVE_FORCE_ADDRESS = 1 << 1,
+ /**
+ * Force reserving memory at the requested address, but fail if a
+ * preexisting mapping collides with the request.
+ */
+ EAL_RESERVE_FORCE_ADDRESS_NOREPLACE = 1 << 2,
};
/**
diff --git a/lib/eal/include/rte_eal_paging.h b/lib/eal/include/rte_eal_paging.h
index c60317d0f5..7b1983b615 100644
--- a/lib/eal/include/rte_eal_paging.h
+++ b/lib/eal/include/rte_eal_paging.h
@@ -34,7 +34,12 @@ enum rte_map_flags {
* may remove all other mappings in the requested region. However,
* it is not required to do so, thus mapping with this flag may fail.
*/
- RTE_MAP_FORCE_ADDRESS = 1 << 3
+ RTE_MAP_FORCE_ADDRESS = 1 << 3,
+ /**
+ * Force mapping to the requested address, but fail if a preexisting
+ * mapping collides with the request.
+ */
+ RTE_MAP_FORCE_ADDRESS_NOREPLACE = 1 << 4,
};
/**
diff --git a/lib/eal/unix/eal_unix_memory.c b/lib/eal/unix/eal_unix_memory.c
index c540f1e838..61e914b8db 100644
--- a/lib/eal/unix/eal_unix_memory.c
+++ b/lib/eal/unix/eal_unix_memory.c
@@ -17,11 +17,13 @@
#ifdef RTE_EXEC_ENV_LINUX
#define EAL_DONTDUMP MADV_DONTDUMP
#define EAL_DODUMP MADV_DODUMP
+#define EAL_FIXED_NOREPLACE MAP_FIXED_NOREPLACE
Is this available in all supported Linux kernel versions?
--
Thanks,
Anatoly
