[dpdk-dev] [PATCH v2] eal: Support running as unprivileged user
Ben Walker
benjamin.walker at intel.com
Tue Jan 3 23:56:00 CET 2017
For Linux kernel 4.0 and newer, the ability to obtain
physical page frame numbers for unprivileged users from
/proc/self/pagemap was removed. Instead, when an IOMMU
is present, simply choose our own DMA addresses instead.
Signed-off-by: Ben Walker <benjamin.walker at intel.com>
---
lib/librte_eal/common/eal_private.h | 12 +++++
lib/librte_eal/linuxapp/eal/eal_memory.c | 75 +++++++++++++++++++++++---------
lib/librte_eal/linuxapp/eal/eal_pci.c | 6 ++-
3 files changed, 71 insertions(+), 22 deletions(-)
diff --git a/lib/librte_eal/common/eal_private.h b/lib/librte_eal/common/eal_private.h
index 9e7d8f6..8b2d323 100644
--- a/lib/librte_eal/common/eal_private.h
+++ b/lib/librte_eal/common/eal_private.h
@@ -34,6 +34,7 @@
#ifndef _EAL_PRIVATE_H_
#define _EAL_PRIVATE_H_
+#include <stdbool.h>
#include <stdio.h>
#include <rte_pci.h>
@@ -301,4 +302,15 @@ int rte_eal_hugepage_init(void);
*/
int rte_eal_hugepage_attach(void);
+/**
+ * Returns true if the system is able to obtain
+ * physical addresses. Return false if using DMA
+ * addresses through an IOMMU.
+ *
+ * Drivers based on uio will not load unless physical
+ * addresses are obtainable. It is only possible to get
+ * physical addresses when running as a privileged user.
+ */
+bool rte_eal_using_phys_addrs(void);
+
#endif /* _EAL_PRIVATE_H_ */
diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
index a956bb2..8678ae9 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -64,6 +64,7 @@
#define _FILE_OFFSET_BITS 64
#include <errno.h>
#include <stdarg.h>
+#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
@@ -122,26 +123,24 @@ int rte_xen_dom0_supported(void)
static uint64_t baseaddr_offset;
-static unsigned proc_pagemap_readable;
+static bool phys_addrs_available = true;
#define RANDOMIZE_VA_SPACE_FILE "/proc/sys/kernel/randomize_va_space"
static void
-test_proc_pagemap_readable(void)
+test_phys_addrs_available(void)
{
- int fd = open("/proc/self/pagemap", O_RDONLY);
+ uint64_t tmp;
+ phys_addr_t physaddr;
- if (fd < 0) {
+ physaddr = rte_mem_virt2phy(&tmp);
+ if (physaddr == RTE_BAD_PHYS_ADDR) {
RTE_LOG(ERR, EAL,
- "Cannot open /proc/self/pagemap: %s. "
- "virt2phys address translation will not work\n",
+ "Cannot obtain physical addresses: %s. "
+ "Only vfio will function.\n",
strerror(errno));
- return;
+ phys_addrs_available = false;
}
-
- /* Is readable */
- close(fd);
- proc_pagemap_readable = 1;
}
/* Lock page in physical memory and prevent from swapping. */
@@ -190,7 +189,7 @@ rte_mem_virt2phy(const void *virtaddr)
}
/* Cannot parse /proc/self/pagemap, no need to log errors everywhere */
- if (!proc_pagemap_readable)
+ if (!phys_addrs_available)
return RTE_BAD_PHYS_ADDR;
/* standard page size */
@@ -229,6 +228,9 @@ rte_mem_virt2phy(const void *virtaddr)
* the pfn (page frame number) are bits 0-54 (see
* pagemap.txt in linux Documentation)
*/
+ if ((page & 0x7fffffffffffffULL) == 0)
+ return RTE_BAD_PHYS_ADDR;
+
physaddr = ((page & 0x7fffffffffffffULL) * page_size)
+ ((unsigned long)virtaddr % page_size);
@@ -242,7 +244,7 @@ rte_mem_virt2phy(const void *virtaddr)
static int
find_physaddrs(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi)
{
- unsigned i;
+ unsigned int i;
phys_addr_t addr;
for (i = 0; i < hpi->num_pages[0]; i++) {
@@ -255,6 +257,22 @@ find_physaddrs(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi)
}
/*
+ * For each hugepage in hugepg_tbl, fill the physaddr value sequentially.
+ */
+static int
+set_physaddrs(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi)
+{
+ unsigned int i;
+ phys_addr_t addr = 0;
+
+ for (i = 0; i < hpi->num_pages[0]; i++) {
+ hugepg_tbl[i].physaddr = addr;
+ addr += hugepg_tbl[i].size;
+ }
+ return 0;
+}
+
+/*
* Check whether address-space layout randomization is enabled in
* the kernel. This is important for multi-process as it can prevent
* two processes mapping data to the same virtual address
@@ -951,7 +969,7 @@ rte_eal_hugepage_init(void)
int nr_hugefiles, nr_hugepages = 0;
void *addr;
- test_proc_pagemap_readable();
+ test_phys_addrs_available();
memset(used_hp, 0, sizeof(used_hp));
@@ -1043,11 +1061,22 @@ rte_eal_hugepage_init(void)
continue;
}
- /* find physical addresses and sockets for each hugepage */
- if (find_physaddrs(&tmp_hp[hp_offset], hpi) < 0){
- RTE_LOG(DEBUG, EAL, "Failed to find phys addr for %u MB pages\n",
- (unsigned)(hpi->hugepage_sz / 0x100000));
- goto fail;
+ if (phys_addrs_available) {
+ /* find physical addresses for each hugepage */
+ if (find_physaddrs(&tmp_hp[hp_offset], hpi) < 0) {
+ RTE_LOG(DEBUG, EAL, "Failed to find phys addr "
+ "for %u MB pages\n",
+ (unsigned int)(hpi->hugepage_sz / 0x100000));
+ goto fail;
+ }
+ } else {
+ /* set physical addresses for each hugepage */
+ if (set_physaddrs(&tmp_hp[hp_offset], hpi) < 0) {
+ RTE_LOG(DEBUG, EAL, "Failed to set phys addr "
+ "for %u MB pages\n",
+ (unsigned int)(hpi->hugepage_sz / 0x100000));
+ goto fail;
+ }
}
if (find_numasocket(&tmp_hp[hp_offset], hpi) < 0){
@@ -1289,7 +1318,7 @@ rte_eal_hugepage_attach(void)
"into secondary processes\n");
}
- test_proc_pagemap_readable();
+ test_phys_addrs_available();
if (internal_config.xen_dom0_support) {
#ifdef RTE_LIBRTE_XEN_DOM0
@@ -1426,3 +1455,9 @@ rte_eal_hugepage_attach(void)
close(fd_hugepage);
return -1;
}
+
+bool
+rte_eal_using_phys_addrs(void)
+{
+ return phys_addrs_available;
+}
diff --git a/lib/librte_eal/linuxapp/eal/eal_pci.c b/lib/librte_eal/linuxapp/eal/eal_pci.c
index 4350134..cfbfedf 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci.c
@@ -99,8 +99,10 @@ rte_eal_pci_map_device(struct rte_pci_device *dev)
break;
case RTE_KDRV_IGB_UIO:
case RTE_KDRV_UIO_GENERIC:
- /* map resources for devices that use uio */
- ret = pci_uio_map_resource(dev);
+ if (rte_eal_using_phys_addrs()) {
+ /* map resources for devices that use uio */
+ ret = pci_uio_map_resource(dev);
+ }
break;
default:
RTE_LOG(DEBUG, EAL,
--
2.9.3
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