From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <simon.kagstrom@netinsight.net>
Received: from ernst.netinsight.se (ernst.netinsight.se [194.16.221.21])
 by dpdk.org (Postfix) with SMTP id D2ECBC536
 for <dev@dpdk.org>; Wed, 24 Jun 2015 10:33:59 +0200 (CEST)
Received: from miho (unverified [10.100.1.152]) by ernst.netinsight.se
 (EMWAC SMTPRS 0.83) with SMTP id <B0030297463@ernst.netinsight.se>;
 Wed, 24 Jun 2015 10:33:52 +0200
Date: Wed, 24 Jun 2015 10:33:52 +0200
From: Simon Kagstrom <simon.kagstrom@netinsight.net>
To: dev@dpdk.org
Message-ID: <20150624103352.58d20fb3@miho>
X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.27; x86_64-pc-linux-gnu)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Subject: [dpdk-dev] [PATCH v2] mem: Warn once if /proc/self/pagemap is
	unreadable
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Wed, 24 Jun 2015 08:34:00 -0000

Newer kernels make this unreadable for security reasons for non-roots.
Running the application will then fill the logs with

  rte_mem_virt2phy: cannot open /proc/self/pagemap

messages.

However, there are cases when DPDK is and should be run as non-root,
without the need for virtual-to-physical address translations: a
typical example is when working with PCAP input/output. This patch
adds a start-time check for /proc/self/pagemap readability, and
directly returns an error code from rte_mem_virt2phy().

This way, there is only a one-time warning at startup instead of
constant warnings all the time.

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: Johan Faltstrom <johan.faltstrom@netinsight.net>
---
ChangeLog:

v2: Fix use with huge pages.

 lib/librte_eal/linuxapp/eal/eal_memory.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
index 9b8d946..f4a1936 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -111,6 +111,8 @@
 
 static uint64_t baseaddr_offset;
 
+static unsigned proc_pagemap_readable;
+
 #define RANDOMIZE_VA_SPACE_FILE "/proc/sys/kernel/randomize_va_space"
 
 /* Lock page in physical memory and prevent from swapping. */
@@ -135,6 +137,10 @@ rte_mem_virt2phy(const void *virtaddr)
 	int page_size;
 	off_t offset;
 
+	/* Cannot parse /proc/self/pagemap, no need to log errors everywhere */
+	if (!proc_pagemap_readable)
+		return RTE_BAD_PHYS_ADDR;
+
 	/* standard page size */
 	page_size = getpagesize();
 
@@ -1546,12 +1552,31 @@ rte_eal_memdevice_init(void)
 	return 0;
 }
 
+static int
+test_proc_pagemap_readable(void)
+{
+	int fd = open("/proc/self/pagemap", O_RDONLY);
+
+	if (fd < 0)
+		return 0;
+	/* Is readable */
+	close(fd);
+
+	return 1;
+}
 
 /* init memory subsystem */
 int
 rte_eal_memory_init(void)
 {
 	RTE_LOG(INFO, EAL, "Setting up memory...\n");
+
+	proc_pagemap_readable = test_proc_pagemap_readable();
+	if (!proc_pagemap_readable)
+		RTE_LOG(ERR, EAL,
+		        "Cannot open /proc/self/pagemap: %s. virt2phys address translation will not work\n",
+			strerror(errno));
+
 	const int retval = rte_eal_process_type() == RTE_PROC_PRIMARY ?
 			rte_eal_hugepage_init() :
 			rte_eal_hugepage_attach();
-- 
1.9.1