Add iSCSI iBFT support (v0.4.6)

This patch (v0.4.6) adds /sysfs/firmware/ibft/[initiator|targetX|ethernetX] directories along with text properties which export the the iSCSI Boot Firmware Table (iBFT) structure.

What is iSCSI Boot Firmware Table? It is a mechanism for the iSCSI tools to extract from the machine NICs the iSCSI connection information so that they can automagically mount the iSCSI share/target. Currently the iSCSI information is hard-coded in the initrd. The /sysfs entries are read-only one-name-and-value fields.

The usual set of data exposed is:

# for a in `find /sys/firmware/ibft/ -type f -print`; do  echo -n "$a: ";  cat $a; done
/sys/firmware/ibft/target0/target-name: iqn.2007.com.intel-sbx44:storage-10gb
/sys/firmware/ibft/target0/nic-assoc: 0
/sys/firmware/ibft/target0/chap-type: 0
/sys/firmware/ibft/target0/lun: 00000000
/sys/firmware/ibft/target0/port: 3260
/sys/firmware/ibft/target0/ip-addr: 192.168.79.116
/sys/firmware/ibft/target0/flags: 3
/sys/firmware/ibft/target0/index: 0
/sys/firmware/ibft/ethernet0/mac: 00:11:25:9d:8b:01
/sys/firmware/ibft/ethernet0/vlan: 0
/sys/firmware/ibft/ethernet0/gateway: 192.168.79.254
/sys/firmware/ibft/ethernet0/origin: 0
/sys/firmware/ibft/ethernet0/subnet-mask: 255.255.252.0
/sys/firmware/ibft/ethernet0/ip-addr: 192.168.77.41
/sys/firmware/ibft/ethernet0/flags: 7
/sys/firmware/ibft/ethernet0/index: 0
/sys/firmware/ibft/initiator/initiator-name: iqn.2007-07.com:konrad.initiator
/sys/firmware/ibft/initiator/flags: 3
/sys/firmware/ibft/initiator/index: 0

For full details of the IBFT structure please take a look at:
ftp://ftp.software.ibm.com/systems/support/system_x_pdf/ibm_iscsi_boot_firmware_table_v1.02.pdf

---

 Documentation/ABI/testing/sysfs-ibft |   23 
 arch/x86/kernel/setup_32.c           |    3 
 arch/x86/kernel/setup_64.c           |    4 
 drivers/firmware/Kconfig             |   20 
 drivers/firmware/Makefile            |    2 
 drivers/firmware/iscsi_ibft.c        |  988 +++++++++++++++++++++++++++++++++++
 drivers/firmware/iscsi_ibft_find.c   |   77 ++
 include/linux/iscsi_ibft.h           |   52 +
 8 files changed, 1169 insertions(+)

new file mode 100644
index 0000000..062c009
@@ -0,0 +1,23 @@
+What:		/sys/firmware/ibft/initiator
+Date:		November 2007
+Contact:	Konrad Rzeszutek <[email protected]>
+Description:	The /sys/firmware/ibft/initiator directory will contain
+		files that expose the iSCSI Boot Firmware Table initiator data.
+		Usually this contains the Initiator name.
+
+What:		/sys/firmware/ibft/targetX
+Date:		November 2007
+Contact:	Konrad Rzeszutek <[email protected]>
+Description:	The /sys/firmware/ibft/targetX directory will contain
+		files that expose the iSCSI Boot Firmware Table target data.
+		Usually this contains the target's IP address, boot LUN,
+		target name, and what NIC it is associated with. It can also
+		contain the CHAP name (and password), the reverse CHAP
+		name (and password)
+
+What:		/sys/firmware/ibft/ethernetX
+Date:		November 2007
+Contact:	Konrad Rzeszutek <[email protected]>
+Description:	The /sys/firmware/ibft/ethernetX directory will contain
+		files that expose the iSCSI Boot Firmware Table NIC data.
+		This can this can the IP address, MAC, and gateway of the NIC.

index 9c24b45..5da7b8d 100644
@@ -39,6 +39,7 @@
 #include <linux/efi.h>
 #include <linux/init.h>
 #include <linux/edd.h>
+#include <linux/iscsi_ibft.h>
 #include <linux/nodemask.h>
 #include <linux/kexec.h>
 #include <linux/crash_dump.h>

@@ -496,6 +497,8 @@ void __init setup_bootmem_allocator(void)
 	}
 #endif
 	reserve_crashkernel();
+
+	reserve_ibft_region();
 }
 
 /*

index 30d94d1..3393f2d 100644
@@ -33,6 +33,7 @@
 #include <linux/acpi.h>
 #include <linux/kallsyms.h>
 #include <linux/edd.h>
+#include <linux/iscsi_ibft.h>
 #include <linux/mmzone.h>
 #include <linux/kexec.h>
 #include <linux/cpufreq.h>

@@ -403,6 +404,9 @@ void __init setup_arch(char **cmdline_p)
 	}
 #endif
 	reserve_crashkernel();
+
+	reserve_ibft_region();
+
 	paging_init();
 
 #ifdef CONFIG_PCI

index 05f02a3..81a3e59 100644
@@ -93,4 +93,24 @@ config DMIID
 	  information from userspace through /sys/class/dmi/id/ or if you want
 	  DMI-based module auto-loading.
 
+config ISCSI_IBFT_FIND
+	bool "iSCSI Boot Firmware Table Attributes"
+	depends on X86 || IA64
+	default n
+	help
+	  This option enables the kernel to find the region of memory
+	  in which the ISCSI Boot Firmware Table (iBFT) resides. This
+	  is necessary for iSCSI Boot Firmware Table Attributes module to work
+	  properly.
+
+config ISCSI_IBFT
+	tristate "iSCSI Boot Firmware Table Attributes module"
+	depends on ISCSI_IBFT_FIND
+	default	n
+	help
+	  This option enables support for detection and exposing of iSCSI
+	  Boot Firmware Table (iBFT) via sysfs to userspace. If you wish to
+	  detect iSCSI boot parameters dynamically during system boot, say Y.
+	  Otherwise, say N.
+
 endmenu

index 8d4ebc8..4c91471 100644
@@ -8,3 +8,5 @@ obj-$(CONFIG_EFI_PCDP)		+= pcdp.o
 obj-$(CONFIG_DELL_RBU)          += dell_rbu.o
 obj-$(CONFIG_DCDBAS)		+= dcdbas.o
 obj-$(CONFIG_DMIID)		+= dmi-id.o
+obj-$(CONFIG_ISCSI_IBFT_FIND)	+= iscsi_ibft_find.o
+obj-$(CONFIG_ISCSI_IBFT)	+= iscsi_ibft.o

Some pieces of the patch are obviously wrong: find_ibft() shouldn't be in ibft_init ... if ibft_phys was zero, it means the bootmem reservation wasn't done and you shouldn't be poking about in memory which has likely now been overwritten.

Also, why is ibft_phys the global variable you pass? You never actually want to use the physical address, what you always end up using is the kernel virtual address.

I'd simply use the ibft variable to point to the virtual address of the ibft or null if not found, then you can throw out all the phys_to_virt() calls.

Also, move the reserve_bootmem into the ibft_find routines and ensure they're only called once on boot. Refuse to attach the ibft driver if the virtual pointer ibft is null.

James

And note that the reserve_bootmem() interface is about to change.

http://userweb.kernel.org/~akpm/mmotm/broken-out/introduce-flags-for-reserve_bootmem.patch

Fixed.

Fixed.

James,

Thanks for your review. If you wouldn't mind, can you take a look at the version 0.4.7 (http://lkml.org/lkml/2008/2/8/350) which has your suggestions incorporated.

Thanks again.