[block] Allow use of a non-default EFI SAN boot filename
Some older operating systems (e.g. RHEL6) use a non-default filename
on the root disk and rely on setting an EFI variable to point to the
bootloader. This does not work when performing a SAN boot on a
machine where the EFI variable is not present.
Fix by allowing a non-default filename to be specified via the
"sanboot --filename" option or the "san-filename" setting. For
example:
sanboot --filename \efi\redhat\grub.efi \
iscsi:192.168.0.1::::iqn.2010-04.org.ipxe.demo:rhel6
or
option ipxe.san-filename code 188 = string;
option ipxe.san-filename "\\efi\\redhat\\grub.efi";
option root-path "iscsi:192.168.0.1::::iqn.2010-04.org.ipxe.demo:rhel6";
Originally-implemented-by: Vishvananda Ishaya Abrams <vish.ishaya@oracle.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Describe all SAN devices via ACPI tables such as the iBFT. For tables
that can describe only a single device (i.e. the aBFT and sBFT), one
table is installed per device. For multi-device tables (i.e. the
iBFT), all devices are described in a single table.
An underlying SAN device connection may be closed at the time that we
need to construct an ACPI table. We therefore introduce the concept
of an "ACPI descriptor" which enables the SAN boot code to maintain an
opaque pointer to the underlying object, and an "ACPI model" which can
build tables from a list of such descriptors. This separates the
lifecycles of ACPI descriptions from the lifecycles of the block
device interfaces, and allows for construction of the ACPI tables even
if the block device interface has been closed.
For a multipath SAN device, iPXE will wait until sufficient
information is available to describe all devices but will not wait for
all paths to connect successfully. For example: with a multipath
iSCSI boot iPXE will wait until at least one path has become available
and name resolution has completed on all other paths. We do this
since the iBFT has to include IP addresses rather than DNS names. We
will commence booting without waiting for the inactive paths to either
become available or close; this avoids unnecessary boot delays.
Note that the Linux kernel will refuse to accept an iBFT with more
than two NIC or target structures. We therefore describe only the
NICs that are actually required in order to reach the described
targets. Any iBFT with at most two targets is therefore guaranteed to
describe at most two NICs.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add basic support for multipath block devices. The "sanboot" and
"sanhook" commands now accept a list of SAN URIs. We open all URIs
concurrently. The first connection to become available for issuing
block device commands is marked as the active path and used for all
subsequent commands; all other connections are then closed. Whenever
the active path fails, we reopen all URIs and repeat the process.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[efi] Provide ACPI table description for SAN devices
Provide a basic proof of concept ACPI table description (e.g. iBFT for
iSCSI) for SAN devices in a UEFI environment, using a control flow
that is functionally identical to that used in a BIOS environment.
Originally-implemented-by: Vishvananda Ishaya Abrams <vish.ishaya@oracle.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The concept of the SAN drive number is meaningful only in a BIOS
environment, where it represents the INT13 drive number (0x80 for the
first hard disk). We retain this concept in a UEFI environment to
allow for a simple way for iPXE commands to refer to SAN drives.
Centralise the concept of the default drive number, since it is shared
between all supported environments.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown