End users almost certainly don't care whether the underlying interface
is SNP or NII/UNDI. Try to minimise surprise and unnecessary
documentation by including the NII driver whenever the SNP driver is
requested.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
iPXE itself exposes a dummy NII protocol with no UNDI. Avoid
potentially dereferencing a NULL pointer by checking for a non-zero
UNDI address.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some UEFI network drivers provide a software UNDI interface which is
exposed via the Network Interface Identifier Protocol (NII), rather
than providing a Simple Network Protocol (SNP).
The UEFI platform firmware will usually include the SnpDxe driver,
which attaches to NII and provides an SNP interface. The SNP
interface is usually provided on the same handle as the underlying NII
device. This causes problems for our EFI driver model: when
efi_driver_connect() detaches existing drivers from the handle it will
cause the SNP interface to be uninstalled, and so our SNP driver will
not be able to attach to the handle. The platform firmware will
eventually reattach the SnpDxe driver and may attach us to the SNP
handle, but we have no way to prevent other drivers from attaching
first.
Fix by providing a driver which can attach directly to the NII
protocol, using the software UNDI interface to drive the network
device.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The snpnet driver uses netdev_tx_defer() and so must ensure that space
in the (single-entry) transmit descriptor ring is freed up before
calling netdev_tx_complete().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The EDK2 codebase uses -malign-double for 32-bit builds, which causes
64-bit integers to be naturally aligned. This affects the layout of
some structures (including EFI_BLOCK_IO_MEDIA).
This mirrors wimboot commit 7b8f39d ("[build] Fix building of 32-bit
UEFI version").
Signed-off-by: Michael Brown <mcb30@ipxe.org>
As of commit 03f0c23 ("[ipoib] Expose Ethernet-compatible eIPoIB
link-layer addresses and headers"), all link layers have used
addresses which fit within the DHCP chaddr field. The dhcp_chaddr()
function was therefore made obsolete by this commit, but was
accidentally left present (though unused) in the source code.
Remove the dhcp_chaddr() function and the only remaining use of it,
unnecessarily introduced in commit 08bcc0f ("[dhcp] Check for matching
chaddr in received DHCP packets").
Reported-by: Wissam Shoukair <wissams@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
On large networks a DHCP XID collision is possible. Fix by explicitly
checking the chaddr in received DHCP packets.
Originally-fixed-by: Wissam Shoukair <wissams@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some UEFI platforms will fail the call to LoadImage() with
EFI_INVALID_PARAMETER if we do not provide a device path (even though
we are providing a non-NULL SourceBuffer).
Fix by providing an empty device path for the call to LoadImage() in
efi_image_probe().
The call to LoadImage() in efi_image_exec() already constructs and
provides a device path (based on the most recently opened SNP device),
and so does not require this fix.
Reported-by: NICOLAS CATTIE <nicolas.cattie@mpsa.com>
Tested-by: NICOLAS CATTIE <nicolas.cattie@mpsa.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add the ID for the LM variant and differentiate it from the I217-V.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add utility for constructing EFI fat binaries (dual 32/64-bit
binaries, usable only on Apple EFI systems).
This utility is not part of the standard build process. To use it:
make util/efifatbin bin-i386-efi/ipxe.efi bin-x86_64-efi/ipxe.efi
and then
./util/efifatbin bin-*-efi/ipxe.efi fat-ipxe.efi
Requested-by: Brandon Penglase <bpenglase-ipxe@spaceservices.net>
Tested-by: Brandon Penglase <bpenglase-ipxe@spaceservices.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow a straightforward "make clean" or "make veryclean" to apply to
all binary directories (using the shell pattern "bin{,-*}").
Individual binary directories can be cleaned using e.g.
make bin clean
make bin-x86_64-efi clean
Reported-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We currently require information about the underlying PCI device to
populate the snpnet device's name and description. If the underlying
device is not a PCI device, this will fail and prevent the device from
being registered.
Fix by falling back to populating the device description with
information based on the EFI handle, if no PCI device information is
available.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some UEFI systems (observed with a Hyper-V virtual machine) do not
provide EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL. Make this an optional
protocol (and fail any attempts to access PCI configuration space via
the root bridge if the protocol is missing).
Reported-by: Colin Blacker <Colin.Blacker@computerplanet.co.uk>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Under UEFI, reads from PCI configuration space may fail. If this
happens, we should return all-ones (which will mimic the behaviour of
an absent PCI device).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some systems will install a child of the SNP device and use this as
our loaded image's device handle, duplicating the installation of the
underlying SNP protocol onto the child device handle. On such
systems, we want to end up driving the parent device (and
disconnecting any other drivers, such as MNP, which may be attached to
the parent device).
Fix by recording the SNP protocol instance at initialisation time, and
using this to match against device handles (rather than simply
comparing the handles themselves).
Reported-by: Jarrod Johnson <jarrod.b.johnson@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Propagate our modified EFI system table to any images loaded by the
image that we wrap, thereby allowing us to observe boot services calls
made by all subsequent EFI images.
Also show details of intercepted ExitBootServices() calls. When
wrapping is used, exiting boot services will almost certainly fail,
but this at least allows us to see when it happens.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The .mrom payload has a code type of 0xff and so the initialisation
length field (single byte at offset 0x02) does not need to be
present. Use only the PCI header's image length field, which allows
the .mrom payload to be up to 32MB in size.
Inspired-by: Swift Geek <swiftgeek@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
mromprefix.S currently uses the initialisation length field (single
byte at offset 0x02) to determine the length of a ROM image within a
multi-image ROM BAR. For PCI ROM images with a code type other than
0, the initialisation length field may not be present.
Fix by using the PCI header's image length field instead.
Inspired-by: Swift Geek <swiftgeek@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Option::ROM currently uses the initialisation length field (single
byte at offset 0x02) to determine the length of a ROM image within a
multi-image ROM file. For PCI ROM images with a code type other than
0, the initialisation length field may not be present.
Fix by using the PCI header's image length field instead. Note that
this does not prevent us from correctly handling ISA ROMs, since ISA
ROMs do not support multiple images within a single ROM BAR anyway.
Inspired-by: Swift Geek <swiftgeek@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
With extremely unlucky timing, it is possible to interrupt a build and
cause make to delete config/named.h (and possibly any local
configuration headers).
Mark config/named.h and all local configuration headers as .PRECIOUS
to prevent make from ever deleting them.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The build process has for a long time assumed that every ROM is a PCI
ROM, and will always include the PCI header and PCI-related
functionality (such as checking the PCI BIOS version, including the
PCI bus:dev.fn address within the ROM product name string, etc.).
While real ISA cards are no longer in use, some virtualisation
environments (notably VirtualBox) have support only for ISA ROMs.
This can cause problems: in particular, VirtualBox will call our
initialisation entry point with random garbage in %ax, which we then
treat as the PCI bus:dev.fn address of the autoboot device: this
generally prevents the default boot sequence from using any network
devices.
Create .isarom and .pcirom prefixes which can be used to explicitly
specify the type of ROM to be created. (Note that the .mrom prefix
always implies a PCI ROM, since the .mrom mechanism relies on
reconfiguring PCI BARs.)
Make .rom a magic prefix which will automatically select the
appropriate PCI or ISA ROM prefix for ROMs defined via a PCI_ROM() or
ISA_ROM() macro. To maintain backwards compatibility, we default to
building a PCI ROM for anything which is not directly derived from a
PCI_ROM() or ISA_ROM() macro (e.g. bin/intel.rom).
Add a selection of targets to "make everything" to ensure that the
(relatively obscure) ISA ROM build process is included within the
per-commit QA checks.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Since some PnP BIOSes fail to set %es:di to point to the PnP signature
on entry, we identify a PnP BIOS by scanning through the top 64kB of
base memory looking for the PnP structure. We therefore don't
actually use the values of %es:di provided to the initialisation entry
point, and so there is no need to preserve them.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
ICH8 devices have an errata which requires us to reconfigure the
packet buffer size (PBS) register, and correspondingly adjust the
packet buffer allocation (PBA) register. The "Intel I/O Controller
Hub ICH8/9/10 and 82566/82567/82562V Software Developer's Manual"
notes for the PBS register that:
10.4.20 Packet Buffer Size - PBS (01008h; R/W)
Note: The default setting of this register is 20 KB and is
incorrect. This register must be programmed to 16 KB.
Initial value: 0014h
0018h (ICH9/ICH10)
It is unclear from this comment precisely which devices require the
workaround to be applied. We currently attempt to err on the side of
caution: if we detect an initial value of either 0x14 or 0x18 then the
workaround will be applied. If the workaround is applied
unnecessarily, then the effect should be just that we use less than
the full amount of the available packet buffer memory.
Unfortunately this approach does not play nicely with other device
drivers. For example, the Linux e1000e driver will rewrite PBA while
assuming that PBS still contains the default value, which can result
in inconsistent values between the two registers, and a corresponding
inability to transmit or receive packets. Even more unfortunately,
the contents of PBS and PBA are not reset by anything less than a
power cycle, meaning that this error condition will survive a hardware
reset.
The Linux driver (written and maintained by Intel) applies the PBS/PBA
errata workaround only for devices in the ICH8 family, identified via
the PCI device ID. Adopt a similar approach, using the PCI_ROM()
driver data field to indicate when the workaround is required.
Reported-by: Donald Bindner <dbindner@truman.edu>
Debugged-by: Donald Bindner <dbindner@truman.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow named configurations to be specified via the CONFIG=... build
parameter. For headers in config/*.h which support named
configurations, the following files will be included when building
with CONFIG=<name>:
- config/defaults/<platform>.h (e.g. config/defaults/pcbios.h)
- config/<header>.h
- config/<name>/<header>.h (only if the directory config/<name> exists)
- config/local/<header>.h (autocreated if necessary)
- config/local/<name>/<header>.h (autocreated if necessary)
This mechanism allows for predefined named configurations to be
checked in to the source tree, as a directory config/<name> containing
all of the required header files.
The mechanism also allows for users to define multiple local
configurations, by creating header files in the directory
config/local/<name>.
Note that the config/*.h files which are used only to configure
internal iPXE APIs (e.g. config/ioapi.h) cannot be modified via a
named configuration. This avoids rebuilding the entire iPXE codebase
whenever switching to a different named configuration.
Inspired-by: Robin Smidsrød <robin@smidsrod.no>
Tested-by: Robin Smidsrød <robin@smidsrod.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Under some circumstances (e.g. if iPXE itself is booted via iSCSI, or
after an unclean reboot), the backend may not be in the expected
InitWait state when iPXE starts up.
There is no generic reset mechanism for Xenbus devices. Recent
versions of xen-netback will gracefully perform all of the required
steps if the frontend sets its state to Initialising. Older versions
(such as that found in XenServer 6.2.0) require the frontend to
transition through Closed before reaching Initialising.
Add a reset mechanism for netfront devices which does the following:
- read current backend state
- if backend state is anything other than InitWait, then set the
frontend state to Closed and wait for the backend to also reach
Closed
- set the frontend state to Initialising and wait for the backend to
reach InitWait.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Using version 1 grant tables limits guests to using 16TB of grantable
RAM, and prevents the use of subpage grants. Some versions of the Xen
hypervisor refuse to allow the grant table version to be set after the
first grant references have been created, so the loaded operating
system may be stuck with whatever choice we make here. We therefore
currently use version 2 grant tables, since they give the most
flexibility to the loaded OS.
Current versions (7.2.0) of the Windows PV drivers have no support for
version 2 grant tables, and will merrily create version 1 entries in
what the hypervisor believes to be a version 2 table. This causes
some confusion.
Avoid this problem by attempting to use version 1 tables, since
otherwise we may render Windows unable to boot.
Play nicely with other potential bootloaders by accepting either
version 1 or version 2 grant tables (if we are unable to set our
requested version).
Note that the use of version 1 tables on a 64-bit system introduces a
possible failure path in which a frame number cannot fit into the
32-bit field within the v1 structure. This in turn introduces
additional failure paths into netfront_transmit() and
netfront_refill_rx().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
At some point during XenServer development history, the Windows PV
drivers changed to using a PCI device ID of 5853:0002 rather than
5853:0001. Current (7.2.0) drivers will bind to either 5853:0001 or
5853:0002, and the general approach taken by the world at large
(including Amazon EC2) seems to be to use only 5853:0001.
However, the current version of XenServer (6.2.0) will create the
platform device as 5853:0002 (via the platform:device_id VM parameter)
for any VMs created using the built-in templates for Windows Vista or
later.
Accept either PCI ID, since the underlying device is identical.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The behavior observed in the Apple EFI (1.10) RecieveFilters() call
is:
- failure if any of the PROMISCUOUS or MULTICAST filters are
included
- success if only UNICAST is included, however the result is
UNICAST|BROADCAST
- success if only UNICAST and BROADCAST are included
- if UNICAST, or UNICAST|BROADCAST are used, but the previous call
tried (and failed) to set UNICAST|BROADCAST|MULTICAST, then the
result is UNICAST|BROADCAST|MULTICAST
Work around this apparently broken SNP implementation by trying
RecieveFilterMask, then falling back to UNICAST|BROADCAST|MULTICAST,
then UNICAST|BROADCAST, and finally UNICAST.
Modified-by: Michael Brown <mcb30@ipxe.org>
Tested-by: Curtis Larsen <larsen@dixie.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some EFI 1.10 systems (observed on an Apple iMac) do not allow us to
open the device path protocol with an attribute of
EFI_OPEN_PROTOCOL_BY_DRIVER and so we cannot maintain a safe,
long-lived pointer to the device path. Work around this by instead
opening the device path protocol with an attribute of
EFI_OPEN_PROTOCOL_GET_PROTOCOL whenever we need to use it.
Debugged-by: Curtis Larsen <larsen@dixie.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
According to the UEFI specification, the MCastFilter parameter (which
we currently pass as NULL, along with a zero MCastFilterCnt) is
optional only if ResetMCastFilter is true.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The ComponentName and ComponentName2 protocols differ only in the
standard which is used for language name codes.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Try very hard to avoid ever doing something invalid while attempting
to generate a debug message.
Debugged-by: Curtis Larsen <larsen@dixie.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Dump the existing openers of a protocol whenever we are unable to open
a protocol using attributes of BY_DEVICE, EXCLUSIVE, or
BY_CHILD_CONTROLLER.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
efi_file_install() and efi_download_install() are both used to install
onto existing handles. There is therefore no need to allow for each
of their calls to InstallMultipleProtocolInterfaces() to create a new
handle.
By passing the handle directly (rather than a pointer to the handle),
we avoid potential confusion (and erroneous debug message colours).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The EFI headers define EFI_HANDLE as a void pointer, which renders
type checking on anything dealing with EFI handles somewhat useless.
Work around this bizarre sabotage attempt by redefining EFI_HANDLE as
a pointer to an anonymous structure.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Using efi_devpath_text() is marginally more efficient if we already
have the device path protocol available, but the mild increase in
efficiency is not worth compromising the clarity of the pattern:
DBGC ( device, "THING %p %s ...", device, efi_handle_name ( device ) );
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Provide a function efi_handle_name() (as a generalisation of
efi_handle_devpath_text()) which tries various methods to produce a
human-readable name for an EFI handle.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
HII seems to fail on several systems. Since it is non-essential,
treat HII problems as non-fatal.
Debugged-by: Curtis Larsen <larsen@dixie.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Reject network devices which appear to be duplicates of those already
available via a different underlying hardware device. On a Xen PV-HVM
system, this allows us to filter out the emulated PCI NICs (which
would otherwise appear alongside the netfront NICs).
Note that we cannot use the Xen facility to "unplug" the emulated PCI
NICs, since there is no guarantee that the OS we subsequently load
will have a native netfront driver.
We permit devices with the same MAC address if they are attached to
the same underlying hardware device (e.g. VLAN devices).
Inspired-by: Marin Hannache <git@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some EFI 1.10 implementations (observed with a mid-2011 iMac) seem to
fail to fill in the DeviceHandle for our loaded images. It is
plausible that these implementations fill in the DeviceHandle only if
loading the image from a device path (rather than directly from a
memory buffer).
Work around this problem by filling in DeviceHandle if the firmware
leaves it empty.
We cannot sensibly fill in FilePath, because we have no way of knowing
whether or not the firmware will treat this as a pointer to be freed
when the image returns.
Reported-by: Curtis Larsen <larsen@dixie.edu>
Tested-by: Curtis Larsen <larsen@dixie.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
If the StartImage() call returns with no error, then the image must
have been started and returned successfully. It either unloaded
itself, or it intended to remain loaded (e.g. it was a driver). We
therefore do not unload successful images.
If there was an error, we attempt to unload the image. This may not
work. In particular, there is no way to tell whether an error
returned from StartImage() was due to being unable to start the image
(in which case we probably should call UnloadImage()), or due to the
image itself returning an error (in which case we probably should not
call UnloadImage()). We therefore ignore any failures from the
UnloadImage() call itself.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We currently treat network devices as available for use via the SNP
API only if RX queue processing has been frozen. (This is similar in
spirit to the way that RX queue processing is frozen for the network
device currently exposed via the PXE API.)
The default state of a freshly created network device is for the RX
queue to not be frozen, and thus to be unavailable for use via SNP.
This causes problems when devices are added through code paths other
than _efidrv_start() (which explicitly releases devices for use via
SNP).
We don't actually need to freeze RX queue processing, since calls via
the SNP API will always use netdev_poll() rather than net_poll(), and
so will never trigger the RX queue processing code path anyway.
We can therefore simplify the code to use a single global flag to
indicate whether network devices are claimed for use by iPXE or
available for use via SNP. Using a global flag allows the default
state for dynamically created network devices to behave sensibly.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add basic support for Xen PV-HVM domains (detected via the Xen
platform PCI device with IDs 5853:0001), including support for
accessing configuration via XenStore and enumerating devices via
XenBus.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Import selected headers from the xen/include/public directory of the
Xen repository at git://xenbits.xen.org/xen.git
The script ./include/xen/import.pl can be used to automatically import
any required headers and their dependencies (in a similar fashion to
./include/ipxe/efi/import.pl). Trailing whitespace is stripped and an
appropriate FILE_LICENCE declaration is added to each header file.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit 24bbaf6 ("[lotest] Allow loopback testing on shared networks")
introduced a regression in which loopback testing packets would be
accepted from any network device. This produces unexpected results,
such as VLAN loopback testing succeeding even when incorrectly using
the underlying trunk device as either transmitter or receiver.
Fix by discarding any loopback testing packets which arrive on a
network device other than the current loopback testing receiver.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The $(BIN)/version.%.o target will fail if iPXE is built within a
non-git repository, e.g. when the user downloaded and extracted an
archive containing iPXE sources, *and* if any parent directory of the
iPXE sources is a git repository (or even contains a directory named
".git"). This is because git will by default ascend the directory
tree and look for ".git".
The problem typically manifests on source based distributions, see for
example https://bugs.gentoo.org/show_bug.cgi?id=482804
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some switches do not allow an individual link (as defined in IEEE Std
802.3ad-2000 section 43.3.5) to work alone in a link aggregation group
as described in section 43.3.6. This is verified on Dell's
PowerConnect M6220, based on the Broadcom Strata XGS-IV chipset.
Set the LACP_STATE_AGGREGATABLE flag in the actor.state field to
announce link aggregation in the response LACPDU, which will have the
switch enable the link aggregation group and allow frames to pass.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When a 32-bit iPXE binary is running on a system which allocates PCI
memory BARs above 4GB, our PCI subsystem will return the base address
for any such BARs as zero (with a warning message if DEBUG=pci is
enabled). Currently, ioremap() will happily map an address pointing
to the start of physical memory, providing no sensible indication of
failure.
Fix by always returning NULL if we are asked to ioremap() a zero bus
address.
With a totally flat memory model (e.g. under EFI), this provides an
accurate failure indication since no PCI peripheral will be mapped to
the zero bus address.
With the librm memory model, there is the possibility of a spurious
NULL return from ioremap() if the bus address happens to be equal to
virt_offset. Under the current virtual memory map, the NULL virtual
address will always be the start of .textdata, and so this problem
cannot occur; a NULL return from ioremap() will always be an accurate
failure indication.
Debugged-by: Anton D. Kachalov <mouse@yandex-team.ru>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
On some older EFI 1.10 implementations (observed with an old iMac), we
must use the (now obsolete) EFI_CONSOLE_CONTROL_PROTOCOL to switch the
console into text mode.
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The EFI_CONSOLE_CONTROL_PROTOCOL does not exist in the current UEFI
specification, but is required to enable text output on some older EFI
1.10 implementations (observed on an old iMac).
The header is not present in any of the standard include directories,
but can still be found in the EDK2 codebase as part of
EdkCompatibilityPkg.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When building with DEBUG=efi_wrap, print details of calls made by the
loaded image to selected boot services functions.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The EFI FAT filesystem driver has a bug: if a block device contains no
FAT filesystem but does have an EFI_SIMPLE_FILE_SYSTEM_PROTOCOL
instance, the FAT driver will assume that it must have previously
installed the EFI_SIMPLE_FILE_SYSTEM_PROTOCOL. This causes the FAT
driver to claim control of our device, and to refuse to stop driving
it, which prevents us from later uninstalling correctly.
Work around this bug by opening the disk I/O protocol ourselves,
thereby preventing the FAT driver from opening it.
Note that the alternative approach of opening the block I/O protocol
(and thereby in theory preventing DiskIo from attaching to the block
I/O protocol) causes an endless loop of calls to our DRIVER_STOP
method when starting the EFI shell. I have no idea why this is.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When functioning as an EFI driver, drivers can be disconnected and
reconnected multiple times (e.g. via the EFI shell "connect" command,
or by running an executable such as ipxe.efi which will temporarily
disconnect existing drivers).
Minimise surprise by resetting the network device index to zero
whenever the last device is unregistered. This is not foolproof, but
it does handle the common case of having all devices unregistered and
then reregistered in the original order.
Signed-off-by: Michael Brown <mcb30@ipxe.org>