The EFI SNP/MNP driver wrapper is a trivial layer that exists only to
allow for the separation of "snponly.efi" as a build target. Review
this trivial wrapper and mark it as permitted for UEFI Secure Boot.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The chainloaded-device-only "snponly" driver already drags in support
for driving SNP, NII, and MNP devices, on the basis that the user
generally doesn't care which UEFI API is used and just wants to boot
from the same network device that was used to load iPXE.
The multi-device "snp" driver already drags in support for driving SNP
and NII devices, but does not drag in support for MNP devices.
There is essentially zero code size overhead to dragging in support
for MNP devices, since this support is always present in any iPXE
application build anyway (as part of the code to download
"autoexec.ipxe" prior to installing our own drivers).
Minimise surprise by dragging in support for MNP devices whenever
using the "snp" driver, following the same reasoning used for the
"snponly" driver.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The UEFI model for wireless network boot cannot sensibly be described
without cursing. Commit 758a504 ("[efi] Inhibit calls to Shutdown()
for wireless SNP devices") attempts to work around some of the known
issues.
Experimentation shows that on at least some platforms (observed with a
Lenovo ThinkPad T14s Gen 5) the vendor SNP driver is broken to the
point of being unusable in anything other than the single use case
envisioned by the firwmare authors. Doing almost anything directly
via the SNP protocol interface has a greater than 50% chance of
locking up the system.
Assume, in the absence of any evidence to the contrary so far, that
vendor SNP drivers for wireless network devices are so badly written
as to be unusable. Refuse to even attempt to interact with these
drivers via the SNP or NII protocol interfaces.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow for greater control over the process used to disconnect existing
drivers from a device handle, by converting the "exclude" field from a
simple protocol GUID to a per-driver method.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
UEFI does not provide a direct method to disconnect the existing
driver of a specific protocol from a handle. We currently use
DisconnectController() to remove all drivers from a handle that we
want to drive ourselves, and then rely on recursion in the call to
ConnectController() to reconnect any drivers that did not need to be
disconnected in the first place.
Experience shows that OEMs tend not to ever test the disconnection
code paths in their UEFI drivers, and it is common to find drivers
that refuse to disconnect, fail to close opened handles, fail to
function correctly after reconnection, or lock up the entire system.
Implement a more selective form of disconnection, in which we use
OpenProtocolInformation() to identify the driver associated with a
specific protocol, and then disconnect only that driver.
Perform disconnections in reverse order of attachment priority, since
this is the order likely to minimise the number of cascaded implicit
disconnections.
This allows our MNP driver to avoid performing any disconnections at
all, since it does not require exclusive access to the MNP protocol.
It also avoids performing unnecessary disconnections and reconnections
of unrelated drivers such as the "UEFI WiFi Connection Manager" that
attaches to wireless network interfaces in order to manage wireless
network associations.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Define an ordering for internal EFI drivers on the basis of how close
the driver is to the hardware, and attempt to start drivers in this
order.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We want exclusive access to the network device, both for performance
reasons and because we perform operations such as EAPoL that affect
the entire link. We currently drive the network card via either a
native hardware driver or via the SNP or NII/UNDI interfaces, both of
which grant us this exclusive access.
Add an alternative driver that drives the network card non-exclusively
via the EFI_MANAGED_NETWORK_PROTOCOL interface. This can function as
a fallback for situations where neither SNP nor NII/UNDI interfaces
are functional, and also opens up the possibility of non-destructively
installing a temporary network device over which to download the
autoexec.ipxe script.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
UEFI has the mildly annoying habit of installing copies of the
EFI_SIMPLE_NETWORK_PROTOCOL instance on the IPv4 and IPv6 child device
handles. This can cause iPXE's SNP driver to attempt to bind to a
copy of the EFI_SIMPLE_NETWORK_PROTOCOL that iPXE itself provided on a
different handle.
Fix by refusing to bind to an SNP (or NII) handle if there exists
another instance of the same protocol further up the device path (on
the basis that we always want to bind to the highest possible device).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The raw EFI_HANDLE value is almost never useful to know, and simply
adds noise to the already verbose debug messages. Improve the
legibility of debug messages by using only the name generated by
efi_handle_name().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
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>
Rewrite the SNP NIC driver to use non-blocking and deferrable
transmissions, to provide link status detection, to provide
information about the underlying (PCI) hardware device, and to avoid
unnecessary I/O buffer allocations during receive polling.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
