On platforms where we expect ACPI tables to exist, use the serial port
defined by the ACPI Serial Port Console Redirection (SPCR) table by
default, falling back to the fixed serial port defined at build time.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The BIOS may provide an ACPI Serial Port Console Redirection (SPCR)
table to describe the serial port to be used for early boot messages.
Add support for parsing the SPCR and instantiating a 16550-based UART.
We do not currently attempt to support other types of UART, since iPXE
does not yet have drivers for other types.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
An ACPI Generic Address Structure (GAS) may be used to describe the
location of a peripheral such as an early boot console. Add the
relevant definitions and provide acpi_ioremap() as a helper function
to map a region described using this structure.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Make the current baud rate (if specified) a property of the UART, to
allow the default_serial_console() function to specify the default
baud rate as well as the default UART device.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use the combined accessors ioread8() and iowrite8() to read and write
16550 UART registers, to allow the decision between using MMIO and
port I/O to be made at runtime.
Minimise the increase in code size for x86 by ignoring the register
shift, since this is essentially used only for non-x86 SoCs.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some devices (such as a 16550 UART) may be accessed via either MMIO or
port I/O. This is currently forced to be a compile-time decision.
For example: we currently access a 16550 UART via port I/O on x86 and
via MMIO on any other platform.
PCI UARTs with MMIO BARs do exist but are not currently supported in
an x86 build of iPXE. Some AWS EC2 systems (observed on a c6i.metal
instance in eu-west-2) provide only a PCI MMIO UART, and it is
therefore currently impossible to get serial output from iPXE on these
instance types.
Add ioread8(), ioread16(), etc accessors that will select between MMIO
and port I/O at the point of use. For non-x86 platforms where we
currently have no port I/O support, these simply become wrappers
around the corresponding readb(), readw(), etc MMIO accessors. On
x86, we use the fairly well-known trick of treating any 16-bit address
(below 64kB) as a port I/O address.
This trick works even in the i386 BIOS build of iPXE (where virtual
addresses are offset from physical addresses by a runtime constant),
since the first 64kB of the virtual address space will correspond to
the iPXE binary itself (along with its uninitialised-data space), and
so must be RAM rather than a valid MMIO address range.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Setting the base address for a 64-bit BAR requires two separate 32-bit
writes to configuration space, and so will necessarily result in the
BAR temporarily holding an invalid partially written address.
Some hypervisors (observed on an AWS EC2 c7a.medium instance in
eu-west-2) will assume that guests will write BAR values only while
decoding is disabled, and may not rebuild MMIO mappings for the guest
if the BAR registers are written while decoding is enabled. The
effect of this is that MMIO accesses are not routed through to the
device even though inspection from within the guest shows that every
single PCI configuration register has the correct value. Writes to
the device will be ignored, and reads will return the all-ones pattern
that typically indicates a nonexistent device.
With the ENA network driver now using low latency transmit queues,
this results in the transmit descriptors being lost (since the MMIO
writes to BAR2 never reach the device), which in turn causes the
device to lock up as soon as the transmit doorbell is rung for the
first time.
Fix by disabling decoding of memory and I/O cycles while setting a BAR
address (as we already do while sizing a BAR), so that the invalid
partial address can never be decoded and so that hypervisors will
rebuild MMIO mappings as expected.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Experiments suggest that the instance type is exposed via the SMBIOS
product name. Include this information within the default output,
since it is often helpful in debugging.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The queue base address is meaningless for a low latency queue, since
the queue entries are written directly to the on-device memory. Any
non-zero queue base address will be safely ignored by the hardware,
but leaves open the possibility that future revisions could treat it
as an error.
Leave this field as zero, to match the behaviour of the Linux driver.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
On some newer (7th and 8th generation) instance types, the 32-bit
build of iPXE cannot access PCI configuration space since the ECAM is
placed outside of the 32-bit address space. The visible symptom is
that iPXE fails to detect any network devices.
The public AMIs are all now built as 64-bit binaries, but there is
nothing that prevents the building and importing of a 32-bit AMI.
There are still potentially valid use cases for 32-bit AMIs (e.g. if
planning to use the AMI only for older instance types), and so we
cannot sensibly prevent this error at build time.
Display the build architecture as part of the AWS EC2 embedded script,
to at least allow for easy identification of this particular failure
mode at run time.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Making images public is blocked by default in new AWS regions. Remove
this block automatically whenever creating a public image.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit a801244 ("[ena] Increase receive ring size to 128 entries")
increased the receive ring size to 128 entries (while leaving the fill
level at 16), since using a smaller receive ring caused unexplained
failures on some instance types.
The original hardware bug that resulted in that commit seems to have
been fixed: experiments suggest that the original failure (observed on
a c6i.large instance in eu-west-2) will no longer reproduce when using
a receive ring containing only 16 entries (as was the case prior to
that commit).
Newer generations of the ENA hardware (observed on an m8i.large
instance in eu-south-2) seem to have a new and exciting hardware bug:
these instance types appear to use a hash of the received packet
header to determine which portion of the (out-of-order) receive ring
to use. If that portion of the ring happens to be empty (e.g. because
only 32 entries of the 128-entry ring are filled at any one time),
then the packet will be silently dropped.
Work around this new hardware bug by reducing the receive ring size
down to the current fill level of 32 entries. This appears to work on
all current instance types (but has not been exhaustively tested).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Avoid running out of transmit descriptors when sending TCP ACKs by
increasing the transmit queue size to match the increased received
fill level.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Experiments suggest that at least some instance types (observed with
c6i.large in eu-west-2) experience high packet drop rates with only 16
receive buffers allocated. Increase the fill level to 32 buffers.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Newer generations of the ENA hardware require the use of low latency
transmit queues, where the submission queues and the initial portion
of the transmitted packet are written to on-device memory via BAR2
instead of being read from host memory.
Detect support for low latency queues and set the placement policy
appropriately. We attempt the use of low latency queues only if the
device reports that it supports inline headers, 128-byte entries, and
two descriptors prior to the inlined header, on the basis that we
don't care about using low latency queues on older versions of the
hardware since those versions will support normal host memory
submission queues anyway.
We reuse the redundant memory allocated for the submission queue as
the bounce buffer for constructing the descriptors and inlined packet
data, since this avoids needing a separate allocation just for the
bounce buffer.
We construct a metadata submission queue entry prior to the actual
submission queue entry, since experimentation suggests that newer
generations of the hardware require this to be present even though it
conveys no information beyond its own existence.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Avoid spurious assertion failures by ensuring that references to
uncompleted transmit buffers are not retained after the device has
been closed.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Newer generations of the ENA hardware require the use of low latency
transmit queues, where the submission queues and the initial portion
of the transmitted packet are written to on-device memory via BAR2
instead of being read from host memory.
Prepare for this by mapping the on-device memory BAR. As with the
register BAR, we may need to steal a base address from the upstream
PCI bridge since the BIOS on some instance types (observed with an
m8i.metal-48xl instance in eu-south-2) will fail to assign an address
to the device.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use pci_bar_set() when we need to set a device base address (on
instance types such as c6i.metal where the BIOS fails to do so), so
that 64-bit BARs will be handled automatically.
This particular issue has so far been observed only on 6th generation
instances. These use 32-bit BARs, and so the lack of support for
handling 64-bit BARs has not caused any observable issue.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Provide pci_bar_set() to handle setting the base address for a
potentially 64-bit BAR, and rewrite pci_bar_size() to correctly handle
sizing of 64-bit BARs.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
RFC 7627 states that renegotiation becomes no longer secure under
various circumstances when the non-extended master secret is used.
The description of the precise set of circumstances is spread across
various points within the document and is not entirely clear.
Avoid a superset of the circumstances in which renegotiation
apparently becomes insecure by refusing renegotiation completely
unless the extended master secret is used.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
RFC 7627 section 5.3 states that the client must abort the handshake
if the server attempts to resume a session where the master secret
calculation method stored in the session does not match the method
used for the connection being resumed.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
RFC 7627 defines the Extended Master Secret (EMS) as an alternative
calculation that uses the digest of all handshake messages rather than
just the client and server random bytes.
Add support for negotiating the Extended Master Secret extension and
performing the relevant calculation of the master secret.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The calculation for the extended master secret as defined in RFC 7627
relies upon the digest of all handshake messages up to and including
the Client Key Exchange.
Facilitate this calculation by generating the master secret only after
sending the Client Key Exchange message.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Experimentation suggests that rearming the interrupt once per observed
completion is not sufficient: we still see occasional delays during
which the hardware fails to write out completions.
As described in commit d2e1e59 ("[gve] Use dummy interrupt to trigger
completion writeback in DQO mode"), there is no documentation around
the precise semantics of the interrupt rearming mechanism, and so
experimentation is the only available guide. Switch to rearming both
TX and RX interrupts unconditionally on every poll, since this
produces better experimental results.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The DQO-QPL operating mode uses registered queue page lists but still
requires the raw DMA address (rather than the linear offset within the
QPL) to be provided in transmit and receive descriptors.
Set the queue page list base device address appropriately.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The hardware reports descriptor and packet completions separately for
the transmit ring. We currently ignore descriptor completions (since
we cannot free up the transmit buffers in the queue page list and
advance the consumer counter until the packet has also completed).
Now that transmit completions are written out immediately (instead of
being delayed until 128 bytes of completions are available), there is
no value in retaining the descriptor completions.
Omit descriptor completions entirely, and reduce the transmit fill
level back down to its original value.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When operating in the DQO operating mode, the device will defer
writing transmit and receive completions until an entire internal
cacheline (128 bytes) is full, or until an associated interrupt is
asserted. Since each receive descriptor is 32 bytes, this will cause
received packets to be effectively delayed until up to three further
packets have arrived. When network traffic volumes are very low (such
as during DHCP, DNS lookups, or TCP handshakes), this typically
induces delays of up to 30 seconds and results in a very poor user
experience.
Work around this hardware problem in the same way as for the Intel
40GbE and 100GbE NICs: by enabling dummy MSI-X interrupts to trick the
hardware into believing that it needs to write out completions to host
memory.
There is no documentation around the interrupt rearming mechanism.
The value written to the interrupt doorbell does not include a
consumer counter value, and so must be relying on some undocumented
ordering constraints. Comments in the Linux driver source suggest
that the authors believe that the device will automatically and
atomically mask an MSI-X interrupt at the point of asserting it, that
any further interrupts arriving before the doorbell is written will be
recorded in the pending bit array, and that writing the doorbell will
therefore immediately assert a new interrupt if needed.
In the absence of any documentation, choose to rearm the interrupt
once per observed completion. This is overkill, but is less impactful
than the alternative of rearming the interrupt unconditionally on
every poll.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Ensure that remainder of completion records are read only after
verifying the generation bit (or sequence number).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use the default dummy MSI-X target address that is now allocated and
configured automatically by pci_msix_enable().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Interrupts as such are not used in iPXE, which operates in polling
mode. However, some network cards (such as the Intel 40GbE and 100GbE
NICs) will defer writing out completions until the point of asserting
an MSI-X interrupt.
From the point of view of the PCI device, asserting an MSI-X interrupt
is just a 32-bit DMA write of an opaque value to an opaque target
address. The PCI device has no know to know whether or not the target
address corresponds to a real APIC.
We can therefore trick the PCI device into believing that it is
asserting an MSI-X interrupt, by configuring it to write an opaque
32-bit value to a dummy target address in host memory. This is
sufficient to trigger the associated write of the completions to host
memory.
Allocate a dummy target address when enabling MSI-X on a PCI device,
and map all interrupts to this target address by default.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Select a preferred operating mode from those advertised as supported
by the device, falling back to the oldest known mode (GQI-QPL) if
no modes are advertised.
Since there are devices in existence that support only QPL addressing,
and since we want to minimise code size, we choose to always use a
single fixed ring buffer even when using raw DMA addressing. Having
paid this penalty, we therefore choose to prefer QPL over RDA since
this allows the (virtual) hardware to minimise the number of page
table manipulations required. We similarly prefer GQI over DQO since
this minimises the amount of work we have to do: in particular, the RX
descriptor ring contents can remain untouched for the lifetime of the
device and refills require only a doorbell write.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add support for the "DQO" out-of-order transmit and receive queue
formats. These are almost entirely different in format and usage (and
even endianness) from the original "GQI" in-order transmit and receive
queues, and arguably should belong to a completely different device
with a different PCI ID. However, Google chose to essentially crowbar
two unrelated device models into the same virtual hardware, and so we
must handle both of these device models within the same driver.
Most of the new code exists solely to handle the differences in
descriptor sizes and formats. Out-of-order completions are handled
via a buffer ID ring (as with other devices supporting out-of-order
completions, such as the Xen, Hyper-V, and Amazon virtual NICs). A
slight twist is that on the transmit datapath (but not the receive
datapath) the Google NIC provides only one completion per packet
instead of one completion per descriptor, and so we must record the
list of chained buffer IDs in a separate array at the time of
transmission.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We cancel any pending transmissions when (re)starting the device since
any transmissions that were initiated before the admin queue reset
will not complete.
The network device core will also cancel any pending transmissions
after the device is closed. If the device is closed with some
transmissions still pending and is then reopened, this will therefore
result in a stale I/O buffer being passed to netdev_tx_complete_err()
when the device is restarted.
This error has not been observed in practice since transmissions
generally complete almost immediately and it is therefore unlikely
that the device will ever be closed with transmissions still pending.
With out-of-order queues, the device seems to delay transmit
completions (with no upper time limit) until a complete batch is
available to be written out as a block of 128 bytes. It is therefore
very likely that the device will be closed with transmissions still
pending.
Fix by ensuring that we have dropped all references to transmit I/O
buffers before returning from gve_close().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Handle async events related to link speed change, link speed config
change, and port phy config changes.
Signed-off-by: Joseph Wong <joseph.wong@broadcom.com>
The descriptors and completions in the DQO operating mode are not the
same sizes as the equivalent structures in the GQI operating mode.
Allow the queue stride size to vary by operating mode (and therefore
to be known only after reading the device descriptor and selecting the
operating mode).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Rename data structures and constants that are specific to the GQI
operating mode, to allow for a cleaner separation from other operating
modes.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
We currently assume that the buffer index is equal to the descriptor
ring index, which is correct only for in-order queues.
Out-of-order queues will include a buffer tag value that is copied
from the descriptor to the completion. Redefine the data buffers as
being indexed by this tag value (rather than by the descriptor ring
index), and add a circular ring buffer to allow for tags to be reused
in whatever order they are released by the hardware.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Raw DMA addressing allows the transmit and receive descriptors to
provide the DMA address of the data buffer directly, without requiring
the use of a pre-registered queue page list. It is modelled in the
device as a magic "raw DMA" queue page list (with QPL ID 0xffffffff)
covering the whole of the DMA address space.
When using raw DMA addressing, the transmit and receive datapaths
could use the normal pattern of mapping I/O buffers directly, and
avoid copying packet data into and out of the fixed queue page list
ring buffer. However, since we must retain support for queue page
list addressing (which requires this additional copying), we choose to
minimise code size by continuing to use the fixed ring buffer even
when using raw DMA addressing.
Add support for using raw DMA addressing by setting the queue page
list base device address appropriately, omitting the commands to
register and unregister the queue page lists, and specifying the raw
DMA QPL ID when creating the TX and RX queues.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow for the existence of a queue page list where the base device
address is non-zero, as will be the case for the raw DMA addressing
(RDA) operating mode.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The "create TX queue" and "create RX queue" commands have fields for
the descriptor and completion ring sizes, which are currently left
unpopulated since they are not required for the original GQI-QPL
operating mode.
Populate these fields, and allow for the possibility that a transmit
completion ring exists (which will be the case when using the DQO
operating mode).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The GVE family supports two incompatible descriptor queue formats:
* GQI: in-order descriptor queues
* DQO: out-of-order descriptor queues
and two addressing modes:
* QPL: pre-registered queue page list addressing
* RDA: raw DMA addressing
All four combinations (GQI-QPL, GQI-RDA, DQO-QPL, and DQO-RDA) are
theoretically supported by the Linux driver, which is essentially the
only public reference provided by Google. The original versions of
the GVE NIC supported only GQI-QPL mode, and so the iPXE driver is
written to target this mode, on the assumption that it would continue
to be supported by all models of the GVE NIC.
This assumption turns out to be incorrect: Google does not deem it
necessary to retain backwards compatibility. Some newer machine types
(such as a4-highgpu-8g) support only the DQO-RDA operating mode.
Add a definition of operating mode, and pass this as an explicit
parameter to the "configure device resources" admin queue command. We
choose a representation that subtracts one from the value passed in
this command, since this happens to allow us to decompose the mode
into two independent bits (one representing the use of DQO descriptor
format, one representing the use of QPL addressing).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The Linux driver occasionally uses the terminology "packet descriptor"
to refer to the portion of the descriptor excluding the buffer
address. This is not a helpful separation, and merely adds
complexity.
Simplify the code by removing this artifical separation.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Provide space for the device to return its list of supported options.
Parse the option list and record the existence of each option in a
support bitmask.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
