Simplify core methods in the VirtIO bus handling code by ensuring proper
error propagation. This makes initialization of queues, handling changes
in device configuration, and other core patterns more readable as well.
It also allows us to remove the obnoxious pattern of checking for
boolean "success" and if we get false answer then returning an actual
errno code.
When a device is plugged into the machine (and hence, when
`Device::try_create()` is called), then we attempt to load a driver by
calling that driver's probe function.
At any one given time, there can be an abitrary number of USB drivers in
the system. The way driver mapping works (i.e, a device is inserted, and
a potentially matching driver is probed) requires us to have
instantiated driver objects _before_ a device is inserted. This leaves
us with a slight "chicken and egg" problem. We cannot call the probe
function before the driver is initialised, but we need to know _what_
driver to initialise.
This section is designed to store pointers to functions that are called
during the last stage of the early `_init` sequence in the Kernel. The
accompanying macro in `USBDriver` emits a symbol, based on the driver
name, into this table that is then automatically called.
This way, we enforce a "common" driver model; driver developers are not
only required to write their driver and inherit from `USB::Driver`, but
are also required to have a free floating init function that registers
their driver with the USB Core.
The VirtIO specification defines many types of devices with different
purposes, and it also defines 3 possible transport mediums where devices
could be connected to the host machine.
We only care about the PCIe transport, but this commit puts the actual
foundations for supporting the lean MMIO transport too in the future.
To ensure things are kept abstracted but still functional, the VirtIO
transport code is responsible for what is deemed as related to an actual
transport type - allocation of interrupt handlers and tinkering with low
level transport-related registers, etc.
Instead, use the FixedCharBuffer class to ensure we always use a static
buffer storage for these names. This ensures that if a Process or a
Thread were created, there's a guarantee that setting a new name will
never fail, as only copying of strings should be done to that static
storage.
The limits which are set are 32 characters for processes' names and 64
characters for thread names - this is because threads' names could be
more verbose than processes' names.
Since we never check a kernel process's state like a userland process,
it's possible for a kernel process to ignore the fact that someone is
trying to kill it, and continue running. This is not desireable if we
want to properly shutdown all processes, including Kernel ones.
To ensure actual PS2 code is not tied to the i8042 code, we make them
separated in the following ways:
- PS2KeyboardDevice and PS2MouseDevice classes are no longer inheriting
from the IRQHandler class. Instead we have specific IRQHandler derived
class for the i8042 controller implementation, which is used to ensure
that we don't end up mixing PS2 code with low-level interrupt handling
functionality. In the future this means that we could add a driver for
other PS2 controllers that might have only one interrupt handler but
multiple PS2 devices are attached, therefore, making it easier to put
the right propagation flow from the controller driver all the way to
the HID core code.
- A simple abstraction layer is added between the PS2 command set which
devices could use and the actual implementation low-level commands.
This means that the code in PS2MouseDevice and PS2KeyboardDevice
classes is no longer tied to i8042 implementation-specific commands,
so now these objects could send PS2 commands to their PS2 controller
and get a PS2Response which abstracts the given response too.
The HIDController class is removed and instead adding SerialIOController
class. The HIDController class was a mistake - there's no such thing in
real hardware as host controller only for human interface devices
(VirtIO PCI input controller being the exception here, but it could be
technically treated as serial IO controller too).
Instead, we simply add a new abstraction layer - the SerialIO "bus",
which will hold all the code that is related to serial communications
with other devices. A PS2 controller is simply a serial IO controller,
and the Intel 8042 Controller is simply a specific implementation of a
PS2 controller.
This has KString, KBuffer, DoubleBuffer, KBufferBuilder, IOWindow,
UserOrKernelBuffer and ScopedCritical classes being moved to the
Kernel/Library subdirectory.
Also, move the panic and assertions handling code to that directory.
That's what this class really is; in fact that's what the first line of
the comment says it is.
This commit does not rename the main files, since those will contain
other time-related classes in a little bit.
Extend reserve_irqs, allocate_irq, enable_interrupt and
disable_interrupt API to add MSI support in PCI device.
The current changes only implement single MSI message support.
TODOs have been added to support Multiple MSI Message (MME) support in
the future.
Add a struct named MSIInfo that stores all the relevant MSI
information as a part of PCI DeviceIdentifier struct.
Populate the MSI struct during the PCI device init.
Add reserve_irqs, allocate_irq, enable_interrupt and disable_interrupt
API to a PCI device.
reserve_irqs() can be used by a device driver that would like to
reserve irqs for MSI(x) interrupts. The API returns the type of IRQ
that was reserved by the PCI device. If the PCI device does not support
MSI(x), then it is a noop.
allocate_irq() API can be used to allocate an IRQ at an index. For
MSIx the driver needs to map the vector table into the memory and add
the corresponding IRQ at the given index. This API will return the
actual IRQ that was used so that the driver can use it create interrupt
handler for that IRQ.
{enable, disable}_interrupt API is used to enable or disable a
particular IRQ at the given index. It is a noop for pin-based
interrupts. This could be used by IRQHandler to enable or disable an
interrupt.
Add a struct named MSIxInfo that stores all the relevant MSIx
information as a part of PCI DeviceIdentifier struct.
Populate the MSIx struct during the PCI device init. As the
DeviceIdentifier struct need to populate MSIx info, don't mark
DeviceIdentifier as const in the PCI::Device class.
Rename the initialize method to initialize_virtio_resources so it's
clear what this method is intended for.
To ensure healthier device initialization, we could also return the type
of ErrorOr<void> from this method, so in all overriden instances and in
the original method code, we could leverage TRY() pattern which also
does simplify the code a bit.
To do this we also need to get rid of LockRefPtrs in the USB code as
well.
Most of the SysFS nodes are statically generated during boot and are not
mutated afterwards.
The same goes for general device code - once we generate the appropriate
SysFS nodes, we almost never mutate the node pointers afterwards, making
locking unnecessary.
These were easy to pick-up as these pointers are assigned during the
construction point and are never changed afterwards.
This small change to these pointers will ensure that our code will not
accidentally assign these pointers with a new object which is always a
kind of bug we will want to prevent.
- Instead of taking the first new thread as an out-parameter, we now
bundle the process and its first thread in a struct and use that
as the return value.
- Make all Process factory functions return ErrorOr. Use this to convert
some places to more TRY().
- Drop the "try_" prefix on Process factory functions.
This is an implementation that tries to follow the spec as closely as
possible, and works with Qemu's Intel HDA and some bare metal HDA
controllers out there. Compiling with `INTEL_HDA_DEBUG=on` will provide
a lot of detailed information that could help us getting this to work
on more bare metal controllers as well :^)
Output format is limited to `i16` samples for now.
This configuration exposes a suboptimal mechanism to access other
VirtIO device configurations. It is also the only configuration to use a
zero length for a configuration structure, and specify a valid BAR which
triggered a kernel panic when attaching a virtio-gpu-pci device before
95b15e4901 was applied.
The real solution for that problem is to ignore this configuration type
because we never actually use it. It means that we can VERIFY that all
other configuration types have a valid length, as being expected.
These configurations are simply invalid. Ignoring those allow us to boot
with the virtio-gpu-pci device (in addition to the already supported
virtio-vga PCI device).
This patch switches away from {Nonnull,}LockRefPtr to the non-locking
smart pointers throughout the kernel.
I've looked at the handful of places where these were being persisted
and I don't see any race situations.
Note that the process file descriptor table (Process::m_fds) was already
guarded via MutexProtected.
