If we are in a shared interrupt handler, the called handlers might
indicate it was not their interrupt, so we should not increment the
call counter of these handlers.
Currently, when passing buffers into VirtIOQueues, we use scatter-gather
lists, which contain an internal vector of buffers. This vector is
allocated, filled and the destroy whenever we try to provide buffers
into a virtqueue, which would happen a lot in performance cricital code
(the main transport mechanism for certain paravirtualized devices).
This commit moves it over to using VirtIOQueueChains and building the
chain in place in the VirtIOQueue. Also included are a bunch of fixups
for the VirtIO Console device, making it use an internal VM::RingBuffer
instead.
We want to move this out of the AHCI subsystem into the VM system,
since other parts of the kernel may need to perform scatter-gather IO.
We rename the current VM::ScatterGatherList impl that's used in the
virtio subsystem to VM::ScatterGatherRefList, since its distinguishing
feature from the AHCI scatter-gather list is that it doesn't own its
buffers.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
This command line flag can be used to disable VirtIO support on
certain configurations (native windows) where interfacing with
virtio devices can cause qemu to freeze.
This is a very basic implementation that only requests 4096 bytes
of entropy from the host once, but its still high quality entropy
so it should be a good fix for #4490 (boot-time entropy starvation)
for virtualized environments.
Co-authored-by: Sahan <sahan.h.fernando@gmail.com>
This commit includes a lot of small changes and additions needed to
finalize the base implementation of VirtIOQueues and VirtDevices:
* The device specific driver implementation now has to handle setting
up the queues it needs before letting the base device class know it
finised initialization
* Supplying buffers to VirtQueues is now done via ScatterGatherLists
instead of arbitary buffer pointers - this ensures the pointers are
physical and allows us to follow the specification in regards to the
requirement that individual descriptors must point to physically
contiguous buffers. This can be further improved in the future by
implementating support for the Indirect-Descriptors feature (as
defined by the specification) to reduce descriptor usage for very
fragmented buffers.
* When supplying buffers to a VirtQueue the driver must supply a
(temporarily-)unique token (usually the supplied buffer's virtual
address) to ensure the driver can discern which buffer has finished
processing by the device in the case in which the device does not
offer the F_IN_ORDER feature.
* Device drivers now handle queue updates (supplied buffers being
returned from the device) by implementing a single pure virtual
method instead of setting a seperate callback for each queue
* Two new VirtQueue methods were added to allow the device driver
to either discard or get used/returned buffers from the device by
cleanly removing them off the descriptor chain (This also allows
the VirtQueue implementation to reuse those freed descriptors)
This also includes the necessary changes to the VirtIOConsole
implementation to match these interface changes.
Co-authored-by: Sahan <sahan.h.fernando@gmail.com>
This patch allocates a physical page for each of the virtqueues and
memcpys to it when receiving a buffer to get a physical, aligned
contiguous buffer as required by the virtio specification.
Co-authored-by: Sahan <sahan.h.fernando@gmail.com>
This patch actually enables virtio queues after configuring them
so the device can use them, it also enables interrupt handling in
VirtIODevice so they are not ignored.
Co-authored-by: Sahan <sahan.h.fernando@gmail.com>
Raw pointers were mostly replaced with smart pointers and references
where appropriate based on kling and smartcomputer7's suggestions :)
Co-authored-by: Sahan <sahan.h.fernando@gmail.com>
Based on pull #3236 by tomuta, this is still very much WIP but will
eventually allow us to switch from the considerably slower method of
knocking on port 0xe9 for each character
Co-authored-by: Tom <tomut@yahoo.com>
Co-authored-by: Sahan <sahan.h.fernando@gmail.com>
Based on pull #3236 by tomuta, this adds helper methods for generic
device initialization, and partily-broken virtqueue helper methods
Co-authored-by: Tom <tomut@yahoo.com>
Co-authored-by: Sahan <sahan.h.fernando@gmail.com>
