tjh.dev
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1443962
3
928
Clone this repository
https://tangled.org/tjh.dev/kernel
https://tangled.org/did:plc:65gha4t3avpfpzmvpbwovss7/kernel
git@gordian.tjh.dev:tjh.dev/kernel
git@gordian.tjh.dev:did:plc:65gha4t3avpfpzmvpbwovss7/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Download tar.gz
Get the show on the road...
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Do a braindump of the way things are supposed to work.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Add the required interfaces to map, unmap and update a VLPI.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Add the required interfaces to schedule a VPE and perform a
VINVALL command.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
When creating a VM, it is very convenient to have an irq domain
containing all the doorbell interrupts associated with that VM
(each interrupt representing a VPE).
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
A long time ago, GITS_CTLR[1] used to be called GITC_CTLR.EnableVLPI.
It has been subsequently deprecated and is now an "Implementation
Defined" bit that may ot may not be set for GICv4. Brilliant.
And the current crop of the FastModel requires that bit for VLPIs
to be enabled. Oh well... Let's set it and find out what breaks.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
While the doorbell interrupts are usually driven by the HW itself,
having a way to trigger them independently has proved to be a
really useful debug feature. As it is actually very little code,
let's add it to the VPE irqchip operations.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
After moving a VPE from a redistributor to another, we're still left
with a potential pending doorbell interrupt on the old redistributor.
That interrupt should be moved to the new one to be either cleared
or take, depending on what the hypervisor wishes to do.
So let's move it right after having execited VMOVP. This doesn't
add much cost in the !DirectLPI case (we trade a DISCARD for a MOVI),
and the cost of the DIRECTLPI case should be minimal (two extra MMIO
accesses).
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
When we don't have the DirectLPI feature, we must work around the
architecture shortcomings to be able to perform the required
maintenance (interrupt masking, clearing and injection).
For this, we create a fake device whose sole purpose is to
provide a way to issue commands as if we were dealing with LPIs
coming from that device (while they actually originate from
the ITS). This fake device doesn't have LPIs allocated to it,
but instead uses the VPE LPIs.
Of course, this could be a real bottleneck, and a naive
implementation would require 6 commands to issue an invalidation.
Instead, let's allocate at least one event per physical CPU
(rounded up to the next power of 2), and opportunistically
map the VPE doorbell to an event. This doorbell will be mapped
until we roll over and need to reallocate this slot.
This ensures that most of the time, we only need 2 commands
to issue an INV, INT or CLEAR, making the performance a lot
better, given that we always issue a CLEAR on entry, and
an INV on each side of a trapped WFI.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
The normal course of action when allocating the ITS' view of a
device is to allocate the corresponding LPIs. But we're about
to introduce devices that borrow their interrupts from
some other entities.
So let's make the allocation optional.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
When masking/unmasking a doorbell interrupt, it is necessary
to issue an invalidation to the corresponding redistributor.
We use the DirectLPI feature by writting directly to the corresponding
redistributor.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
When we're about to run a vcpu, it is crucial that the redistributor
associated with the physical CPU is being told about the new residency.
This is abstracted by hijacking the irq_set_affinity method for the
doorbell interrupt associated with the VPE. It is expected that the
hypervisor will call this method before scheduling the VPE.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
When a guest issues a INVALL command targetting a collection, it must
be translated into a VINVALL for the VPE that has this collection.
This patch implements a hook that offers this functionallity to the
hypervisor.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
README