While parts of the VGIC support a large number of vcpus (we
bravely allow up to 512), other parts are more limited.
One of these limits is visible in the KVM_IRQ_LINE ioctl, which
only allows 256 vcpus to be signalled when using the CPU or PPI
types. Unfortunately, we've cornered ourselves badly by allocating
all the bits in the irq field.
Since the irq_type subfield (8 bit wide) is currently only taking
the values 0, 1 and 2 (and we have been careful not to allow anything
else), let's reduce this field to only 4 bits, and allocate the
remaining 4 bits to a vcpu2_index, which acts as a multiplier:
vcpu_id = 256 * vcpu2_index + vcpu_index
With that, and a new capability (KVM_CAP_ARM_IRQ_LINE_LAYOUT_2)
allowing this to be discovered, it becomes possible to inject
PPIs to up to 4096 vcpus. But please just don't.
Whilst we're there, add a clarification about the use of KVM_IRQ_LINE
on arm, which is not completely conditionned by KVM_CAP_IRQCHIP.
Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
from the massive RST conversion; a few other small fixes as well.
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Merge tag 'docs-5.3-1' of git://git.lwn.net/linux
Pull documentation fixes from Jonathan Corbet:
"This is mostly a set of follow-on fixes from Mauro fixing various
fallout from the massive RST conversion; a few other small fixes as
well"
* tag 'docs-5.3-1' of git://git.lwn.net/linux: (21 commits)
docs: phy: Drop duplicate 'be made'
doc:it_IT: translations in process/
docs/vm: transhuge: fix typo in madvise reference
doc:it_IT: rephrase statement
doc:it_IT: align translation to mainline
docs: load_config.py: ensure subdirs end with "/"
docs: virtual: add it to the documentation body
docs: remove extra conf.py files
docs: load_config.py: avoid needing a conf.py just due to LaTeX docs
scripts/sphinx-pre-install: seek for Noto CJK fonts for pdf output
scripts/sphinx-pre-install: cleanup Gentoo checks
scripts/sphinx-pre-install: fix latexmk dependencies
scripts/sphinx-pre-install: don't use LaTeX with CentOS 7
scripts/sphinx-pre-install: fix script for RHEL/CentOS
docs: conf.py: only use CJK if the font is available
docs: conf.py: add CJK package needed by translations
docs: pdf: add all Documentation/*/index.rst to PDF output
docs: fix broken doc references due to renames
docs: power: add it to to the main documentation index
docs: powerpc: convert docs to ReST and rename to *.rst
...
Renaming docs seems to be en vogue at the moment, so fix on of the
grossly misnamed directories. We usually never use "virtual" as
a shortcut for virtualization in the kernel, but always virt,
as seen in the virt/ top-level directory. Fix up the documentation
to match that.
Fixes: ed16648eb5 ("Move kvm, uml, and lguest subdirectories under a common "virtual" directory, I.E:")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
