In some scenarios, such as buggy guest or incorrect configuration of the
VMM and firmware description data, userspace will detect a memory access
to a portion of the IPA, which is not mapped to any MMIO region.
For this purpose, the appropriate action is to inject an external abort
to the guest. The kernel already has functionality to inject an
external abort, but we need to wire up a signal from user space that
lets user space tell the kernel to do this.
It turns out, we already have the set event functionality which we can
perfectly reuse for this.
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
For a long time, if a guest accessed memory outside of a memslot using
any of the load/store instructions in the architecture which doesn't
supply decoding information in the ESR_EL2 (the ISV bit is not set), the
kernel would print the following message and terminate the VM as a
result of returning -ENOSYS to userspace:
load/store instruction decoding not implemented
The reason behind this message is that KVM assumes that all accesses
outside a memslot is an MMIO access which should be handled by
userspace, and we originally expected to eventually implement some sort
of decoding of load/store instructions where the ISV bit was not set.
However, it turns out that many of the instructions which don't provide
decoding information on abort are not safe to use for MMIO accesses, and
the remaining few that would potentially make sense to use on MMIO
accesses, such as those with register writeback, are not used in
practice. It also turns out that fetching an instruction from guest
memory can be a pretty horrible affair, involving stopping all CPUs on
SMP systems, handling multiple corner cases of address translation in
software, and more. It doesn't appear likely that we'll ever implement
this in the kernel.
What is much more common is that a user has misconfigured his/her guest
and is actually not accessing an MMIO region, but just hitting some
random hole in the IPA space. In this scenario, the error message above
is almost misleading and has led to a great deal of confusion over the
years.
It is, nevertheless, ABI to userspace, and we therefore need to
introduce a new capability that userspace explicitly enables to change
behavior.
This patch introduces KVM_CAP_ARM_NISV_TO_USER (NISV meaning Non-ISV)
which does exactly that, and introduces a new exit reason to report the
event to userspace. User space can then emulate an exception to the
guest, restart the guest, suspend the guest, or take any other
appropriate action as per the policy of the running system.
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
When calling the KVM_SET_GUEST_DEBUG ioctl, userspace might request
the next instruction to be single stepped via the
KVM_GUESTDBG_SINGLESTEP control bit of the kvm_guest_debug structure.
This patch adds the KVM_CAP_PPC_GUEST_DEBUG_SSTEP capability in order
to inform userspace about the state of single stepping support.
We currently don't have support for guest single stepping implemented
in Book3S HV so the capability is only present for Book3S PR and
BookE.
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Hyper-V direct tlb flush function should be enabled for
guest that only uses Hyper-V hypercall. User space
hypervisor(e.g, Qemu) can disable KVM identification in
CPUID and just exposes Hyper-V identification to make
sure the precondition. Add new KVM capability KVM_CAP_
HYPERV_DIRECT_TLBFLUSH for user space to enable Hyper-V
direct tlb function and this function is default to be
disabled in KVM.
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Userspace can use ioctl KVM_SET_MSRS to update a set of MSRs of guest.
This ioctl set specified MSRs one by one. If it fails to set an MSR,
e.g., due to setting reserved bits, the MSR is not supported/emulated by
KVM, etc..., it stops processing the MSR list and returns the number of
MSRs have been set successfully.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- New ITS translation cache
- Allow up to 512 CPUs to be supported with GICv3 (for real this time)
- Now call kvm_arch_vcpu_blocking early in the blocking sequence
- Tidy-up device mappings in S2 when DIC is available
- Clean icache invalidation on VMID rollover
- General cleanup
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Merge tag 'kvmarm-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm updates for 5.4
- New ITS translation cache
- Allow up to 512 CPUs to be supported with GICv3 (for real this time)
- Now call kvm_arch_vcpu_blocking early in the blocking sequence
- Tidy-up device mappings in S2 when DIC is available
- Clean icache invalidation on VMID rollover
- General cleanup
- Some prep for extending the uses of the rmap array
- Various minor fixes
- Commits from the powerpc topic/ppc-kvm branch, which fix a problem
with interrupts arriving after free_irq, causing host hangs and crashes.
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Merge tag 'kvm-ppc-next-5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD
PPC KVM update for 5.4
- Some prep for extending the uses of the rmap array
- Various minor fixes
- Commits from the powerpc topic/ppc-kvm branch, which fix a problem
with interrupts arriving after free_irq, causing host hangs and crashes.
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>
Explicitly specify the valid ranges for size and ar, and reword
buf requirements a bit.
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lkml.kernel.org/r/20190829124746.28665-1-cohuck@redhat.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Rename "access" to "mmio_access" to match the other MMIO cache members
and to make it more obvious that it's tracking the access permissions
for the MMIO cache.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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>
Christoffer Dall