linux.git/virt/kvm/eventfd.c, branch v5.8

Merge tag 'kvmarm-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2020-06-01T08:26:27+00:00

KVM/arm64 updates for Linux 5.8:

- Move the arch-specific code into arch/arm64/kvm
- Start the post-32bit cleanup
- Cherry-pick a few non-invasive pre-NV patches

KVM: Fix spelling in code comments

2020-05-16T14:05:01+00:00

Fix spelling and typos (e.g., repeated words) in comments.

Signed-off-by: Fuad Tabba 
Signed-off-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20200401140310.29701-1-tabba@google.com

kvm/eventfd: remove unneeded conversion to bool

2020-05-13T16:14:58+00:00

The '==' expression itself is bool, no need to convert it to bool again.
This fixes the following coccicheck warning:

virt/kvm/eventfd.c:724:38-43: WARNING: conversion to bool not needed
here

Signed-off-by: Jason Yan 
Message-Id: <20200420123805.4494-1-yanaijie@huawei.com>
Reviewed-by: Peter Xu 
Signed-off-by: Paolo Bonzini

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504

2019-06-19T15:09:56+00:00

Based on 1 normalized pattern(s):

  this file is free software you can redistribute it and or modify it
  under the terms of version 2 of the gnu general public license as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 51 franklin st fifth floor boston ma 02110
  1301 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 8 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Enrico Weigelt 
Reviewed-by: Kate Stewart 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081207.443595178@linutronix.de
Signed-off-by: Greg Kroah-Hartman

kvm: Check irqchip mode before assign irqfd

2019-05-24T19:27:12+00:00

When assigning kvm irqfd we didn't check the irqchip mode but we allow
KVM_IRQFD to succeed with all the irqchip modes.  However it does not
make much sense to create irqfd even without the kernel chips.  Let's
provide a arch-dependent helper to check whether a specific irqfd is
allowed by the arch.  At least for x86, it should make sense to check:

- when irqchip mode is NONE, all irqfds should be disallowed, and,

- when irqchip mode is SPLIT, irqfds that are with resamplefd should
  be disallowed.

For either of the case, previously we'll silently ignore the irq or
the irq ack event if the irqchip mode is incorrect.  However that can
cause misterious guest behaviors and it can be hard to triage.  Let's
fail KVM_IRQFD even earlier to detect these incorrect configurations.

CC: Paolo Bonzini 
CC: Radim Krčmář 
CC: Alex Williamson 
CC: Eduardo Habkost 
Signed-off-by: Peter Xu 
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini

kvm: don't redefine flags as something else

2019-03-28T16:28:59+00:00

The function irqfd_wakeup() has flags defined as __poll_t and then it
has additional flags which is used for irqflags.

Redefine the inner flags variable as iflags so it does not shadow the
outer flags.

Cc: Paolo Bonzini 
Cc: "Radim Krčmář" 
Cc: kvm@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Paolo Bonzini

kvm: Add memcg accounting to KVM allocations

2019-02-20T21:48:29+00:00

There are many KVM kernel memory allocations which are tied to the life of
the VM process and should be charged to the VM process's cgroup. If the
allocations aren't tied to the process, the OOM killer will not know
that killing the process will free the associated kernel memory.
Add __GFP_ACCOUNT flags to many of the allocations which are not yet being
charged to the VM process's cgroup.

Tested:
	Ran all kvm-unit-tests on a 64 bit Haswell machine, the patch
	introduced no new failures.
	Ran a kernel memory accounting test which creates a VM to touch
	memory and then checks that the kernel memory allocated for the
	process is within certain bounds.
	With this patch we account for much more of the vmalloc and slab memory
	allocated for the VM.

There remain a few allocations which should be charged to the VM's
cgroup but are not. In they include:
        vcpu->run
        kvm->coalesced_mmio_ring
There allocations are unaccounted in this patch because they are mapped
to userspace, and accounting them to a cgroup causes problems. This
should be addressed in a future patch.

Signed-off-by: Ben Gardon 
Reviewed-by: Shakeel Butt 
Signed-off-by: Paolo Bonzini

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2018-07-18T18:08:44+00:00

Pull kvm fixes from Paolo Bonzini:
 "Miscellaneous bugfixes, plus a small patchlet related to Spectre v2"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvmclock: fix TSC calibration for nested guests
  KVM: VMX: Mark VMXArea with revision_id of physical CPU even when eVMCS enabled
  KVM: irqfd: fix race between EPOLLHUP and irq_bypass_register_consumer
  KVM/Eventfd: Avoid crash when assign and deassign specific eventfd in parallel.
  x86/kvmclock: set pvti_cpu0_va after enabling kvmclock
  x86/kvm/Kconfig: Ensure CRYPTO_DEV_CCP_DD state at minimum matches KVM_AMD
  kvm: nVMX: Restore exit qual for VM-entry failure due to MSR loading
  x86/kvm/vmx: don't read current->thread.{fs,gs}base of legacy tasks
  KVM: VMX: support MSR_IA32_ARCH_CAPABILITIES as a feature MSR

KVM: irqfd: fix race between EPOLLHUP and irq_bypass_register_consumer

2018-07-18T09:31:27+00:00

A comment warning against this bug is there, but the code is not doing what
the comment says.  Therefore it is possible that an EPOLLHUP races against
irq_bypass_register_consumer.  The EPOLLHUP handler schedules irqfd_shutdown,
and if that runs soon enough, you get a use-after-free.

Reported-by: syzbot 
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini 
Reviewed-by: David Hildenbrand

KVM/Eventfd: Avoid crash when assign and deassign specific eventfd in parallel.

2018-07-18T09:31:27+00:00

Syzbot reports crashes in kvm_irqfd_assign(), caused by use-after-free
when kvm_irqfd_assign() and kvm_irqfd_deassign() run in parallel
for one specific eventfd. When the assign path hasn't finished but irqfd
has been added to kvm->irqfds.items list, another thead may deassign the
eventfd and free struct kvm_kernel_irqfd(). The assign path then uses
the struct kvm_kernel_irqfd that has been freed by deassign path. To avoid
such issue, keep irqfd under kvm->irq_srcu protection after the irqfd
has been added to kvm->irqfds.items list, and call synchronize_srcu()
in irq_shutdown() to make sure that irqfd has been fully initialized in
the assign path.

Reported-by: Dmitry Vyukov 
Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: Dmitry Vyukov 
Signed-off-by: Tianyu Lan 
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini