kvm/eventfd: use list_for_each_entry when deassign ioeventfd

Simpify kvm_deassign_ioeventfd_idx to use list_for_each_entry as the
loop just ends at the entry that's found and deleted.

Note, coalesc

kvm/eventfd: use list_for_each_entry when deassign ioeventfd

Simpify kvm_deassign_ioeventfd_idx to use list_for_each_entry as the
loop just ends at the entry that's found and deleted.

Note, coalesced_mmio_ops and ioeventfd_ops are the only instances of
kvm_io_device_ops that implement a destructor, all other callers of
kvm_io_bus_unregister_dev() are unaffected by this change.

Suggested-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230207123713.3905-3-wei.w.wang@intel.com
[sean: call out that only select users implement a destructor]
Signed-off-by: Sean Christopherson <seanjc@google.com>

show more ...

KVM: destruct kvm_io_device while unregistering it from kvm_io_bus

Current usage of kvm_io_device requires users to destruct it with an extra
call of kvm_iodevice_destructor after the device gets un

KVM: destruct kvm_io_device while unregistering it from kvm_io_bus

Current usage of kvm_io_device requires users to destruct it with an extra
call of kvm_iodevice_destructor after the device gets unregistered from
kvm_io_bus. This is not necessary and can cause errors if a user forgot
to make the extra call.

Simplify the usage by combining kvm_iodevice_destructor into
kvm_io_bus_unregister_dev. This reduces LOCs a bit for users and can
avoid the leakage of destructing the device explicitly.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230207123713.3905-2-wei.w.wang@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

show more ...

KVM: Don't kfree(NULL) on kzalloc() failure in kvm_assign_ioeventfd_idx()

On kzalloc() failure, taking the `goto fail` path leads to kfree(NULL).
Such no-op has no use. Move it out.

Signed-off-by:

KVM: Don't kfree(NULL) on kzalloc() failure in kvm_assign_ioeventfd_idx()

On kzalloc() failure, taking the `goto fail` path leads to kfree(NULL).
Such no-op has no use. Move it out.

Signed-off-by: Michal Luczaj <mhal@rbox.co>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20230327175457.735903-1-mhal@rbox.co
Signed-off-by: Sean Christopherson <seanjc@google.com>

show more ...

KVM: x86/ioapic: Resample the pending state of an IRQ when unmasking

KVM irqfd based emulation of level-triggered interrupts doesn't work
quite correctly in some cases, particularly in the case of i

KVM: x86/ioapic: Resample the pending state of an IRQ when unmasking

KVM irqfd based emulation of level-triggered interrupts doesn't work
quite correctly in some cases, particularly in the case of interrupts
that are handled in a Linux guest as oneshot interrupts (IRQF_ONESHOT).
Such an interrupt is acked to the device in its threaded irq handler,
i.e. later than it is acked to the interrupt controller (EOI at the end
of hardirq), not earlier.

Linux keeps such interrupt masked until its threaded handler finishes,
to prevent the EOI from re-asserting an unacknowledged interrupt.
However, with KVM + vfio (or whatever is listening on the resamplefd)
we always notify resamplefd at the EOI, so vfio prematurely unmasks the
host physical IRQ, thus a new physical interrupt is fired in the host.
This extra interrupt in the host is not a problem per se. The problem is
that it is unconditionally queued for injection into the guest, so the
guest sees an extra bogus interrupt. [*]

There are observed at least 2 user-visible issues caused by those
extra erroneous interrupts for a oneshot irq in the guest:

1. System suspend aborted due to a pending wakeup interrupt from
ChromeOS EC (drivers/platform/chrome/cros_ec.c).
2. Annoying "invalid report id data" errors from ELAN0000 touchpad
(drivers/input/mouse/elan_i2c_core.c), flooding the guest dmesg
every time the touchpad is touched.

The core issue here is that by the time when the guest unmasks the IRQ,
the physical IRQ line is no longer asserted (since the guest has
acked the interrupt to the device in the meantime), yet we
unconditionally inject the interrupt queued into the guest by the
previous resampling. So to fix the issue, we need a way to detect that
the IRQ is no longer pending, and cancel the queued interrupt in this
case.

With IOAPIC we are not able to probe the physical IRQ line state
directly (at least not if the underlying physical interrupt controller
is an IOAPIC too), so in this patch we use irqfd resampler for that.
Namely, instead of injecting the queued interrupt, we just notify the
resampler that this interrupt is done. If the IRQ line is actually
already deasserted, we are done. If it is still asserted, a new
interrupt will be shortly triggered through irqfd and injected into the
guest.

In the case if there is no irqfd resampler registered for this IRQ, we
cannot fix the issue, so we keep the existing behavior: immediately
unconditionally inject the queued interrupt.

This patch fixes the issue for x86 IOAPIC only. In the long run, we can
fix it for other irqchips and other architectures too, possibly taking
advantage of reading the physical state of the IRQ line, which is
possible with some other irqchips (e.g. with arm64 GIC, maybe even with
the legacy x86 PIC).

[*] In this description we assume that the interrupt is a physical host
interrupt forwarded to the guest e.g. by vfio. Potentially the same
issue may occur also with a purely virtual interrupt from an
emulated device, e.g. if the guest handles this interrupt, again, as
a oneshot interrupt.

Signed-off-by: Dmytro Maluka <dmy@semihalf.com>
Link: https://lore.kernel.org/kvm/31420943-8c5f-125c-a5ee-d2fde2700083@semihalf.com/
Link: https://lore.kernel.org/lkml/87o7wrug0w.wl-maz@kernel.org/
Message-Id: <20230322204344.50138-3-dmy@semihalf.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

show more ...

KVM: irqfd: Make resampler_list an RCU list

It is useful to be able to do read-only traversal of the list of all the
registered irqfd resamplers without locking the resampler_lock mutex.
In particul

KVM: irqfd: Make resampler_list an RCU list

It is useful to be able to do read-only traversal of the list of all the
registered irqfd resamplers without locking the resampler_lock mutex.
In particular, we are going to traverse it to search for a resampler
registered for the given irq of an irqchip, and that will be done with
an irqchip spinlock (ioapic->lock) held, so it is undesirable to lock a
mutex in this context. So turn this list into an RCU list.

For protecting the read side, reuse kvm->irq_srcu which is already used
for protecting a number of irq related things (kvm->irq_routing,
irqfd->resampler->list, kvm->irq_ack_notifier_list,
kvm->arch.mask_notifier_list).

Signed-off-by: Dmytro Maluka <dmy@semihalf.com>
Message-Id: <20230322204344.50138-2-dmy@semihalf.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

show more ...

KVM: eventfd: Fix false positive RCU usage warning

The splat below can be seen when running kvm-unit-test:

=============================
WARNING: suspicious RCU usage
5.18.0-rc7 #5 T

KVM: eventfd: Fix false positive RCU usage warning

The splat below can be seen when running kvm-unit-test:

=============================
WARNING: suspicious RCU usage
5.18.0-rc7 #5 Tainted: G IOE
-----------------------------
/home/kernel/linux/arch/x86/kvm/../../../virt/kvm/eventfd.c:80 RCU-list traversed in non-reader section!!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
4 locks held by qemu-system-x86/35124:
#0: ffff9725391d80b8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x77/0x710 [kvm]
#1: ffffbd25cfb2a0b8 (&kvm->srcu){....}-{0:0}, at: vcpu_enter_guest+0xdeb/0x1900 [kvm]
#2: ffffbd25cfb2b920 (&kvm->irq_srcu){....}-{0:0}, at: kvm_hv_notify_acked_sint+0x79/0x1e0 [kvm]
#3: ffffbd25cfb2b920 (&kvm->irq_srcu){....}-{0:0}, at: irqfd_resampler_ack+0x5/0x110 [kvm]

stack backtrace:
CPU: 2 PID: 35124 Comm: qemu-system-x86 Tainted: G IOE 5.18.0-rc7 #5
Call Trace:
<TASK>
dump_stack_lvl+0x6c/0x9b
irqfd_resampler_ack+0xfd/0x110 [kvm]
kvm_notify_acked_gsi+0x32/0x90 [kvm]
kvm_hv_notify_acked_sint+0xc5/0x1e0 [kvm]
kvm_hv_set_msr_common+0xec1/0x1160 [kvm]
kvm_set_msr_common+0x7c3/0xf60 [kvm]
vmx_set_msr+0x394/0x1240 [kvm_intel]
kvm_set_msr_ignored_check+0x86/0x200 [kvm]
kvm_emulate_wrmsr+0x4f/0x1f0 [kvm]
vmx_handle_exit+0x6fb/0x7e0 [kvm_intel]
vcpu_enter_guest+0xe5a/0x1900 [kvm]
kvm_arch_vcpu_ioctl_run+0x16e/0xac0 [kvm]
kvm_vcpu_ioctl+0x279/0x710 [kvm]
__x64_sys_ioctl+0x83/0xb0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae

resampler-list is protected by irq_srcu (see kvm_irqfd_assign), so fix
the false positive by using list_for_each_entry_srcu().

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1652950153-12489-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

show more ...

KVM: eventfd: Fix false positive RCU usage warning

Fix the following false positive warning:
=============================
WARNING: suspicious RCU usage
5.16.0-rc4+ #57 Not tainted
-------------

KVM: eventfd: Fix false positive RCU usage warning

Fix the following false positive warning:
=============================
WARNING: suspicious RCU usage
5.16.0-rc4+ #57 Not tainted
-----------------------------
arch/x86/kvm/../../../virt/kvm/eventfd.c:484 RCU-list traversed in non-reader section!!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
3 locks held by fc_vcpu 0/330:
#0: ffff8884835fc0b0 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x88/0x6f0 [kvm]
#1: ffffc90004c0bb68 (&kvm->srcu){....}-{0:0}, at: vcpu_enter_guest+0x600/0x1860 [kvm]
#2: ffffc90004c0c1d0 (&kvm->irq_srcu){....}-{0:0}, at: kvm_notify_acked_irq+0x36/0x180 [kvm]

stack backtrace:
CPU: 26 PID: 330 Comm: fc_vcpu 0 Not tainted 5.16.0-rc4+
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x44/0x57
kvm_notify_acked_gsi+0x6b/0x70 [kvm]
kvm_notify_acked_irq+0x8d/0x180 [kvm]
kvm_ioapic_update_eoi+0x92/0x240 [kvm]
kvm_apic_set_eoi_accelerated+0x2a/0xe0 [kvm]
handle_apic_eoi_induced+0x3d/0x60 [kvm_intel]
vmx_handle_exit+0x19c/0x6a0 [kvm_intel]
vcpu_enter_guest+0x66e/0x1860 [kvm]
kvm_arch_vcpu_ioctl_run+0x438/0x7f0 [kvm]
kvm_vcpu_ioctl+0x38a/0x6f0 [kvm]
__x64_sys_ioctl+0x89/0xc0
do_syscall_64+0x3a/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae

Since kvm_unregister_irq_ack_notifier() does synchronize_srcu(&kvm->irq_srcu),
kvm->irq_ack_notifier_list is protected by kvm->irq_srcu. In fact,
kvm->irq_srcu SRCU read lock is held in kvm_notify_acked_irq(), making it
a false positive warning. So use hlist_for_each_entry_srcu() instead of
hlist_for_each_entry_rcu().

Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
Message-Id: <f98bac4f5052bad2c26df9ad50f7019e40434512.1643265976.git.houwenlong.hwl@antgroup.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

show more ...

kvm: irqfd: avoid update unmodified entries of the routing

All of the irqfds would to be updated when update the irq
routing, it's too expensive if there're too many irqfds.

However we can reduce t

kvm: irqfd: avoid update unmodified entries of the routing

All of the irqfds would to be updated when update the irq
routing, it's too expensive if there're too many irqfds.

However we can reduce the cost by avoid some unnecessary
updates. For irqs of MSI type on X86, the update can be
saved if the msi values are not change.

The vfio migration could receives benefit from this optimi-
zaiton. The test VM has 128 vcpus and 8 VF (with 65 vectors
enabled), so the VM has more than 520 irqfds. We mesure the
cost of the vfio_msix_enable (in QEMU, it would set routing
for each irqfd) for each VF, and we can see the total cost
can be significantly reduced.

Origin Apply this Patch
1st 8 4
2nd 15 5
3rd 22 6
4th 24 6
5th 36 7
6th 44 7
7th 51 8
8th 58 8
Total 258ms 51ms

We're also tring to optimize the QEMU part [1], but it's still
worth to optimize the KVM to gain more benefits.

[1] https://lists.gnu.org/archive/html/qemu-devel/2021-08/msg04215.html

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Message-Id: <20210827080003.2689-1-longpeng2@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

show more ...

KVM: eventfd: Fix false positive RCU usage warning

[ Upstream commit 6a0c61703e3a5d67845a4b275e1d9d7bc1b5aad7 ]

Fix the following false positive warning:
=============================
WARNING: su

KVM: eventfd: Fix false positive RCU usage warning

[ Upstream commit 6a0c61703e3a5d67845a4b275e1d9d7bc1b5aad7 ]

Fix the following false positive warning:
=============================
WARNING: suspicious RCU usage
5.16.0-rc4+ #57 Not tainted
-----------------------------
arch/x86/kvm/../../../virt/kvm/eventfd.c:484 RCU-list traversed in non-reader section!!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
3 locks held by fc_vcpu 0/330:
#0: ffff8884835fc0b0 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x88/0x6f0 [kvm]
#1: ffffc90004c0bb68 (&kvm->srcu){....}-{0:0}, at: vcpu_enter_guest+0x600/0x1860 [kvm]
#2: ffffc90004c0c1d0 (&kvm->irq_srcu){....}-{0:0}, at: kvm_notify_acked_irq+0x36/0x180 [kvm]

stack backtrace:
CPU: 26 PID: 330 Comm: fc_vcpu 0 Not tainted 5.16.0-rc4+
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x44/0x57
kvm_notify_acked_gsi+0x6b/0x70 [kvm]
kvm_notify_acked_irq+0x8d/0x180 [kvm]
kvm_ioapic_update_eoi+0x92/0x240 [kvm]
kvm_apic_set_eoi_accelerated+0x2a/0xe0 [kvm]
handle_apic_eoi_induced+0x3d/0x60 [kvm_intel]
vmx_handle_exit+0x19c/0x6a0 [kvm_intel]
vcpu_enter_guest+0x66e/0x1860 [kvm]
kvm_arch_vcpu_ioctl_run+0x438/0x7f0 [kvm]
kvm_vcpu_ioctl+0x38a/0x6f0 [kvm]
__x64_sys_ioctl+0x89/0xc0
do_syscall_64+0x3a/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae

Since kvm_unregister_irq_ack_notifier() does synchronize_srcu(&kvm->irq_srcu),
kvm->irq_ack_notifier_list is protected by kvm->irq_srcu. In fact,
kvm->irq_srcu SRCU read lock is held in kvm_notify_acked_irq(), making it
a false positive warning. So use hlist_for_each_entry_srcu() instead of
hlist_for_each_entry_rcu().

Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Hou Wenlong <houwenlong93@linux.alibaba.com>
Message-Id: <f98bac4f5052bad2c26df9ad50f7019e40434512.1643265976.git.houwenlong.hwl@antgroup.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

kvm/eventfd: Drain events from eventfd in irqfd_wakeup()

Don't allow the events to accumulate in the eventfd counter, drain them
as they are handled.

Signed-off-by: David Woodhouse <dwmw@amazon.co.

kvm/eventfd: Drain events from eventfd in irqfd_wakeup()

Don't allow the events to accumulate in the eventfd counter, drain them
as they are handled.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20201027135523.646811-4-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

show more ...

kvm/eventfd: Use priority waitqueue to catch events before userspace

As far as I can tell, when we use posted interrupts we silently cut off
the events from userspace, if it's listening on the same

kvm/eventfd: Use priority waitqueue to catch events before userspace

As far as I can tell, when we use posted interrupts we silently cut off
the events from userspace, if it's listening on the same eventfd that
feeds the irqfd.

I like that behaviour. Let's do it all the time, even without posted
interrupts. It makes it much easier to handle IRQ remapping invalidation
without having to constantly add/remove the fd from the userspace poll
set. We can just leave userspace polling on it, and the bypass will...
well... bypass it.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20201026175325.585623-2-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

show more ...

kvm/eventfd: move wildcard calculation outside loop

There is no need to calculate wildcard in each iteration
since wildcard is not changed.

Signed-off-by: Yi Li <yili@winhong.com>
Message-Id: <2020

kvm/eventfd: move wildcard calculation outside loop

There is no need to calculate wildcard in each iteration
since wildcard is not changed.

Signed-off-by: Yi Li <yili@winhong.com>
Message-Id: <20200911055652.3041762-1-yili@winhong.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

show more ...

kvm/eventfd: Use sequence counter with associated spinlock

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not

kvm/eventfd: Use sequence counter with associated spinlock

A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_spinlock_t data type, which allows to associate a
spinlock with the sequence counter. This enables lockdep to verify that
the spinlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lkml.kernel.org/r/20200720155530.1173732-24-a.darwish@linutronix.de

show more ...

KVM: Fix spelling in code comments

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

Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https:/

KVM: Fix spelling in code comments

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

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

show more ...

kvm/eventfd: remove unneeded conversion to bool

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: W

kvm/eventfd: remove unneeded conversion to bool

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

show more ...

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

Based on 1 normalized pattern(s):

this file is free software you can redistribute it and or modify it
under the terms of versi

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

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 <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081207.443595178@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

kvm: Check irqchip mode before assign irqfd

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 sen

kvm: Check irqchip mode before assign irqfd

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 <pbonzini@redhat.com>
CC: Radim Krčmář <rkrcmar@redhat.com>
CC: Alex Williamson <alex.williamson@redhat.com>
CC: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

show more ...

kvm: don't redefine flags as something else

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

kvm: don't redefine flags as something else

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 <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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kvm: Add memcg accounting to KVM allocations

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
alloca

kvm: Add memcg accounting to KVM allocations

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 <bgardon@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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KVM: irqfd: fix race between EPOLLHUP and irq_bypass_register_consumer

A comment warning against this bug is there, but the code is not doing what
the comment says. Therefore it is possible that an

KVM: irqfd: fix race between EPOLLHUP and irq_bypass_register_consumer

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 <syzkaller@googlegroups.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>

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

Syzbot reports crashes in kvm_irqfd_assign(), caused by use-after-free
when kvm_irqfd_assign() and kvm_irqfd_deassign(

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

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 <dvyukov@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Tianyu Lan <tianyu.lan@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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fs: add new vfs_poll and file_can_poll helpers

These abstract out calls to the poll method in preparation for changes
in how we poll.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg

fs: add new vfs_poll and file_can_poll helpers

These abstract out calls to the poll method in preparation for changes
in how we poll.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

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vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAN

vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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annotate poll-related wait keys

__poll_t is also used as wait key in some waitqueues.
Verify that wait_..._poll() gets __poll_t as key and
provide a helper for wakeup functions to get back to
that _

annotate poll-related wait keys

__poll_t is also used as wait key in some waitqueues.
Verify that wait_..._poll() gets __poll_t as key and
provide a helper for wakeup functions to get back to
that __poll_t value.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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anntotate the places where ->poll() return values go

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>