linux.git/virt/kvm/eventfd.c, branch v4.9

KVM: fix OOPS on flush_work

2016-10-26T12:06:51+00:00

The conversion done by commit 3706feacd007 ("KVM: Remove deprecated
create_singlethread_workqueue") is broken.  It flushes a single work
item &irqfd->shutdown instead of all of them, and even worse if there
is no irqfd on the list then you get a NULL pointer dereference.
Revert the virt/kvm/eventfd.c part of that patch; to avoid the
deprecated function, just allocate our own workqueue---it does
not even have to be unbound---with alloc_workqueue.

Fixes: 3706feacd007
Reviewed-by: Cornelia Huck 
Signed-off-by: Paolo Bonzini

KVM: Remove deprecated create_singlethread_workqueue

2016-09-07T17:34:28+00:00

The workqueue "irqfd_cleanup_wq" queues a single work item
&irqfd->shutdown and hence doesn't require ordering. It is a host-wide
workqueue for issuing deferred shutdown requests aggregated from all
vm* instances. It is not being used on a memory reclaim path.
Hence, it has been converted to use system_wq.
The work item has been flushed in kvm_irqfd_release().

The workqueue "wqueue" queues a single work item &timer->expired
and hence doesn't require ordering. Also, it is not being used on
a memory reclaim path. Hence, it has been converted to use system_wq.

System workqueues have been able to handle high level of concurrency
for a long time now and hence it's not required to have a singlethreaded
workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue
created with create_singlethread_workqueue(), system_wq allows multiple
work items to overlap executions even on the same CPU; however, a
per-cpu workqueue doesn't have any CPU locality or global ordering
guarantee unless the target CPU is explicitly specified and thus the
increase of local concurrency shouldn't make any difference.

Signed-off-by: Bhaktipriya Shridhar 
Signed-off-by: Paolo Bonzini

kvm: Conditionally register IRQ bypass consumer

2016-05-11T20:37:55+00:00

If we don't support a mechanism for bypassing IRQs, don't register as
a consumer.  This eliminates meaningless dev_info()s when the connect
fails between producer and consumer, such as on AMD systems where
kvm_x86_ops->update_pi_irte is not implemented

Signed-off-by: Alex Williamson 
Signed-off-by: Paolo Bonzini

KVM: x86: merge kvm_arch_set_irq with kvm_set_msi_inatomic

2015-11-04T15:24:35+00:00

We do not want to do too much work in atomic context, in particular
not walking all the VCPUs of the virtual machine.  So we want
to distinguish the architecture-specific injection function for irqfd
from kvm_set_msi.  Since it's still empty, reuse the newly added
kvm_arch_set_irq and rename it to kvm_arch_set_irq_inatomic.

Reviewed-by: Radim Krčmář 
Signed-off-by: Paolo Bonzini

kvm/eventfd: add arch-specific set_irq

2015-10-16T08:34:29+00:00

Allow for arch-specific interrupt types to be set.  For that, add
kvm_arch_set_irq() which takes interrupt type-specific action if it
recognizes the interrupt type given, and -EWOULDBLOCK otherwise.

The default implementation always returns -EWOULDBLOCK.

Signed-off-by: Andrey Smetanin 
Reviewed-by: Roman Kagan 
Signed-off-by: Denis V. Lunev 
CC: Vitaly Kuznetsov 
CC: "K. Y. Srinivasan" 
CC: Gleb Natapov 
CC: Paolo Bonzini 
Signed-off-by: Paolo Bonzini

kvm/eventfd: factor out kvm_notify_acked_gsi()

2015-10-16T08:34:29+00:00

Factor out kvm_notify_acked_gsi() helper to iterate over EOI listeners
and notify those matching the given gsi.

It will be reused in the upcoming Hyper-V SynIC implementation.

Signed-off-by: Andrey Smetanin 
Reviewed-by: Roman Kagan 
Signed-off-by: Denis V. Lunev 
CC: Vitaly Kuznetsov 
CC: "K. Y. Srinivasan" 
CC: Gleb Natapov 
CC: Paolo Bonzini 
Signed-off-by: Paolo Bonzini

kvm/eventfd: avoid loop inside irqfd_update()

2015-10-16T08:34:28+00:00

The loop(for) inside irqfd_update() is unnecessary
because any other value for irq_entry.type will just trigger
schedule_work(&irqfd->inject) in irqfd_wakeup.

Signed-off-by: Andrey Smetanin 
Reviewed-by: Roman Kagan 
Signed-off-by: Denis V. Lunev 
CC: Vitaly Kuznetsov 
CC: "K. Y. Srinivasan" 
CC: Gleb Natapov 
CC: Paolo Bonzini 
Signed-off-by: Paolo Bonzini

KVM: Add an arch specific hooks in 'struct kvm_kernel_irqfd'

2015-10-01T13:06:47+00:00

This patch adds an arch specific hooks 'arch_update' in
'struct kvm_kernel_irqfd'. On Intel side, it is used to
update the IRTE when VT-d posted-interrupts is used.

Signed-off-by: Feng Wu 
Reviewed-by: Alex Williamson 
Signed-off-by: Paolo Bonzini

KVM: eventfd: add irq bypass consumer management

2015-10-01T13:06:46+00:00

This patch adds the registration/unregistration of an
irq_bypass_consumer on irqfd assignment/deassignment.

Signed-off-by: Eric Auger 
Signed-off-by: Feng Wu 
Reviewed-by: Alex Williamson 
Signed-off-by: Paolo Bonzini

KVM: introduce kvm_arch functions for IRQ bypass

2015-10-01T13:06:45+00:00

This patch introduces
- kvm_arch_irq_bypass_add_producer
- kvm_arch_irq_bypass_del_producer
- kvm_arch_irq_bypass_stop
- kvm_arch_irq_bypass_start

They make possible to specialize the KVM IRQ bypass consumer in
case CONFIG_KVM_HAVE_IRQ_BYPASS is set.

Signed-off-by: Eric Auger 
[Add weak implementations of the callbacks. - Feng]
Signed-off-by: Feng Wu 
Reviewed-by: Alex Williamson 
Signed-off-by: Paolo Bonzini