diff options
| author | Dmytro Maluka <dmy@semihalf.com> | 2023-03-22 21:43:43 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-03-27 10:13:28 -0400 |
| commit | d583fbd7066a2dea43050521a95d9770f7d7593e (patch) | |
| tree | 4ced8cc1d8e18a2af60394d1f9bd7274e9d4d2c3 /include | |
| parent | e5c972c1fadacc858b6a564d056f177275238040 (diff) | |
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/kvm_host.h | 1 | ||||
| -rw-r--r-- | include/linux/kvm_irqfd.h | 2 |
2 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 8ada23756b0e..9f508c8e66e1 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -755,6 +755,7 @@ struct kvm { struct { spinlock_t lock; struct list_head items; + /* resampler_list update side is protected by resampler_lock. */ struct list_head resampler_list; struct mutex resampler_lock; } irqfds; diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h index dac047abdba7..8ad43692e3bb 100644 --- a/include/linux/kvm_irqfd.h +++ b/include/linux/kvm_irqfd.h @@ -31,7 +31,7 @@ struct kvm_kernel_irqfd_resampler { /* * Entry in list of kvm->irqfd.resampler_list. Use for sharing * resamplers among irqfds on the same gsi. - * Accessed and modified under kvm->irqfds.resampler_lock + * RCU list modified under kvm->irqfds.resampler_lock */ struct list_head link; }; |