From 5ea5ca3c2b4bf4090232e18cfc515dcb52f914a6 Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Tue, 7 Feb 2023 20:37:12 +0800 Subject: 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 Reviewed-by: Sean Christopherson Link: https://lore.kernel.org/r/20230207123713.3905-2-wei.w.wang@intel.com Signed-off-by: Sean Christopherson --- virt/kvm/coalesced_mmio.c | 9 ++------- virt/kvm/eventfd.c | 1 - virt/kvm/kvm_main.c | 23 +++++++++++++++-------- 3 files changed, 17 insertions(+), 16 deletions(-) (limited to 'virt') diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c index 5ef88f5a0864..1b90acb6e3fe 100644 --- a/virt/kvm/coalesced_mmio.c +++ b/virt/kvm/coalesced_mmio.c @@ -186,15 +186,10 @@ int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm, coalesced_mmio_in_range(dev, zone->addr, zone->size)) { r = kvm_io_bus_unregister_dev(kvm, zone->pio ? KVM_PIO_BUS : KVM_MMIO_BUS, &dev->dev); - - kvm_iodevice_destructor(&dev->dev); - /* * On failure, unregister destroys all devices on the - * bus _except_ the target device, i.e. coalesced_zones - * has been modified. Bail after destroying the target - * device, there's no need to restart the walk as there - * aren't any zones left. + * bus, including the target device. There's no need + * to restart the walk as there aren't any zones left. */ if (r) break; diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index 7c42441425cf..4d47fffe03d9 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -931,7 +931,6 @@ kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx, bus = kvm_get_bus(kvm, bus_idx); if (bus) bus->ioeventfd_count--; - ioeventfd_release(p); ret = 0; break; } diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 64dd940c549e..b8242607392a 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -5297,6 +5297,12 @@ static void hardware_disable_all(void) } #endif /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */ +static void kvm_iodevice_destructor(struct kvm_io_device *dev) +{ + if (dev->ops->destructor) + dev->ops->destructor(dev); +} + static void kvm_io_bus_destroy(struct kvm_io_bus *bus) { int i; @@ -5520,7 +5526,7 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx, struct kvm_io_device *dev) { - int i, j; + int i; struct kvm_io_bus *new_bus, *bus; lockdep_assert_held(&kvm->slots_lock); @@ -5550,18 +5556,19 @@ int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx, rcu_assign_pointer(kvm->buses[bus_idx], new_bus); synchronize_srcu_expedited(&kvm->srcu); - /* Destroy the old bus _after_ installing the (null) bus. */ + /* + * If NULL bus is installed, destroy the old bus, including all the + * attached devices. Otherwise, destroy the caller's device only. + */ if (!new_bus) { pr_err("kvm: failed to shrink bus, removing it completely\n"); - for (j = 0; j < bus->dev_count; j++) { - if (j == i) - continue; - kvm_iodevice_destructor(bus->range[j].dev); - } + kvm_io_bus_destroy(bus); + return -ENOMEM; } + kvm_iodevice_destructor(dev); kfree(bus); - return new_bus ? 0 : -ENOMEM; + return 0; } struct kvm_io_device *kvm_io_bus_get_dev(struct kvm *kvm, enum kvm_bus bus_idx, -- cgit