From 090b7aff27120cdae76a346a70db394844fea598 Mon Sep 17 00:00:00 2001 From: Gregory Haskins Date: Tue, 7 Jul 2009 17:08:44 -0400 Subject: KVM: make io_bus interface more robust Today kvm_io_bus_regsiter_dev() returns void and will internally BUG_ON if it fails. We want to create dynamic MMIO/PIO entries driven from userspace later in the series, so we need to enhance the code to be more robust with the following changes: 1) Add a return value to the registration function 2) Fix up all the callsites to check the return code, handle any failures, and percolate the error up to the caller. 3) Add an unregister function that collapses holes in the array Signed-off-by: Gregory Haskins Acked-by: Michael S. Tsirkin Signed-off-by: Avi Kivity --- virt/kvm/kvm_main.c | 39 ++++++++++++++++++++++++++++++++++----- 1 file changed, 34 insertions(+), 5 deletions(-) (limited to 'virt/kvm/kvm_main.c') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index fc1b58a..9c2fd02 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2533,21 +2533,50 @@ int kvm_io_bus_read(struct kvm_io_bus *bus, gpa_t addr, int len, void *val) return -EOPNOTSUPP; } -void kvm_io_bus_register_dev(struct kvm *kvm, struct kvm_io_bus *bus, +int kvm_io_bus_register_dev(struct kvm *kvm, struct kvm_io_bus *bus, struct kvm_io_device *dev) { + int ret; + down_write(&kvm->slots_lock); - __kvm_io_bus_register_dev(bus, dev); + ret = __kvm_io_bus_register_dev(bus, dev); up_write(&kvm->slots_lock); + + return ret; } /* An unlocked version. Caller must have write lock on slots_lock. */ -void __kvm_io_bus_register_dev(struct kvm_io_bus *bus, - struct kvm_io_device *dev) +int __kvm_io_bus_register_dev(struct kvm_io_bus *bus, + struct kvm_io_device *dev) { - BUG_ON(bus->dev_count > (NR_IOBUS_DEVS-1)); + if (bus->dev_count > NR_IOBUS_DEVS-1) + return -ENOSPC; bus->devs[bus->dev_count++] = dev; + + return 0; +} + +void kvm_io_bus_unregister_dev(struct kvm *kvm, + struct kvm_io_bus *bus, + struct kvm_io_device *dev) +{ + down_write(&kvm->slots_lock); + __kvm_io_bus_unregister_dev(bus, dev); + up_write(&kvm->slots_lock); +} + +/* An unlocked version. Caller must have write lock on slots_lock. */ +void __kvm_io_bus_unregister_dev(struct kvm_io_bus *bus, + struct kvm_io_device *dev) +{ + int i; + + for (i = 0; i < bus->dev_count; i++) + if (bus->devs[i] == dev) { + bus->devs[i] = bus->devs[--bus->dev_count]; + break; + } } static struct notifier_block kvm_cpu_notifier = { -- cgit v1.1