On Thu, Mar 08, 2012 at 10:03:55AM +0800, Amos Kong wrote:
> This patch makes the kvm_io_range array can be resized dynamically.
>
> Signed-off-by: Amos Kong <akong@xxxxxxxxxx>
> ---
> include/linux/kvm_host.h | 5 +++--
> virt/kvm/kvm_main.c | 38 ++++++++++++++++++--------------------
> 2 files changed, 21 insertions(+), 22 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index e42d85a..8a6c1a3 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -67,10 +67,11 @@ struct kvm_io_range {
> struct kvm_io_device *dev;
> };
>
> +#define NR_IOBUS_DEVS 300
> +
> struct kvm_io_bus {
> int dev_count;
> -#define NR_IOBUS_DEVS 300
> - struct kvm_io_range range[NR_IOBUS_DEVS];
> + struct kvm_io_range range[];
> };
>
> enum kvm_bus {
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 94e148e..f6ee1e2 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2393,9 +2393,6 @@ int kvm_io_bus_sort_cmp(const void *p1, const void *p2)
> int kvm_io_bus_insert_dev(struct kvm_io_bus *bus, struct kvm_io_device *dev,
> gpa_t addr, int len)
> {
> - if (bus->dev_count == NR_IOBUS_DEVS)
> - return -ENOSPC;
> -
> bus->range[bus->dev_count++] = (struct kvm_io_range) {
> .addr = addr,
> .len = len,
> @@ -2495,12 +2492,15 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
> struct kvm_io_bus *new_bus, *bus;
>
> bus = kvm->buses[bus_idx];
> - if (bus->dev_count > NR_IOBUS_DEVS-1)
> + if (bus->dev_count > NR_IOBUS_DEVS - 1)
> return -ENOSPC;
>
> - new_bus = kmemdup(bus, sizeof(struct kvm_io_bus), GFP_KERNEL);
> + new_bus = kzalloc(sizeof(*bus) + ((bus->dev_count + 1) *
> + sizeof(struct kvm_io_range)), GFP_KERNEL);
> if (!new_bus)
> return -ENOMEM;
> + memcpy(new_bus, bus, sizeof(*bus) + (bus->dev_count *
> + sizeof(struct kvm_io_range)));
> kvm_io_bus_insert_dev(new_bus, dev, addr, len);
> rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
> synchronize_srcu_expedited(&kvm->srcu);
> @@ -2517,27 +2517,25 @@ int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
> struct kvm_io_bus *new_bus, *bus;
>
> bus = kvm->buses[bus_idx];
> -
> - new_bus = kmemdup(bus, sizeof(*bus), GFP_KERNEL);
> - if (!new_bus)
> - return -ENOMEM;
> -
> r = -ENOENT;
> - for (i = 0; i < new_bus->dev_count; i++)
> - if (new_bus->range[i].dev == dev) {
> + for (i = 0; i < bus->dev_count; i++)
> + if (bus->range[i].dev == dev) {
> r = 0;
> - new_bus->dev_count--;
> - new_bus->range[i] = new_bus->range[new_bus->dev_count];
> - sort(new_bus->range, new_bus->dev_count,
> - sizeof(struct kvm_io_range),
> - kvm_io_bus_sort_cmp, NULL);
> break;
> }
>
> - if (r) {
> - kfree(new_bus);
> + if (r)
> return r;
> - }
> +
> + new_bus = kzalloc(sizeof(*bus) + ((bus->dev_count - 1) *
> + sizeof(struct kvm_io_range)), GFP_KERNEL);
> + if (!new_bus)
> + return -ENOMEM;
> +
> + new_bus->dev_count--;
Was just zeroed above?
> + memcpy(new_bus->range, bus->range, i * sizeof(struct kvm_io_range));
> + memcpy(new_bus->range + i, bus->range + i + 1,
> + (new_bus->dev_count - i) * sizeof(struct kvm_io_range));
Did you mean "i" as an indice for ->range[] ?
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