Re: [PATCH] KVM: Add reading critical region for kvm_io_bus_read/write

Avi Kivity
2010-12-06T12:58:14Z

On 12/06/2010 10:44 AM, Sheng Yang wrote:
> Seems we missed it.
>
> Signed-off-by: Sheng Yang<sheng@linux.intel.com>
> ---
> Do we need this, or slot_lock covered this?
>
> virt/kvm/kvm_main.c | 24 ++++++++++++++++--------
> 1 files changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index c4ee364..3e71b91 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2228,28 +2228,36 @@ static void kvm_io_bus_destroy(struct kvm_io_bus *bus)
> int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
> int len, const void *val)
> {
> - int i;
> + int i, idx, r = -EOPNOTSUPP;
> struct kvm_io_bus *bus;
>
> + idx = srcu_read_lock(&kvm->srcu);
> bus = srcu_dereference(kvm->buses[bus_idx],&kvm->srcu);
> for (i = 0; i< bus->dev_count; i++)
> - if (!kvm_iodevice_write(bus->devs[i], addr, len, val))
> - return 0;
> - return -EOPNOTSUPP;
> + if (!kvm_iodevice_write(bus->devs[i], addr, len, val)) {
> + r = 0;
> + break;
> + }
> + srcu_read_unlock(&kvm->srcu, idx);
> + return r;
> }

Isn't this already taken care of by srcu_read_lock() in
vcpu_enter_guest(), just before calling ->handle_exit()?

--
error compiling committee.c: too many arguments to function