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

[Avi Kivity <avi@redhat.com>]

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