Re: [PATCH v2 3/3] vfio: ap: AP Queue Interrupt Control VFIO ioctl calls

From: Cornelia Huck
Date: Thu Nov 29 2018 - 06:37:44 EST


On Thu, 22 Nov 2018 18:11:15 +0100
Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:

> This is the implementation of the VFIO ioctl calls to handle
> the AQIC interception and use GISA to handle interrupts.
>
> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> ---
> drivers/s390/crypto/vfio_ap_ops.c | 110 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 109 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 272ef42..f6e942f 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -895,12 +895,121 @@ static int vfio_ap_mdev_get_device_info(unsigned long arg)
> return copy_to_user((void __user *)arg, &info, minsz);
> }
>
> +static unsigned long vfio_ap_get_nib(struct kvm *kvm, struct vfio_ap_aqic *parm)
> +{
> + struct s390_io_adapter *adapter;
> + struct s390_map_info *map;
> + unsigned long nib;
> + int found = 0;
> +
> + /* find the adapter */
> + if (parm->adapter_id > MAX_S390_IO_ADAPTERS)
> + return 0;
> +
> + adapter = kvm->arch.adapters[parm->adapter_id];
> + if (!adapter)
> + return 0;
> +
> + down_write(&adapter->maps_lock);
> + list_for_each_entry(map, &adapter->maps, list) {
> + if (map->guest_addr == parm->nib) {
> + found = 1;
> + break;
> + }
> + }
> + up_write(&adapter->maps_lock);

Regardless of which user space interface you ultimately use: I think
you should leave poking the adapter handling innards to the adapter
code and instead create and use an interface to look up the mapping
from the guest address.

> +
> + if (!found)
> + return 0;
> +
> + nib = (unsigned long) page_address(map->page);
> + nib += (map->guest_addr & 0x0fff);
> +
> + return nib;
> +}