Re: [PATCH 1/3] s390x/pci: avoid double enable/disable of aif

[Eric Farman <farman@linux.ibm.com>]

On Tue, 2024-01-16 at 17:31 -0500, Matthew Rosato wrote:
> Use a flag to keep track of whether AIF is currently enabled.  This
> can be
> used to avoid enabling/disabling AIF multiple times as well as to
> determine
> whether or not it should be disabled during reset processing.
> 
> Fixes: d0bc7091c2 ("s390x/pci: enable adapter event notification for
> interpreted devices")
> Reported-by: Cédric Le Goater <clg@redhat.com>
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> ---
>  hw/s390x/s390-pci-kvm.c         | 25 +++++++++++++++++++++++--
>  include/hw/s390x/s390-pci-bus.h |  1 +
>  2 files changed, 24 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/s390x/s390-pci-kvm.c b/hw/s390x/s390-pci-kvm.c
> index ff41e4106d..f7e10cfa72 100644
> --- a/hw/s390x/s390-pci-kvm.c
> +++ b/hw/s390x/s390-pci-kvm.c
> @@ -27,6 +27,7 @@ bool s390_pci_kvm_interp_allowed(void)
>  
>  int s390_pci_kvm_aif_enable(S390PCIBusDevice *pbdev, ZpciFib *fib,
> bool assist)
>  {
> +    int rc;
>      struct kvm_s390_zpci_op args = {
>          .fh = pbdev->fh,
>          .op = KVM_S390_ZPCIOP_REG_AEN,
> @@ -38,15 +39,35 @@ int s390_pci_kvm_aif_enable(S390PCIBusDevice
> *pbdev, ZpciFib *fib, bool assist)
>          .u.reg_aen.flags = (assist) ? 0 :
> KVM_S390_ZPCIOP_REGAEN_HOST
>      };
>  
> -    return kvm_vm_ioctl(kvm_state, KVM_S390_ZPCI_OP, &args);
> +    if (pbdev->aif) {
> +        return -EINVAL;
> +    }
> +
> +    rc = kvm_vm_ioctl(kvm_state, KVM_S390_ZPCI_OP, &args);
> +    if (rc == 0) {
> +        pbdev->aif = true;
> +    }
> +
> +    return rc;
>  }
>  
>  int s390_pci_kvm_aif_disable(S390PCIBusDevice *pbdev)
>  {
> +    int rc;
> +
>      struct kvm_s390_zpci_op args = {
>          .fh = pbdev->fh,
>          .op = KVM_S390_ZPCIOP_DEREG_AEN
>      };
>  
> -    return kvm_vm_ioctl(kvm_state, KVM_S390_ZPCI_OP, &args);
> +    if (!pbdev->aif) {
> +        return -EINVAL;
> +    }
> +
> +    rc = kvm_vm_ioctl(kvm_state, KVM_S390_ZPCI_OP, &args);
> +    if (rc == 0) {
> +        pbev->aif = false;

s/pbev/pbdev/

You fix this in patch 2. :)

With that fixed:

Reviewed-by: Eric Farman <farman@linux.ibm.com>

> +    }
> +
> +    return rc;
>  }
> diff --git a/include/hw/s390x/s390-pci-bus.h b/include/hw/s390x/s390-
> pci-bus.h
> index b1bdbeaeb5..435e788867 100644
> --- a/include/hw/s390x/s390-pci-bus.h
> +++ b/include/hw/s390x/s390-pci-bus.h
> @@ -361,6 +361,7 @@ struct S390PCIBusDevice {
>      bool unplug_requested;
>      bool interp;
>      bool forwarding_assist;
> +    bool aif;
>      QTAILQ_ENTRY(S390PCIBusDevice) link;
>  };
>