On Fri, 18 Sep 2020 13:02:34 -0400 Tony Krowiak <[email protected]> wrote:
> Attempting to unregister Guest Interruption Subclass (GISC) when the > link between the matrix mdev and KVM has been removed results in the > following: > > "Kernel panic -not syncing: Fatal exception: panic_on_oops" I'm wondering how we get there (why are we unregistering the gisc if the mdev and kvm are not yet linked or are already unlinked?), so I agree that the actual backchain would be helpful here. > > This patch fixes this bug by verifying the matrix mdev and KVM are still > linked prior to unregistering the GISC. > > Signed-off-by: Tony Krowiak <[email protected]> > --- > drivers/s390/crypto/vfio_ap_ops.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/drivers/s390/crypto/vfio_ap_ops.c > b/drivers/s390/crypto/vfio_ap_ops.c > index e0bde8518745..847a88642644 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -119,11 +119,15 @@ static void vfio_ap_wait_for_irqclear(int apqn) > */ > static void vfio_ap_free_aqic_resources(struct vfio_ap_queue *q) > { > - if (q->saved_isc != VFIO_AP_ISC_INVALID && q->matrix_mdev) If checking for ->kvm is the right thing to do, I agree that moving the check here would be easier to read. > - kvm_s390_gisc_unregister(q->matrix_mdev->kvm, q->saved_isc); > - if (q->saved_pfn && q->matrix_mdev) > - vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev), > - &q->saved_pfn, 1); > + if (q->matrix_mdev) { > + if (q->saved_isc != VFIO_AP_ISC_INVALID && q->matrix_mdev->kvm) > + kvm_s390_gisc_unregister(q->matrix_mdev->kvm, > + q->saved_isc); > + if (q->saved_pfn) > + vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev), > + &q->saved_pfn, 1); > + } > + > q->saved_pfn = 0; > q->saved_isc = VFIO_AP_ISC_INVALID; > }
