On 4/12/22 9:55 AM, Jason Gunthorpe wrote:
On Tue, Apr 12, 2022 at 09:39:44AM -0400, Matthew Rosato wrote:
On 4/8/22 8:45 AM, Jason Gunthorpe wrote:
On Mon, Apr 04, 2022 at 01:43:44PM -0400, Matthew Rosato wrote:
At the time a KVM is associated with a vfio group, s390x zPCI devices
must register a special guest indication (GISA designation) to allow
for the use of interpretive execution facilities. This indication is
used to ensure that only the specified KVM can interact with the device.
Similarly, the indication must be removed once the KVM is no longer
associated with the device.
This patch adds an s390-specific hook to invoke a KVM registration routine
for each device associated with the iommu group; in reality, it will be a
NOP for all but zPCI devices on s390x.
Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
virt/kvm/vfio.c | 35 ++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)
I wonder if this should be done in the vfio_pci side from the existing
kvm notifier
So you mean rather than hooking into virt as I do here, drive something out
of drivers/vfio/vfio.c:vfio_group_set_kvm? Note, the kvm notifier is
handled in vfio, not vfio_pci, so if you want to handle it in vfio_pci I
think we'd need to add a new routine to vfio_device_ops and only define it
vfio_pci for s390
I've been thinking about doing that anyhow, exactly for reasons like
this..
static const struct vfio_device_ops vfio_pci_ops = {
.name = "vfio-pci",
[...]
#ifdef CONFIG_S390
.set_kvm = vfio_pci_zdev_set_kvm,
#endif
};
and something like...
void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)
{
struct vfio_device *vdev;
group->kvm = kvm;
mutex_lock(&group->device_lock);
list_for_each_entry(vdev, &group->device_list, group_next) {
if (vdev->ops->set_kvm)
it->ops->set_kvm(vdev, kvm);
}
mutex_unlock(&group->device_lock);
Almost, the device should be open before calling the callback
And you have to inject a callback during open if the device is opened
after the kvm was set.
But I don't think you need to do this, you can just register a
notifier in zpci when it hooks open_device like everything else,
right?
Yes, that would also work -- I was registering a notifier for a few
prior versions of this series (granted, not from open_device) but got
the impression I should avoid registering a notifier from within
vfio_pci_zdev.
I will go ahead and add register/unregister notifiers hooked from
vfio_pci_core_finish_enable/vfio_pci_core_close_device for zpci (e.g.
vfio_pci_zdev_{open,close}) and use the notifier events to drive the
routines from patch 15.
