Re: [PATCH v5 11/13] KVM: s390: implement mediated device open callback

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 06/05/2018 08:19 AM, Pierre Morel wrote:
On 30/05/2018 16:33, Tony Krowiak wrote:
On 05/24/2018 05:08 AM, Pierre Morel wrote:
On 23/05/2018 16:45, Tony Krowiak wrote:
On 05/16/2018 04:03 AM, Pierre Morel wrote:
On 07/05/2018 17:11, Tony Krowiak wrote:
Implements the open callback on the mediated matrix device.
The function registers a group notifier to receive notification
of the VFIO_GROUP_NOTIFY_SET_KVM event. When notified,
the vfio_ap device driver will get access to the guest's
kvm structure. With access to this structure the driver will:

1. Ensure that only one mediated device is opened for the guest

You should explain why.


2. Configure access to the AP devices for the guest.

...snip...
+void kvm_ap_refcount_inc(struct kvm *kvm)
+{
+    atomic_inc(&kvm->arch.crypto.aprefs);
+}
+EXPORT_SYMBOL(kvm_ap_refcount_inc);
+
+void kvm_ap_refcount_dec(struct kvm *kvm)
+{
+    atomic_dec(&kvm->arch.crypto.aprefs);
+}
+EXPORT_SYMBOL(kvm_ap_refcount_dec);

Why are these functions inside kvm-ap ?
Will anyone use this outer of vfio-ap ?

As I've stated before, I made the choice to contain all interfaces that access KVM in kvm-ap because I don't think it is appropriate for the device driver to have to have "knowledge" of the inner workings of KVM. Why does it matter whether any entity outside of the vfio_ap device driver calls
these functions? I could ask a similar question if the interfaces were
contained in vfio-ap; what if another device driver needs access to these
interfaces?

This is very driver specific and only used during initialization.
It is not a common property of the cryptographic interface.

I really think you should handle this inside the driver.

We are going to have to agree to disagree on this one. Is it not possible that future drivers - e.g., when full virtualization is implemented - will
require access to KVM?

I do not think that an access to KVM is required for full virtualization.

You may be right, but at this point, there is no guarantee. I stand by my
design on this one.








[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux