Messages in this thread | | | Subject | Re: [PATCH v4 13/15] KVM: s390: configure the guest's AP devices | From | Pierre Morel <> | Date | Mon, 16 Apr 2018 15:05:58 +0200 |
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On 15/04/2018 23:22, Tony Krowiak wrote: > Registers a group notifier during the open of the mediated > matrix device to get information on KVM presence through the > VFIO_GROUP_NOTIFY_SET_KVM event. When notified, the pointer > to the kvm structure is saved inside the mediated matrix > device. Once the VFIO AP device driver has access to KVM, > access to the APs can be configured for the guest. > > Access to APs is configured when the file descriptor for the > mediated matrix device is opened by userspace. The items to be > configured are: > > 1. The ECA.28 bit in the SIE state description determines whether > AP instructions are interpreted by the hardware or intercepted. > The VFIO AP device driver relies interpretive execution of > AP instructions so the ECA.28 bit will be set > > 2. Guest access to AP adapters, usage domains and control domains > is controlled by three bit masks referenced from the > Crypto Control Block (CRYCB) referenced from the guest's SIE state > description: > > * The AP Mask (APM) controls access to the AP adapters. Each bit > in the APM represents an adapter number - from most significant > to least significant bit - from 0 to 255. The bits in the APM > are set according to the adapter numbers assigned to the mediated > matrix device via its 'assign_adapter' sysfs attribute file. > > * The AP Queue (AQM) controls access to the AP queues. Each bit > in the AQM represents an AP queue index - from most significant > to least significant bit - from 0 to 255. A queue index references > a specific domain and is synonymous with the domian number. The > bits in the AQM are set according to the domain numbers assigned > to the mediated matrix device via its 'assign_domain' sysfs > attribute file. > > * The AP Domain Mask (ADM) controls access to the AP control domains. > Each bit in the ADM represents a control domain - from most > significant to least significant bit - from 0-255. The > bits in the ADM are set according to the domain numbers assigned > to the mediated matrix device via its 'assign_control_domain' > sysfs attribute file. > > Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com> > --- > drivers/s390/crypto/vfio_ap_ops.c | 50 +++++++++++++++++++++++++++++++++ > drivers/s390/crypto/vfio_ap_private.h | 2 + > 2 files changed, 52 insertions(+), 0 deletions(-) > > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > index bc2b05e..e3ff5ab 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -53,6 +53,54 @@ static int vfio_ap_mdev_remove(struct mdev_device *mdev) > return 0; > } > > +static int vfio_ap_mdev_group_notifier(struct notifier_block *nb, > + unsigned long action, void *data) > +{ > + struct ap_matrix_mdev *matrix_mdev; > + > + if (action == VFIO_GROUP_NOTIFY_SET_KVM) { > + matrix_mdev = container_of(nb, struct ap_matrix_mdev, > + group_notifier); > + matrix_mdev->kvm = data; > + } > + > + return NOTIFY_OK; > +} > + > +static int vfio_ap_mdev_open(struct mdev_device *mdev) > +{ > + struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev); > + unsigned long events; > + int ret; > + > + matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier; > + events = VFIO_GROUP_NOTIFY_SET_KVM; > + > + ret = vfio_register_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, > + &events, &matrix_mdev->group_notifier); > + if (ret) > + return ret; > + > + ret = kvm_ap_interpret_instructions(matrix_mdev->kvm, true);
Do you need this call ? apie is always enabled in KVM if AP instructions are available.
Setting or not the interpretation is done for the VM in a all. It is not the right place to do it here since open is device dependent.
Or we only have one device in the VM at a time. In this case, shouldn't we make it official by returning -EEXIST for the second call?
> + if (ret) > + return ret; > + > + ret = kvm_ap_configure_matrix(matrix_mdev->kvm, > + matrix_mdev->matrix); > + > + return ret; > +} > + > +static void vfio_ap_mdev_release(struct mdev_device *mdev) > +{ > + struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev); > + > + kvm_ap_deconfigure_matrix(matrix_mdev->kvm); > + kvm_ap_interpret_instructions(matrix_mdev->kvm, false);
This call clears the apie in KVM. This is only OK if we have a single device present until the end of the VM, otherwise AP instructions in the guest will fail after the release until the end of the VM or until a new device is plugged.
> + vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, > + &matrix_mdev->group_notifier); > +} > + > static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf) > { > return sprintf(buf, "%s\n", VFIO_AP_MDEV_NAME_HWVIRT); > @@ -754,6 +802,8 @@ static ssize_t matrix_show(struct device *dev, struct device_attribute *attr, > .mdev_attr_groups = vfio_ap_mdev_attr_groups, > .create = vfio_ap_mdev_create, > .remove = vfio_ap_mdev_remove, > + .open = vfio_ap_mdev_open, > + .release = vfio_ap_mdev_release, > }; > > int vfio_ap_mdev_register(struct ap_matrix *ap_matrix) > diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h > index f248faf..48e2806 100644 > --- a/drivers/s390/crypto/vfio_ap_private.h > +++ b/drivers/s390/crypto/vfio_ap_private.h > @@ -31,6 +31,8 @@ struct ap_matrix { > > struct ap_matrix_mdev { > struct kvm_ap_matrix *matrix; > + struct notifier_block group_notifier; > + struct kvm *kvm; > }; > > static inline struct ap_matrix *to_ap_matrix(struct device *dev)
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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