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    SubjectRe: [PATCH v4 5/7] s390: ap: implement PAPQ AQIC interception in kernel
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    On 2/22/19 10:29 AM, Pierre Morel wrote:
    > We register the AP PQAP instruction hook during the open
    > of the mediated device. And unregister it on release.
    >
    > In the AP PQAP instruction hook, if we receive a demand to
    > enable IRQs,
    > - we retrieve the vfio_ap_queue based on the APQN we receive
    > in REG1,
    > - we retrieve the page of the guest address, (NIB), from
    > register REG2
    > - we the mediated device to use the VFIO pinning infratrsucture
    > to pin the page of the guest address,
    > - we retrieve the pointer to KVM to register the guest ISC
    > and retrieve the host ISC
    > - finaly we activate GISA
    >
    > If we receive a demand to disable IRQs,
    > - we deactivate GISA
    > - unregister from the GIB
    > - unping the NIB
    >
    > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
    > ---
    > arch/s390/include/asm/kvm_host.h | 1 +
    > drivers/s390/crypto/ap_bus.h | 1 +
    > drivers/s390/crypto/vfio_ap_ops.c | 199 +++++++++++++++++++++++++++++++++-
    > drivers/s390/crypto/vfio_ap_private.h | 1 +
    > 4 files changed, 199 insertions(+), 3 deletions(-)
    >
    > diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
    > index 49cc8b0..5f3bb8c 100644
    > --- a/arch/s390/include/asm/kvm_host.h
    > +++ b/arch/s390/include/asm/kvm_host.h
    > @@ -720,6 +720,7 @@ struct kvm_s390_cpu_model {
    > struct kvm_s390_crypto {
    > struct kvm_s390_crypto_cb *crycb;
    > int (*pqap_hook)(struct kvm_vcpu *vcpu);
    > + void *vfio_private;
    > __u32 crycbd;
    > __u8 aes_kw;
    > __u8 dea_kw;
    > diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
    > index bfc66e4..323f2aa 100644
    > --- a/drivers/s390/crypto/ap_bus.h
    > +++ b/drivers/s390/crypto/ap_bus.h
    > @@ -43,6 +43,7 @@ static inline int ap_test_bit(unsigned int *ptr, unsigned int nr)
    > #define AP_RESPONSE_BUSY 0x05
    > #define AP_RESPONSE_INVALID_ADDRESS 0x06
    > #define AP_RESPONSE_OTHERWISE_CHANGED 0x07
    > +#define AP_RESPONSE_INVALID_GISA 0x08
    > #define AP_RESPONSE_Q_FULL 0x10
    > #define AP_RESPONSE_NO_PENDING_REPLY 0x10
    > #define AP_RESPONSE_INDEX_TOO_BIG 0x11
    > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
    > index 1b5130a..0196065 100644
    > --- a/drivers/s390/crypto/vfio_ap_ops.c
    > +++ b/drivers/s390/crypto/vfio_ap_ops.c
    > @@ -43,7 +43,7 @@ struct vfio_ap_queue *vfio_ap_get_queue(int apqn, struct list_head *l)
    > return NULL;
    > }
    >
    > -static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q)
    > +int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q)
    > {
    > struct ap_queue_status status;
    > int retry = 20;
    > @@ -75,6 +75,27 @@ static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q)
    > return -EBUSY;
    > }
    >
    > +/**
    > + * vfio_ap_free_irq:
    > + * @q: The vfio_ap_queue
    > + *
    > + * Unpin the guest NIB
    > + * Unregister the ISC from the GIB alert
    > + * Clear the vfio_ap_queue intern fields
    > + */
    > +static void vfio_ap_free_irq(struct vfio_ap_queue *q)
    > +{
    > + if (!q)
    > + return;
    > + if (q->g_pfn)
    > + vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev), &q->g_pfn, 1);
    > + if (q->isc)
    > + kvm_s390_gisc_unregister(q->matrix_mdev->kvm, q->isc);
    > + q->nib = 0;
    > + q->isc = 0;
    > + q->g_pfn = 0;
    > +}
    > +
    > static void vfio_ap_matrix_init(struct ap_config_info *info,
    > struct ap_matrix *matrix)
    > {
    > @@ -97,6 +118,7 @@ static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
    > }
    >
    > INIT_LIST_HEAD(&matrix_mdev->qlist);
    > + matrix_mdev->mdev = mdev;
    > vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
    > mdev_set_drvdata(mdev, matrix_mdev);
    > mutex_lock(&matrix_dev->lock);
    > @@ -109,10 +131,16 @@ static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
    > static int vfio_ap_mdev_remove(struct mdev_device *mdev)
    > {
    > struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
    > + struct vfio_ap_queue *q, *qtmp;
    >
    > if (matrix_mdev->kvm)
    > return -EBUSY;
    >
    > + list_for_each_entry_safe(q, qtmp, &matrix_mdev->qlist, list) {
    > + q->matrix_mdev = NULL;
    > + vfio_ap_mdev_reset_queue(q);
    > + list_move(&q->list, &matrix_dev->free_list);
    > + }
    > mutex_lock(&matrix_dev->lock);
    > list_del(&matrix_mdev->node);
    > mutex_unlock(&matrix_dev->lock);
    > @@ -748,6 +776,161 @@ static const struct attribute_group *vfio_ap_mdev_attr_groups[] = {
    > };
    >
    > /**
    > + * vfio_ap_clrirq: Disable Interruption for a APQN
    > + *
    > + * @dev: the device associated with the ap_queue
    > + * @q: the vfio_ap_queue holding AQIC parameters
    > + *
    > + * Issue the host side PQAP/AQIC
    > + * On success: unpin the NIB saved in *q and unregister from GIB
    > + * interface
    > + *
    > + * Return the ap_queue_status returned by the ap_aqic()
    > + */
    > +static struct ap_queue_status vfio_ap_clrirq(struct vfio_ap_queue *q)
    > +{
    > + struct ap_qirq_ctrl aqic_gisa = {};
    > + struct ap_queue_status status;
    > +
    > + status = ap_aqic(q->apqn, aqic_gisa, NULL);
    > + if (!status.response_code)
    > + vfio_ap_free_irq(q);
    > +
    > + return status;
    > +}
    > +
    > +/**
    > + * vfio_ap_setirq: Enable Interruption for a APQN
    > + *
    > + * @dev: the device associated with the ap_queue
    > + * @q: the vfio_ap_queue holding AQIC parameters
    > + *
    > + * Pin the NIB saved in *q
    > + * Register the guest ISC to GIB interface and retrieve the
    > + * host ISC to issue the host side PQAP/AQIC
    > + *
    > + * Response.status may be set to following Response Code in case of error:
    > + * - AP_RESPONSE_INVALID_ADDRESS: vfio_pin_pages failed
    > + * - AP_RESPONSE_OTHERWISE_CHANGED: Hypervizor GISA internal error
    > + *
    > + * Otherwise return the ap_queue_status returned by the ap_aqic()
    > + */
    > +static struct ap_queue_status vfio_ap_setirq(struct vfio_ap_queue *q)
    > +{
    > + struct ap_qirq_ctrl aqic_gisa = {};
    > + struct ap_queue_status status = {};
    > + struct kvm_s390_gisa *gisa;
    > + struct kvm *kvm;
    > + unsigned long g_pfn, h_nib, h_pfn;
    > + int ret;
    > +
    > + kvm = q->matrix_mdev->kvm;
    > + gisa = kvm->arch.gisa_int.origin;
    > +
    > + g_pfn = q->nib >> PAGE_SHIFT;
    > + ret = vfio_pin_pages(mdev_dev(q->matrix_mdev->mdev), &g_pfn, 1,
    > + IOMMU_READ | IOMMU_WRITE, &h_pfn);
    > + switch (ret) {
    > + case 1:
    > + break;
    > + case -EINVAL:
    > + case -E2BIG:
    > + status.response_code = AP_RESPONSE_INVALID_ADDRESS;
    > + /* Fallthrough */
    > + default:
    > + return status;
    > + }
    > +
    > + h_nib = (h_pfn << PAGE_SHIFT) | (q->nib & ~PAGE_MASK);
    > + aqic_gisa.gisc = q->isc;
    > + aqic_gisa.isc = kvm_s390_gisc_register(kvm, q->isc);
    > + aqic_gisa.ir = 1;
    > + aqic_gisa.gisa = gisa->next_alert >> 4;
    > +
    > + status = ap_aqic(q->apqn, aqic_gisa, (void *)h_nib);
    > + switch (status.response_code) {
    > + case AP_RESPONSE_NORMAL:
    > + if (q->g_pfn)
    > + vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev),
    > + &q->g_pfn, 1);
    > + q->g_pfn = g_pfn;
    > + break;
    > + case AP_RESPONSE_OTHERWISE_CHANGED:
    > + vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev), &g_pfn, 1);
    > + break;
    > + case AP_RESPONSE_INVALID_GISA:
    > + status.response_code = AP_RESPONSE_INVALID_ADDRESS;
    > + default: /* Fall Through */
    > + pr_warn("%s: apqn %04x: response: %02x\n", __func__, q->apqn,
    > + status.response_code);
    > + vfio_ap_free_irq(q);
    > + break;
    > + }
    > +
    > + return status;
    > +}
    > +
    > +/**
    > + * handle_pqap: PQAP instruction callback
    > + *
    > + * @vcpu: The vcpu on which we received the PQAP instruction
    > + *
    > + * Get the general register contents to initialize internal variables.
    > + * REG[0]: APQN
    > + * REG[1]: IR and ISC
    > + * REG[2]: NIB
    > + *
    > + * Response.status may be set to following Response Code:
    > + * - AP_RESPONSE_Q_NOT_AVAIL: if the queue is not available
    > + * - AP_RESPONSE_DECONFIGURED: if the queue is not configured
    > + * - AP_RESPONSE_NORMAL (0) : in case of successs
    > + * Check vfio_ap_setirq() and vfio_ap_clrirq() for other possible RC.
    > + *
    > + * Return 0 if we could handle the request inside KVM.
    > + * otherwise, returns -EOPNOTSUPP to let QEMU handle the fault.
    > + */
    > +static int handle_pqap(struct kvm_vcpu *vcpu)

    Change this function name to handle_pqap_aqic

    > +{
    > + uint64_t status;
    > + uint16_t apqn;
    > + struct vfio_ap_queue *q;
    > + struct ap_queue_status qstatus = {};
    > + struct ap_matrix_mdev *matrix_mdev;
    > +
    > + /* If we do not use the AIV facility just go to userland */
    > + if (!(vcpu->arch.sie_block->eca & ECA_AIV))
    > + return -EOPNOTSUPP;
    > +
    > + apqn = vcpu->run->s.regs.gprs[0] & 0xffff;
    > + matrix_mdev = vcpu->kvm->arch.crypto.vfio_private;
    > + if (!matrix_mdev)
    > + return -EOPNOTSUPP;
    > + q = vfio_ap_get_queue(apqn, &matrix_mdev->qlist);
    > + if (!q) {
    > + qstatus.response_code = AP_RESPONSE_Q_NOT_AVAIL;
    > + goto out;
    > + }
    > +
    > + status = vcpu->run->s.regs.gprs[1];
    > +
    > + /* If IR bit(16) is set we enable the interrupt */
    > + if ((status >> (63 - 16)) & 0x01) {
    > + q->isc = status & 0x07;
    > + q->nib = vcpu->run->s.regs.gprs[2];
    > + qstatus = vfio_ap_setirq(q);
    > + if (qstatus.response_code) {
    > + q->nib = 0;
    > + q->isc = 0;
    > + }
    > + } else
    > + qstatus = vfio_ap_clrirq(q);
    > +
    > +out:
    > + memcpy(&vcpu->run->s.regs.gprs[1], &qstatus, sizeof(qstatus));
    > + return 0;
    > +}

    Add this function:

    static int handle_pqap(struct kvm_vcpu *vcpu)
    {
    int ret;
    uint8_t fc;

    fc = vcpu->run->s.regs.gprs[0] >> 24;
    switch (fc) {
    case 0x03:
    ret = handle_pqap_aqic(vcpu);
    break;
    default:
    ret = -EOPNOTSUPP;
    break;
    }

    return ret;
    }

    > +
    > + /*
    > * vfio_ap_mdev_iommu_notifier: IOMMU notifier callback
    > *
    > * @nb: The notifier block
    > @@ -767,9 +950,10 @@ static int vfio_ap_mdev_iommu_notifier(struct notifier_block *nb,
    >
    > if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) {
    > struct vfio_iommu_type1_dma_unmap *unmap = data;
    > - unsigned long g_pfn = unmap->iova >> PAGE_SHIFT;
    > + unsigned long pfn = unmap->iova >> PAGE_SHIFT;
    >
    > - vfio_unpin_pages(mdev_dev(matrix_mdev->mdev), &g_pfn, 1);
    > + if (matrix_mdev->mdev)
    > + vfio_unpin_pages(mdev_dev(matrix_mdev->mdev), &pfn, 1);
    > return NOTIFY_OK;
    > }
    >
    > @@ -879,6 +1063,11 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev)
    > if (ret)
    > goto err_group;
    >
    > + if (!matrix_mdev->kvm) {
    > + ret = -ENODEV;
    > + goto err_iommu;
    > + }
    > +
    > matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier;
    > events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
    >
    > @@ -887,6 +1076,8 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev)
    > if (ret)
    > goto err_iommu;
    >
    > + matrix_mdev->kvm->arch.crypto.pqap_hook = handle_pqap;
    > + matrix_mdev->kvm->arch.crypto.vfio_private = matrix_mdev;

    I do not see this used anywhere, why do we need it?

    > return 0;
    >
    > err_iommu:
    > @@ -905,6 +1096,8 @@ static void vfio_ap_mdev_release(struct mdev_device *mdev)
    > kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
    >
    > vfio_ap_mdev_reset_queues(mdev);
    > + matrix_mdev->kvm->arch.crypto.pqap_hook = NULL;
    > + matrix_mdev->kvm->arch.crypto.vfio_private = NULL;

    Ditto

    > vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
    > &matrix_mdev->group_notifier);
    > vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
    > diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
    > index e535735..e2fd2c0 100644
    > --- a/drivers/s390/crypto/vfio_ap_private.h
    > +++ b/drivers/s390/crypto/vfio_ap_private.h
    > @@ -94,6 +94,7 @@ struct vfio_ap_queue {
    > struct list_head list;
    > struct ap_matrix_mdev *matrix_mdev;
    > unsigned long nib;
    > + unsigned long g_pfn;

    Can't this be calculated from the nib?

    > int apqn;
    > unsigned char isc;
    > };
    >

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