lkml.org 
[lkml]   [2019]   [Feb]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    SubjectRe: [PATCH v3 7/9] s390: ap: implement PAPQ AQIC interception in kernel
    From
    Date
    On 2/14/19 8:51 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>
    > ---
    > drivers/s390/crypto/ap_bus.h | 1 +
    > drivers/s390/crypto/vfio_ap_ops.c | 191 +++++++++++++++++++++++++++++++++-
    > drivers/s390/crypto/vfio_ap_private.h | 2 +
    > 3 files changed, 191 insertions(+), 3 deletions(-)
    >
    > 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 6eddc2c..5664cf3 100644
    > --- a/drivers/s390/crypto/vfio_ap_ops.c
    > +++ b/drivers/s390/crypto/vfio_ap_ops.c
    > @@ -77,6 +77,28 @@ static void vfio_ap_put_queue(struct vfio_ap_queue *q)
    > q->dev = NULL;
    > }
    >
    > +/**
    > + * 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)
    > +{
    > + unsigned long pfn = q->nib >> PAGE_SHIFT;
    > +
    > + if (!q)
    > + return;
    > + if (q->nib)
    > + vfio_unpin_pages(mdev_dev(q->matrix->mdev), &pfn, 1);
    > + if (q->isc)
    > + kvm_s390_gisc_unregister(q->matrix->kvm, q->isc);
    > + q->nib = 0;
    > + q->isc = 0;
    > +}
    > +
    > static void vfio_ap_matrix_init(struct ap_config_info *info,
    > struct ap_matrix *matrix)
    > {
    > @@ -98,6 +120,7 @@ static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
    > return -ENOMEM;
    > }
    >
    > + 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);
    > @@ -781,6 +804,156 @@ 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->kvm;
    > + gisa = kvm->arch.gisa_int.origin;
    > +
    > + g_pfn = q->nib >> PAGE_SHIFT;
    > + ret = vfio_pin_pages(mdev_dev(q->matrix->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);
    > + if (status.response_code == AP_RESPONSE_INVALID_GISA) {
    > + status.response_code = AP_RESPONSE_OTHERWISE_CHANGED;
    > + pr_warn("vfio_ap: apqn %02x.%04x: AP_RESPONSE_INVALID_GISA\n",
    > + (q->apqn >> 8) & 0xff, q->apqn & 0xff);
    > + }
    > +
    > + if (status.response_code)
    > + vfio_ap_free_irq(q);
    > +
    > + 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.
    > + */

    This function be nothing more than a switch statement for the
    function code sent with the PQAP instruction. Each case should
    be a call to a appropriate PQAP function handler. This will make
    it much easier to add additional handlers for the 6 other
    PQAP functions if necessary at some time down the road.

    > +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);
    default:
    ret = -EOPNOTSUPP;
    }

    return ret;
    }

    static int handle_pqap_aqic(struct kvm_vcpu *vcpu) {
    > + uint64_t status;
    > + uint16_t apqn;
    struct device *qdev;
    > + 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;
    > + q = vfio_ap_get_queue(apqn);

    Replace with:
    qdev = vfio_ap_get_queue_dev(apqn);

    > + if (!q) {

    Replace with:
    if (!qdev)

    > + qstatus.response_code = AP_RESPONSE_Q_NOT_AVAIL;
    > + goto out;
    > + }
    > +
    > + /* Check if the queue is associated with a guest matrix */

    Add this:
    q = dev_get_drvdata(qdev);

    > + matrix_mdev = q->matrix;
    > + if (!matrix_mdev || !matrix_mdev->kvm) {
    > + qstatus.response_code = AP_RESPONSE_DECONFIGURED

    > + 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));
    > + vfio_ap_put_queue(q);

    Replace with:
    put_device(qdev);

    Can we just do a put_device(qdev) right after we get it since we only
    need it to get the drvdata, or do we need to wait until the other work
    is done?

    > + return 0;
    > +}
    > +
    > + /*
    > * vfio_ap_mdev_iommu_notifier: IOMMU notifier callback
    > *
    > * @nb: The notifier block
    > @@ -802,7 +975,9 @@ static int vfio_ap_mdev_iommu_notifier(struct notifier_block *nb,
    > struct vfio_iommu_type1_dma_unmap *unmap = data;
    > unsigned long g_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),
    > + &g_pfn, 1);
    > return NOTIFY_OK;
    > }
    >
    > @@ -877,11 +1052,15 @@ static int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,
    > unsigned int retry)
    > {
    > struct ap_queue_status status;
    > + struct vfio_ap_queue *q;
    > +
    > + q = vfio_ap_get_queue(AP_MKQID(apid, apqi));
    >
    > do {
    > status = ap_zapq(AP_MKQID(apid, apqi));
    > switch (status.response_code) {
    > case AP_RESPONSE_NORMAL:
    > + vfio_ap_free_irq(q);
    > return 0;
    > case AP_RESPONSE_RESET_IN_PROGRESS:
    > case AP_RESPONSE_BUSY:
    > @@ -999,6 +1178,11 @@ 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;
    >
    > @@ -1011,6 +1195,7 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev)
    > if (ret)
    > goto err_associate;
    >
    > + matrix_mdev->kvm->arch.crypto.pqap_hook = handle_pqap;
    > return 0;
    >
    > err_associate:
    > @@ -1031,12 +1216,12 @@ static void vfio_ap_mdev_release(struct mdev_device *mdev)
    > if (matrix_mdev->kvm)
    > kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
    >
    > - vfio_ap_mdev_reset_queues(mdev);
    > + matrix_mdev->kvm->arch.crypto.pqap_hook = NULL;
    > + vfio_ap_dissociate_queues(matrix_mdev);
    > vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
    > &matrix_mdev->group_notifier);
    > vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
    > &matrix_mdev->iommu_notifier);
    > - vfio_ap_dissociate_queues(matrix_mdev);
    > matrix_mdev->kvm = NULL;
    > module_put(THIS_MODULE);
    > }
    > diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
    > index 2781720..16c99e9 100644
    > --- a/drivers/s390/crypto/vfio_ap_private.h
    > +++ b/drivers/s390/crypto/vfio_ap_private.h
    > @@ -92,5 +92,7 @@ struct vfio_ap_queue {
    > struct device *dev;
    > int apqn;
    > struct ap_matrix_mdev *matrix;
    > + unsigned long nib;
    > + unsigned char isc;

    > };
    > #endif /* _VFIO_AP_PRIVATE_H_ */
    >

    \
     
     \ /
      Last update: 2019-02-16 00:12    [W:5.510 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site