Re: [PATCH v3 7/9] s390: ap: implement PAPQ AQIC interception in kernel

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

 



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@xxxxxxxxxxxxx>
---
  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_ */





[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