[RFC 18/19] KVM: s390: New ioctl to configure KVM guest's AP matrix

[Tony Krowiak]

Implements an ioctl to configure the adapters, usage domains
and control domains to which a KVM guest will be granted
access. The ioctl is invoked using the VFIO mediated matrix
device's file descriptor.

Guest access to AP adapters, usage domains and control domains
is controlled by three bit masks referenced from the
guest's SIE state description: The AP Mask (APM) controls
access to the AP adapters; the AP Queue Mask (AQM) controls
access to the AP usage domains; and the AP Domain Mask (ADM)
controls access to the AP control domains. Each bit
in the APM represents an adapter, from left to right,
starting with adapter 0. Each bit in the AQM represents
a usage domain, from left to right, starting with domain 0.
Each bit in the ADM represents a control domain, from left
to right, starting with domain 0.

The APM, AQM and ADM bit masks will be populated from the
bit masks stored in the corresponding mediated matrix device's
sysfs files. The bit masks will also be returned by the ioctl
call to the caller.

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx>
---
 drivers/s390/crypto/vfio_ap_matrix_ops.c |   68 +++++++++++++++++++++++++++++-
 include/uapi/linux/vfio.h                |   20 +++++++++
 2 files changed, 86 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_matrix_ops.c b/drivers/s390/crypto/vfio_ap_matrix_ops.c
index 74ea8db..d81e3ab 100644
--- a/drivers/s390/crypto/vfio_ap_matrix_ops.c
+++ b/drivers/s390/crypto/vfio_ap_matrix_ops.c
@@ -160,8 +160,69 @@ static int ap_matrix_mdev_get_device_info(unsigned long arg)
 	return copy_to_user((void __user *)arg, &info, minsz);
 }
 
-static ssize_t ap_matrix_mdev_ioctl(struct mdev_device *mdev,
-				    unsigned int cmd, unsigned long arg)
+static int ap_matrix_configure(struct mdev_device *mdev)
+{
+	int ret;
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+	ret = ap_config_matrix(matrix_mdev->kvm, &matrix_mdev->masks);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int ap_matrix_copy_to_user(struct mdev_device *mdev,
+				  struct vfio_ap_matrix_config *mcfg,
+				  unsigned long arg)
+{
+	size_t i;
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+
+	for (i = 0; i < AP_MATRIX_MASK_INDICES; i++) {
+		if (i < VFIO_AP_MATRIX_MASK_INDICES) {
+			mcfg->apm[i] = matrix_mdev->masks.apm[i];
+			mcfg->aqm[i] = matrix_mdev->masks.aqm[i];
+			mcfg->adm[i] = matrix_mdev->masks.adm[i];
+		}
+	}
+
+	if (copy_to_user((void __user *)arg, &mcfg, sizeof(mcfg)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static ssize_t ap_matrix_mdev_configure(struct mdev_device *mdev,
+					unsigned long arg)
+{
+	int ret;
+	unsigned long minsz;
+	struct vfio_ap_matrix_config mcfg;
+
+	minsz = offsetofend(struct vfio_ap_matrix_config, adm);
+
+	if (copy_from_user(&mcfg, (void __user *)arg, minsz))
+		return -EFAULT;
+
+	if (mcfg.argsz < minsz) {
+		pr_err("%s: Argument size %u less than min size %li",
+		       VFIO_AP_MATRIX_MODULE_NAME, mcfg.argsz, minsz);
+		return -EINVAL;
+	}
+
+	ret = ap_matrix_configure(mdev);
+	if (ret)
+		return ret;
+
+	ret = ap_matrix_copy_to_user(mdev, &mcfg, arg);
+
+	return 0;
+}
+
+static long ap_matrix_mdev_ioctl(struct mdev_device *mdev,
+				 unsigned int cmd, unsigned long arg)
 {
 	int ret;
 
@@ -169,6 +230,9 @@ static ssize_t ap_matrix_mdev_ioctl(struct mdev_device *mdev,
 	case VFIO_DEVICE_GET_INFO:
 		ret = ap_matrix_mdev_get_device_info(arg);
 		break;
+	case VFIO_AP_MATRIX_CONFIGURE:
+		ret = ap_matrix_mdev_configure(mdev, arg);
+		break;
 	default:
 		pr_err("%s: ioctl command %d is not a supported command",
 		       VFIO_AP_MATRIX_MODULE_NAME, cmd);
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 08f1ab4..2d96c57 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -716,6 +716,26 @@ struct vfio_iommu_spapr_tce_remove {
 };
 #define VFIO_IOMMU_SPAPR_TCE_REMOVE	_IO(VFIO_TYPE, VFIO_BASE + 20)
 
+/**
+ * VFIO_AP_MATRIX_CONFIGURE		_IO(VFIO_TYPE, VFIO_BASE + 21
+ *
+ * Configure the AP matrix for a KVM guest.
+ */
+#define VFIO_AP_MATRIX_CONFIGURE	_IO(VFIO_TYPE, VFIO_BASE + 21)
+
+#define VFIO_AP_MATRIX_MASK_INDICES	4
+#define VFIO_AP_MATTRIX_MASK_BYTES	(VFIO_AP_MATRIX_MASK_INDICES * \
+					 sizeof(__u64))
+#define VFIO_AP_MATRIX_MASK_BITS	(VFIO_AP_MATTRIX_MASK_BYTES * 8)
+
+struct vfio_ap_matrix_config {
+	__u32 argsz;
+	__u32 flags;
+	/* out */
+	__u64 apm[VFIO_AP_MATRIX_MASK_INDICES];
+	__u64 aqm[VFIO_AP_MATRIX_MASK_INDICES];
+	__u64 adm[VFIO_AP_MATRIX_MASK_INDICES];
+};
 /* ***************************************************************** */
 
 #endif /* _UAPIVFIO_H */
-- 
1.7.1