[PATCH 13/32] KVM: s390: pci: add basic kvm_zdev structure

[Matthew Rosato <mjrosato@xxxxxxxxxxxxx>]

This structure will be used to carry kvm passthrough information related to
zPCI devices.

Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
---
 arch/s390/include/asm/kvm_pci.h | 29 +++++++++++++++++
 arch/s390/include/asm/pci.h     |  3 ++
 arch/s390/kvm/Makefile          |  2 +-
 arch/s390/kvm/pci.c             | 57 +++++++++++++++++++++++++++++++++
 4 files changed, 90 insertions(+), 1 deletion(-)
 create mode 100644 arch/s390/include/asm/kvm_pci.h
 create mode 100644 arch/s390/kvm/pci.c

diff --git a/arch/s390/include/asm/kvm_pci.h b/arch/s390/include/asm/kvm_pci.h
new file mode 100644
index 000000000000..3e491a39704c
--- /dev/null
+++ b/arch/s390/include/asm/kvm_pci.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * KVM PCI Passthrough for virtual machines on s390
+ *
+ * Copyright IBM Corp. 2021
+ *
+ *    Author(s): Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
+ */
+
+
+#ifndef ASM_KVM_PCI_H
+#define ASM_KVM_PCI_H
+
+#include <linux/types.h>
+#include <linux/kvm_types.h>
+#include <linux/kvm_host.h>
+#include <linux/kvm.h>
+#include <linux/pci.h>
+
+struct kvm_zdev {
+	struct zpci_dev *zdev;
+	struct kvm *kvm;
+};
+
+extern int kvm_s390_pci_dev_open(struct zpci_dev *zdev);
+extern void kvm_s390_pci_dev_release(struct zpci_dev *zdev);
+extern int kvm_s390_pci_attach_kvm(struct zpci_dev *zdev, struct kvm *kvm);
+
+#endif /* ASM_KVM_PCI_H */
diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index 86f43644756d..32810e1ed308 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -97,6 +97,7 @@ struct zpci_bar_struct {
 };
 
 struct s390_domain;
+struct kvm_zdev;
 
 #define ZPCI_FUNCTIONS_PER_BUS 256
 struct zpci_bus {
@@ -190,6 +191,8 @@ struct zpci_dev {
 	struct dentry	*debugfs_dev;
 
 	struct s390_domain *s390_domain; /* s390 IOMMU domain data */
+
+	struct kvm_zdev *kzdev; /* passthrough data */
 };
 
 static inline bool zdev_enabled(struct zpci_dev *zdev)
diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
index b3aaadc60ead..95ea865e5d29 100644
--- a/arch/s390/kvm/Makefile
+++ b/arch/s390/kvm/Makefile
@@ -10,6 +10,6 @@ common-objs = $(KVM)/kvm_main.o $(KVM)/eventfd.o  $(KVM)/async_pf.o \
 ccflags-y := -Ivirt/kvm -Iarch/s390/kvm
 
 kvm-objs := $(common-objs) kvm-s390.o intercept.o interrupt.o priv.o sigp.o
-kvm-objs += diag.o gaccess.o guestdbg.o vsie.o pv.o
+kvm-objs += diag.o gaccess.o guestdbg.o vsie.o pv.o pci.o
 
 obj-$(CONFIG_KVM) += kvm.o
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
new file mode 100644
index 000000000000..ecfc458a5b39
--- /dev/null
+++ b/arch/s390/kvm/pci.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * s390 kvm PCI passthrough support
+ *
+ * Copyright IBM Corp. 2021
+ *
+ *    Author(s): Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
+ */
+
+#include <linux/kvm_host.h>
+#include <linux/pci.h>
+#include <asm/kvm_pci.h>
+
+int kvm_s390_pci_dev_open(struct zpci_dev *zdev)
+{
+	struct kvm_zdev *kzdev;
+
+	if (zdev == NULL)
+		return -ENODEV;
+
+	kzdev = kzalloc(sizeof(struct kvm_zdev), GFP_KERNEL);
+	if (!kzdev)
+		return -ENOMEM;
+
+	kzdev->zdev = zdev;
+	zdev->kzdev = kzdev;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_dev_open);
+
+void kvm_s390_pci_dev_release(struct zpci_dev *zdev)
+{
+	struct kvm_zdev *kzdev;
+
+	if (!zdev || !zdev->kzdev)
+		return;
+
+	kzdev = zdev->kzdev;
+	WARN_ON(kzdev->zdev != zdev);
+	zdev->kzdev = 0;
+	kfree(kzdev);
+
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_dev_release);
+
+int kvm_s390_pci_attach_kvm(struct zpci_dev *zdev, struct kvm *kvm)
+{
+	struct kvm_zdev *kzdev = zdev->kzdev;
+
+	if (!kzdev)
+		return -ENODEV;
+
+	kzdev->kvm = kvm;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_attach_kvm);
-- 
2.27.0