Re: [PATCH v2 14/30] KVM: s390: pci: add basic kvm_zdev structure

From: Pierre Morel
Date: Tue Jan 18 2022 - 12:30:33 EST




On 1/17/22 17:25, Pierre Morel wrote:


On 1/14/22 21:31, Matthew Rosato wrote:
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             | 46 +++++++++++++++++++++++++++++++++
  4 files changed, 79 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..aafee2976929
--- /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>
+ */
+
+

One blank line too much.

Otherwise, look good to me.

Reviewed-by: Pierre Morel <pmorel@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;
+};
+
+int kvm_s390_pci_dev_open(struct zpci_dev *zdev);
+void kvm_s390_pci_dev_release(struct zpci_dev *zdev);
+void 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 f3cd2da8128c..9b6c657d8d31 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..a26f4fe7b680 100644
--- a/arch/s390/kvm/Makefile
+++ b/arch/s390/kvm/Makefile
@@ -11,5 +11,5 @@ ccflags-y := -Ivirt/kvm -Iarch/s390/kvm
  kvm-objs := $(common-objs) kvm-s390.o intercept.o interrupt.o priv.o sigp.o
  kvm-objs += diag.o gaccess.o guestdbg.o vsie.o pv.o
-
+kvm-$(CONFIG_PCI) += 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..1c33bc7bf2bd
--- /dev/null
+++ b/arch/s390/kvm/pci.c
@@ -0,0 +1,46 @@
+// 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;
+
+    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;
+
+    kzdev = zdev->kzdev;
+    WARN_ON(kzdev->zdev != zdev);
+    zdev->kzdev = 0;
+    kfree(kzdev);
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_dev_release);
+
+void kvm_s390_pci_attach_kvm(struct zpci_dev *zdev, struct kvm *kvm)
+{
+    struct kvm_zdev *kzdev = zdev->kzdev;
+
+    kzdev->kvm = kvm;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_attach_kvm);



Working now on patch 24, I am not sure that this function is necessary.
the only purpose seems to set kzdev->kvm = kvm while we already know kzdev in the caller.



--
Pierre Morel
IBM Lab Boeblingen