[PATCH v5 19/21] KVM: s390: add KVM_S390_ZPCI_OP to manage guest zPCI devices

Matthew Rosato
2022-04-04T21:23:16Z

The KVM_S390_ZPCI_OP ioctl provides a mechanism for managing
hardware-assisted virtualization features for s390X zPCI passthrough.
Add the first 2 operations, which can be used to enable/disable
the specified device for Adapter Event Notification interpretation.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
Documentation/virt/kvm/api.rst | 45 +++++++++++++++++++++++
arch/s390/kvm/kvm-s390.c | 23 ++++++++++++
arch/s390/kvm/pci.c | 65 ++++++++++++++++++++++++++++++++++
arch/s390/kvm/pci.h | 2 ++
include/uapi/linux/kvm.h | 31 ++++++++++++++++
5 files changed, 166 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index d13fa6600467..474f502c2ea0 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -5645,6 +5645,51 @@ enabled with ``arch_prctl()``, but this may change in the future.
The offsets of the state save areas in struct kvm_xsave follow the contents
of CPUID leaf 0xD on the host.

+4.135 KVM_S390_ZPCI_OP
+--------------------
+
+:Capability: KVM_CAP_S390_ZPCI_OP
+:Architectures: s390
+:Type: vcpu ioctl
+:Parameters: struct kvm_s390_zpci_op (in)
+:Returns: 0 on success, <0 on error
+
+Used to manage hardware-assisted virtualization features for zPCI devices.
+
+Parameters are specified via the following structure::
+
+ struct kvm_s390_zpci_op {
+ /* in */
+ __u32 fh; /* target device */
+ __u8 op; /* operation to perform */
+ __u8 pad[3];
+ union {
+ /* for KVM_S390_ZPCIOP_REG_AEN */
+ struct {
+ __u64 ibv; /* Guest addr of interrupt bit vector */
+ __u64 sb; /* Guest addr of summary bit */
+ __u32 flags;
+ __u32 noi; /* Number of interrupts */
+ __u8 isc; /* Guest interrupt subclass */
+ __u8 sbo; /* Offset of guest summary bit vector */
+ __u16 pad;
+ } reg_aen;
+ __u64 reserved[8];
+ } u;
+ };
+
+The type of operation is specified in the "op" field.
+KVM_S390_ZPCIOP_REG_AEN is used to register the VM for adapter event
+notification interpretation, which will allow firmware delivery of adapter
+events directly to the vm, with KVM providing a backup delivery mechanism;
+KVM_S390_ZPCIOP_DEREG_AEN is used to subsequently disable interpretation of
+adapter event notifications.
+
+The target zPCI function must also be specified via the "fh" field. For the
+KVM_S390_ZPCIOP_REG_AEN operation, additional information to establish firmware
+delivery must be provided via the "reg_aen" struct.
+
+The "reserved" field is meant for future extensions.

5. The kvm_run structure
========================
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 704d85214f4f..65a53e22f686 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -616,6 +616,12 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_S390_PROTECTED:
r = is_prot_virt_host();
break;
+ case KVM_CAP_S390_ZPCI_OP:
+ if (kvm_s390_pci_interp_allowed())
+ r = 1;
+ else
+ r = 0;
+ break;
default:
r = 0;
}
@@ -2621,6 +2627,23 @@ long kvm_arch_vm_ioctl(struct file *filp,
r = -EFAULT;
break;
}
+ case KVM_S390_ZPCI_OP: {
+ struct kvm_s390_zpci_op args;
+
+ r = -EINVAL;
+ if (!IS_ENABLED(CONFIG_VFIO_PCI))
+ break;
+ if (copy_from_user(&args, argp, sizeof(args))) {
+ r = -EFAULT;
+ break;
+ }
+ r = kvm_s390_pci_zpci_op(kvm, &args);
+ if (r)
+ break;
+ if (copy_to_user(argp, &args, sizeof(args)))
+ r = -EFAULT;
+ break;
+ }
default:
r = -ENOTTY;
}
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index 66565f5f3f43..d941657bcb39 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -588,6 +588,71 @@ void kvm_s390_pci_clear_list(struct kvm *kvm)
unregister_kvm(kzdev->zdev);
}

+static struct kvm_zdev *get_kzdev_by_fh(struct kvm *kvm, u32 fh)
+{
+ struct kvm_zdev *kzdev, *retval = NULL;
+
+ spin_lock(&kvm->arch.kzdev_list_lock);
+ list_for_each_entry(kzdev, &kvm->arch.kzdev_list, entry) {
+ if (kzdev->zdev->fh == fh) {
+ retval = kzdev;
+ break;
+ }
+ }
+ spin_unlock(&kvm->arch.kzdev_list_lock);
+
+ return retval;
+}
+
+static int kvm_s390_pci_zpci_reg_aen(struct zpci_dev *zdev,
+ struct kvm_s390_zpci_op *args)
+{
+ struct zpci_fib fib = {};
+
+ fib.fmt0.aibv = args->u.reg_aen.ibv;
+ fib.fmt0.isc = args->u.reg_aen.isc;
+ fib.fmt0.noi = args->u.reg_aen.noi;
+ if (args->u.reg_aen.sb != 0) {
+ fib.fmt0.aisb = args->u.reg_aen.sb;
+ fib.fmt0.aisbo = args->u.reg_aen.sbo;
+ fib.fmt0.sum = 1;
+ } else {
+ fib.fmt0.aisb = 0;
+ fib.fmt0.aisbo = 0;
+ fib.fmt0.sum = 0;
+ }
+
+ if (args->u.reg_aen.flags & KVM_S390_ZPCIOP_REGAEN_HOST)
+ return kvm_s390_pci_aif_enable(zdev, &fib, true);
+ else
+ return kvm_s390_pci_aif_enable(zdev, &fib, false);
+}
+
+int kvm_s390_pci_zpci_op(struct kvm *kvm, struct kvm_s390_zpci_op *args)
+{
+ struct kvm_zdev *kzdev;
+ struct zpci_dev *zdev;
+ int r;
+
+ kzdev = get_kzdev_by_fh(kvm, args->fh);
+ if (!kzdev)
+ return -ENODEV;
+ zdev = kzdev->zdev;
+
+ switch (args->op) {
+ case KVM_S390_ZPCIOP_REG_AEN:
+ r = kvm_s390_pci_zpci_reg_aen(zdev, args);
+ break;
+ case KVM_S390_ZPCIOP_DEREG_AEN:
+ r = kvm_s390_pci_aif_disable(zdev, false);
+ break;
+ default:
+ r = -EINVAL;
+ }
+
+ return r;
+}
+
int kvm_s390_pci_init(void)
{
aift = kzalloc(sizeof(struct zpci_aift), GFP_KERNEL);
diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h
index cb5ec3208923..b053b50c0904 100644
--- a/arch/s390/kvm/pci.h
+++ b/arch/s390/kvm/pci.h
@@ -59,6 +59,8 @@ void kvm_s390_pci_aen_exit(void);
void kvm_s390_pci_init_list(struct kvm *kvm);
void kvm_s390_pci_clear_list(struct kvm *kvm);

+int kvm_s390_pci_zpci_op(struct kvm *kvm, struct kvm_s390_zpci_op *args);
+
int kvm_s390_pci_init(void);

static inline bool kvm_s390_pci_interp_allowed(void)
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 91a6fe4e02c0..014adb30d42c 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1144,6 +1144,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_S390_MEM_OP_EXTENSION 211
#define KVM_CAP_PMU_CAPABILITY 212
#define KVM_CAP_DISABLE_QUIRKS2 213
+#define KVM_CAP_S390_ZPCI_OP 214

#ifdef KVM_CAP_IRQ_ROUTING

@@ -2060,4 +2061,34 @@ struct kvm_stats_desc {
/* Available with KVM_CAP_XSAVE2 */
#define KVM_GET_XSAVE2 _IOR(KVMIO, 0xcf, struct kvm_xsave)

+/* Available with KVM_CAP_S390_ZPCI_OP */
+#define KVM_S390_ZPCI_OP _IOW(KVMIO, 0xd0, struct kvm_s390_zpci_op)
+
+struct kvm_s390_zpci_op {
+ /* in */
+ __u32 fh; /* target device */
+ __u8 op; /* operation to perform */
+ __u8 pad[3];
+ union {
+ /* for KVM_S390_ZPCIOP_REG_AEN */
+ struct {
+ __u64 ibv; /* Guest addr of interrupt bit vector */
+ __u64 sb; /* Guest addr of summary bit */
+ __u32 flags;
+ __u32 noi; /* Number of interrupts */
+ __u8 isc; /* Guest interrupt subclass */
+ __u8 sbo; /* Offset of guest summary bit vector */
+ __u16 pad;
+ } reg_aen;
+ __u64 reserved[8];
+ } u;
+};
+
+/* types for kvm_s390_zpci_op->op */
+#define KVM_S390_ZPCIOP_REG_AEN 0
+#define KVM_S390_ZPCIOP_DEREG_AEN 1
+
+/* flags for kvm_s390_zpci_op->u.reg_aen.flags */
+#define KVM_S390_ZPCIOP_REGAEN_HOST (1 << 0)
+
#endif /* __LINUX_KVM_H */
--
2.27.0