[GIT PULL 20/42] KVM: s390: add KVM_S390_ZPCI_OP to manage guest zPCI devices

Claudio Imbrenda
2022-07-21T16:13:27Z

From: Matthew Rosato <mjrosato@linux.ibm.com>

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>
Acked-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20220606203325.110625-21-mjrosato@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
---
Documentation/virt/kvm/api.rst | 47 +++++++++++++++++++
arch/s390/kvm/kvm-s390.c | 16 +++++++
arch/s390/kvm/pci.c | 85 ++++++++++++++++++++++++++++++++++
arch/s390/kvm/pci.h | 2 +
include/uapi/linux/kvm.h | 31 +++++++++++++
5 files changed, 181 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 11e00a46c610..d58354e9af8f 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -5802,6 +5802,53 @@ of CPUID leaf 0xD on the host.

This ioctl injects an event channel interrupt directly to the guest vCPU.

+4.137 KVM_S390_ZPCI_OP
+--------------------
+
+:Capability: KVM_CAP_S390_ZPCI_OP
+:Architectures: s390
+:Type: vm 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 "pad" and "reserved" fields may be used for future extensions and should be
+set to 0s by userspace.
+
5. The kvm_run structure
========================

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 4758bb731199..f214e0fc62ed 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -618,6 +618,9 @@ 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:
+ r = kvm_s390_pci_interp_allowed();
+ break;
default:
r = 0;
}
@@ -2629,6 +2632,19 @@ 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_ZDEV_KVM))
+ break;
+ if (copy_from_user(&args, argp, sizeof(args))) {
+ r = -EFAULT;
+ break;
+ }
+ r = kvm_s390_pci_zpci_op(kvm, &args);
+ break;
+ }
default:
r = -ENOTTY;
}
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index 24211741deb0..4946fb7757d6 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -585,6 +585,91 @@ void kvm_s390_pci_clear_list(struct kvm *kvm)
spin_unlock(&kvm->arch.kzdev_list_lock);
}

+static struct zpci_dev *get_zdev_from_kvm_by_fh(struct kvm *kvm, u32 fh)
+{
+ struct zpci_dev *zdev = NULL;
+ struct kvm_zdev *kzdev;
+
+ spin_lock(&kvm->arch.kzdev_list_lock);
+ list_for_each_entry(kzdev, &kvm->arch.kzdev_list, entry) {
+ if (kzdev->zdev->fh == fh) {
+ zdev = kzdev->zdev;
+ break;
+ }
+ }
+ spin_unlock(&kvm->arch.kzdev_list_lock);
+
+ return zdev;
+}
+
+static int kvm_s390_pci_zpci_reg_aen(struct zpci_dev *zdev,
+ struct kvm_s390_zpci_op *args)
+{
+ struct zpci_fib fib = {};
+ bool hostflag;
+
+ 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;
+ }
+
+ hostflag = !(args->u.reg_aen.flags & KVM_S390_ZPCIOP_REGAEN_HOST);
+ return kvm_s390_pci_aif_enable(zdev, &fib, hostflag);
+}
+
+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;
+
+ zdev = get_zdev_from_kvm_by_fh(kvm, args->fh);
+ if (!zdev)
+ return -ENODEV;
+
+ mutex_lock(&zdev->kzdev_lock);
+ mutex_lock(&kvm->lock);
+
+ kzdev = zdev->kzdev;
+ if (!kzdev) {
+ r = -ENODEV;
+ goto out;
+ }
+ if (kzdev->kvm != kvm) {
+ r = -EPERM;
+ goto out;
+ }
+
+ switch (args->op) {
+ case KVM_S390_ZPCIOP_REG_AEN:
+ /* Fail on unknown flags */
+ if (args->u.reg_aen.flags & ~KVM_S390_ZPCIOP_REGAEN_HOST) {
+ r = -EINVAL;
+ break;
+ }
+ 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;
+ }
+
+out:
+ mutex_unlock(&kvm->lock);
+ mutex_unlock(&zdev->kzdev_lock);
+ 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 fb2b91b76e0c..0351382e990f 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);
void kvm_s390_pci_exit(void);

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 5088bd9f1922..2f302e2287d1 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1157,6 +1157,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_VM_TSC_CONTROL 214
#define KVM_CAP_SYSTEM_EVENT_DATA 215
#define KVM_CAP_ARM_SYSTEM_SUSPEND 216
+#define KVM_CAP_S390_ZPCI_OP 221

#ifdef KVM_CAP_IRQ_ROUTING

@@ -2118,4 +2119,34 @@ 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, 0xd1, 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 */
--
2.36.1