From 1d6e9e4d324260b8d17010b860951a6de16ee937 Mon Sep 17 00:00:00 2001 From: Pierre Morel Date: Fri, 19 Aug 2022 14:29:45 +0200 Subject: [PATCH] KVM: s390: pci: Hook to access KVM lowlevel from VFIO We have a cross dependency between KVM and VFIO when using s390 vfio_pci_zdev extensions for PCI passthrough To be able to keep both subsystem modular we add a registering hook inside the S390 core code. This fixes a build problem when VFIO is built-in and KVM is built as a module. Reported-by: Randy Dunlap Reported-by: kernel test robot Reviewed-by: Matthew Rosato Reviewed-by: Niklas Schnelle Signed-off-by: Pierre Morel Fixes: 09340b2fca007 ("KVM: s390: pci: add routines to start/stop interpretive execution") Cc: Acked-by: Janosch Frank Acked-by: Randy Dunlap # build-tested Link: https://lore.kernel.org/r/20220819122945.9309-1-pmorel@linux.ibm.com Message-Id: <20220819122945.9309-1-pmorel@linux.ibm.com> Signed-off-by: Janosch Frank (backported from commit ca922fecda6caa5162409406dc3b663062d75089) [MR: adjust commit to accomodate vfio-pci-zdev usage of KVM_GROUP_NOTIFY] Signed-off-by: Matthew Rosato --- arch/s390/include/asm/kvm_host.h | 17 ++++++----------- arch/s390/kvm/pci.c | 12 ++++++++---- arch/s390/pci/Makefile | 2 +- arch/s390/pci/pci_kvm_hook.c | 11 +++++++++++ drivers/vfio/pci/vfio_pci_zdev.c | 7 ++++--- 5 files changed, 30 insertions(+), 19 deletions(-) create mode 100644 arch/s390/pci/pci_kvm_hook.c diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 543997217694..4feba365e49b 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -1023,16 +1023,11 @@ void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu); #define __KVM_HAVE_ARCH_VM_FREE void kvm_arch_free_vm(struct kvm *kvm); -#ifdef CONFIG_VFIO_PCI_ZDEV_KVM -int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm); -void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev); -#else -static inline int kvm_s390_pci_register_kvm(struct zpci_dev *dev, - struct kvm *kvm) -{ - return -EPERM; -} -static inline void kvm_s390_pci_unregister_kvm(struct zpci_dev *dev) {} -#endif +struct zpci_kvm_hook { + int (*kvm_register)(void *opaque, struct kvm *kvm); + void (*kvm_unregister)(void *opaque); +}; + +extern struct zpci_kvm_hook zpci_kvm_hook; #endif diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c index 4946fb7757d6..bb8c335d17b9 100644 --- a/arch/s390/kvm/pci.c +++ b/arch/s390/kvm/pci.c @@ -431,8 +431,9 @@ static void kvm_s390_pci_dev_release(struct zpci_dev *zdev) * available, enable them and let userspace indicate whether or not they will * be used (specify SHM bit to disable). */ -int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm) +static int kvm_s390_pci_register_kvm(void *opaque, struct kvm *kvm) { + struct zpci_dev *zdev = opaque; int rc; if (!zdev) @@ -510,10 +511,10 @@ int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm) kvm_put_kvm(kvm); return rc; } -EXPORT_SYMBOL_GPL(kvm_s390_pci_register_kvm); -void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev) +static void kvm_s390_pci_unregister_kvm(void *opaque) { + struct zpci_dev *zdev = opaque; struct kvm *kvm; if (!zdev) @@ -566,7 +567,6 @@ void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev) kvm_put_kvm(kvm); } -EXPORT_SYMBOL_GPL(kvm_s390_pci_unregister_kvm); void kvm_s390_pci_init_list(struct kvm *kvm) { @@ -678,6 +678,8 @@ int kvm_s390_pci_init(void) spin_lock_init(&aift->gait_lock); mutex_init(&aift->aift_lock); + zpci_kvm_hook.kvm_register = kvm_s390_pci_register_kvm; + zpci_kvm_hook.kvm_unregister = kvm_s390_pci_unregister_kvm; return 0; } @@ -685,6 +687,8 @@ int kvm_s390_pci_init(void) void kvm_s390_pci_exit(void) { mutex_destroy(&aift->aift_lock); + zpci_kvm_hook.kvm_register = NULL; + zpci_kvm_hook.kvm_unregister = NULL; kfree(aift); } diff --git a/arch/s390/pci/Makefile b/arch/s390/pci/Makefile index bf557a1b789c..5ae31ca9dd44 100644 --- a/arch/s390/pci/Makefile +++ b/arch/s390/pci/Makefile @@ -5,5 +5,5 @@ obj-$(CONFIG_PCI) += pci.o pci_irq.o pci_dma.o pci_clp.o pci_sysfs.o \ pci_event.o pci_debug.o pci_insn.o pci_mmio.o \ - pci_bus.o + pci_bus.o pci_kvm_hook.o obj-$(CONFIG_PCI_IOV) += pci_iov.o diff --git a/arch/s390/pci/pci_kvm_hook.c b/arch/s390/pci/pci_kvm_hook.c new file mode 100644 index 000000000000..ff34baf50a3e --- /dev/null +++ b/arch/s390/pci/pci_kvm_hook.c @@ -0,0 +1,11 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * VFIO ZPCI devices support + * + * Copyright (C) IBM Corp. 2022. All rights reserved. + * Author(s): Pierre Morel + */ +#include + +struct zpci_kvm_hook zpci_kvm_hook; +EXPORT_SYMBOL_GPL(zpci_kvm_hook); diff --git a/drivers/vfio/pci/vfio_pci_zdev.c b/drivers/vfio/pci/vfio_pci_zdev.c index 6819b3e4e159..932c90c78406 100644 --- a/drivers/vfio/pci/vfio_pci_zdev.c +++ b/drivers/vfio/pci/vfio_pci_zdev.c @@ -147,9 +147,9 @@ static int vfio_pci_zdev_group_notifier(struct notifier_block *nb, struct zpci_dev *zdev = container_of(nb, struct zpci_dev, kvm_group_nb); - if (action == VFIO_GROUP_NOTIFY_SET_KVM) { + if (action == VFIO_GROUP_NOTIFY_SET_KVM && zpci_kvm_hook.kvm_register) { if (data) { - if (kvm_s390_pci_register_kvm(zdev, data)) + if (zpci_kvm_hook.kvm_register(zdev, data)) return NOTIFY_BAD; } } @@ -197,5 +197,6 @@ void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev) if (!zdev || !zdev->kzdev) return; - kvm_s390_pci_unregister_kvm(zdev); + if (zpci_kvm_hook.kvm_unregister) + zpci_kvm_hook.kvm_unregister(zdev); } -- 2.40.1