From ca922fecda6caa5162409406dc3b663062d75089 Mon Sep 17 00:00:00 2001
From: Pierre Morel <pmorel@linux.ibm.com>
Date: Fri, 19 Aug 2022 14:29:45 +0200
Subject: 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 <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Fixes: 09340b2fca007 ("KVM: s390: pci: add routines to start/stop interpretive execution")
Cc: <stable@vger.kernel.org>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # 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 <frankja@linux.ibm.com>
---
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 +++++++++++
4 files changed, 26 insertions(+), 16 deletions(-)
create mode 100644 arch/s390/pci/pci_kvm_hook.c
(limited to 'arch/s390')
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index f39092e0ceaa..b1e98a9ed152 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -1038,16 +1038,11 @@ static inline void kvm_arch_vcpu_unblocking(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 @@ err:
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 @@ out:
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 <pmorel@linux.ibm.com>
+ */
+#include <linux/kvm_host.h>
+
+struct zpci_kvm_hook zpci_kvm_hook;
+EXPORT_SYMBOL_GPL(zpci_kvm_hook);
--
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