From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- include/kvm/iodev.h | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 include/kvm/iodev.h (limited to 'include/kvm/iodev.h') diff --git a/include/kvm/iodev.h b/include/kvm/iodev.h new file mode 100644 index 000000000..56619e332 --- /dev/null +++ b/include/kvm/iodev.h @@ -0,0 +1,58 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef __KVM_IODEV_H__ +#define __KVM_IODEV_H__ + +#include +#include + +struct kvm_io_device; +struct kvm_vcpu; + +/** + * kvm_io_device_ops are called under kvm slots_lock. + * read and write handlers return 0 if the transaction has been handled, + * or non-zero to have it passed to the next device. + **/ +struct kvm_io_device_ops { + int (*read)(struct kvm_vcpu *vcpu, + struct kvm_io_device *this, + gpa_t addr, + int len, + void *val); + int (*write)(struct kvm_vcpu *vcpu, + struct kvm_io_device *this, + gpa_t addr, + int len, + const void *val); + void (*destructor)(struct kvm_io_device *this); +}; + + +struct kvm_io_device { + const struct kvm_io_device_ops *ops; +}; + +static inline void kvm_iodevice_init(struct kvm_io_device *dev, + const struct kvm_io_device_ops *ops) +{ + dev->ops = ops; +} + +static inline int kvm_iodevice_read(struct kvm_vcpu *vcpu, + struct kvm_io_device *dev, gpa_t addr, + int l, void *v) +{ + return dev->ops->read ? dev->ops->read(vcpu, dev, addr, l, v) + : -EOPNOTSUPP; +} + +static inline int kvm_iodevice_write(struct kvm_vcpu *vcpu, + struct kvm_io_device *dev, gpa_t addr, + int l, const void *v) +{ + return dev->ops->write ? dev->ops->write(vcpu, dev, addr, l, v) + : -EOPNOTSUPP; +} + +#endif /* __KVM_IODEV_H__ */ -- cgit v1.3.1