x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

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 <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 52 insertions, 0 deletions

diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
new file mode 100644
index 000000000..52eb7e4ba
--- /dev/null
+++ b/drivers/virt/Kconfig
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Virtualization support drivers
+#
+
+menuconfig VIRT_DRIVERS
+	bool "Virtualization drivers"
+	help
+	  Say Y here to get to see options for device drivers that support
+	  virtualization environments.
+
+	  If you say N, all options in this submenu will be skipped and disabled.
+
+if VIRT_DRIVERS
+
+config VMGENID
+	tristate "Virtual Machine Generation ID driver"
+	default y
+	help
+	  Say Y here to use the hypervisor-provided Virtual Machine Generation ID
+	  to reseed the RNG when the VM is cloned. This is highly recommended if
+	  you intend to do any rollback / cloning / snapshotting of VMs.
+
+	  Prefer Y to M so that this protection is activated very early.
+
+config FSL_HV_MANAGER
+	tristate "Freescale hypervisor management driver"
+	depends on FSL_SOC
+	select EPAPR_PARAVIRT
+	help
+          The Freescale hypervisor management driver provides several services
+	  to drivers and applications related to the Freescale hypervisor:
+
+          1) An ioctl interface for querying and managing partitions.
+
+          2) A file interface to reading incoming doorbells.
+
+          3) An interrupt handler for shutting down the partition upon
+	     receiving the shutdown doorbell from a manager partition.
+
+          4) A kernel interface for receiving callbacks when a managed
+	     partition shuts down.
+
+source "drivers/virt/vboxguest/Kconfig"
+
+source "drivers/virt/nitro_enclaves/Kconfig"
+
+source "drivers/virt/acrn/Kconfig"
+
+endif
+
+source "drivers/virt/coco/Kconfig"