From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- drivers/acpi/container.c | 117 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100644 drivers/acpi/container.c (limited to 'drivers/acpi/container.c') diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c new file mode 100644 index 000000000..f138a4335 --- /dev/null +++ b/drivers/acpi/container.c @@ -0,0 +1,117 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * container.c - ACPI Generic Container Driver + * + * Copyright (C) 2004 Anil S Keshavamurthy (anil.s.keshavamurthy@intel.com) + * Copyright (C) 2004 Keiichiro Tokunaga (tokunaga.keiich@jp.fujitsu.com) + * Copyright (C) 2004 Motoyuki Ito (motoyuki@soft.fujitsu.com) + * Copyright (C) 2004 FUJITSU LIMITED + * Copyright (C) 2004, 2013 Intel Corp. + * Author: Rafael J. Wysocki + */ +#include +#include + +#include "internal.h" + +static const struct acpi_device_id container_device_ids[] = { + {"ACPI0004", 0}, + {"PNP0A05", 0}, + {"PNP0A06", 0}, + {"", 0}, +}; + +#ifdef CONFIG_ACPI_CONTAINER + +static int check_offline(struct acpi_device *adev, void *not_used) +{ + if (acpi_scan_is_offline(adev, false)) + return 0; + + return -EBUSY; +} + +static int acpi_container_offline(struct container_dev *cdev) +{ + /* Check all of the dependent devices' physical companions. */ + return acpi_dev_for_each_child(ACPI_COMPANION(&cdev->dev), check_offline, NULL); +} + +static void acpi_container_release(struct device *dev) +{ + kfree(to_container_dev(dev)); +} + +static int container_device_attach(struct acpi_device *adev, + const struct acpi_device_id *not_used) +{ + struct container_dev *cdev; + struct device *dev; + int ret; + + if (adev->flags.is_dock_station) + return 0; + + cdev = kzalloc_obj(*cdev); + if (!cdev) + return -ENOMEM; + + cdev->offline = acpi_container_offline; + dev = &cdev->dev; + dev->bus = &container_subsys; + dev_set_name(dev, "%s", dev_name(&adev->dev)); + ACPI_COMPANION_SET(dev, adev); + dev->release = acpi_container_release; + ret = device_register(dev); + if (ret) { + put_device(dev); + return ret; + } + adev->driver_data = dev; + return 1; +} + +static void container_device_detach(struct acpi_device *adev) +{ + struct device *dev = acpi_driver_data(adev); + + adev->driver_data = NULL; + if (dev) + device_unregister(dev); +} + +static void container_device_online(struct acpi_device *adev) +{ + struct device *dev = acpi_driver_data(adev); + + kobject_uevent(&dev->kobj, KOBJ_ONLINE); +} + +static struct acpi_scan_handler container_handler = { + .ids = container_device_ids, + .attach = container_device_attach, + .detach = container_device_detach, + .hotplug = { + .enabled = true, + .demand_offline = true, + .notify_online = container_device_online, + }, +}; + +void __init acpi_container_init(void) +{ + acpi_scan_add_handler(&container_handler); +} + +#else + +static struct acpi_scan_handler container_handler = { + .ids = container_device_ids, +}; + +void __init acpi_container_init(void) +{ + acpi_scan_add_handler_with_hotplug(&container_handler, "container"); +} + +#endif /* CONFIG_ACPI_CONTAINER */ -- cgit v1.3.1