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/input/apm-power.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 122 insertions(+) create mode 100644 drivers/input/apm-power.c (limited to 'drivers/input/apm-power.c') diff --git a/drivers/input/apm-power.c b/drivers/input/apm-power.c new file mode 100644 index 000000000..028fcaf4c --- /dev/null +++ b/drivers/input/apm-power.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Input Power Event -> APM Bridge + * + * Copyright (c) 2007 Richard Purdie + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include + +static void system_power_event(unsigned int keycode) +{ + switch (keycode) { + case KEY_SUSPEND: + apm_queue_event(APM_USER_SUSPEND); + pr_info("Requesting system suspend...\n"); + break; + default: + break; + } +} + +static void apmpower_event(struct input_handle *handle, unsigned int type, + unsigned int code, int value) +{ + /* only react on key down events */ + if (value != 1) + return; + + switch (type) { + case EV_PWR: + system_power_event(code); + break; + + default: + break; + } +} + +static int apmpower_connect(struct input_handler *handler, + struct input_dev *dev, + const struct input_device_id *id) +{ + struct input_handle *handle; + int error; + + handle = kzalloc_obj(struct input_handle); + if (!handle) + return -ENOMEM; + + handle->dev = dev; + handle->handler = handler; + handle->name = "apm-power"; + + error = input_register_handle(handle); + if (error) { + pr_err("Failed to register input power handler, error %d\n", + error); + kfree(handle); + return error; + } + + error = input_open_device(handle); + if (error) { + pr_err("Failed to open input power device, error %d\n", error); + input_unregister_handle(handle); + kfree(handle); + return error; + } + + return 0; +} + +static void apmpower_disconnect(struct input_handle *handle) +{ + input_close_device(handle); + input_unregister_handle(handle); + kfree(handle); +} + +static const struct input_device_id apmpower_ids[] = { + { + .flags = INPUT_DEVICE_ID_MATCH_EVBIT, + .evbit = { BIT_MASK(EV_PWR) }, + }, + { }, +}; + +MODULE_DEVICE_TABLE(input, apmpower_ids); + +static struct input_handler apmpower_handler = { + .event = apmpower_event, + .connect = apmpower_connect, + .disconnect = apmpower_disconnect, + .name = "apm-power", + .id_table = apmpower_ids, +}; + +static int __init apmpower_init(void) +{ + return input_register_handler(&apmpower_handler); +} + +static void __exit apmpower_exit(void) +{ + input_unregister_handler(&apmpower_handler); +} + +module_init(apmpower_init); +module_exit(apmpower_exit); + +MODULE_AUTHOR("Richard Purdie "); +MODULE_DESCRIPTION("Input Power Event -> APM Bridge"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1