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/misc/cpcap-pwrbutton.c | 112 +++++++++++++++++++++++++++++++++++ 1 file changed, 112 insertions(+) create mode 100644 drivers/input/misc/cpcap-pwrbutton.c (limited to 'drivers/input/misc/cpcap-pwrbutton.c') diff --git a/drivers/input/misc/cpcap-pwrbutton.c b/drivers/input/misc/cpcap-pwrbutton.c new file mode 100644 index 000000000..85cddb847 --- /dev/null +++ b/drivers/input/misc/cpcap-pwrbutton.c @@ -0,0 +1,112 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * CPCAP Power Button Input Driver + * + * Copyright (C) 2017 Sebastian Reichel + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define CPCAP_IRQ_ON 23 +#define CPCAP_IRQ_ON_BITMASK (1 << (CPCAP_IRQ_ON % 16)) + +struct cpcap_power_button { + struct regmap *regmap; + struct input_dev *idev; + struct device *dev; +}; + +static irqreturn_t powerbutton_irq(int irq, void *_button) +{ + struct cpcap_power_button *button = _button; + int val; + + val = cpcap_sense_virq(button->regmap, irq); + if (val < 0) { + dev_err(button->dev, "irq read failed: %d", val); + return IRQ_HANDLED; + } + + pm_wakeup_event(button->dev, 0); + input_report_key(button->idev, KEY_POWER, val); + input_sync(button->idev); + + return IRQ_HANDLED; +} + +static int cpcap_power_button_probe(struct platform_device *pdev) +{ + struct cpcap_power_button *button; + int irq; + int err; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + button = devm_kmalloc(&pdev->dev, sizeof(*button), GFP_KERNEL); + if (!button) + return -ENOMEM; + + button->idev = devm_input_allocate_device(&pdev->dev); + if (!button->idev) + return -ENOMEM; + + button->regmap = dev_get_regmap(pdev->dev.parent, NULL); + if (!button->regmap) + return -ENODEV; + + button->dev = &pdev->dev; + + button->idev->name = "cpcap-pwrbutton"; + button->idev->phys = "cpcap-pwrbutton/input0"; + input_set_capability(button->idev, EV_KEY, KEY_POWER); + + err = devm_request_threaded_irq(&pdev->dev, irq, NULL, + powerbutton_irq, IRQF_ONESHOT, "cpcap_pwrbutton", button); + if (err < 0) { + dev_err(&pdev->dev, "IRQ request failed: %d\n", err); + return err; + } + + err = input_register_device(button->idev); + if (err) { + dev_err(&pdev->dev, "Input register failed: %d\n", err); + return err; + } + + device_init_wakeup(&pdev->dev, true); + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id cpcap_pwrbutton_dt_match_table[] = { + { .compatible = "motorola,cpcap-pwrbutton" }, + {}, +}; +MODULE_DEVICE_TABLE(of, cpcap_pwrbutton_dt_match_table); +#endif + +static struct platform_driver cpcap_power_button_driver = { + .probe = cpcap_power_button_probe, + .driver = { + .name = "cpcap-pwrbutton", + .of_match_table = of_match_ptr(cpcap_pwrbutton_dt_match_table), + }, +}; +module_platform_driver(cpcap_power_button_driver); + +MODULE_ALIAS("platform:cpcap-pwrbutton"); +MODULE_DESCRIPTION("CPCAP Power Button"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Sebastian Reichel "); -- cgit v1.3.1