KVM: SEV: Do cache maintenance on the source VM during intra-host migrationgrafted

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 <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260923163721.1584779-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 266 insertions, 0 deletions

diff --git a/drivers/input/misc/mc13783-pwrbutton.c b/drivers/input/misc/mc13783-pwrbutton.c
new file mode 100644
index 000000000..cb781ce96
--- /dev/null
+++ b/drivers/input/misc/mc13783-pwrbutton.c
@@ -0,0 +1,266 @@
+/*
+ * Copyright (C) 2011 Philippe Rétornaz
+ *
+ * Based on twl4030-pwrbutton driver by:
+ *     Peter De Schrijver <peter.de-schrijver@nokia.com>
+ *     Felipe Balbi <felipe.balbi@nokia.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335  USA
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/mc13783.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+struct mc13783_pwrb {
+	struct input_dev *pwr;
+	struct mc13xxx *mc13783;
+#define MC13783_PWRB_B1_POL_INVERT	(1 << 0)
+#define MC13783_PWRB_B2_POL_INVERT	(1 << 1)
+#define MC13783_PWRB_B3_POL_INVERT	(1 << 2)
+	int flags;
+	unsigned short keymap[3];
+};
+
+#define MC13783_REG_INTERRUPT_SENSE_1		5
+#define MC13783_IRQSENSE1_ONOFD1S		(1 << 3)
+#define MC13783_IRQSENSE1_ONOFD2S		(1 << 4)
+#define MC13783_IRQSENSE1_ONOFD3S		(1 << 5)
+
+#define MC13783_REG_POWER_CONTROL_2		15
+#define MC13783_POWER_CONTROL_2_ON1BDBNC	4
+#define MC13783_POWER_CONTROL_2_ON2BDBNC	6
+#define MC13783_POWER_CONTROL_2_ON3BDBNC	8
+#define MC13783_POWER_CONTROL_2_ON1BRSTEN	(1 << 1)
+#define MC13783_POWER_CONTROL_2_ON2BRSTEN	(1 << 2)
+#define MC13783_POWER_CONTROL_2_ON3BRSTEN	(1 << 3)
+
+static irqreturn_t button_irq(int irq, void *_priv)
+{
+	struct mc13783_pwrb *priv = _priv;
+	int val;
+
+	mc13xxx_reg_read(priv->mc13783, MC13783_REG_INTERRUPT_SENSE_1, &val);
+
+	switch (irq) {
+	case MC13783_IRQ_ONOFD1:
+		val = val & MC13783_IRQSENSE1_ONOFD1S ? 1 : 0;
+		if (priv->flags & MC13783_PWRB_B1_POL_INVERT)
+			val ^= 1;
+		input_report_key(priv->pwr, priv->keymap[0], val);
+		break;
+
+	case MC13783_IRQ_ONOFD2:
+		val = val & MC13783_IRQSENSE1_ONOFD2S ? 1 : 0;
+		if (priv->flags & MC13783_PWRB_B2_POL_INVERT)
+			val ^= 1;
+		input_report_key(priv->pwr, priv->keymap[1], val);
+		break;
+
+	case MC13783_IRQ_ONOFD3:
+		val = val & MC13783_IRQSENSE1_ONOFD3S ? 1 : 0;
+		if (priv->flags & MC13783_PWRB_B3_POL_INVERT)
+			val ^= 1;
+		input_report_key(priv->pwr, priv->keymap[2], val);
+		break;
+	}
+
+	input_sync(priv->pwr);
+
+	return IRQ_HANDLED;
+}
+
+static int mc13783_pwrbutton_probe(struct platform_device *pdev)
+{
+	const struct mc13xxx_buttons_platform_data *pdata;
+	struct mc13xxx *mc13783 = dev_get_drvdata(pdev->dev.parent);
+	struct input_dev *pwr;
+	struct mc13783_pwrb *priv;
+	int err = 0;
+	int reg = 0;
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (!pdata) {
+		dev_err(&pdev->dev, "missing platform data\n");
+		return -ENODEV;
+	}
+
+	pwr = input_allocate_device();
+	if (!pwr) {
+		dev_dbg(&pdev->dev, "Can't allocate power button\n");
+		return -ENOMEM;
+	}
+
+	priv = kzalloc_obj(*priv);
+	if (!priv) {
+		err = -ENOMEM;
+		dev_dbg(&pdev->dev, "Can't allocate power button\n");
+		goto free_input_dev;
+	}
+
+	reg |= (pdata->b1on_flags & 0x3) << MC13783_POWER_CONTROL_2_ON1BDBNC;
+	reg |= (pdata->b2on_flags & 0x3) << MC13783_POWER_CONTROL_2_ON2BDBNC;
+	reg |= (pdata->b3on_flags & 0x3) << MC13783_POWER_CONTROL_2_ON3BDBNC;
+
+	priv->pwr = pwr;
+	priv->mc13783 = mc13783;
+
+	mc13xxx_lock(mc13783);
+
+	if (pdata->b1on_flags & MC13783_BUTTON_ENABLE) {
+		priv->keymap[0] = pdata->b1on_key;
+		if (pdata->b1on_key != KEY_RESERVED)
+			__set_bit(pdata->b1on_key, pwr->keybit);
+
+		if (pdata->b1on_flags & MC13783_BUTTON_POL_INVERT)
+			priv->flags |= MC13783_PWRB_B1_POL_INVERT;
+
+		if (pdata->b1on_flags & MC13783_BUTTON_RESET_EN)
+			reg |= MC13783_POWER_CONTROL_2_ON1BRSTEN;
+
+		err = mc13xxx_irq_request(mc13783, MC13783_IRQ_ONOFD1,
+					  button_irq, "b1on", priv);
+		if (err) {
+			dev_dbg(&pdev->dev, "Can't request irq\n");
+			goto free_priv;
+		}
+	}
+
+	if (pdata->b2on_flags & MC13783_BUTTON_ENABLE) {
+		priv->keymap[1] = pdata->b2on_key;
+		if (pdata->b2on_key != KEY_RESERVED)
+			__set_bit(pdata->b2on_key, pwr->keybit);
+
+		if (pdata->b2on_flags & MC13783_BUTTON_POL_INVERT)
+			priv->flags |= MC13783_PWRB_B2_POL_INVERT;
+
+		if (pdata->b2on_flags & MC13783_BUTTON_RESET_EN)
+			reg |= MC13783_POWER_CONTROL_2_ON2BRSTEN;
+
+		err = mc13xxx_irq_request(mc13783, MC13783_IRQ_ONOFD2,
+					  button_irq, "b2on", priv);
+		if (err) {
+			dev_dbg(&pdev->dev, "Can't request irq\n");
+			goto free_irq_b1;
+		}
+	}
+
+	if (pdata->b3on_flags & MC13783_BUTTON_ENABLE) {
+		priv->keymap[2] = pdata->b3on_key;
+		if (pdata->b3on_key != KEY_RESERVED)
+			__set_bit(pdata->b3on_key, pwr->keybit);
+
+		if (pdata->b3on_flags & MC13783_BUTTON_POL_INVERT)
+			priv->flags |= MC13783_PWRB_B3_POL_INVERT;
+
+		if (pdata->b3on_flags & MC13783_BUTTON_RESET_EN)
+			reg |= MC13783_POWER_CONTROL_2_ON3BRSTEN;
+
+		err = mc13xxx_irq_request(mc13783, MC13783_IRQ_ONOFD3,
+					  button_irq, "b3on", priv);
+		if (err) {
+			dev_dbg(&pdev->dev, "Can't request irq: %d\n", err);
+			goto free_irq_b2;
+		}
+	}
+
+	mc13xxx_reg_rmw(mc13783, MC13783_REG_POWER_CONTROL_2, 0x3FE, reg);
+
+	mc13xxx_unlock(mc13783);
+
+	pwr->name = "mc13783_pwrbutton";
+	pwr->phys = "mc13783_pwrbutton/input0";
+	pwr->dev.parent = &pdev->dev;
+
+	pwr->keycode = priv->keymap;
+	pwr->keycodemax = ARRAY_SIZE(priv->keymap);
+	pwr->keycodesize = sizeof(priv->keymap[0]);
+	__set_bit(EV_KEY, pwr->evbit);
+
+	err = input_register_device(pwr);
+	if (err) {
+		dev_dbg(&pdev->dev, "Can't register power button: %d\n", err);
+		goto free_irq;
+	}
+
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+
+free_irq:
+	mc13xxx_lock(mc13783);
+
+	if (pdata->b3on_flags & MC13783_BUTTON_ENABLE)
+		mc13xxx_irq_free(mc13783, MC13783_IRQ_ONOFD3, priv);
+
+free_irq_b2:
+	if (pdata->b2on_flags & MC13783_BUTTON_ENABLE)
+		mc13xxx_irq_free(mc13783, MC13783_IRQ_ONOFD2, priv);
+
+free_irq_b1:
+	if (pdata->b1on_flags & MC13783_BUTTON_ENABLE)
+		mc13xxx_irq_free(mc13783, MC13783_IRQ_ONOFD1, priv);
+
+free_priv:
+	mc13xxx_unlock(mc13783);
+	kfree(priv);
+
+free_input_dev:
+	input_free_device(pwr);
+
+	return err;
+}
+
+static void mc13783_pwrbutton_remove(struct platform_device *pdev)
+{
+	struct mc13783_pwrb *priv = platform_get_drvdata(pdev);
+	const struct mc13xxx_buttons_platform_data *pdata;
+
+	pdata = dev_get_platdata(&pdev->dev);
+
+	mc13xxx_lock(priv->mc13783);
+
+	if (pdata->b3on_flags & MC13783_BUTTON_ENABLE)
+		mc13xxx_irq_free(priv->mc13783, MC13783_IRQ_ONOFD3, priv);
+	if (pdata->b2on_flags & MC13783_BUTTON_ENABLE)
+		mc13xxx_irq_free(priv->mc13783, MC13783_IRQ_ONOFD2, priv);
+	if (pdata->b1on_flags & MC13783_BUTTON_ENABLE)
+		mc13xxx_irq_free(priv->mc13783, MC13783_IRQ_ONOFD1, priv);
+
+	mc13xxx_unlock(priv->mc13783);
+
+	input_unregister_device(priv->pwr);
+	kfree(priv);
+}
+
+static struct platform_driver mc13783_pwrbutton_driver = {
+	.probe		= mc13783_pwrbutton_probe,
+	.remove		= mc13783_pwrbutton_remove,
+	.driver		= {
+		.name	= "mc13783-pwrbutton",
+	},
+};
+
+module_platform_driver(mc13783_pwrbutton_driver);
+
+MODULE_ALIAS("platform:mc13783-pwrbutton");
+MODULE_DESCRIPTION("MC13783 Power Button");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Philippe Retornaz");