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, 232 insertions, 0 deletions

diff --git a/sound/soc/codecs/max9768.c b/sound/soc/codecs/max9768.c
new file mode 100644
index 000000000..8621d9bdb
--- /dev/null
+++ b/sound/soc/codecs/max9768.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MAX9768 AMP driver
+ *
+ * Copyright (C) 2011, 2012 by Wolfram Sang, Pengutronix e.K.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regmap.h>
+
+#include <sound/core.h>
+#include <sound/soc.h>
+#include <sound/tlv.h>
+#include <sound/max9768.h>
+
+/* "Registers" */
+#define MAX9768_VOL 0
+#define MAX9768_CTRL 3
+
+/* Commands */
+#define MAX9768_CTRL_PWM 0x15
+#define MAX9768_CTRL_FILTERLESS 0x16
+
+struct max9768 {
+	struct regmap *regmap;
+	struct gpio_desc *mute;
+	struct gpio_desc *shdn;
+	u32 flags;
+};
+
+static const struct reg_default max9768_default_regs[] = {
+	{ 0, 0 },
+	{ 3,  MAX9768_CTRL_FILTERLESS},
+};
+
+static int max9768_get_gpio(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_component *c = snd_kcontrol_chip(kcontrol);
+	struct max9768 *max9768 = snd_soc_component_get_drvdata(c);
+	int val = gpiod_get_value_cansleep(max9768->mute);
+
+	ucontrol->value.integer.value[0] = !val;
+
+	return 0;
+}
+
+static int max9768_set_gpio(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_component *c = snd_kcontrol_chip(kcontrol);
+	struct max9768 *max9768 = snd_soc_component_get_drvdata(c);
+	bool val = !ucontrol->value.integer.value[0];
+	int ret;
+
+	if (val != gpiod_get_value_cansleep(max9768->mute))
+		ret = 1;
+	else
+		ret = 0;
+
+	gpiod_set_value_cansleep(max9768->mute, val);
+
+	return ret;
+}
+
+static const DECLARE_TLV_DB_RANGE(volume_tlv,
+	0, 0, TLV_DB_SCALE_ITEM(-16150, 0, 0),
+	1, 1, TLV_DB_SCALE_ITEM(-9280, 0, 0),
+	2, 2, TLV_DB_SCALE_ITEM(-9030, 0, 0),
+	3, 3, TLV_DB_SCALE_ITEM(-8680, 0, 0),
+	4, 4, TLV_DB_SCALE_ITEM(-8430, 0, 0),
+	5, 5, TLV_DB_SCALE_ITEM(-8080, 0, 0),
+	6, 6, TLV_DB_SCALE_ITEM(-7830, 0, 0),
+	7, 7, TLV_DB_SCALE_ITEM(-7470, 0, 0),
+	8, 8, TLV_DB_SCALE_ITEM(-7220, 0, 0),
+	9, 9, TLV_DB_SCALE_ITEM(-6870, 0, 0),
+	10, 10, TLV_DB_SCALE_ITEM(-6620, 0, 0),
+	11, 11, TLV_DB_SCALE_ITEM(-6270, 0, 0),
+	12, 12, TLV_DB_SCALE_ITEM(-6020, 0, 0),
+	13, 13, TLV_DB_SCALE_ITEM(-5670, 0, 0),
+	14, 14, TLV_DB_SCALE_ITEM(-5420, 0, 0),
+	15, 17, TLV_DB_SCALE_ITEM(-5060, 250, 0),
+	18, 18, TLV_DB_SCALE_ITEM(-4370, 0, 0),
+	19, 19, TLV_DB_SCALE_ITEM(-4210, 0, 0),
+	20, 20, TLV_DB_SCALE_ITEM(-3960, 0, 0),
+	21, 21, TLV_DB_SCALE_ITEM(-3760, 0, 0),
+	22, 22, TLV_DB_SCALE_ITEM(-3600, 0, 0),
+	23, 23, TLV_DB_SCALE_ITEM(-3340, 0, 0),
+	24, 24, TLV_DB_SCALE_ITEM(-3150, 0, 0),
+	25, 25, TLV_DB_SCALE_ITEM(-2980, 0, 0),
+	26, 26, TLV_DB_SCALE_ITEM(-2720, 0, 0),
+	27, 27, TLV_DB_SCALE_ITEM(-2520, 0, 0),
+	28, 30, TLV_DB_SCALE_ITEM(-2350, 190, 0),
+	31, 31, TLV_DB_SCALE_ITEM(-1750, 0, 0),
+	32, 34, TLV_DB_SCALE_ITEM(-1640, 100, 0),
+	35, 37, TLV_DB_SCALE_ITEM(-1310, 110, 0),
+	38, 39, TLV_DB_SCALE_ITEM(-990, 100, 0),
+	40, 40, TLV_DB_SCALE_ITEM(-710, 0, 0),
+	41, 41, TLV_DB_SCALE_ITEM(-600, 0, 0),
+	42, 42, TLV_DB_SCALE_ITEM(-500, 0, 0),
+	43, 43, TLV_DB_SCALE_ITEM(-340, 0, 0),
+	44, 44, TLV_DB_SCALE_ITEM(-190, 0, 0),
+	45, 45, TLV_DB_SCALE_ITEM(-50, 0, 0),
+	46, 46, TLV_DB_SCALE_ITEM(50, 0, 0),
+	47, 50, TLV_DB_SCALE_ITEM(120, 40, 0),
+	51, 57, TLV_DB_SCALE_ITEM(290, 50, 0),
+	58, 58, TLV_DB_SCALE_ITEM(650, 0, 0),
+	59, 62, TLV_DB_SCALE_ITEM(700, 60, 0),
+	63, 63, TLV_DB_SCALE_ITEM(950, 0, 0)
+);
+
+static const struct snd_kcontrol_new max9768_volume[] = {
+	SOC_SINGLE_TLV("Playback Volume", MAX9768_VOL, 0, 63, 0, volume_tlv),
+};
+
+static const struct snd_kcontrol_new max9768_mute[] = {
+	SOC_SINGLE_BOOL_EXT("Playback Switch", 0, max9768_get_gpio, max9768_set_gpio),
+};
+
+static const struct snd_soc_dapm_widget max9768_dapm_widgets[] = {
+SND_SOC_DAPM_INPUT("IN"),
+
+SND_SOC_DAPM_OUTPUT("OUT+"),
+SND_SOC_DAPM_OUTPUT("OUT-"),
+};
+
+static const struct snd_soc_dapm_route max9768_dapm_routes[] = {
+	{ "OUT+", NULL, "IN" },
+	{ "OUT-", NULL, "IN" },
+};
+
+static int max9768_probe(struct snd_soc_component *component)
+{
+	struct max9768 *max9768 = snd_soc_component_get_drvdata(component);
+	int ret;
+
+	if (max9768->flags & MAX9768_FLAG_CLASSIC_PWM) {
+		ret = regmap_write(max9768->regmap, MAX9768_CTRL,
+			MAX9768_CTRL_PWM);
+		if (ret)
+			return ret;
+	}
+
+	if (max9768->mute) {
+		ret = snd_soc_add_component_controls(component, max9768_mute,
+				ARRAY_SIZE(max9768_mute));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct snd_soc_component_driver max9768_component_driver = {
+	.probe = max9768_probe,
+	.controls = max9768_volume,
+	.num_controls = ARRAY_SIZE(max9768_volume),
+	.dapm_widgets = max9768_dapm_widgets,
+	.num_dapm_widgets = ARRAY_SIZE(max9768_dapm_widgets),
+	.dapm_routes = max9768_dapm_routes,
+	.num_dapm_routes = ARRAY_SIZE(max9768_dapm_routes),
+};
+
+static const struct regmap_config max9768_i2c_regmap_config = {
+	.reg_bits = 2,
+	.val_bits = 6,
+	.max_register = 3,
+	.reg_defaults = max9768_default_regs,
+	.num_reg_defaults = ARRAY_SIZE(max9768_default_regs),
+	.cache_type = REGCACHE_RBTREE,
+};
+
+static int max9768_i2c_probe(struct i2c_client *client)
+{
+	struct max9768 *max9768;
+	struct max9768_pdata *pdata = client->dev.platform_data;
+
+	max9768 = devm_kzalloc(&client->dev, sizeof(*max9768), GFP_KERNEL);
+	if (!max9768)
+		return -ENOMEM;
+
+	/* Mute on powerup to avoid clicks */
+	max9768->mute = devm_gpiod_get_optional(&client->dev,
+						"mute",
+						GPIOD_OUT_HIGH);
+	if (IS_ERR(max9768->mute))
+		return PTR_ERR(max9768->mute);
+	gpiod_set_consumer_name(max9768->mute, "MAX9768 Mute");
+
+	/* Activate chip by releasing shutdown, enables I2C */
+	max9768->shdn = devm_gpiod_get_optional(&client->dev,
+						"shutdown",
+						GPIOD_OUT_HIGH);
+	if (IS_ERR(max9768->shdn))
+		return PTR_ERR(max9768->shdn);
+	gpiod_set_consumer_name(max9768->shdn, "MAX9768 Shutdown");
+
+	if (pdata)
+		max9768->flags = pdata->flags;
+
+	i2c_set_clientdata(client, max9768);
+
+	max9768->regmap = devm_regmap_init_i2c(client, &max9768_i2c_regmap_config);
+	if (IS_ERR(max9768->regmap))
+		return PTR_ERR(max9768->regmap);
+
+	return devm_snd_soc_register_component(&client->dev,
+		&max9768_component_driver, NULL, 0);
+}
+
+static const struct i2c_device_id max9768_i2c_id[] = {
+	{ .name = "max9768" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max9768_i2c_id);
+
+static struct i2c_driver max9768_i2c_driver = {
+	.driver = {
+		.name = "max9768",
+	},
+	.probe = max9768_i2c_probe,
+	.id_table = max9768_i2c_id,
+};
+module_i2c_driver(max9768_i2c_driver);
+
+MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("ASoC MAX9768 amplifier driver");
+MODULE_LICENSE("GPL v2");