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, 171 insertions, 0 deletions

diff --git a/sound/soc/codecs/max9877.c b/sound/soc/codecs/max9877.c
new file mode 100644
index 000000000..7cd07b6f9
--- /dev/null
+++ b/sound/soc/codecs/max9877.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * max9877.c  --  amp driver for max9877
+ *
+ * Copyright (C) 2009 Samsung Electronics Co.Ltd
+ * Author: Joonyoung Shim <jy0922.shim@samsung.com>
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include <sound/soc.h>
+#include <sound/tlv.h>
+
+#include "max9877.h"
+
+static const struct reg_default max9877_regs[] = {
+	{ 0, 0x40 },
+	{ 1, 0x00 },
+	{ 2, 0x00 },
+	{ 3, 0x00 },
+	{ 4, 0x49 },
+};
+
+static const DECLARE_TLV_DB_RANGE(max9877_pgain_tlv,
+	0, 1, TLV_DB_SCALE_ITEM(0, 900, 0),
+	2, 2, TLV_DB_SCALE_ITEM(2000, 0, 0)
+);
+
+static const DECLARE_TLV_DB_RANGE(max9877_output_tlv,
+	0, 7, TLV_DB_SCALE_ITEM(-7900, 400, 1),
+	8, 15, TLV_DB_SCALE_ITEM(-4700, 300, 0),
+	16, 23, TLV_DB_SCALE_ITEM(-2300, 200, 0),
+	24, 31, TLV_DB_SCALE_ITEM(-700, 100, 0)
+);
+
+static const char *max9877_out_mode[] = {
+	"INA -> SPK",
+	"INA -> HP",
+	"INA -> SPK and HP",
+	"INB -> SPK",
+	"INB -> HP",
+	"INB -> SPK and HP",
+	"INA + INB -> SPK",
+	"INA + INB -> HP",
+	"INA + INB -> SPK and HP",
+};
+
+static const char *max9877_osc_mode[] = {
+	"1176KHz",
+	"1100KHz",
+	"700KHz",
+};
+
+static const struct soc_enum max9877_enum[] = {
+	SOC_ENUM_SINGLE(MAX9877_OUTPUT_MODE, 0, ARRAY_SIZE(max9877_out_mode),
+			max9877_out_mode),
+	SOC_ENUM_SINGLE(MAX9877_OUTPUT_MODE, MAX9877_OSC_OFFSET,
+			ARRAY_SIZE(max9877_osc_mode), max9877_osc_mode),
+};
+
+static const struct snd_kcontrol_new max9877_controls[] = {
+	SOC_SINGLE_TLV("MAX9877 PGAINA Playback Volume",
+		       MAX9877_INPUT_MODE, 0, 2, 0, max9877_pgain_tlv),
+	SOC_SINGLE_TLV("MAX9877 PGAINB Playback Volume",
+		       MAX9877_INPUT_MODE, 2, 2, 0, max9877_pgain_tlv),
+	SOC_SINGLE_TLV("MAX9877 Amp Speaker Playback Volume",
+		       MAX9877_SPK_VOLUME, 0, 31, 0, max9877_output_tlv),
+	SOC_DOUBLE_R_TLV("MAX9877 Amp HP Playback Volume",
+			 MAX9877_HPL_VOLUME, MAX9877_HPR_VOLUME, 0, 31, 0,
+			 max9877_output_tlv),
+	SOC_SINGLE("MAX9877 INB Stereo Switch",
+		   MAX9877_INPUT_MODE, 4, 1, 1),
+	SOC_SINGLE("MAX9877 INA Stereo Switch",
+		   MAX9877_INPUT_MODE, 5, 1, 1),
+	SOC_SINGLE("MAX9877 Zero-crossing detection Switch",
+		   MAX9877_INPUT_MODE, 6, 1, 0),
+	SOC_SINGLE("MAX9877 Bypass Mode Switch",
+		   MAX9877_OUTPUT_MODE, 6, 1, 0),
+	SOC_ENUM("MAX9877 Output Mode", max9877_enum[0]),
+	SOC_ENUM("MAX9877 Oscillator Mode", max9877_enum[1]),
+};
+
+static const struct snd_soc_dapm_widget max9877_dapm_widgets[] = {
+SND_SOC_DAPM_INPUT("INA1"),
+SND_SOC_DAPM_INPUT("INA2"),
+SND_SOC_DAPM_INPUT("INB1"),
+SND_SOC_DAPM_INPUT("INB2"),
+SND_SOC_DAPM_INPUT("RXIN+"),
+SND_SOC_DAPM_INPUT("RXIN-"),
+
+SND_SOC_DAPM_PGA("SHDN", MAX9877_OUTPUT_MODE, 7, 1, NULL, 0),
+
+SND_SOC_DAPM_OUTPUT("OUT+"),
+SND_SOC_DAPM_OUTPUT("OUT-"),
+SND_SOC_DAPM_OUTPUT("HPL"),
+SND_SOC_DAPM_OUTPUT("HPR"),
+};
+
+static const struct snd_soc_dapm_route max9877_dapm_routes[] = {
+	{ "SHDN", NULL, "INA1" },
+	{ "SHDN", NULL, "INA2" },
+	{ "SHDN", NULL, "INB1" },
+	{ "SHDN", NULL, "INB2" },
+
+	{ "OUT+", NULL, "RXIN+" },
+	{ "OUT+", NULL, "SHDN" },
+
+	{ "OUT-", NULL, "SHDN" },
+	{ "OUT-", NULL, "RXIN-" },
+
+	{ "HPL", NULL, "SHDN" },
+	{ "HPR", NULL, "SHDN" },
+};
+
+static const struct snd_soc_component_driver max9877_component_driver = {
+	.controls = max9877_controls,
+	.num_controls = ARRAY_SIZE(max9877_controls),
+
+	.dapm_widgets = max9877_dapm_widgets,
+	.num_dapm_widgets = ARRAY_SIZE(max9877_dapm_widgets),
+	.dapm_routes = max9877_dapm_routes,
+	.num_dapm_routes = ARRAY_SIZE(max9877_dapm_routes),
+};
+
+static const struct regmap_config max9877_regmap = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.reg_defaults = max9877_regs,
+	.num_reg_defaults = ARRAY_SIZE(max9877_regs),
+	.cache_type = REGCACHE_RBTREE,
+};
+
+static int max9877_i2c_probe(struct i2c_client *client)
+{
+	struct regmap *regmap;
+	int i;
+
+	regmap = devm_regmap_init_i2c(client, &max9877_regmap);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	/* Ensure the device is in reset state */
+	for (i = 0; i < ARRAY_SIZE(max9877_regs); i++)
+		regmap_write(regmap, max9877_regs[i].reg, max9877_regs[i].def);
+
+	return devm_snd_soc_register_component(&client->dev,
+			&max9877_component_driver, NULL, 0);
+}
+
+static const struct i2c_device_id max9877_i2c_id[] = {
+	{ .name = "max9877" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max9877_i2c_id);
+
+static struct i2c_driver max9877_i2c_driver = {
+	.driver = {
+		.name = "max9877",
+	},
+	.probe = max9877_i2c_probe,
+	.id_table = max9877_i2c_id,
+};
+
+module_i2c_driver(max9877_i2c_driver);
+
+MODULE_DESCRIPTION("ASoC MAX9877 amp driver");
+MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");
+MODULE_LICENSE("GPL");