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, 154 insertions, 0 deletions

diff --git a/sound/soc/codecs/rt1015p.c b/sound/soc/codecs/rt1015p.c
new file mode 100644
index 000000000..44e7fe3c3
--- /dev/null
+++ b/sound/soc/codecs/rt1015p.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// rt1015p.c  --  RT1015P ALSA SoC audio amplifier driver
+//
+// Copyright 2020 The Linux Foundation. All rights reserved.
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <sound/pcm.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+#include <sound/soc-dapm.h>
+
+struct rt1015p_priv {
+	struct gpio_desc *sdb;
+	bool calib_done;
+};
+
+static int rt1015p_sdb_event(struct snd_soc_dapm_widget *w,
+		struct snd_kcontrol *kcontrol, int event)
+{
+	struct snd_soc_component *component =
+		snd_soc_dapm_to_component(w->dapm);
+	struct rt1015p_priv *rt1015p =
+		snd_soc_component_get_drvdata(component);
+
+	if (!rt1015p->sdb)
+		return 0;
+
+	switch (event) {
+	case SND_SOC_DAPM_PRE_PMU:
+		gpiod_set_value_cansleep(rt1015p->sdb, 1);
+		dev_dbg(component->dev, "set sdb to 1");
+
+		if (!rt1015p->calib_done) {
+			msleep(300);
+			rt1015p->calib_done = true;
+		}
+		break;
+	case SND_SOC_DAPM_POST_PMD:
+		gpiod_set_value_cansleep(rt1015p->sdb, 0);
+		dev_dbg(component->dev, "set sdb to 0");
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static const struct snd_soc_dapm_widget rt1015p_dapm_widgets[] = {
+	SND_SOC_DAPM_OUTPUT("Speaker"),
+	SND_SOC_DAPM_OUT_DRV_E("SDB", SND_SOC_NOPM, 0, 0, NULL, 0,
+			rt1015p_sdb_event,
+			SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_POST_PMD),
+};
+
+static const struct snd_soc_dapm_route rt1015p_dapm_routes[] = {
+	{"SDB", NULL, "HiFi Playback"},
+	{"Speaker", NULL, "SDB"},
+};
+
+#ifdef CONFIG_PM
+static int rt1015p_suspend(struct snd_soc_component *component)
+{
+	struct rt1015p_priv *rt1015p = snd_soc_component_get_drvdata(component);
+
+	rt1015p->calib_done = false;
+	return 0;
+}
+#else
+#define rt1015p_suspend NULL
+#endif
+
+static const struct snd_soc_component_driver rt1015p_component_driver = {
+	.suspend		= rt1015p_suspend,
+	.dapm_widgets		= rt1015p_dapm_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(rt1015p_dapm_widgets),
+	.dapm_routes		= rt1015p_dapm_routes,
+	.num_dapm_routes	= ARRAY_SIZE(rt1015p_dapm_routes),
+	.idle_bias_on		= 1,
+	.use_pmdown_time	= 1,
+	.endianness		= 1,
+};
+
+static struct snd_soc_dai_driver rt1015p_dai_driver = {
+	.name = "HiFi",
+	.playback = {
+		.stream_name	= "HiFi Playback",
+		.formats	= SNDRV_PCM_FMTBIT_S24 |
+					SNDRV_PCM_FMTBIT_S32,
+		.rates		= SNDRV_PCM_RATE_48000,
+		.channels_min	= 1,
+		.channels_max	= 2,
+	},
+};
+
+static int rt1015p_platform_probe(struct platform_device *pdev)
+{
+	struct rt1015p_priv *rt1015p;
+
+	rt1015p = devm_kzalloc(&pdev->dev, sizeof(*rt1015p), GFP_KERNEL);
+	if (!rt1015p)
+		return -ENOMEM;
+
+	rt1015p->sdb = devm_gpiod_get_optional(&pdev->dev,
+				"sdb", GPIOD_OUT_LOW);
+	if (IS_ERR(rt1015p->sdb))
+		return PTR_ERR(rt1015p->sdb);
+
+	dev_set_drvdata(&pdev->dev, rt1015p);
+
+	return devm_snd_soc_register_component(&pdev->dev,
+			&rt1015p_component_driver,
+			&rt1015p_dai_driver, 1);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id rt1015p_device_id[] = {
+	{ .compatible = "realtek,rt1015p" },
+	{ .compatible = "realtek,rt1019p" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, rt1015p_device_id);
+#endif
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id rt1015p_acpi_match[] = {
+	{ "RTL1015", 0},
+	{ "RTL1019", 0},
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, rt1015p_acpi_match);
+#endif
+
+static struct platform_driver rt1015p_platform_driver = {
+	.driver = {
+		.name = "rt1015p",
+		.of_match_table = of_match_ptr(rt1015p_device_id),
+		.acpi_match_table = ACPI_PTR(rt1015p_acpi_match),
+	},
+	.probe = rt1015p_platform_probe,
+};
+module_platform_driver(rt1015p_platform_driver);
+
+MODULE_DESCRIPTION("ASoC RT1015P driver");
+MODULE_LICENSE("GPL v2");