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, 396 insertions, 0 deletions

diff --git a/sound/soc/codecs/hda.c b/sound/soc/codecs/hda.c
new file mode 100644
index 000000000..237b0b060
--- /dev/null
+++ b/sound/soc/codecs/hda.c
@@ -0,0 +1,396 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright(c) 2021-2022 Intel Corporation
+//
+// Author: Cezary Rojewski <cezary.rojewski@intel.com>
+//
+
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <sound/soc.h>
+#include <sound/hdaudio_ext.h>
+#include <sound/hda_i915.h>
+#include <sound/hda_codec.h>
+#include "hda.h"
+
+static int hda_codec_create_dais(struct hda_codec *codec, int pcm_count,
+				 struct snd_soc_dai_driver **drivers)
+{
+	struct device *dev = &codec->core.dev;
+	struct snd_soc_dai_driver *drvs;
+	struct hda_pcm *pcm;
+	int i;
+
+	drvs = devm_kcalloc(dev, pcm_count, sizeof(*drvs), GFP_KERNEL);
+	if (!drvs)
+		return -ENOMEM;
+
+	pcm = list_first_entry(&codec->pcm_list_head, struct hda_pcm, list);
+
+	for (i = 0; i < pcm_count; i++, pcm = list_next_entry(pcm, list)) {
+		struct snd_soc_pcm_stream *stream;
+		int dir;
+
+		dev_info(dev, "creating for %s %d\n", pcm->name, i);
+		drvs[i].id = i;
+		drvs[i].name = pcm->name;
+		drvs[i].ops = &snd_soc_hda_codec_dai_ops;
+
+		dir = SNDRV_PCM_STREAM_PLAYBACK;
+		stream = &drvs[i].playback;
+		if (!pcm->stream[dir].substreams) {
+			dev_info(dev, "skipping playback dai for %s\n", pcm->name);
+			goto capture_dais;
+		}
+
+		stream->stream_name =
+			devm_kasprintf(dev, GFP_KERNEL, "%s %s", pcm->name,
+				       snd_pcm_direction_name(dir));
+		if (!stream->stream_name)
+			return -ENOMEM;
+		stream->channels_min = pcm->stream[dir].channels_min;
+		stream->channels_max = pcm->stream[dir].channels_max;
+		stream->rates = pcm->stream[dir].rates;
+		stream->formats = pcm->stream[dir].formats;
+		stream->subformats = pcm->stream[dir].subformats;
+		stream->sig_bits = pcm->stream[dir].maxbps;
+
+capture_dais:
+		dir = SNDRV_PCM_STREAM_CAPTURE;
+		stream = &drvs[i].capture;
+		if (!pcm->stream[dir].substreams) {
+			dev_info(dev, "skipping capture dai for %s\n", pcm->name);
+			continue;
+		}
+
+		stream->stream_name =
+			devm_kasprintf(dev, GFP_KERNEL, "%s %s", pcm->name,
+				       snd_pcm_direction_name(dir));
+		if (!stream->stream_name)
+			return -ENOMEM;
+		stream->channels_min = pcm->stream[dir].channels_min;
+		stream->channels_max = pcm->stream[dir].channels_max;
+		stream->rates = pcm->stream[dir].rates;
+		stream->formats = pcm->stream[dir].formats;
+		stream->subformats = pcm->stream[dir].subformats;
+		stream->sig_bits = pcm->stream[dir].maxbps;
+	}
+
+	*drivers = drvs;
+	return 0;
+}
+
+static int hda_codec_register_dais(struct hda_codec *codec, struct snd_soc_component *component)
+{
+	struct snd_soc_dai_driver *drvs = NULL;
+	struct snd_soc_dapm_context *dapm;
+	struct hda_pcm *pcm;
+	int ret, pcm_count = 0;
+
+	if (list_empty(&codec->pcm_list_head))
+		return -EINVAL;
+	list_for_each_entry(pcm, &codec->pcm_list_head, list)
+		pcm_count++;
+
+	ret = hda_codec_create_dais(codec, pcm_count, &drvs);
+	if (ret < 0)
+		return ret;
+
+	dapm = snd_soc_component_to_dapm(component);
+
+	list_for_each_entry(pcm, &codec->pcm_list_head, list) {
+		struct snd_soc_dai *dai;
+
+		dai = snd_soc_register_dai(component, drvs, false);
+		if (!dai) {
+			dev_err(component->dev, "register dai for %s failed\n", pcm->name);
+			return -EINVAL;
+		}
+
+		ret = snd_soc_dapm_new_dai_widgets(dapm, dai);
+		if (ret < 0) {
+			dev_err(component->dev, "create widgets failed: %d\n", ret);
+			snd_soc_unregister_dai(dai);
+			return ret;
+		}
+
+		snd_soc_dai_init_dma_data(dai, &pcm->stream[0], &pcm->stream[1]);
+		drvs++;
+	}
+
+	return 0;
+}
+
+static void hda_codec_unregister_dais(struct hda_codec *codec,
+				      struct snd_soc_component *component)
+{
+	struct snd_soc_dai *dai, *save;
+	struct hda_pcm *pcm;
+
+	for_each_component_dais_safe(component, dai, save) {
+		int stream;
+
+		list_for_each_entry(pcm, &codec->pcm_list_head, list) {
+			if (strcmp(dai->driver->name, pcm->name))
+				continue;
+
+			for_each_pcm_streams(stream)
+				snd_soc_dapm_free_widget(snd_soc_dai_get_widget(dai, stream));
+
+			snd_soc_unregister_dai(dai);
+			break;
+		}
+	}
+}
+
+int hda_codec_probe_complete(struct hda_codec *codec)
+{
+	struct hdac_device *hdev = &codec->core;
+	struct hdac_bus *bus = hdev->bus;
+	int ret;
+
+	ret = snd_hda_codec_build_controls(codec);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "unable to create controls %d\n", ret);
+		return ret;
+	}
+
+	/* Bus suspended codecs as it does not manage their pm */
+	pm_runtime_set_active(&hdev->dev);
+	/* rpm was forbidden in snd_hda_codec_device_new() */
+	snd_hda_codec_set_power_save(codec, 2000);
+	snd_hda_codec_register(codec);
+
+	/* Complement pm_runtime_get_sync(bus) in probe */
+	pm_runtime_put_autosuspend(bus->dev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hda_codec_probe_complete);
+
+/* Expects codec with usage_count=1 and status=suspended */
+static int hda_codec_probe(struct snd_soc_component *component)
+{
+	struct hda_codec *codec = dev_to_hda_codec(component->dev);
+	struct hda_codec_driver *driver = hda_codec_to_driver(codec);
+	struct hdac_device *hdev = &codec->core;
+	struct hdac_bus *bus = hdev->bus;
+	struct hdac_ext_link *hlink;
+	int ret;
+
+#ifdef CONFIG_PM
+	WARN_ON(atomic_read(&hdev->dev.power.usage_count) != 1 ||
+		!pm_runtime_status_suspended(&hdev->dev));
+#endif
+
+	hlink = snd_hdac_ext_bus_get_hlink_by_addr(bus, hdev->addr);
+	if (!hlink) {
+		dev_err(&hdev->dev, "hdac link not found\n");
+		return -EIO;
+	}
+
+	pm_runtime_get_sync(bus->dev);
+	if (hda_codec_is_display(codec))
+		snd_hdac_display_power(bus, hdev->addr, true);
+	snd_hdac_ext_bus_link_get(bus, hlink);
+
+	ret = snd_hda_codec_device_new(codec->bus, component->card->snd_card, hdev->addr, codec,
+				       false);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "codec create failed: %d\n", ret);
+		goto device_new_err;
+	}
+
+	ret = snd_hda_codec_set_name(codec, codec->preset->name);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "set name: %s failed: %d\n", codec->preset->name, ret);
+		goto err;
+	}
+
+	ret = snd_hdac_regmap_init(&codec->core);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "regmap init failed: %d\n", ret);
+		goto err;
+	}
+
+	if (WARN_ON(!(driver->ops && driver->ops->probe))) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	ret = driver->ops->probe(codec, codec->preset);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "codec init failed: %d\n", ret);
+		goto err;
+	}
+
+	ret = snd_hda_codec_parse_pcms(codec);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "unable to map pcms to dai: %d\n", ret);
+		goto parse_pcms_err;
+	}
+
+	ret = hda_codec_register_dais(codec, component);
+	if (ret < 0) {
+		dev_err(&hdev->dev, "update dais failed: %d\n", ret);
+		goto parse_pcms_err;
+	}
+
+	if (!hda_codec_is_display(codec)) {
+		ret = hda_codec_probe_complete(codec);
+		if (ret < 0)
+			goto complete_err;
+	}
+
+	codec->core.lazy_cache = true;
+
+	return 0;
+
+complete_err:
+	hda_codec_unregister_dais(codec, component);
+parse_pcms_err:
+	if (driver->ops->remove)
+		driver->ops->remove(codec);
+err:
+	snd_hda_codec_cleanup_for_unbind(codec);
+device_new_err:
+	if (hda_codec_is_display(codec))
+		snd_hdac_display_power(bus, hdev->addr, false);
+
+	snd_hdac_ext_bus_link_put(bus, hlink);
+
+	pm_runtime_put_autosuspend(bus->dev);
+	return ret;
+}
+
+/* Leaves codec with usage_count=1 and status=suspended */
+static void hda_codec_remove(struct snd_soc_component *component)
+{
+	struct hda_codec *codec = dev_to_hda_codec(component->dev);
+	struct hda_codec_driver *driver = hda_codec_to_driver(codec);
+	struct hdac_device *hdev = &codec->core;
+	struct hdac_bus *bus = hdev->bus;
+	struct hdac_ext_link *hlink;
+	bool was_registered = codec->core.registered;
+
+	/* Don't allow any more runtime suspends */
+	pm_runtime_forbid(&hdev->dev);
+
+	hda_codec_unregister_dais(codec, component);
+
+	if (driver->ops->remove)
+		driver->ops->remove(codec);
+
+	snd_hda_codec_cleanup_for_unbind(codec);
+	pm_runtime_put_noidle(&hdev->dev);
+	/* snd_hdac_device_exit() is only called on bus remove */
+	pm_runtime_set_suspended(&hdev->dev);
+
+	if (hda_codec_is_display(codec))
+		snd_hdac_display_power(bus, hdev->addr, false);
+
+	hlink = snd_hdac_ext_bus_get_hlink_by_addr(bus, hdev->addr);
+	if (hlink)
+		snd_hdac_ext_bus_link_put(bus, hlink);
+	/*
+	 * HDMI card's hda_codec_probe_complete() (see late_probe()) may
+	 * not be called due to early error, leaving bus uc unbalanced
+	 */
+	if (!was_registered) {
+		pm_runtime_put_autosuspend(bus->dev);
+	}
+
+#ifdef CONFIG_PM
+	WARN_ON(atomic_read(&hdev->dev.power.usage_count) != 1 ||
+		!pm_runtime_status_suspended(&hdev->dev));
+#endif
+}
+
+static const struct snd_soc_dapm_route hda_dapm_routes[] = {
+	{"AIF1TX", NULL, "Codec Input Pin1"},
+	{"AIF2TX", NULL, "Codec Input Pin2"},
+	{"AIF3TX", NULL, "Codec Input Pin3"},
+
+	{"Codec Output Pin1", NULL, "AIF1RX"},
+	{"Codec Output Pin2", NULL, "AIF2RX"},
+	{"Codec Output Pin3", NULL, "AIF3RX"},
+};
+
+static const struct snd_soc_dapm_widget hda_dapm_widgets[] = {
+	/* Audio Interface */
+	SND_SOC_DAPM_AIF_IN("AIF1RX", "Analog Codec Playback", 0, SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_AIF_IN("AIF2RX", "Digital Codec Playback", 0, SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_AIF_IN("AIF3RX", "Alt Analog Codec Playback", 0, SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_AIF_OUT("AIF1TX", "Analog Codec Capture", 0, SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_AIF_OUT("AIF2TX", "Digital Codec Capture", 0, SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_AIF_OUT("AIF3TX", "Alt Analog Codec Capture", 0, SND_SOC_NOPM, 0, 0),
+
+	/* Input Pins */
+	SND_SOC_DAPM_INPUT("Codec Input Pin1"),
+	SND_SOC_DAPM_INPUT("Codec Input Pin2"),
+	SND_SOC_DAPM_INPUT("Codec Input Pin3"),
+
+	/* Output Pins */
+	SND_SOC_DAPM_OUTPUT("Codec Output Pin1"),
+	SND_SOC_DAPM_OUTPUT("Codec Output Pin2"),
+	SND_SOC_DAPM_OUTPUT("Codec Output Pin3"),
+};
+
+static struct snd_soc_dai_driver card_binder_dai = {
+	.id = -1,
+	.name = "codec-probing-DAI",
+};
+
+static int hda_hdev_attach(struct hdac_device *hdev)
+{
+	struct hda_codec *codec = dev_to_hda_codec(&hdev->dev);
+	struct snd_soc_component_driver *comp_drv;
+
+	if (hda_codec_is_display(codec) && !hdev->bus->audio_component) {
+		dev_dbg(&hdev->dev, "no i915, skip registration for 0x%08x\n", hdev->vendor_id);
+		return -ENODEV;
+	}
+
+	comp_drv = devm_kzalloc(&hdev->dev, sizeof(*comp_drv), GFP_KERNEL);
+	if (!comp_drv)
+		return -ENOMEM;
+
+	/*
+	 * It's save to rely on dev_name() rather than a copy as component
+	 * driver's lifetime is directly tied to hda codec one
+	 */
+	comp_drv->name = dev_name(&hdev->dev);
+	comp_drv->probe = hda_codec_probe;
+	comp_drv->remove = hda_codec_remove;
+	comp_drv->idle_bias_on = false;
+	if (!hda_codec_is_display(codec)) {
+		comp_drv->dapm_widgets = hda_dapm_widgets;
+		comp_drv->num_dapm_widgets = ARRAY_SIZE(hda_dapm_widgets);
+		comp_drv->dapm_routes = hda_dapm_routes;
+		comp_drv->num_dapm_routes = ARRAY_SIZE(hda_dapm_routes);
+	}
+
+	return snd_soc_register_component(&hdev->dev, comp_drv, &card_binder_dai, 1);
+}
+
+static int hda_hdev_detach(struct hdac_device *hdev)
+{
+	struct hda_codec *codec = dev_to_hda_codec(&hdev->dev);
+
+	if (codec->core.registered)
+		cancel_delayed_work_sync(&codec->jackpoll_work);
+
+	snd_soc_unregister_component(&hdev->dev);
+
+	return 0;
+}
+
+const struct hdac_ext_bus_ops soc_hda_ext_bus_ops = {
+	.hdev_attach = hda_hdev_attach,
+	.hdev_detach = hda_hdev_detach,
+};
+EXPORT_SYMBOL_GPL(soc_hda_ext_bus_ops);
+
+MODULE_DESCRIPTION("HD-Audio codec driver");
+MODULE_AUTHOR("Cezary Rojewski <cezary.rojewski@intel.com>");
+MODULE_LICENSE("GPL");