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, 345 insertions, 0 deletions

diff --git a/sound/hda/common/bind.c b/sound/hda/common/bind.c
new file mode 100644
index 000000000..6a728a773
--- /dev/null
+++ b/sound/hda/common/bind.c
@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HD-audio codec driver binding
+ * Copyright (c) Takashi Iwai <tiwai@suse.de>
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/export.h>
+#include <linux/pm.h>
+#include <sound/core.h>
+#include <sound/hda_codec.h>
+#include "hda_local.h"
+#include "hda_jack.h"
+
+/*
+ * find a matching codec id
+ */
+static int hda_codec_match(struct hdac_device *dev, const struct hdac_driver *drv)
+{
+	struct hda_codec *codec = container_of(dev, struct hda_codec, core);
+	const struct hda_codec_driver *driver =
+		container_of(drv, struct hda_codec_driver, core);
+	const struct hda_device_id *list;
+	/* check probe_id instead of vendor_id if set */
+	u32 id = codec->probe_id ? codec->probe_id : codec->core.vendor_id;
+	u32 rev_id = codec->core.revision_id;
+
+	for (list = driver->id; list->vendor_id; list++) {
+		if (list->vendor_id == id &&
+		    (!list->rev_id || list->rev_id == rev_id)) {
+			codec->preset = list;
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/* process an unsolicited event */
+static void hda_codec_unsol_event(struct hdac_device *dev, unsigned int ev)
+{
+	struct hda_codec *codec = container_of(dev, struct hda_codec, core);
+	struct hda_codec_driver *driver = hda_codec_to_driver(codec);
+
+	/* ignore unsol events during shutdown */
+	if (codec->card->shutdown || codec->bus->shutdown)
+		return;
+
+	/* ignore unsol events during system suspend/resume */
+	if (codec->core.dev.power.power_state.event != PM_EVENT_ON)
+		return;
+
+	if (driver->ops->unsol_event)
+		driver->ops->unsol_event(codec, ev);
+}
+
+/**
+ * snd_hda_codec_set_name - set the codec name
+ * @codec: the HDA codec
+ * @name: name string to set
+ */
+int snd_hda_codec_set_name(struct hda_codec *codec, const char *name)
+{
+	int err;
+
+	if (!name)
+		return 0;
+	err = snd_hdac_device_set_chip_name(&codec->core, name);
+	if (err < 0)
+		return err;
+
+	/* update the mixer name */
+	if (!*codec->card->mixername ||
+	    codec->bus->mixer_assigned >= codec->core.addr) {
+		snprintf(codec->card->mixername,
+			 sizeof(codec->card->mixername), "%s %s",
+			 codec->core.vendor_name, codec->core.chip_name);
+		codec->bus->mixer_assigned = codec->core.addr;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_hda_codec_set_name);
+
+static int hda_codec_driver_probe(struct device *dev)
+{
+	struct hda_codec *codec = dev_to_hda_codec(dev);
+	struct module *owner = dev->driver->owner;
+	struct hda_codec_driver *driver = hda_codec_to_driver(codec);
+	int err;
+
+	if (codec->bus->core.ext_ops) {
+		if (WARN_ON(!codec->bus->core.ext_ops->hdev_attach))
+			return -EINVAL;
+		return codec->bus->core.ext_ops->hdev_attach(&codec->core);
+	}
+
+	if (WARN_ON(!codec->preset))
+		return -EINVAL;
+
+	err = snd_hda_codec_set_name(codec, codec->preset->name);
+	if (err < 0)
+		goto error;
+	err = snd_hdac_regmap_init(&codec->core);
+	if (err < 0)
+		goto error;
+
+	if (!try_module_get(owner)) {
+		err = -EINVAL;
+		goto error;
+	}
+
+	if (WARN_ON(!(driver->ops && driver->ops->probe))) {
+		err = -EINVAL;
+		goto error_module_put;
+	}
+
+	err = driver->ops->probe(codec, codec->preset);
+	if (err < 0)
+		goto error_module_put;
+	err = snd_hda_codec_build_pcms(codec);
+	if (err < 0)
+		goto error_module;
+	err = snd_hda_codec_build_controls(codec);
+	if (err < 0)
+		goto error_module;
+	/* only register after the bus probe finished; otherwise it's racy */
+	if (!codec->bus->bus_probing && codec->card->registered) {
+		err = snd_card_register(codec->card);
+		if (err < 0)
+			goto error_module;
+		snd_hda_codec_register(codec);
+	}
+
+	codec->core.lazy_cache = true;
+	return 0;
+
+ error_module:
+	if (driver->ops->remove)
+		driver->ops->remove(codec);
+ error_module_put:
+	module_put(owner);
+
+ error:
+	snd_hda_codec_cleanup_for_unbind(codec);
+	codec->preset = NULL;
+	return err;
+}
+
+static int hda_codec_driver_remove(struct device *dev)
+{
+	struct hda_codec *codec = dev_to_hda_codec(dev);
+	struct hda_codec_driver *driver = hda_codec_to_driver(codec);
+
+	if (codec->bus->core.ext_ops) {
+		if (WARN_ON(!codec->bus->core.ext_ops->hdev_detach))
+			return -EINVAL;
+		return codec->bus->core.ext_ops->hdev_detach(&codec->core);
+	}
+
+	snd_hda_codec_disconnect_pcms(codec);
+	snd_hda_jack_tbl_disconnect(codec);
+	snd_refcount_sync(&codec->pcm_ref);
+	snd_power_sync_ref(codec->bus->card);
+
+	if (driver->ops->remove)
+		driver->ops->remove(codec);
+	snd_hda_codec_cleanup_for_unbind(codec);
+	codec->preset = NULL;
+	module_put(dev->driver->owner);
+	return 0;
+}
+
+static void hda_codec_driver_shutdown(struct device *dev)
+{
+	snd_hda_codec_shutdown(dev_to_hda_codec(dev));
+}
+
+int __hda_codec_driver_register(struct hda_codec_driver *drv, const char *name,
+			       struct module *owner)
+{
+	drv->core.driver.name = name;
+	drv->core.driver.owner = owner;
+	drv->core.driver.bus = &snd_hda_bus_type;
+	drv->core.driver.probe = hda_codec_driver_probe;
+	drv->core.driver.remove = hda_codec_driver_remove;
+	drv->core.driver.shutdown = hda_codec_driver_shutdown;
+	drv->core.driver.pm = pm_ptr(&hda_codec_driver_pm);
+	drv->core.type = HDA_DEV_LEGACY;
+	drv->core.match = hda_codec_match;
+	drv->core.unsol_event = hda_codec_unsol_event;
+	return driver_register(&drv->core.driver);
+}
+EXPORT_SYMBOL_GPL(__hda_codec_driver_register);
+
+void hda_codec_driver_unregister(struct hda_codec_driver *drv)
+{
+	driver_unregister(&drv->core.driver);
+}
+EXPORT_SYMBOL_GPL(hda_codec_driver_unregister);
+
+static inline bool codec_probed(struct hda_codec *codec)
+{
+	return device_attach(hda_codec_dev(codec)) > 0 && codec->preset;
+}
+
+/* try to auto-load codec module */
+static void request_codec_module(struct hda_codec *codec)
+{
+#ifdef MODULE
+	char modalias[32];
+	const char *mod = NULL;
+
+	switch (codec->probe_id) {
+	case HDA_CODEC_ID_GENERIC_HDMI:
+#if IS_MODULE(CONFIG_SND_HDA_CODEC_HDMI)
+		mod = "snd-hda-codec-hdmi";
+#endif
+		break;
+	case HDA_CODEC_ID_GENERIC:
+#if IS_MODULE(CONFIG_SND_HDA_GENERIC)
+		mod = "snd-hda-codec-generic";
+#endif
+		break;
+	default:
+		snd_hdac_codec_modalias(&codec->core, modalias, sizeof(modalias));
+		mod = modalias;
+		break;
+	}
+
+	if (mod)
+		request_module(mod);
+#endif /* MODULE */
+}
+
+/* try to auto-load and bind the codec module */
+static void codec_bind_module(struct hda_codec *codec)
+{
+#ifdef MODULE
+	request_codec_module(codec);
+	if (codec_probed(codec))
+		return;
+#endif
+}
+
+#if IS_ENABLED(CONFIG_SND_HDA_CODEC_HDMI)
+/* if all audio out widgets are digital, let's assume the codec as a HDMI/DP */
+static bool is_likely_hdmi_codec(struct hda_codec *codec)
+{
+	hda_nid_t nid;
+
+	/*
+	 * For ASoC users, if snd_hda_hdmi_codec module is denylisted and any
+	 * event causes i915 enumeration to fail, ->wcaps remains uninitialized.
+	 */
+	if (!codec->wcaps)
+		return true;
+
+	for_each_hda_codec_node(nid, codec) {
+		unsigned int wcaps = get_wcaps(codec, nid);
+		switch (get_wcaps_type(wcaps)) {
+		case AC_WID_AUD_IN:
+			return false; /* HDMI parser supports only HDMI out */
+		case AC_WID_AUD_OUT:
+			if (!(wcaps & AC_WCAP_DIGITAL))
+				return false;
+			break;
+		}
+	}
+	return true;
+}
+#else
+/* no HDMI codec parser support */
+#define is_likely_hdmi_codec(codec)	false
+#endif /* CONFIG_SND_HDA_CODEC_HDMI */
+
+static int codec_bind_generic(struct hda_codec *codec)
+{
+	if (codec->probe_id)
+		return -ENODEV;
+
+	if (is_likely_hdmi_codec(codec)) {
+		codec->probe_id = HDA_CODEC_ID_GENERIC_HDMI;
+		request_codec_module(codec);
+		if (codec_probed(codec))
+			return 0;
+	}
+
+	codec->probe_id = HDA_CODEC_ID_GENERIC;
+	request_codec_module(codec);
+	if (codec_probed(codec))
+		return 0;
+	return -ENODEV;
+}
+
+#if IS_ENABLED(CONFIG_SND_HDA_GENERIC)
+#define is_generic_config(codec) \
+	(codec->modelname && !strcmp(codec->modelname, "generic"))
+#else
+#define is_generic_config(codec)	0
+#endif
+
+/**
+ * snd_hda_codec_configure - (Re-)configure the HD-audio codec
+ * @codec: the HDA codec
+ *
+ * Start parsing of the given codec tree and (re-)initialize the whole
+ * codec driver binding.
+ *
+ * Returns 0 if successful or a negative error code.
+ */
+int snd_hda_codec_configure(struct hda_codec *codec)
+{
+	int err;
+
+	if (codec->configured)
+		return 0;
+
+	if (is_generic_config(codec))
+		codec->probe_id = HDA_CODEC_ID_GENERIC;
+	else
+		codec->probe_id = 0;
+
+	if (!device_is_registered(&codec->core.dev)) {
+		err = snd_hdac_device_register(&codec->core);
+		if (err < 0)
+			return err;
+	}
+
+	if (!codec->preset)
+		codec_bind_module(codec);
+	if (!codec->preset) {
+		err = codec_bind_generic(codec);
+		if (err < 0) {
+			codec_dbg(codec, "Unable to bind the codec\n");
+			return err;
+		}
+	}
+
+	codec->configured = 1;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_hda_codec_configure);