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, 233 insertions, 0 deletions

diff --git a/sound/virtio/virtio_jack.c b/sound/virtio/virtio_jack.c
new file mode 100644
index 000000000..68e40c7f5
--- /dev/null
+++ b/sound/virtio/virtio_jack.c
@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * virtio-snd: Virtio sound device
+ * Copyright (C) 2021 OpenSynergy GmbH
+ */
+#include <linux/virtio_config.h>
+#include <sound/jack.h>
+#include <sound/hda_verbs.h>
+
+#include "virtio_card.h"
+
+/**
+ * DOC: Implementation Status
+ *
+ * At the moment jacks have a simple implementation and can only be used to
+ * receive notifications about a plugged in/out device.
+ *
+ * VIRTIO_SND_R_JACK_REMAP
+ *   is not supported
+ */
+
+/**
+ * struct virtio_jack - VirtIO jack.
+ * @jack: Kernel jack control.
+ * @nid: Functional group node identifier.
+ * @features: Jack virtio feature bit map (1 << VIRTIO_SND_JACK_F_XXX).
+ * @defconf: Pin default configuration value.
+ * @caps: Pin capabilities value.
+ * @connected: Current jack connection status.
+ * @type: Kernel jack type (SND_JACK_XXX).
+ */
+struct virtio_jack {
+	struct snd_jack *jack;
+	u32 nid;
+	u32 features;
+	u32 defconf;
+	u32 caps;
+	bool connected;
+	int type;
+};
+
+/**
+ * virtsnd_jack_get_label() - Get the name string for the jack.
+ * @vjack: VirtIO jack.
+ *
+ * Returns the jack name based on the default pin configuration value (see HDA
+ * specification).
+ *
+ * Context: Any context.
+ * Return: Name string.
+ */
+static const char *virtsnd_jack_get_label(struct virtio_jack *vjack)
+{
+	unsigned int defconf = vjack->defconf;
+	unsigned int device =
+		(defconf & AC_DEFCFG_DEVICE) >> AC_DEFCFG_DEVICE_SHIFT;
+	unsigned int location =
+		(defconf & AC_DEFCFG_LOCATION) >> AC_DEFCFG_LOCATION_SHIFT;
+
+	switch (device) {
+	case AC_JACK_LINE_OUT:
+		return "Line Out";
+	case AC_JACK_SPEAKER:
+		return "Speaker";
+	case AC_JACK_HP_OUT:
+		return "Headphone";
+	case AC_JACK_CD:
+		return "CD";
+	case AC_JACK_SPDIF_OUT:
+	case AC_JACK_DIG_OTHER_OUT:
+		if (location == AC_JACK_LOC_HDMI)
+			return "HDMI Out";
+		else
+			return "SPDIF Out";
+	case AC_JACK_LINE_IN:
+		return "Line";
+	case AC_JACK_AUX:
+		return "Aux";
+	case AC_JACK_MIC_IN:
+		return "Mic";
+	case AC_JACK_SPDIF_IN:
+		return "SPDIF In";
+	case AC_JACK_DIG_OTHER_IN:
+		return "Digital In";
+	default:
+		return "Misc";
+	}
+}
+
+/**
+ * virtsnd_jack_get_type() - Get the type for the jack.
+ * @vjack: VirtIO jack.
+ *
+ * Returns the jack type based on the default pin configuration value (see HDA
+ * specification).
+ *
+ * Context: Any context.
+ * Return: SND_JACK_XXX value.
+ */
+static int virtsnd_jack_get_type(struct virtio_jack *vjack)
+{
+	unsigned int defconf = vjack->defconf;
+	unsigned int device =
+		(defconf & AC_DEFCFG_DEVICE) >> AC_DEFCFG_DEVICE_SHIFT;
+
+	switch (device) {
+	case AC_JACK_LINE_OUT:
+	case AC_JACK_SPEAKER:
+		return SND_JACK_LINEOUT;
+	case AC_JACK_HP_OUT:
+		return SND_JACK_HEADPHONE;
+	case AC_JACK_SPDIF_OUT:
+	case AC_JACK_DIG_OTHER_OUT:
+		return SND_JACK_AVOUT;
+	case AC_JACK_MIC_IN:
+		return SND_JACK_MICROPHONE;
+	default:
+		return SND_JACK_LINEIN;
+	}
+}
+
+/**
+ * virtsnd_jack_parse_cfg() - Parse the jack configuration.
+ * @snd: VirtIO sound device.
+ *
+ * This function is called during initial device initialization.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+int virtsnd_jack_parse_cfg(struct virtio_snd *snd)
+{
+	struct virtio_device *vdev = snd->vdev;
+	struct virtio_snd_jack_info *info;
+	u32 i;
+	int rc;
+
+	virtio_cread_le(vdev, struct virtio_snd_config, jacks, &snd->njacks);
+	if (!snd->njacks)
+		return 0;
+
+	snd->jacks = devm_kcalloc(&vdev->dev, snd->njacks, sizeof(*snd->jacks),
+				  GFP_KERNEL);
+	if (!snd->jacks)
+		return -ENOMEM;
+
+	info = kzalloc_objs(*info, snd->njacks);
+	if (!info)
+		return -ENOMEM;
+
+	rc = virtsnd_ctl_query_info(snd, VIRTIO_SND_R_JACK_INFO, 0, snd->njacks,
+				    sizeof(*info), info);
+	if (rc)
+		goto on_exit;
+
+	for (i = 0; i < snd->njacks; ++i) {
+		struct virtio_jack *vjack = &snd->jacks[i];
+
+		vjack->nid = le32_to_cpu(info[i].hdr.hda_fn_nid);
+		vjack->features = le32_to_cpu(info[i].features);
+		vjack->defconf = le32_to_cpu(info[i].hda_reg_defconf);
+		vjack->caps = le32_to_cpu(info[i].hda_reg_caps);
+		vjack->connected = info[i].connected;
+	}
+
+on_exit:
+	kfree(info);
+
+	return rc;
+}
+
+/**
+ * virtsnd_jack_build_devs() - Build ALSA controls for jacks.
+ * @snd: VirtIO sound device.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+int virtsnd_jack_build_devs(struct virtio_snd *snd)
+{
+	u32 i;
+	int rc;
+
+	for (i = 0; i < snd->njacks; ++i) {
+		struct virtio_jack *vjack = &snd->jacks[i];
+
+		vjack->type = virtsnd_jack_get_type(vjack);
+
+		rc = snd_jack_new(snd->card, virtsnd_jack_get_label(vjack),
+				  vjack->type, &vjack->jack, true, true);
+		if (rc)
+			return rc;
+
+		if (vjack->jack)
+			vjack->jack->private_data = vjack;
+
+		snd_jack_report(vjack->jack,
+				vjack->connected ? vjack->type : 0);
+	}
+
+	return 0;
+}
+
+/**
+ * virtsnd_jack_event() - Handle the jack event notification.
+ * @snd: VirtIO sound device.
+ * @event: VirtIO sound event.
+ *
+ * Context: Interrupt context.
+ */
+void virtsnd_jack_event(struct virtio_snd *snd, struct virtio_snd_event *event)
+{
+	u32 jack_id = le32_to_cpu(event->data);
+	struct virtio_jack *vjack;
+
+	if (jack_id >= snd->njacks)
+		return;
+
+	vjack = &snd->jacks[jack_id];
+
+	switch (le32_to_cpu(event->hdr.code)) {
+	case VIRTIO_SND_EVT_JACK_CONNECTED:
+		vjack->connected = true;
+		break;
+	case VIRTIO_SND_EVT_JACK_DISCONNECTED:
+		vjack->connected = false;
+		break;
+	default:
+		return;
+	}
+
+	snd_jack_report(vjack->jack, vjack->connected ? vjack->type : 0);
+}