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, 104 insertions, 0 deletions

diff --git a/sound/soc/sof/sof-of-dev.c b/sound/soc/sof/sof-of-dev.c
new file mode 100644
index 000000000..3ccfcfb14
--- /dev/null
+++ b/sound/soc/sof/sof-of-dev.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// Copyright 2019 NXP
+//
+// Author: Daniel Baluta <daniel.baluta@nxp.com>
+//
+
+#include <linux/firmware.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/pm_runtime.h>
+#include <sound/sof.h>
+
+#include "sof-of-dev.h"
+#include "ops.h"
+
+static char *fw_path;
+module_param(fw_path, charp, 0444);
+MODULE_PARM_DESC(fw_path, "deprecated - moved to snd-sof module.");
+
+static char *fw_filename;
+module_param(fw_filename, charp, 0444);
+MODULE_PARM_DESC(fw_filename, "deprecated - moved to snd-sof module.");
+
+static char *tplg_path;
+module_param(tplg_path, charp, 0444);
+MODULE_PARM_DESC(tplg_path, "deprecated - moved to snd-sof module.");
+
+static char *tplg_filename;
+module_param(tplg_filename, charp, 0444);
+MODULE_PARM_DESC(tplg_filename, "deprecated - moved to snd-sof module.");
+
+EXPORT_DEV_PM_OPS(sof_of_pm) = {
+	.prepare = snd_sof_prepare,
+	.complete = snd_sof_complete,
+	SYSTEM_SLEEP_PM_OPS(snd_sof_suspend, snd_sof_resume)
+	RUNTIME_PM_OPS(snd_sof_runtime_suspend, snd_sof_runtime_resume, NULL)
+};
+
+static void sof_of_probe_complete(struct device *dev)
+{
+	/* allow runtime_pm */
+	pm_runtime_set_autosuspend_delay(dev, SND_SOF_SUSPEND_DELAY_MS);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+}
+
+int sof_of_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct sof_dev_desc *desc;
+	struct snd_sof_pdata *sof_pdata;
+
+	dev_info(&pdev->dev, "DT DSP detected");
+
+	sof_pdata = devm_kzalloc(dev, sizeof(*sof_pdata), GFP_KERNEL);
+	if (!sof_pdata)
+		return -ENOMEM;
+
+	desc = device_get_match_data(dev);
+	if (!desc)
+		return -ENODEV;
+
+	if (!desc->ops) {
+		dev_err(dev, "error: no matching DT descriptor ops\n");
+		return -ENODEV;
+	}
+
+	sof_pdata->desc = desc;
+	sof_pdata->dev = &pdev->dev;
+
+	sof_pdata->ipc_file_profile_base.ipc_type = desc->ipc_default;
+	sof_pdata->ipc_file_profile_base.fw_path = fw_path;
+	sof_pdata->ipc_file_profile_base.tplg_path = tplg_path;
+	sof_pdata->ipc_file_profile_base.fw_name = fw_filename;
+	sof_pdata->ipc_file_profile_base.tplg_name = tplg_filename;
+
+	/* set callback to be called on successful device probe to enable runtime_pm */
+	sof_pdata->sof_probe_complete = sof_of_probe_complete;
+
+	/* call sof helper for DSP hardware probe */
+	return snd_sof_device_probe(dev, sof_pdata);
+}
+EXPORT_SYMBOL(sof_of_probe);
+
+void sof_of_remove(struct platform_device *pdev)
+{
+	pm_runtime_disable(&pdev->dev);
+
+	/* call sof helper for DSP hardware remove */
+	snd_sof_device_remove(&pdev->dev);
+}
+EXPORT_SYMBOL(sof_of_remove);
+
+void sof_of_shutdown(struct platform_device *pdev)
+{
+	snd_sof_device_shutdown(&pdev->dev);
+}
+EXPORT_SYMBOL(sof_of_shutdown);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("SOF support for OF/DT platforms");