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, 190 insertions, 0 deletions

diff --git a/sound/soc/sof/loader.c b/sound/soc/sof/loader.c
new file mode 100644
index 000000000..0baf316b0
--- /dev/null
+++ b/sound/soc/sof/loader.c
@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license.  When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2018 Intel Corporation
+//
+// Author: Liam Girdwood <liam.r.girdwood@linux.intel.com>
+//
+// Generic firmware loader.
+//
+
+#include <linux/firmware.h>
+#include "sof-priv.h"
+#include "ops.h"
+
+int snd_sof_load_firmware_raw(struct snd_sof_dev *sdev)
+{
+	struct snd_sof_pdata *plat_data = sdev->pdata;
+	const char *fw_filename;
+	ssize_t ext_man_size;
+	int ret;
+
+	/* Don't request firmware again if firmware is already requested */
+	if (sdev->basefw.fw)
+		return 0;
+
+	fw_filename = kasprintf(GFP_KERNEL, "%s/%s",
+				plat_data->fw_filename_prefix,
+				plat_data->fw_filename);
+	if (!fw_filename)
+		return -ENOMEM;
+
+	ret = request_firmware(&sdev->basefw.fw, fw_filename, sdev->dev);
+
+	if (ret < 0) {
+		dev_err(sdev->dev,
+			"error: sof firmware file is missing, you might need to\n");
+		dev_err(sdev->dev,
+			"       download it from https://github.com/thesofproject/sof-bin/\n");
+		goto err;
+	} else {
+		dev_dbg(sdev->dev, "request_firmware %s successful\n",
+			fw_filename);
+	}
+
+	/* check for extended manifest */
+	ext_man_size = sdev->ipc->ops->fw_loader->parse_ext_manifest(sdev);
+	if (ext_man_size > 0) {
+		/* when no error occurred, drop extended manifest */
+		sdev->basefw.payload_offset = ext_man_size;
+	} else if (!ext_man_size) {
+		/* No extended manifest, so nothing to skip during FW load */
+		dev_dbg(sdev->dev, "firmware doesn't contain extended manifest\n");
+	} else {
+		ret = ext_man_size;
+		dev_err(sdev->dev, "error: firmware %s contains unsupported or invalid extended manifest: %d\n",
+			fw_filename, ret);
+	}
+
+err:
+	kfree(fw_filename);
+
+	return ret;
+}
+EXPORT_SYMBOL(snd_sof_load_firmware_raw);
+
+int snd_sof_load_firmware_memcpy(struct snd_sof_dev *sdev)
+{
+	int ret;
+
+	ret = snd_sof_load_firmware_raw(sdev);
+	if (ret < 0)
+		return ret;
+
+	/* make sure the FW header and file is valid */
+	ret = sdev->ipc->ops->fw_loader->validate(sdev);
+	if (ret < 0) {
+		dev_err(sdev->dev, "error: invalid FW header\n");
+		goto error;
+	}
+
+	/* prepare the DSP for FW loading */
+	ret = snd_sof_dsp_reset(sdev);
+	if (ret < 0) {
+		dev_err(sdev->dev, "error: failed to reset DSP\n");
+		goto error;
+	}
+
+	/* parse and load firmware modules to DSP */
+	if (sdev->ipc->ops->fw_loader->load_fw_to_dsp) {
+		ret = sdev->ipc->ops->fw_loader->load_fw_to_dsp(sdev);
+		if (ret < 0) {
+			dev_err(sdev->dev, "Firmware loading failed\n");
+			goto error;
+		}
+	}
+
+	return 0;
+
+error:
+	release_firmware(sdev->basefw.fw);
+	sdev->basefw.fw = NULL;
+	return ret;
+
+}
+EXPORT_SYMBOL(snd_sof_load_firmware_memcpy);
+
+int snd_sof_run_firmware(struct snd_sof_dev *sdev)
+{
+	int ret;
+
+	init_waitqueue_head(&sdev->boot_wait);
+
+	/* (re-)enable dsp dump */
+	sdev->dbg_dump_printed = false;
+	sdev->ipc_dump_printed = false;
+
+	/* create read-only fw_version debugfs to store boot version info */
+	if (sdev->first_boot) {
+		ret = snd_sof_debugfs_buf_item(sdev, &sdev->fw_version,
+					       sizeof(sdev->fw_version),
+					       "fw_version", 0444);
+		/* errors are only due to memory allocation, not debugfs */
+		if (ret < 0) {
+			dev_err(sdev->dev, "snd_sof_debugfs_buf_item failed\n");
+			return ret;
+		}
+	}
+
+	/* perform pre fw run operations */
+	ret = snd_sof_dsp_pre_fw_run(sdev);
+	if (ret < 0) {
+		dev_err(sdev->dev, "failed pre fw run op\n");
+		return ret;
+	}
+
+	dev_dbg(sdev->dev, "booting DSP firmware\n");
+
+	/* boot the firmware on the DSP */
+	ret = snd_sof_dsp_run(sdev);
+	if (ret < 0) {
+		snd_sof_dsp_dbg_dump(sdev, "Failed to start DSP",
+				     SOF_DBG_DUMP_MBOX | SOF_DBG_DUMP_PCI);
+		return ret;
+	}
+
+	/*
+	 * now wait for the DSP to boot. There are 3 possible outcomes:
+	 * 1. Boot wait times out indicating FW boot failure.
+	 * 2. FW boots successfully and fw_ready op succeeds.
+	 * 3. FW boots but fw_ready op fails.
+	 */
+	ret = wait_event_timeout(sdev->boot_wait,
+				 sdev->fw_state > SOF_FW_BOOT_IN_PROGRESS,
+				 msecs_to_jiffies(sdev->boot_timeout));
+	if (ret == 0) {
+		snd_sof_dsp_dbg_dump(sdev, "Firmware boot failure due to timeout",
+				     SOF_DBG_DUMP_REGS | SOF_DBG_DUMP_MBOX |
+				     SOF_DBG_DUMP_TEXT | SOF_DBG_DUMP_PCI);
+		return -EIO;
+	}
+
+	if (sdev->fw_state == SOF_FW_BOOT_READY_FAILED)
+		return -EIO; /* FW boots but fw_ready op failed */
+
+	dev_dbg(sdev->dev, "firmware boot complete\n");
+	sof_set_fw_state(sdev, SOF_FW_BOOT_COMPLETE);
+
+	/* perform post fw run operations */
+	ret = snd_sof_dsp_post_fw_run(sdev);
+	if (ret < 0) {
+		dev_err(sdev->dev, "error: failed post fw run op\n");
+		return ret;
+	}
+
+	if (sdev->ipc->ops->post_fw_boot)
+		return sdev->ipc->ops->post_fw_boot(sdev);
+
+	return 0;
+}
+EXPORT_SYMBOL(snd_sof_run_firmware);
+
+void snd_sof_fw_unload(struct snd_sof_dev *sdev)
+{
+	/* TODO: support module unloading at runtime */
+	release_firmware(sdev->basefw.fw);
+	sdev->basefw.fw = NULL;
+}
+EXPORT_SYMBOL(snd_sof_fw_unload);