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, 73 insertions, 0 deletions

diff --git a/sound/soc/sof/ipc4-telemetry.h b/sound/soc/sof/ipc4-telemetry.h
new file mode 100644
index 000000000..9298f8acc
--- /dev/null
+++ b/sound/soc/sof/ipc4-telemetry.h
@@ -0,0 +1,73 @@
+/* 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) 2023 Intel Corporation
+ */
+
+#ifndef __SOUND_SOC_SOF_IPC4_TELEMETRY_H
+#define __SOUND_SOC_SOF_IPC4_TELEMETRY_H
+
+/* Target code */
+enum sof_ipc4_coredump_tgt_code {
+	COREDUMP_TGT_UNKNOWN = 0,
+	COREDUMP_TGT_X86,
+	COREDUMP_TGT_X86_64,
+	COREDUMP_TGT_ARM_CORTEX_M,
+	COREDUMP_TGT_RISC_V,
+	COREDUMP_TGT_XTENSA,
+};
+
+#define COREDUMP_ARCH_HDR_ID 'A'
+#define COREDUMP_HDR_ID0 'Z'
+#define COREDUMP_HDR_ID1 'E'
+
+#define XTENSA_BLOCK_HDR_VER		2
+#define XTENSA_CORE_DUMP_SEPARATOR	0x0DEC0DEB
+#define XTENSA_CORE_AR_REGS_COUNT	16
+#define XTENSA_SOC_INTEL_ADSP		3
+#define XTENSA_TOOL_CHAIN_ZEPHYR	1
+#define XTENSA_TOOL_CHAIN_XCC		2
+
+/* Coredump header */
+struct sof_ipc4_coredump_hdr {
+	/* 'Z', 'E' as identifier of file */
+	char id[2];
+
+	/* Identify the version of the header */
+	u16 hdr_version;
+
+	/* Indicate which target (e.g. architecture or SoC) */
+	u16 tgt_code;
+
+	/* Size of uintptr_t in power of 2. (e.g. 5 for 32-bit, 6 for 64-bit) */
+	u8 ptr_size_bits;
+
+	u8 flag;
+
+	/* Reason for the fatal error */
+	u32 reason;
+} __packed;
+
+/* Architecture-specific block header */
+struct sof_ipc4_coredump_arch_hdr {
+	/* COREDUMP_ARCH_HDR_ID to indicate this is a architecture-specific block */
+	char id;
+
+	/* Identify the version of this block */
+	u16 hdr_version;
+
+	/* Number of bytes following the header */
+	u16 num_bytes;
+} __packed;
+
+struct sof_ipc4_telemetry_slot_data {
+	u32 separator;
+	struct sof_ipc4_coredump_hdr hdr;
+	struct sof_ipc4_coredump_arch_hdr arch_hdr;
+	u32 arch_data[];
+} __packed;
+
+void sof_ipc4_create_exception_debugfs_node(struct snd_sof_dev *sdev);
+#endif