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, 49 insertions, 0 deletions

diff --git a/include/sound/sof/xtensa.h b/include/sound/sof/xtensa.h
new file mode 100644
index 000000000..ef70f8e26
--- /dev/null
+++ b/include/sound/sof/xtensa.h
@@ -0,0 +1,49 @@
+/* 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
+ */
+
+#ifndef __INCLUDE_SOUND_SOF_XTENSA_H__
+#define __INCLUDE_SOUND_SOF_XTENSA_H__
+
+#include <sound/sof/header.h>
+
+/*
+ * Architecture specific debug
+ */
+
+/* Xtensa Firmware Oops data */
+struct sof_ipc_dsp_oops_xtensa {
+	struct sof_ipc_dsp_oops_arch_hdr arch_hdr;
+	struct sof_ipc_dsp_oops_plat_hdr plat_hdr;
+	uint32_t exccause;
+	uint32_t excvaddr;
+	uint32_t ps;
+	uint32_t epc1;
+	uint32_t epc2;
+	uint32_t epc3;
+	uint32_t epc4;
+	uint32_t epc5;
+	uint32_t epc6;
+	uint32_t epc7;
+	uint32_t eps2;
+	uint32_t eps3;
+	uint32_t eps4;
+	uint32_t eps5;
+	uint32_t eps6;
+	uint32_t eps7;
+	uint32_t depc;
+	uint32_t intenable;
+	uint32_t interrupt;
+	uint32_t sar;
+	uint32_t debugcause;
+	uint32_t windowbase;
+	uint32_t windowstart;
+	uint32_t excsave1;
+	uint32_t ar[];
+}  __packed;
+
+#endif