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, 86 insertions, 0 deletions

diff --git a/drivers/clk/sprd/composite.h b/drivers/clk/sprd/composite.h
new file mode 100644
index 000000000..15cec97d2
--- /dev/null
+++ b/drivers/clk/sprd/composite.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+//
+// Spreadtrum composite clock driver
+//
+// Copyright (C) 2017 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
+
+#ifndef _SPRD_COMPOSITE_H_
+#define _SPRD_COMPOSITE_H_
+
+#include "common.h"
+#include "mux.h"
+#include "div.h"
+
+struct sprd_comp {
+	struct sprd_mux_ssel	mux;
+	struct sprd_div_internal	div;
+	struct sprd_clk_common	common;
+};
+
+#define SPRD_COMP_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, _table,	\
+				 _mshift, _mwidth, _doffset, _dshift,	\
+				 _dwidth, _flags, _fn)			\
+	struct sprd_comp _struct = {					\
+		.mux	= _SPRD_MUX_CLK(_mshift, _mwidth, _table),	\
+		.div	= _SPRD_DIV_CLK(_doffset, _dshift, _dwidth),	\
+		.common = {						\
+			.regmap		= NULL,				\
+			.reg		= _reg,				\
+			.hw.init = _fn(_name, _parent,			\
+				       &sprd_comp_ops, _flags),		\
+		}							\
+	}
+
+#define SPRD_COMP_CLK_TABLE(_struct, _name, _parent, _reg, _table,	\
+			    _mshift, _mwidth, _dshift, _dwidth, _flags)	\
+	SPRD_COMP_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, _table,	\
+				 _mshift, _mwidth, 0x0, _dshift,	\
+				 _dwidth, _flags, CLK_HW_INIT_PARENTS)
+
+#define SPRD_COMP_CLK(_struct, _name, _parent, _reg, _mshift,		\
+		      _mwidth, _dshift, _dwidth, _flags)		\
+	SPRD_COMP_CLK_TABLE(_struct, _name, _parent, _reg, NULL,	\
+			    _mshift, _mwidth, _dshift, _dwidth, _flags)
+
+#define SPRD_COMP_CLK_DATA_TABLE(_struct, _name, _parent, _reg, _table,	\
+				 _mshift, _mwidth, _dshift,		\
+				 _dwidth, _flags)			\
+	SPRD_COMP_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, _table,	\
+				 _mshift, _mwidth, 0x0, _dshift,	\
+				 _dwidth, _flags,			\
+				 CLK_HW_INIT_PARENTS_DATA)
+
+#define SPRD_COMP_CLK_DATA(_struct, _name, _parent, _reg, _mshift,	\
+			   _mwidth, _dshift, _dwidth, _flags)		\
+	SPRD_COMP_CLK_DATA_TABLE(_struct, _name, _parent, _reg, NULL,	\
+				 _mshift, _mwidth, _dshift, _dwidth,	\
+				 _flags)
+
+#define SPRD_COMP_CLK_DATA_TABLE_OFFSET(_struct, _name, _parent, _reg,	\
+					_table, _mshift, _mwidth,	\
+					_doffset, _dshift, _dwidth,	\
+					_flags)				\
+	SPRD_COMP_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, _table,	\
+				 _mshift, _mwidth, _doffset, _dshift,	\
+				 _dwidth, _flags,			\
+				 CLK_HW_INIT_PARENTS_DATA)
+
+#define SPRD_COMP_CLK_DATA_OFFSET(_struct, _name, _parent, _reg,	\
+				  _mshift, _mwidth, _doffset, _dshift,	\
+				  _dwidth, _flags)			\
+	SPRD_COMP_CLK_DATA_TABLE_OFFSET(_struct, _name, _parent, _reg,	\
+					NULL, _mshift, _mwidth,		\
+					_doffset, _dshift, _dwidth,	\
+					_flags)
+
+static inline struct sprd_comp *hw_to_sprd_comp(const struct clk_hw *hw)
+{
+	struct sprd_clk_common *common = hw_to_sprd_clk_common(hw);
+
+	return container_of(common, struct sprd_comp, common);
+}
+
+extern const struct clk_ops sprd_comp_ops;
+
+#endif /* _SPRD_COMPOSITE_H_ */