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, 168 insertions, 0 deletions

diff --git a/drivers/clk/sprd/gate.h b/drivers/clk/sprd/gate.h
new file mode 100644
index 000000000..775519eb1
--- /dev/null
+++ b/drivers/clk/sprd/gate.h
@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+//
+// Spreadtrum gate clock driver
+//
+// Copyright (C) 2017 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
+
+#ifndef _SPRD_GATE_H_
+#define _SPRD_GATE_H_
+
+#include "common.h"
+
+struct sprd_gate {
+	u32			enable_mask;
+	u16			flags;
+	u16			sc_offset;
+	u16			udelay;
+
+	struct sprd_clk_common	common;
+};
+
+/*
+ * sprd_gate->flags is used for:
+ * CLK_GATE_SET_TO_DISABLE	BIT(0)
+ * CLK_GATE_HIWORD_MASK		BIT(1)
+ * CLK_GATE_BIG_ENDIAN		BIT(2)
+ * so we define new flags from	BIT(3)
+ */
+#define SPRD_GATE_NON_AON BIT(3) /* not always powered on, check before read */
+
+#define SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, _udelay, _ops, _fn)	\
+	struct sprd_gate _struct = {					\
+		.enable_mask	= _enable_mask,				\
+		.sc_offset	= _sc_offset,				\
+		.flags		= _gate_flags,				\
+		.udelay		= _udelay,				\
+		.common	= {						\
+			.regmap		= NULL,				\
+			.reg		= _reg,				\
+			.hw.init	= _fn(_name, _parent,		\
+					      _ops, _flags),		\
+		}							\
+	}
+
+#define SPRD_SC_GATE_CLK_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, _udelay, _ops)		\
+	SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, _udelay, _ops, CLK_HW_INIT)
+
+#define SPRD_SC_GATE_CLK_OPS(_struct, _name, _parent, _reg, _sc_offset,	\
+			     _enable_mask, _flags, _gate_flags, _ops)	\
+	SPRD_SC_GATE_CLK_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, 0, _ops)
+
+#define SPRD_SC_GATE_CLK(_struct, _name, _parent, _reg, _sc_offset,	\
+			 _enable_mask, _flags, _gate_flags)		\
+	SPRD_SC_GATE_CLK_OPS(_struct, _name, _parent, _reg, _sc_offset,	\
+			     _enable_mask, _flags, _gate_flags,		\
+			     &sprd_sc_gate_ops)
+
+#define SPRD_GATE_CLK(_struct, _name, _parent, _reg,			\
+		      _enable_mask, _flags, _gate_flags)		\
+	SPRD_SC_GATE_CLK_OPS(_struct, _name, _parent, _reg, 0,		\
+			     _enable_mask, _flags, _gate_flags,		\
+			     &sprd_gate_ops)
+
+#define SPRD_PLL_SC_GATE_CLK(_struct, _name, _parent, _reg, _sc_offset,	\
+			     _enable_mask, _flags, _gate_flags,		\
+			     _udelay)					\
+	SPRD_SC_GATE_CLK_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				    _sc_offset,	_enable_mask, _flags,	\
+				    _gate_flags, _udelay,		\
+				    &sprd_pll_sc_gate_ops)
+
+
+#define SPRD_SC_GATE_CLK_HW_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				       _sc_offset, _enable_mask,	\
+				       _flags, _gate_flags,		\
+				       _udelay, _ops)			\
+	SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, _udelay, _ops,		\
+				    CLK_HW_INIT_HW)
+
+#define SPRD_SC_GATE_CLK_HW_OPS(_struct, _name, _parent, _reg,		\
+				_sc_offset, _enable_mask, _flags,	\
+				_gate_flags, _ops)			\
+	SPRD_SC_GATE_CLK_HW_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				       _sc_offset, _enable_mask,	\
+				       _flags, _gate_flags, 0, _ops)
+
+#define SPRD_SC_GATE_CLK_HW(_struct, _name, _parent, _reg,		\
+			    _sc_offset, _enable_mask, _flags,		\
+			    _gate_flags)				\
+	SPRD_SC_GATE_CLK_HW_OPS(_struct, _name, _parent, _reg,		\
+				_sc_offset, _enable_mask, _flags,	\
+				_gate_flags, &sprd_sc_gate_ops)
+
+#define SPRD_GATE_CLK_HW(_struct, _name, _parent, _reg,			\
+			 _enable_mask, _flags, _gate_flags)		\
+	SPRD_SC_GATE_CLK_HW_OPS(_struct, _name, _parent, _reg, 0,	\
+				_enable_mask, _flags, _gate_flags,	\
+				&sprd_gate_ops)
+
+#define SPRD_PLL_SC_GATE_CLK_HW(_struct, _name, _parent, _reg,		\
+				_sc_offset, _enable_mask, _flags,	\
+				_gate_flags, _udelay)			\
+	SPRD_SC_GATE_CLK_HW_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				       _sc_offset, _enable_mask,	\
+				       _flags, _gate_flags, _udelay,	\
+				       &sprd_pll_sc_gate_ops)
+
+#define SPRD_SC_GATE_CLK_FW_NAME_OPS_UDELAY(_struct, _name, _parent,	\
+					    _reg, _sc_offset,		\
+					    _enable_mask, _flags,	\
+					    _gate_flags, _udelay, _ops)	\
+	SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, _udelay, _ops,		\
+				    CLK_HW_INIT_FW_NAME)
+
+#define SPRD_SC_GATE_CLK_FW_NAME_OPS(_struct, _name, _parent, _reg,	\
+				     _sc_offset, _enable_mask, _flags,	\
+				     _gate_flags, _ops)			\
+	SPRD_SC_GATE_CLK_FW_NAME_OPS_UDELAY(_struct, _name, _parent,	\
+					    _reg, _sc_offset,		\
+					    _enable_mask, _flags,	\
+					    _gate_flags, 0, _ops)
+
+#define SPRD_SC_GATE_CLK_FW_NAME(_struct, _name, _parent, _reg,		\
+				 _sc_offset, _enable_mask, _flags,	\
+				 _gate_flags)				\
+	SPRD_SC_GATE_CLK_FW_NAME_OPS(_struct, _name, _parent, _reg,	\
+				     _sc_offset, _enable_mask, _flags,	\
+				     _gate_flags, &sprd_sc_gate_ops)
+
+#define SPRD_GATE_CLK_FW_NAME(_struct, _name, _parent, _reg,		\
+			      _enable_mask, _flags, _gate_flags)	\
+	SPRD_SC_GATE_CLK_FW_NAME_OPS(_struct, _name, _parent, _reg, 0,	\
+				     _enable_mask, _flags, _gate_flags,	\
+				     &sprd_gate_ops)
+
+#define SPRD_PLL_SC_GATE_CLK_FW_NAME(_struct, _name, _parent, _reg,	\
+				     _sc_offset, _enable_mask, _flags,	\
+				     _gate_flags, _udelay)		\
+	SPRD_SC_GATE_CLK_FW_NAME_OPS_UDELAY(_struct, _name, _parent,	\
+					    _reg, _sc_offset,		\
+					    _enable_mask, _flags,	\
+					    _gate_flags, _udelay,	\
+					    &sprd_pll_sc_gate_ops)
+
+static inline struct sprd_gate *hw_to_sprd_gate(const struct clk_hw *hw)
+{
+	struct sprd_clk_common *common = hw_to_sprd_clk_common(hw);
+
+	return container_of(common, struct sprd_gate, common);
+}
+
+extern const struct clk_ops sprd_gate_ops;
+extern const struct clk_ops sprd_sc_gate_ops;
+extern const struct clk_ops sprd_pll_sc_gate_ops;
+
+#endif /* _SPRD_GATE_H_ */