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, 102 insertions, 0 deletions

diff --git a/drivers/clk/davinci/psc.h b/drivers/clk/davinci/psc.h
new file mode 100644
index 000000000..742672843
--- /dev/null
+++ b/drivers/clk/davinci/psc.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Clock driver for TI Davinci PSC controllers
+ *
+ * Copyright (C) 2018 David Lechner <david@lechnology.com>
+ */
+
+#ifndef __CLK_DAVINCI_PSC_H__
+#define __CLK_DAVINCI_PSC_H__
+
+#include <linux/clk-provider.h>
+#include <linux/types.h>
+
+/* PSC quirk flags */
+#define LPSC_ALWAYS_ENABLED	BIT(0) /* never disable this clock */
+#define LPSC_SET_RATE_PARENT	BIT(1) /* propagate set_rate to parent clock */
+#define LPSC_FORCE		BIT(2) /* requires MDCTL FORCE bit */
+#define LPSC_LOCAL_RESET	BIT(3) /* acts as reset provider */
+
+struct davinci_lpsc_clkdev_info {
+	const char *con_id;
+	const char *dev_id;
+};
+
+#define LPSC_CLKDEV(c, d) {	\
+	.con_id = (c),		\
+	.dev_id = (d)		\
+}
+
+#define LPSC_CLKDEV1(n, c, d) \
+static const struct davinci_lpsc_clkdev_info n[] __initconst = {	\
+	LPSC_CLKDEV((c), (d)),						\
+	{ }								\
+}
+
+#define LPSC_CLKDEV2(n, c1, d1, c2, d2) \
+static const struct davinci_lpsc_clkdev_info n[] __initconst = {	\
+	LPSC_CLKDEV((c1), (d1)),					\
+	LPSC_CLKDEV((c2), (d2)),					\
+	{ }								\
+}
+
+#define LPSC_CLKDEV3(n, c1, d1, c2, d2, c3, d3) \
+static const struct davinci_lpsc_clkdev_info n[] __initconst = {	\
+	LPSC_CLKDEV((c1), (d1)),					\
+	LPSC_CLKDEV((c2), (d2)),					\
+	LPSC_CLKDEV((c3), (d3)),					\
+	{ }								\
+}
+
+/**
+ * davinci_lpsc_clk_info - LPSC module-specific clock information
+ * @name: the clock name
+ * @parent: the parent clock name
+ * @cdevs: optional array of clkdev lookup table info
+ * @md: the local module domain (LPSC id)
+ * @pd: the power domain id
+ * @flags: bitmask of LPSC_* flags
+ */
+struct davinci_lpsc_clk_info {
+	const char *name;
+	const char *parent;
+	const struct davinci_lpsc_clkdev_info *cdevs;
+	u32 md;
+	u32 pd;
+	unsigned long flags;
+};
+
+#define LPSC(m, d, n, p, c, f)	\
+{				\
+	.name	= #n,		\
+	.parent	= #p,		\
+	.cdevs	= (c),		\
+	.md	= (m),		\
+	.pd	= (d),		\
+	.flags	= (f),		\
+}
+
+int davinci_psc_register_clocks(struct device *dev,
+				const struct davinci_lpsc_clk_info *info,
+				u8 num_clks,
+				void __iomem *base);
+
+int of_davinci_psc_clk_init(struct device *dev,
+			    const struct davinci_lpsc_clk_info *info,
+			    u8 num_clks,
+			    void __iomem *base);
+
+/* Device-specific data */
+
+struct davinci_psc_init_data {
+	struct clk_bulk_data *parent_clks;
+	int num_parent_clks;
+	int (*psc_init)(struct device *dev, void __iomem *base);
+};
+
+extern const struct davinci_psc_init_data da850_psc0_init_data;
+extern const struct davinci_psc_init_data da850_psc1_init_data;
+extern const struct davinci_psc_init_data of_da850_psc0_init_data;
+extern const struct davinci_psc_init_data of_da850_psc1_init_data;
+
+#endif /* __CLK_DAVINCI_PSC_H__ */