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, 98 insertions, 0 deletions

diff --git a/drivers/clk/versatile/clk-versatile.c b/drivers/clk/versatile/clk-versatile.c
new file mode 100644
index 000000000..8ed7a179f
--- /dev/null
+++ b/drivers/clk/versatile/clk-versatile.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Clock driver for the ARM Integrator/AP, Integrator/CP, Versatile AB and
+ * Versatile PB boards.
+ * Copyright (C) 2012 Linus Walleij
+ */
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#include "icst.h"
+#include "clk-icst.h"
+
+#define INTEGRATOR_HDR_LOCK_OFFSET	0x14
+
+#define VERSATILE_SYS_OSCCLCD_OFFSET	0x1c
+#define VERSATILE_SYS_LOCK_OFFSET	0x20
+
+/* Base offset for the core module */
+static void __iomem *cm_base;
+
+static const struct icst_params cp_auxosc_params = {
+	.vco_max	= ICST525_VCO_MAX_5V,
+	.vco_min	= ICST525_VCO_MIN,
+	.vd_min 	= 8,
+	.vd_max 	= 263,
+	.rd_min 	= 3,
+	.rd_max 	= 65,
+	.s2div		= icst525_s2div,
+	.idx2s		= icst525_idx2s,
+};
+
+static const struct clk_icst_desc cm_auxosc_desc __initconst = {
+	.params = &cp_auxosc_params,
+	.vco_offset = 0x1c,
+	.lock_offset = INTEGRATOR_HDR_LOCK_OFFSET,
+};
+
+static const struct icst_params versatile_auxosc_params = {
+	.vco_max	= ICST307_VCO_MAX,
+	.vco_min	= ICST307_VCO_MIN,
+	.vd_min		= 4 + 8,
+	.vd_max		= 511 + 8,
+	.rd_min		= 1 + 2,
+	.rd_max		= 127 + 2,
+	.s2div		= icst307_s2div,
+	.idx2s		= icst307_idx2s,
+};
+
+static const struct clk_icst_desc versatile_auxosc_desc __initconst = {
+	.params = &versatile_auxosc_params,
+	.vco_offset = VERSATILE_SYS_OSCCLCD_OFFSET,
+	.lock_offset = VERSATILE_SYS_LOCK_OFFSET,
+};
+static void __init cm_osc_setup(struct device_node *np,
+				const struct clk_icst_desc *desc)
+{
+	struct clk *clk;
+	const char *clk_name = np->name;
+	const char *parent_name;
+
+	if (!cm_base) {
+		/* Remap the core module base if not done yet */
+		struct device_node *parent;
+
+		parent = of_get_parent(np);
+		if (!parent) {
+			pr_err("no parent on core module clock\n");
+			return;
+		}
+		cm_base = of_iomap(parent, 0);
+		of_node_put(parent);
+		if (!cm_base) {
+			pr_err("could not remap core module base\n");
+			return;
+		}
+	}
+
+	parent_name = of_clk_get_parent_name(np, 0);
+	clk = icst_clk_register(NULL, desc, clk_name, parent_name, cm_base);
+	if (!IS_ERR(clk))
+		of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
+
+static void __init of_integrator_cm_osc_setup(struct device_node *np)
+{
+	cm_osc_setup(np, &cm_auxosc_desc);
+}
+CLK_OF_DECLARE(integrator_cm_auxosc_clk,
+	"arm,integrator-cm-auxosc", of_integrator_cm_osc_setup);
+
+static void __init of_versatile_cm_osc_setup(struct device_node *np)
+{
+	cm_osc_setup(np, &versatile_auxosc_desc);
+}
+CLK_OF_DECLARE(versatile_cm_auxosc_clk,
+	       "arm,versatile-cm-auxosc", of_versatile_cm_osc_setup);