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, 142 insertions, 0 deletions

diff --git a/drivers/clk/ti/interface.c b/drivers/clk/ti/interface.c
new file mode 100644
index 000000000..039c8075e
--- /dev/null
+++ b/drivers/clk/ti/interface.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OMAP interface clock support
+ *
+ * Copyright (C) 2013 Texas Instruments, Inc.
+ *
+ * Tero Kristo <t-kristo@ti.com>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/clk/ti.h>
+#include "clock.h"
+
+#undef pr_fmt
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+static const struct clk_ops ti_interface_clk_ops = {
+	.init		= &omap2_init_clk_clkdm,
+	.enable		= &omap2_dflt_clk_enable,
+	.disable	= &omap2_dflt_clk_disable,
+	.is_enabled	= &omap2_dflt_clk_is_enabled,
+};
+
+static struct clk *_register_interface(struct device_node *node,
+				       const char *name,
+				       const char *parent_name,
+				       struct clk_omap_reg *reg, u8 bit_idx,
+				       const struct clk_hw_omap_ops *ops)
+{
+	struct clk_init_data init = { NULL };
+	struct clk_hw_omap *clk_hw;
+	struct clk *clk;
+
+	clk_hw = kzalloc_obj(*clk_hw);
+	if (!clk_hw)
+		return ERR_PTR(-ENOMEM);
+
+	clk_hw->hw.init = &init;
+	clk_hw->ops = ops;
+	memcpy(&clk_hw->enable_reg, reg, sizeof(*reg));
+	clk_hw->enable_bit = bit_idx;
+
+	init.name = name;
+	init.ops = &ti_interface_clk_ops;
+	init.flags = 0;
+
+	init.num_parents = 1;
+	init.parent_names = &parent_name;
+
+	clk = of_ti_clk_register_omap_hw(node, &clk_hw->hw, name);
+
+	if (IS_ERR(clk))
+		kfree(clk_hw);
+
+	return clk;
+}
+
+static void __init _of_ti_interface_clk_setup(struct device_node *node,
+					      const struct clk_hw_omap_ops *ops)
+{
+	struct clk *clk;
+	const char *parent_name;
+	struct clk_omap_reg reg;
+	u8 enable_bit = 0;
+	const char *name;
+
+	if (ti_clk_get_reg_addr(node, 0, &reg))
+		return;
+
+	enable_bit = reg.bit;
+
+	parent_name = of_clk_get_parent_name(node, 0);
+	if (!parent_name) {
+		pr_err("%pOFn must have a parent\n", node);
+		return;
+	}
+
+	name = ti_dt_clk_name(node);
+	clk = _register_interface(node, name, parent_name, &reg,
+				  enable_bit, ops);
+
+	if (!IS_ERR(clk))
+		of_clk_add_provider(node, of_clk_src_simple_get, clk);
+}
+
+static void __init of_ti_interface_clk_setup(struct device_node *node)
+{
+	_of_ti_interface_clk_setup(node, &clkhwops_iclk_wait);
+}
+CLK_OF_DECLARE(ti_interface_clk, "ti,omap3-interface-clock",
+	       of_ti_interface_clk_setup);
+
+static void __init of_ti_no_wait_interface_clk_setup(struct device_node *node)
+{
+	_of_ti_interface_clk_setup(node, &clkhwops_iclk);
+}
+CLK_OF_DECLARE(ti_no_wait_interface_clk, "ti,omap3-no-wait-interface-clock",
+	       of_ti_no_wait_interface_clk_setup);
+
+#ifdef CONFIG_ARCH_OMAP3
+static void __init of_ti_hsotgusb_interface_clk_setup(struct device_node *node)
+{
+	_of_ti_interface_clk_setup(node,
+				   &clkhwops_omap3430es2_iclk_hsotgusb_wait);
+}
+CLK_OF_DECLARE(ti_hsotgusb_interface_clk, "ti,omap3-hsotgusb-interface-clock",
+	       of_ti_hsotgusb_interface_clk_setup);
+
+static void __init of_ti_dss_interface_clk_setup(struct device_node *node)
+{
+	_of_ti_interface_clk_setup(node,
+				   &clkhwops_omap3430es2_iclk_dss_usbhost_wait);
+}
+CLK_OF_DECLARE(ti_dss_interface_clk, "ti,omap3-dss-interface-clock",
+	       of_ti_dss_interface_clk_setup);
+
+static void __init of_ti_ssi_interface_clk_setup(struct device_node *node)
+{
+	_of_ti_interface_clk_setup(node, &clkhwops_omap3430es2_iclk_ssi_wait);
+}
+CLK_OF_DECLARE(ti_ssi_interface_clk, "ti,omap3-ssi-interface-clock",
+	       of_ti_ssi_interface_clk_setup);
+
+static void __init of_ti_am35xx_interface_clk_setup(struct device_node *node)
+{
+	_of_ti_interface_clk_setup(node, &clkhwops_am35xx_ipss_wait);
+}
+CLK_OF_DECLARE(ti_am35xx_interface_clk, "ti,am35xx-interface-clock",
+	       of_ti_am35xx_interface_clk_setup);
+#endif
+
+#ifdef CONFIG_SOC_OMAP2430
+static void __init of_ti_omap2430_interface_clk_setup(struct device_node *node)
+{
+	_of_ti_interface_clk_setup(node, &clkhwops_omap2430_i2chs_wait);
+}
+CLK_OF_DECLARE(ti_omap2430_interface_clk, "ti,omap2430-interface-clock",
+	       of_ti_omap2430_interface_clk_setup);
+#endif