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, 293 insertions, 0 deletions

diff --git a/drivers/pinctrl/pinctrl-generic.c b/drivers/pinctrl/pinctrl-generic.c
new file mode 100644
index 000000000..fd6bdb740
--- /dev/null
+++ b/drivers/pinctrl/pinctrl-generic.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define pr_fmt(fmt) "generic pinconfig core: " fmt
+
+#include <linux/array_size.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinctrl.h>
+
+#include "core.h"
+#include "pinconf.h"
+#include "pinctrl-utils.h"
+#include "pinmux.h"
+
+int pinctrl_generic_to_map(struct pinctrl_dev *pctldev, struct device_node *parent,
+			   struct device_node *np, struct pinctrl_map **maps,
+			   unsigned int *num_maps, unsigned int *num_reserved_maps,
+			   const char **group_names, unsigned int ngroups,
+			   void *data, unsigned int *pins, unsigned int npins)
+{
+	struct device *dev = pctldev->dev;
+	unsigned int num_configs;
+	const char *group_name;
+	unsigned long *configs;
+	int ret, reserve = 1;
+
+	group_name = devm_kasprintf(dev, GFP_KERNEL, "%pOFn.%pOFn", parent, np);
+	if (!group_name)
+		return -ENOMEM;
+
+	group_names[ngroups] = group_name;
+
+	ret = pinctrl_utils_reserve_map(pctldev, maps, num_reserved_maps, num_maps, reserve);
+	if (ret)
+		return ret;
+
+	ret = pinctrl_utils_add_map_mux(pctldev, maps, num_reserved_maps, num_maps, group_name,
+					parent->name);
+	if (ret < 0)
+		goto err_free_map;
+
+	ret = pinctrl_generic_add_group(pctldev, group_name, pins, npins, data);
+	if (ret < 0) {
+		dev_err_probe(dev, ret, "failed to add group %s: %d\n",
+				     group_name, ret);
+		goto err_free_map;
+	}
+
+	ret = pinconf_generic_parse_dt_config(np, pctldev, &configs, &num_configs);
+	if (ret) {
+		dev_err_probe(dev, ret, "failed to parse pin config of group %s\n",
+			group_name);
+		goto err_free_map;
+	}
+
+	if (num_configs == 0)
+		return 0;
+
+	ret = pinctrl_utils_reserve_map(pctldev, maps, num_reserved_maps, num_maps, reserve);
+	if (ret)
+		goto err_free_map;
+
+	ret = pinctrl_utils_add_map_configs(pctldev, maps, num_reserved_maps, num_maps, group_name,
+					    configs,
+			num_configs, PIN_MAP_TYPE_CONFIGS_GROUP);
+	kfree(configs);
+	if (ret)
+		goto err_free_map;
+
+	return 0;
+
+err_free_map:
+	pinctrl_utils_free_map(pctldev, *maps, *num_maps);
+	*maps = NULL;
+	*num_maps = 0;
+	*num_reserved_maps = 0;
+	return ret;
+};
+EXPORT_SYMBOL_GPL(pinctrl_generic_to_map);
+
+static int pinctrl_generic_pins_function_dt_subnode_to_map(struct pinctrl_dev *pctldev,
+							   struct device_node *parent,
+							   struct device_node *np,
+							   struct pinctrl_map **maps,
+							   unsigned int *num_maps,
+							   unsigned int *num_reserved_maps,
+							   const char **group_names,
+							   unsigned int ngroups)
+{
+	struct device *dev = pctldev->dev;
+	unsigned int pin, *pins;
+	const char **functions;
+	int npins, ret;
+
+	npins = of_property_count_u32_elems(np, "pins");
+
+	if (npins < 1) {
+		dev_err(dev, "invalid pinctrl group %pOFn.%pOFn %d\n",
+			parent, np, npins);
+		return npins;
+	}
+
+	pins = devm_kcalloc(dev, npins, sizeof(*pins), GFP_KERNEL);
+	if (!pins)
+		return -ENOMEM;
+
+	functions = devm_kcalloc(dev, npins, sizeof(*functions), GFP_KERNEL);
+	if (!functions)
+		return -ENOMEM;
+
+	for (int i = 0; i < npins; i++) {
+		ret = of_property_read_u32_index(np, "pins", i, &pin);
+		if (ret)
+			return ret;
+
+		pins[i] = pin;
+
+		ret = of_property_read_string(np, "function", &functions[i]);
+		if (ret)
+			return ret;
+	}
+
+	return pinctrl_generic_to_map(pctldev, parent, np, maps, num_maps,
+				      num_reserved_maps, group_names, ngroups,
+				      functions, pins, npins);
+}
+
+static int pinctrl_generic_pinmux_dt_subnode_to_map(struct pinctrl_dev *pctldev,
+						    struct device_node *parent,
+						    struct device_node *np,
+						    struct pinctrl_map **maps,
+						    unsigned int *num_maps,
+						    unsigned int *num_reserved_maps,
+						    const char **group_names,
+						    unsigned int ngroups)
+{
+	struct device *dev = pctldev->dev;
+	unsigned int *pins, *muxes;
+	int npins, ret;
+
+	npins = of_property_count_u32_elems(np, "pinmux");
+
+	if (npins < 1) {
+		dev_err(dev, "invalid pinctrl group %pOFn.%pOFn %d\n",
+			parent, np, npins);
+		return npins;
+	}
+
+	pins = devm_kcalloc(dev, npins, sizeof(*pins), GFP_KERNEL);
+	if (!pins)
+		return -ENOMEM;
+
+	muxes = devm_kcalloc(dev, npins, sizeof(*muxes), GFP_KERNEL);
+	if (!muxes)
+		return -ENOMEM;
+
+	for (int i = 0; i < npins; i++) {
+		unsigned int pinmux;
+
+		ret = of_property_read_u32_index(np, "pinmux", i, &pinmux);
+		if (ret)
+			return ret;
+
+		pins[i] = pinmux >> 16;
+		muxes[i] = pinmux & GENMASK(15, 0);
+	}
+
+	return pinctrl_generic_to_map(pctldev, parent, np, maps, num_maps,
+				      num_reserved_maps, group_names, ngroups,
+				      muxes, pins, npins);
+}
+
+static int pinctrl_generic_dt_node_to_map(struct pinctrl_dev *pctldev,
+					  struct device_node *np,
+					  struct pinctrl_map **maps,
+					  unsigned int *num_maps,
+					  int (dt_subnode_to_map)(
+						  struct pinctrl_dev *,
+						  struct device_node *,
+						  struct device_node *,
+						  struct pinctrl_map **,
+						  unsigned int *,
+						  unsigned int *,
+						  const char **,
+						  unsigned int))
+{
+	struct device *dev = pctldev->dev;
+	struct device_node *child_np;
+	const char **group_names;
+	unsigned int num_reserved_maps = 0;
+	int ngroups = 0;
+	int ret;
+
+	*maps = NULL;
+	*num_maps = 0;
+
+	/*
+	 * Check if this is actually the pins node, or a parent containing
+	 * multiple pins nodes.
+	 */
+	if (!of_property_present(np, "pins"))
+		goto parent;
+
+	group_names = devm_kcalloc(dev, 1, sizeof(*group_names), GFP_KERNEL);
+	if (!group_names)
+		return -ENOMEM;
+
+	ret = dt_subnode_to_map(pctldev, np, np, maps, num_maps,
+				&num_reserved_maps, group_names, ngroups);
+	if (ret) {
+		pinctrl_utils_free_map(pctldev, *maps, *num_maps);
+		return dev_err_probe(dev, ret, "error figuring out mappings for %s\n", np->name);
+	}
+
+	ret = pinmux_generic_add_function(pctldev, np->name, group_names, 1, NULL);
+	if (ret < 0) {
+		pinctrl_utils_free_map(pctldev, *maps, *num_maps);
+		return dev_err_probe(dev, ret, "error adding function %s\n", np->name);
+	}
+
+	return 0;
+
+parent:
+	for_each_available_child_of_node(np, child_np)
+		ngroups += 1;
+
+	group_names = devm_kcalloc(dev, ngroups, sizeof(*group_names), GFP_KERNEL);
+	if (!group_names)
+		return -ENOMEM;
+
+	ngroups = 0;
+	for_each_available_child_of_node_scoped(np, child_np) {
+		ret = dt_subnode_to_map(pctldev, np, child_np, maps, num_maps,
+					&num_reserved_maps, group_names, ngroups);
+		if (ret) {
+			pinctrl_utils_free_map(pctldev, *maps, *num_maps);
+			return dev_err_probe(dev, ret, "error figuring out mappings for %s\n",
+					     np->name);
+		}
+
+		ngroups++;
+	}
+
+	ret = pinmux_generic_add_function(pctldev, np->name, group_names, ngroups, NULL);
+	if (ret < 0) {
+		pinctrl_utils_free_map(pctldev, *maps, *num_maps);
+		return dev_err_probe(dev, ret, "error adding function %s\n", np->name);
+	}
+
+	return 0;
+}
+
+/*
+ * For platforms that do not define groups or functions in the driver, but
+ * instead use the devicetree to describe them. This function will, unlike
+ * pinconf_generic_dt_node_to_map() etc which rely on driver defined groups
+ * and functions, create them in addition to parsing pinconf properties and
+ * adding mappings.
+ */
+int pinctrl_generic_pins_function_dt_node_to_map(struct pinctrl_dev *pctldev,
+						 struct device_node *np,
+						 struct pinctrl_map **maps,
+						 unsigned int *num_maps)
+{
+	return pinctrl_generic_dt_node_to_map(pctldev, np, maps, num_maps,
+					      &pinctrl_generic_pins_function_dt_subnode_to_map);
+}
+EXPORT_SYMBOL_GPL(pinctrl_generic_pins_function_dt_node_to_map);
+
+/*
+ * For platforms that do not define groups or functions in the driver, but
+ * instead use the devicetree to describe them. This function will, unlike
+ * pinconf_generic_dt_node_to_map() etc which rely on driver defined groups
+ * and functions, create them in addition to parsing pinconf properties and
+ * adding mappings.
+ *
+ * It assumes that the upper 16 bits of the pinmux items contain the pin
+ * and the lower 16 the mux setting.
+ */
+int pinctrl_generic_pinmux_dt_node_to_map(struct pinctrl_dev *pctldev,
+					  struct device_node *np,
+					  struct pinctrl_map **maps,
+					  unsigned int *num_maps)
+{
+	return pinctrl_generic_dt_node_to_map(pctldev, np, maps, num_maps,
+					      &pinctrl_generic_pinmux_dt_subnode_to_map);
+};
+EXPORT_SYMBOL_GPL(pinctrl_generic_pinmux_dt_node_to_map);