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, 54 insertions, 0 deletions

diff --git a/drivers/pinctrl/devicetree.h b/drivers/pinctrl/devicetree.h
new file mode 100644
index 000000000..def76aba9
--- /dev/null
+++ b/drivers/pinctrl/devicetree.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Internal interface to pinctrl device tree integration
+ *
+ * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
+ */
+
+#include <linux/errno.h>
+
+struct device_node;
+struct of_phandle_args;
+
+struct pinctrl;
+struct pinctrl_dev;
+
+#ifdef CONFIG_OF
+
+void pinctrl_dt_free_maps(struct pinctrl *p);
+int pinctrl_dt_to_map(struct pinctrl *p, struct pinctrl_dev *pctldev);
+
+int pinctrl_count_index_with_args(const struct device_node *np,
+				  const char *list_name);
+
+int pinctrl_parse_index_with_args(const struct device_node *np,
+				  const char *list_name, int index,
+				  struct of_phandle_args *out_args);
+
+#else
+
+static inline int pinctrl_dt_to_map(struct pinctrl *p,
+				    struct pinctrl_dev *pctldev)
+{
+	return 0;
+}
+
+static inline void pinctrl_dt_free_maps(struct pinctrl *p)
+{
+}
+
+static inline int pinctrl_count_index_with_args(const struct device_node *np,
+						const char *list_name)
+{
+	return -ENODEV;
+}
+
+static inline int
+pinctrl_parse_index_with_args(const struct device_node *np,
+			      const char *list_name, int index,
+			      struct of_phandle_args *out_args)
+{
+	return -ENODEV;
+}
+
+#endif