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, 127 insertions, 0 deletions

diff --git a/drivers/pinctrl/mediatek/mtk-eint.h b/drivers/pinctrl/mediatek/mtk-eint.h
new file mode 100644
index 000000000..3cdd6f631
--- /dev/null
+++ b/drivers/pinctrl/mediatek/mtk-eint.h
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2014-2025 MediaTek Inc.
+ *
+ * Author: Maoguang Meng <maoguang.meng@mediatek.com>
+ *	   Sean Wang <sean.wang@mediatek.com>
+ *	   Hao Chang <ot_chhao.chang@mediatek.com>
+ *	   Qingliang Li <qingliang.li@mediatek.com>
+ */
+#ifndef __MTK_EINT_H
+#define __MTK_EINT_H
+
+#include <linux/irqdomain.h>
+
+struct mtk_eint_regs {
+	unsigned int	stat;
+	unsigned int	ack;
+	unsigned int	mask;
+	unsigned int	mask_set;
+	unsigned int	mask_clr;
+	unsigned int	sens;
+	unsigned int	sens_set;
+	unsigned int	sens_clr;
+	unsigned int	soft;
+	unsigned int	soft_set;
+	unsigned int	soft_clr;
+	unsigned int	pol;
+	unsigned int	pol_set;
+	unsigned int	pol_clr;
+	unsigned int	dom_en;
+	unsigned int	dbnc_ctrl;
+	unsigned int	dbnc_set;
+	unsigned int	dbnc_clr;
+};
+
+struct mtk_eint_hw {
+	u8		port_mask;
+	u8		ports;
+	unsigned int	ap_num;
+	unsigned int	db_cnt;
+	const unsigned int *db_time;
+};
+
+struct mtk_eint_pin {
+	u16 number;
+	u8 instance;
+	u8 index;
+	bool debounce;
+	bool dual_edge;
+};
+
+extern const unsigned int debounce_time_mt2701[];
+extern const unsigned int debounce_time_mt6765[];
+extern const unsigned int debounce_time_mt6795[];
+extern const unsigned int debounce_time_mt6878[];
+
+struct mtk_eint;
+
+struct mtk_eint_xt {
+	int (*get_gpio_n)(void *data, unsigned long eint_n,
+			  unsigned int *gpio_n,
+			  struct gpio_chip **gpio_chip);
+	int (*get_gpio_state)(void *data, unsigned long eint_n);
+	int (*set_gpio_as_eint)(void *data, unsigned long eint_n);
+};
+
+struct mtk_eint {
+	struct device *dev;
+	void __iomem **base;
+	int nbase;
+	u16 *base_pin_num;
+	struct irq_domain *domain;
+	int irq;
+
+	int *dual_edge;
+	u16 **pin_list;
+	u32 **wake_mask;
+	u32 **cur_mask;
+
+	/* Used to fit into various EINT device */
+	const struct mtk_eint_hw *hw;
+	const struct mtk_eint_regs *regs;
+	struct mtk_eint_pin *pins;
+	u16 num_db_time;
+
+	/* Used to fit into various pinctrl device */
+	void *pctl;
+	const struct mtk_eint_xt *gpio_xlate;
+};
+
+#if IS_ENABLED(CONFIG_EINT_MTK)
+int mtk_eint_do_init(struct mtk_eint *eint, struct mtk_eint_pin *eint_pin);
+int mtk_eint_do_suspend(struct mtk_eint *eint);
+int mtk_eint_do_resume(struct mtk_eint *eint);
+int mtk_eint_set_debounce(struct mtk_eint *eint, unsigned long eint_n,
+			  unsigned int debounce);
+int mtk_eint_find_irq(struct mtk_eint *eint, unsigned long eint_n);
+
+#else
+static inline int mtk_eint_do_init(struct mtk_eint *eint,
+				   struct mtk_eint_pin *eint_pin)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int mtk_eint_do_suspend(struct mtk_eint *eint)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int mtk_eint_do_resume(struct mtk_eint *eint)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int mtk_eint_set_debounce(struct mtk_eint *eint, unsigned long eint_n,
+			  unsigned int debounce)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int mtk_eint_find_irq(struct mtk_eint *eint, unsigned long eint_n)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+#endif /* __MTK_EINT_H */