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, 72 insertions, 0 deletions

diff --git a/drivers/clk/mediatek/reset.h b/drivers/clk/mediatek/reset.h
new file mode 100644
index 000000000..562ffd290
--- /dev/null
+++ b/drivers/clk/mediatek/reset.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022 MediaTek Inc.
+ */
+
+#ifndef __DRV_CLK_MTK_RESET_H
+#define __DRV_CLK_MTK_RESET_H
+
+#include <linux/reset-controller.h>
+#include <linux/types.h>
+
+#define RST_NR_PER_BANK 32
+
+/* Infra global controller reset set register */
+#define INFRA_RST0_SET_OFFSET 0x120
+#define INFRA_RST1_SET_OFFSET 0x130
+#define INFRA_RST2_SET_OFFSET 0x140
+#define INFRA_RST3_SET_OFFSET 0x150
+#define INFRA_RST4_SET_OFFSET 0x730
+
+/**
+ * enum mtk_reset_version - Version of MediaTek clock reset controller.
+ * @MTK_RST_SIMPLE: Use the same registers for bit set and clear.
+ * @MTK_RST_SET_CLR: Use separate registers for bit set and clear.
+ * @MTK_RST_MAX: Total quantity of version for MediaTek clock reset controller.
+ */
+enum mtk_reset_version {
+	MTK_RST_SIMPLE = 0,
+	MTK_RST_SET_CLR,
+	MTK_RST_MAX,
+};
+
+/**
+ * struct mtk_clk_rst_desc - Description of MediaTek clock reset.
+ * @version: Reset version which is defined in enum mtk_reset_version.
+ * @rst_bank_ofs: Pointer to an array containing base offsets of the reset register.
+ * @rst_bank_nr: Quantity of reset bank.
+ * @rst_idx_map:Pointer to an array containing ids if input argument is index.
+ *		This array is not necessary if our input argument does not mean index.
+ * @rst_idx_map_nr: Quantity of reset index map.
+ */
+struct mtk_clk_rst_desc {
+	enum mtk_reset_version version;
+	u16 *rst_bank_ofs;
+	u32 rst_bank_nr;
+	u16 *rst_idx_map;
+	u32 rst_idx_map_nr;
+};
+
+/**
+ * struct mtk_clk_rst_data - Data of MediaTek clock reset controller.
+ * @regmap: Pointer to base address of reset register address.
+ * @rcdev: Reset controller device.
+ * @desc: Pointer to description of the reset controller.
+ */
+struct mtk_clk_rst_data {
+	struct regmap *regmap;
+	struct reset_controller_dev rcdev;
+	const struct mtk_clk_rst_desc *desc;
+};
+
+/**
+ * mtk_register_reset_controller - Register mediatek clock reset controller with device
+ * @np: Pointer to device.
+ * @desc: Constant pointer to description of clock reset.
+ *
+ * Return: 0 on success and errorno otherwise.
+ */
+int mtk_register_reset_controller_with_dev(struct device *dev,
+					   const struct mtk_clk_rst_desc *desc);
+
+#endif /* __DRV_CLK_MTK_RESET_H */