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>

5 files changed, 103 insertions, 0 deletions

diff --git a/arch/mips/mobileye/Kconfig b/arch/mips/mobileye/Kconfig
new file mode 100644
index 000000000..8a4868d2e
--- /dev/null
+++ b/arch/mips/mobileye/Kconfig
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0
+if EYEQ
+
+choice
+	prompt "Mobileye EyeQ SoC selection"
+	default MACH_EYEQ5
+	help
+	  Select Mobileye EyeQ MIPS SoC type.
+
+	config MACH_EYEQ5
+		bool "Mobileye EyeQ5 SoC"
+
+	config MACH_EYEQ6H
+		bool "Mobileye EyeQ6H SoC"
+
+	config MACH_EYEQ6LPLUS
+		bool "Mobileye EyeQ6Lplus SoC"
+endchoice
+
+config FIT_IMAGE_FDT_EPM5
+	bool "Include FDT for Mobileye EyeQ5 development platforms"
+	depends on MACH_EYEQ5
+	default n
+	help
+	  Enable this to include the FDT for the EyeQ5 development platforms
+	  from Mobileye in the FIT kernel image.
+	  This requires u-boot on the platform.
+
+endif
diff --git a/arch/mips/mobileye/Makefile b/arch/mips/mobileye/Makefile
new file mode 100644
index 000000000..315c06b68
--- /dev/null
+++ b/arch/mips/mobileye/Makefile
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
diff --git a/arch/mips/mobileye/Platform b/arch/mips/mobileye/Platform
new file mode 100644
index 000000000..93b533492
--- /dev/null
+++ b/arch/mips/mobileye/Platform
@@ -0,0 +1,17 @@
+#
+# Copyright (C) 2016 Imagination Technologies
+# Author: Paul Burton <paul.burton@mips.com>
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation;  either version 2 of the  License, or (at your
+# option) any later version.
+#
+
+load-$(CONFIG_MACH_EYEQ5)	= 0xa800000808000000
+load-$(CONFIG_MACH_EYEQ6H)	= 0xa800000100800000
+load-$(CONFIG_MACH_EYEQ6LPLUS)	= 0xa800000108800000
+all-$(CONFIG_MACH_EYEQ5)	+= vmlinux.gz.itb
+
+its-y					:= vmlinux.its.S
+its-$(CONFIG_FIT_IMAGE_FDT_EPM5)	+= board-epm5.its.S
diff --git a/arch/mips/mobileye/board-epm5.its.S b/arch/mips/mobileye/board-epm5.its.S
new file mode 100644
index 000000000..08e8c4f18
--- /dev/null
+++ b/arch/mips/mobileye/board-epm5.its.S
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
+/ {
+	images {
+		fdt-mobileye-epm5 {
+			description = "Mobileeye MP5 Device Tree";
+			data = /incbin/("boot/dts/mobileye/eyeq5-epm5.dtb");
+			type = "flat_dt";
+			arch = "mips";
+			compression = "none";
+			hash {
+				algo = "sha1";
+			};
+		};
+	};
+
+    configurations {
+		default = "conf-1";
+		conf-1 {
+			description = "Mobileye EPM5 Linux kernel";
+			kernel = "kernel";
+			fdt = "fdt-mobileye-epm5";
+		};
+	};
+};
diff --git a/arch/mips/mobileye/vmlinux.its.S b/arch/mips/mobileye/vmlinux.its.S
new file mode 100644
index 000000000..3e2546765
--- /dev/null
+++ b/arch/mips/mobileye/vmlinux.its.S
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/dts-v1/;
+
+/ {
+	description = KERNEL_NAME;
+	#address-cells = <ADDR_CELLS>;
+
+	images {
+		kernel {
+			description = KERNEL_NAME;
+			data = /incbin/(VMLINUX_BINARY);
+			type = "kernel";
+			arch = "mips";
+			os = "linux";
+			compression = VMLINUX_COMPRESSION;
+			load = /bits/ ADDR_BITS <VMLINUX_LOAD_ADDRESS>;
+			entry = /bits/ ADDR_BITS <VMLINUX_ENTRY_ADDRESS>;
+			hash {
+				algo = "sha1";
+			};
+		};
+	};
+
+	configurations {
+		default = "conf-default";
+
+		conf-default {
+			description = "Generic Linux kernel";
+			kernel = "kernel";
+		};
+	};
+};