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, 71 insertions, 0 deletions

diff --git a/arch/microblaze/Kconfig.platform b/arch/microblaze/Kconfig.platform
new file mode 100644
index 000000000..9cf9007ed
--- /dev/null
+++ b/arch/microblaze/Kconfig.platform
@@ -0,0 +1,71 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# For a description of the syntax of this configuration file,
+# see Documentation/kbuild/kconfig-language.rst.
+#
+# Platform selection Kconfig menu for MicroBlaze targets
+#
+
+menu "Platform options"
+
+config OPT_LIB_FUNCTION
+	bool "Optimized lib function"
+	default y
+	help
+	  Turns on optimized library functions (memcpy and memmove).
+	  They are optimized by using word alignment. This will work
+	  fine if both source and destination are aligned on the same
+	  boundary. However, if they are aligned on different boundaries
+	  shifts will be necessary. This might result in bad performance
+	  on MicroBlaze systems without a barrel shifter.
+
+config OPT_LIB_ASM
+	bool "Optimized lib function ASM"
+	depends on OPT_LIB_FUNCTION && (XILINX_MICROBLAZE0_USE_BARREL = 1)
+	depends on CPU_BIG_ENDIAN
+	default n
+	help
+	  Turns on optimized library functions (memcpy and memmove).
+	  They are written in assembly.
+
+# Definitions for MICROBLAZE0
+comment "Definitions for MICROBLAZE0"
+
+config KERNEL_BASE_ADDR
+	hex "Physical address where Linux Kernel is"
+	default "0x90000000"
+	help
+	  BASE Address for kernel
+
+config XILINX_MICROBLAZE0_FAMILY
+	string "Targeted FPGA family"
+	default "virtex5"
+
+config XILINX_MICROBLAZE0_USE_MSR_INSTR
+	int "USE_MSR_INSTR range (0:1)"
+	default 0
+
+config XILINX_MICROBLAZE0_USE_PCMP_INSTR
+	int "USE_PCMP_INSTR range (0:1)"
+	default 0
+
+config XILINX_MICROBLAZE0_USE_BARREL
+	int "USE_BARREL range (0:1)"
+	default 0
+
+config XILINX_MICROBLAZE0_USE_DIV
+	int "USE_DIV range (0:1)"
+	default 0
+
+config XILINX_MICROBLAZE0_USE_HW_MUL
+	int "USE_HW_MUL values (0=NONE, 1=MUL32, 2=MUL64)"
+	default 0
+
+config XILINX_MICROBLAZE0_USE_FPU
+	int "USE_FPU values (0=NONE, 1=BASIC, 2=EXTENDED)"
+	default 0
+
+config XILINX_MICROBLAZE0_HW_VER
+	string "Core version number"
+	default "7.10.d"
+
+endmenu