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, 56 insertions, 0 deletions

diff --git a/drivers/soc/aspeed/Kconfig b/drivers/soc/aspeed/Kconfig
new file mode 100644
index 000000000..63a656449
--- /dev/null
+++ b/drivers/soc/aspeed/Kconfig
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+if ARCH_ASPEED || COMPILE_TEST
+
+menu "ASPEED SoC drivers"
+
+config ASPEED_LPC_CTRL
+	tristate "ASPEED LPC firmware cycle control"
+	select REGMAP
+	select MFD_SYSCON
+	default ARCH_ASPEED
+	help
+	  Control LPC firmware cycle mappings through ioctl()s. The driver
+	  also provides a read/write interface to a BMC ram region where the
+	  host LPC read/write region can be buffered.
+
+config ASPEED_LPC_SNOOP
+	tristate "ASPEED LPC snoop support"
+	select REGMAP
+	select MFD_SYSCON
+	default ARCH_ASPEED
+	help
+	  Provides a driver to control the LPC snoop interface which
+	  allows the BMC to listen on and save the data written by
+	  the host to an arbitrary LPC I/O port.
+
+config ASPEED_UART_ROUTING
+	tristate "ASPEED uart routing control"
+	select REGMAP
+	select MFD_SYSCON
+	default ARCH_ASPEED
+	help
+	  Provides a driver to control the UART routing paths, allowing
+	  users to perform runtime configuration of the RX muxes among
+	  the UART controllers and I/O pins.
+
+config ASPEED_P2A_CTRL
+	tristate "ASPEED P2A (VGA MMIO to BMC) bridge control"
+	select REGMAP
+	select MFD_SYSCON
+	default ARCH_ASPEED
+	help
+	  Control ASPEED P2A VGA MMIO to BMC mappings through ioctl()s.  The
+	  driver also provides an interface for userspace mappings to a
+	  pre-defined region.
+
+config ASPEED_SOCINFO
+	bool "ASPEED SoC Information driver"
+	select SOC_BUS
+	default ARCH_ASPEED
+	help
+	  Say yes to support decoding of ASPEED BMC information.
+
+endmenu
+
+endif