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>

4 files changed, 85 insertions, 0 deletions

diff --git a/tools/testing/kunit/configs/all_tests.config b/tools/testing/kunit/configs/all_tests.config
new file mode 100644
index 000000000..31e930a0f
--- /dev/null
+++ b/tools/testing/kunit/configs/all_tests.config
@@ -0,0 +1,63 @@
+# This config enables as many tests as possible under UML.
+# It is intended for use in continuous integration systems and similar for
+# automated testing of as much as possible.
+# The config is manually maintained, though it uses KUNIT_ALL_TESTS=y to enable
+# any tests whose dependencies are already satisfied. Please feel free to add
+# more options if they any new tests.
+
+CONFIG_KUNIT=y
+CONFIG_KUNIT_EXAMPLE_TEST=y
+CONFIG_KUNIT_ALL_TESTS=y
+
+CONFIG_FORTIFY_SOURCE=y
+
+CONFIG_IIO=y
+
+CONFIG_EXT4_FS=y
+
+CONFIG_MSDOS_FS=y
+CONFIG_VFAT_FS=y
+
+CONFIG_PCI=y
+CONFIG_USB4=y
+CONFIG_I2C=y
+CONFIG_SPI=y
+CONFIG_GPIOLIB=y
+
+CONFIG_NET=y
+CONFIG_MCTP=y
+CONFIG_MCTP_FLOWS=y
+
+CONFIG_INET=y
+CONFIG_MPTCP=y
+
+CONFIG_NETDEVICES=y
+CONFIG_WLAN=y
+CONFIG_CFG80211=y
+CONFIG_MAC80211=y
+CONFIG_WLAN_VENDOR_INTEL=y
+CONFIG_IWLWIFI=y
+
+CONFIG_DAMON=y
+CONFIG_DAMON_VADDR=y
+CONFIG_DAMON_PADDR=y
+
+CONFIG_REGMAP_BUILD=y
+
+CONFIG_AUDIT=y
+
+CONFIG_CRYPTO_LIB_ENABLE_ALL_FOR_KUNIT=y
+
+CONFIG_PRIME_NUMBERS=y
+
+CONFIG_CRC_ENABLE_ALL_FOR_KUNIT=y
+
+CONFIG_SECURITY=y
+CONFIG_SECURITY_APPARMOR=y
+CONFIG_SECURITY_LANDLOCK=y
+
+CONFIG_SOUND=y
+CONFIG_SND=y
+CONFIG_SND_SOC=y
+CONFIG_SND_SOC_TOPOLOGY_BUILD=y
+CONFIG_SND_SOC_CS35L56_I2C=y
diff --git a/tools/testing/kunit/configs/arch_uml.config b/tools/testing/kunit/configs/arch_uml.config
new file mode 100644
index 000000000..28edf816a
--- /dev/null
+++ b/tools/testing/kunit/configs/arch_uml.config
@@ -0,0 +1,7 @@
+# Config options which are added to UML builds by default
+
+# Enable pci, as a lot of tests require it.
+CONFIG_KUNIT_UML_PCI=y
+
+# Enable FORTIFY_SOURCE for wider checking.
+CONFIG_FORTIFY_SOURCE=y
diff --git a/tools/testing/kunit/configs/coverage_uml.config b/tools/testing/kunit/configs/coverage_uml.config
new file mode 100644
index 000000000..bacb77664
--- /dev/null
+++ b/tools/testing/kunit/configs/coverage_uml.config
@@ -0,0 +1,11 @@
+# This config fragment enables coverage on UML, which is different from the
+# normal gcov used in other arches (no debugfs).
+# Example usage:
+# ./tools/testing/kunit/kunit.py run \
+#   --kunitconfig=tools/testing/kunit/configs/all_tests_uml.config \
+#   --kunitconfig=tools/testing/kunit/configs/coverage_uml.config
+
+CONFIG_DEBUG_KERNEL=y
+CONFIG_DEBUG_INFO=y
+CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y
+CONFIG_GCOV=y
diff --git a/tools/testing/kunit/configs/default.config b/tools/testing/kunit/configs/default.config
new file mode 100644
index 000000000..2f24147c9
--- /dev/null
+++ b/tools/testing/kunit/configs/default.config
@@ -0,0 +1,4 @@
+CONFIG_KUNIT=y
+CONFIG_KUNIT_EXAMPLE_TEST=y
+CONFIG_KUNIT_ALL_TESTS=y
+CONFIG_SPI=y