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, 30 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-spi-eeprom b/Documentation/ABI/testing/sysfs-class-spi-eeprom
new file mode 100644
index 000000000..f4bc7d945
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-spi-eeprom
@@ -0,0 +1,30 @@
+What:		/sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fram
+Date:		June 2021
+KernelVersion:	5.14
+Contact:	Jiri Prchal <jiri.prchal@aksignal.cz>
+Description:
+	Contains the FRAM binary data. Same as EEPROM, just another file
+	name to indicate that it employs ferroelectric process.
+	It performs write operations at bus speed - no write delays.
+
+What:		/sys/class/spi_master/spi<bus>/spi<bus>.<dev>/sernum
+Date:		May 2021
+KernelVersion:	5.14
+Contact:	Jiri Prchal <jiri.prchal@aksignal.cz>
+Description:
+	Contains the serial number of the Cypress FRAM (FM25VN) if it is
+	present.  It will be displayed as a 8 byte hex string, as read
+	from the device.
+
+	This is a read-only attribute.
+
+What:		/sys/class/spi_master/spi<bus>/spi<bus>.<dev>/jedec_id
+Date:		January 2026
+KernelVersion:	6.19
+Contact:	Patrick Wicki <patrick.wicki@siemens.com>
+Description:
+	Contains the raw JEDEC ID bytes returned by the RDID (0x9f) command. The
+	bytes are exposed as a hex string in big-endian order as read from the
+	device.
+
+	This is a read-only attribute.