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, 48 insertions, 0 deletions

diff --git a/drivers/phy/cadence/Kconfig b/drivers/phy/cadence/Kconfig
new file mode 100644
index 000000000..1adde2d99
--- /dev/null
+++ b/drivers/phy/cadence/Kconfig
@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Phy drivers for Cadence PHYs
+#
+
+config PHY_CADENCE_TORRENT
+	tristate "Cadence Torrent PHY driver"
+	depends on OF
+	depends on HAS_IOMEM
+	depends on COMMON_CLK
+	select GENERIC_PHY
+	help
+	  Support for Cadence Torrent PHY.
+
+config PHY_CADENCE_DPHY
+	tristate "Cadence D-PHY Support"
+	depends on HAS_IOMEM && OF
+	select GENERIC_PHY
+	select GENERIC_PHY_MIPI_DPHY
+	help
+	  Choose this option if you have a Cadence D-PHY in your
+	  system. If M is selected, the module will be called
+	  cdns-dphy.
+
+config PHY_CADENCE_DPHY_RX
+	tristate "Cadence D-PHY Rx Support"
+	depends on HAS_IOMEM && OF
+	select GENERIC_PHY
+	select GENERIC_PHY_MIPI_DPHY
+	help
+	  Support for Cadence D-PHY in Rx configuration.
+
+config PHY_CADENCE_SIERRA
+	tristate "Cadence Sierra PHY Driver"
+	depends on OF && HAS_IOMEM && RESET_CONTROLLER
+	depends on COMMON_CLK
+	select GENERIC_PHY
+	help
+	  Enable this to support the Cadence Sierra PHY driver
+
+config PHY_CADENCE_SALVO
+	tristate "Cadence Salvo PHY Driver"
+	depends on OF && HAS_IOMEM
+	select GENERIC_PHY
+	help
+	  Enable this to support the Cadence SALVO PHY driver,
+	  this PHY is a legacy PHY, and only are used for USB3
+	  and USB2.