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, 25 insertions, 0 deletions

diff --git a/drivers/usb/chipidea/otg.h b/drivers/usb/chipidea/otg.h
new file mode 100644
index 000000000..87629b81e
--- /dev/null
+++ b/drivers/usb/chipidea/otg.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2013-2014 Freescale Semiconductor, Inc.
+ *
+ * Author: Peter Chen
+ */
+
+#ifndef __DRIVERS_USB_CHIPIDEA_OTG_H
+#define __DRIVERS_USB_CHIPIDEA_OTG_H
+
+u32 hw_read_otgsc(struct ci_hdrc *ci, u32 mask);
+void hw_write_otgsc(struct ci_hdrc *ci, u32 mask, u32 data);
+int ci_hdrc_otg_init(struct ci_hdrc *ci);
+void ci_hdrc_otg_destroy(struct ci_hdrc *ci);
+enum ci_role ci_otg_role(struct ci_hdrc *ci);
+void ci_handle_vbus_change(struct ci_hdrc *ci);
+void ci_handle_id_switch(struct ci_hdrc *ci);
+static inline void ci_otg_queue_work(struct ci_hdrc *ci)
+{
+	disable_irq_nosync(ci->irq);
+	if (queue_work(ci->wq, &ci->work) == false)
+		enable_irq(ci->irq);
+}
+
+#endif /* __DRIVERS_USB_CHIPIDEA_OTG_H */