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+POWER (PAPR) Protected Execution Facility (PEF)
+===============================================
+
+Protected Execution Facility (PEF), also known as Secure Guest support
+is a feature found on IBM POWER9 and POWER10 processors.
+
+If a suitable firmware including an Ultravisor is installed, it adds
+an extra memory protection mode to the CPU. The ultravisor manages a
+pool of secure memory which cannot be accessed by the hypervisor.
+
+When this feature is enabled in QEMU, a guest can use ultracalls to
+enter "secure mode". This transfers most of its memory to secure
+memory, where it cannot be eavesdropped by a compromised hypervisor.
+
+Launching
+---------
+
+To launch a guest which will be permitted to enter PEF secure mode:
+
+# ${QEMU} \
+ -object pef-guest,id=pef0 \
+ -machine confidential-guest-support=pef0 \
+ ...
+
+Live Migration
+----------------
+
+Live migration is not yet implemented for PEF guests. For
+consistency, we currently prevent migration if the PEF feature is
+enabled, whether or not the guest has actually entered secure mode.