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-rw-r--r--docs/confidential-guest-support.txt3
-rw-r--r--docs/papr-pef.txt30
2 files changed, 33 insertions, 0 deletions
diff --git a/docs/confidential-guest-support.txt b/docs/confidential-guest-support.txt
index bd439ac800..4da4c91bd3 100644
--- a/docs/confidential-guest-support.txt
+++ b/docs/confidential-guest-support.txt
@@ -40,4 +40,7 @@ Currently supported confidential guest mechanisms are:
AMD Secure Encrypted Virtualization (SEV)
docs/amd-memory-encryption.txt
+POWER Protected Execution Facility (PEF)
+ docs/papr-pef.txt
+
Other mechanisms may be supported in future.
diff --git a/docs/papr-pef.txt b/docs/papr-pef.txt
new file mode 100644
index 0000000000..72550e9bf8
--- /dev/null
+++ b/docs/papr-pef.txt
@@ -0,0 +1,30 @@
+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.