docs/confidential-guest-support.txt

   1 Confidential Guest Support
   2 ==========================
   3
   4 Traditionally, hypervisors such as QEMU have complete access to a
   5 guest's memory and other state, meaning that a compromised hypervisor
   6 can compromise any of its guests.  A number of platforms have added
   7 mechanisms in hardware and/or firmware which give guests at least some
   8 protection from a compromised hypervisor.  This is obviously
   9 especially desirable for public cloud environments.
  10
  11 These mechanisms have different names and different modes of
  12 operation, but are often referred to as Secure Guests or Confidential
  13 Guests.  We use the term "Confidential Guest Support" to distinguish
  14 this from other aspects of guest security (such as security against
  15 attacks from other guests, or from network sources).
  16
  17 Running a Confidential Guest
  18 ----------------------------
  19
  20 To run a confidential guest you need to add two command line parameters:
  21
  22 1. Use "-object" to create a "confidential guest support" object.  The
  23    type and parameters will vary with the specific mechanism to be
  24    used
  25 2. Set the "confidential-guest-support" machine parameter to the ID of
  26    the object from (1).
  27
  28 Example (for AMD SEV)::
  29
  30     qemu-system-x86_64 \
  31         <other parameters> \
  32         -machine ...,confidential-guest-support=sev0 \
  33         -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1
  34
  35 Supported mechanisms
  36 --------------------
  37
  38 Currently supported confidential guest mechanisms are:
  39
  40 AMD Secure Encrypted Virtualization (SEV)
  41     docs/amd-memory-encryption.txt
  42
  43 POWER Protected Execution Facility (PEF)
  44     docs/papr-pef.txt
  45
  46 s390x Protected Virtualization (PV)
  47     docs/system/s390x/protvirt.rst
  48
  49 Other mechanisms may be supported in future.