confidential-guest-support.rst (1740B)
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) (see :doc:`i386/amd-memory-encryption`) 41 * POWER Protected Execution Facility (PEF) (see :ref:`power-papr-protected-execution-facility-pef`) 42 * s390x Protected Virtualization (PV) (see :doc:`s390x/protvirt`) 43 44 Other mechanisms may be supported in future.