[mirror_qemu.git] / docs / confidential-guest-support.txt

Confidential Guest Support
==========================

Traditionally, hypervisors such as QEMU have complete access to a
guest's memory and other state, meaning that a compromised hypervisor
can compromise any of its guests.  A number of platforms have added
mechanisms in hardware and/or firmware which give guests at least some
protection from a compromised hypervisor.  This is obviously
especially desirable for public cloud environments.

These mechanisms have different names and different modes of
operation, but are often referred to as Secure Guests or Confidential
Guests.  We use the term "Confidential Guest Support" to distinguish
this from other aspects of guest security (such as security against
attacks from other guests, or from network sources).

Running a Confidential Guest
----------------------------

To run a confidential guest you need to add two command line parameters:

1. Use "-object" to create a "confidential guest support" object.  The
   type and parameters will vary with the specific mechanism to be
   used
2. Set the "confidential-guest-support" machine parameter to the ID of
   the object from (1).

Example (for AMD SEV)::

    qemu-system-x86_64 \
        <other parameters> \
        -machine ...,confidential-guest-support=sev0 \
        -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1

Supported mechanisms
--------------------

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

s390x Protected Virtualization (PV)
    docs/system/s390x/protvirt.rst

Other mechanisms may be supported in future.
Commit	Line	Data
64d19f33 DG	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
6c8ebe30 DG	43	POWER Protected Execution Facility (PEF)
	44	docs/papr-pef.txt
	45
651615d9 DG	46	s390x Protected Virtualization (PV)
	47	docs/system/s390x/protvirt.rst
	48
64d19f33	49	Other mechanisms may be supported in future.