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64d19f3334
Now that we've implemented a generic machine option for configuring various
confidential guest support mechanisms:
1. Update docs/amd-memory-encryption.txt to reference this rather than
the earlier SEV specific option
2. Add a docs/confidential-guest-support.txt to cover the generalities of
the confidential guest support scheme
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
44 lines
1.5 KiB
Plaintext
44 lines
1.5 KiB
Plaintext
Confidential Guest Support
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==========================
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Traditionally, hypervisors such as QEMU have complete access to a
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guest's memory and other state, meaning that a compromised hypervisor
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can compromise any of its guests. A number of platforms have added
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mechanisms in hardware and/or firmware which give guests at least some
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protection from a compromised hypervisor. This is obviously
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especially desirable for public cloud environments.
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These mechanisms have different names and different modes of
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operation, but are often referred to as Secure Guests or Confidential
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Guests. We use the term "Confidential Guest Support" to distinguish
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this from other aspects of guest security (such as security against
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attacks from other guests, or from network sources).
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Running a Confidential Guest
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----------------------------
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To run a confidential guest you need to add two command line parameters:
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1. Use "-object" to create a "confidential guest support" object. The
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type and parameters will vary with the specific mechanism to be
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used
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2. Set the "confidential-guest-support" machine parameter to the ID of
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the object from (1).
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Example (for AMD SEV)::
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qemu-system-x86_64 \
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<other parameters> \
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-machine ...,confidential-guest-support=sev0 \
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-object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1
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Supported mechanisms
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--------------------
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Currently supported confidential guest mechanisms are:
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AMD Secure Encrypted Virtualization (SEV)
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docs/amd-memory-encryption.txt
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Other mechanisms may be supported in future.
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