[PATCH] docs: rstfy confidential guest documentation

* [PATCH] docs: rstfy confidential guest documentation
@ 2022-02-04 16:12 Cornelia Huck
  2022-02-07 12:16 ` Daniel Henrique Barboza
  2022-02-09  7:45 ` Cédric Le Goater
  0 siblings, 2 replies; 3+ messages in thread
From: Cornelia Huck @ 2022-02-04 16:12 UTC (permalink / raw)
  To: qemu-devel
  Cc: Daniel Henrique Barboza, Marcelo Tosatti, Greg Kurz, qemu-ppc,
	Cédric Le Goater, Cornelia Huck, Paolo Bonzini,
	David Gibson

Also rstfy the documentation for AMD SEV, and link it.

The documentation for PEF had been merged into the pseries doc,
fix the reference.

Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---
 MAINTAINERS                                   |   2 +-
 .../confidential-guest-support.rst}           |  15 +--
 .../i386/amd-memory-encryption.rst}           | 102 ++++++++++--------
 docs/system/index.rst                         |   1 +
 docs/system/ppc/pseries.rst                   |   2 +
 docs/system/target-i386.rst                   |   1 +
 6 files changed, 67 insertions(+), 56 deletions(-)
 rename docs/{confidential-guest-support.txt => system/confidential-guest-support.rst} (77%)
 rename docs/{amd-memory-encryption.txt => system/i386/amd-memory-encryption.rst} (62%)

diff --git a/MAINTAINERS b/MAINTAINERS
index 9814580975c5..8944fb561c0b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -408,7 +408,7 @@ M: Paolo Bonzini <pbonzini@redhat.com>
 M: Marcelo Tosatti <mtosatti@redhat.com>
 L: kvm@vger.kernel.org
 S: Supported
-F: docs/amd-memory-encryption.txt
+F: docs/system/i386/amd-memory-encryption.rst
 F: docs/system/i386/sgx.rst
 F: target/i386/kvm/
 F: target/i386/sev*
diff --git a/docs/confidential-guest-support.txt b/docs/system/confidential-guest-support.rst
similarity index 77%
rename from docs/confidential-guest-support.txt
rename to docs/system/confidential-guest-support.rst
index 71d07ba57af8..0c490dbda2b7 100644
--- a/docs/confidential-guest-support.txt
+++ b/docs/system/confidential-guest-support.rst
@@ -19,10 +19,10 @@ 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
+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
+2. Set the ``confidential-guest-support`` machine parameter to the ID of
    the object from (1).
 
 Example (for AMD SEV)::
@@ -37,13 +37,8 @@ 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
+* AMD Secure Encrypted Virtualization (SEV) (see :doc:`i386/amd-memory-encryption`)
+* POWER Protected Execution Facility (PEF) (see :ref:`power-papr-protected-execution-facility-pef`)
+* s390x Protected Virtualization (PV) (see :doc:`s390x/protvirt`)
 
 Other mechanisms may be supported in future.
diff --git a/docs/amd-memory-encryption.txt b/docs/system/i386/amd-memory-encryption.rst
similarity index 62%
rename from docs/amd-memory-encryption.txt
rename to docs/system/i386/amd-memory-encryption.rst
index ffca382b5f5d..215946f813bb 100644
--- a/docs/amd-memory-encryption.txt
+++ b/docs/system/i386/amd-memory-encryption.rst
@@ -1,3 +1,6 @@
+AMD Secure Encrypted Virtualization (SEV)
+=========================================
+
 Secure Encrypted Virtualization (SEV) is a feature found on AMD processors.
 
 SEV is an extension to the AMD-V architecture which supports running encrypted
@@ -24,17 +27,18 @@ the hypervisor to satisfy the requested function.
 
 Launching
 ---------
+
 Boot images (such as bios) must be encrypted before a guest can be booted. The
-MEMORY_ENCRYPT_OP ioctl provides commands to encrypt the images: LAUNCH_START,
-LAUNCH_UPDATE_DATA, LAUNCH_MEASURE and LAUNCH_FINISH. These four commands
+``MEMORY_ENCRYPT_OP`` ioctl provides commands to encrypt the images: ``LAUNCH_START``,
+``LAUNCH_UPDATE_DATA``, ``LAUNCH_MEASURE`` and ``LAUNCH_FINISH``. These four commands
 together generate a fresh memory encryption key for the VM, encrypt the boot
 images and provide a measurement than can be used as an attestation of a
 successful launch.
 
-For a SEV-ES guest, the LAUNCH_UPDATE_VMSA command is also used to encrypt the
+For a SEV-ES guest, the ``LAUNCH_UPDATE_VMSA`` command is also used to encrypt the
 guest register state, or VM save area (VMSA), for all of the guest vCPUs.
 
-LAUNCH_START is called first to create a cryptographic launch context within
+``LAUNCH_START`` is called first to create a cryptographic launch context within
 the firmware. To create this context, guest owner must provide a guest policy,
 its public Diffie-Hellman key (PDH) and session parameters. These inputs
 should be treated as a binary blob and must be passed as-is to the SEV firmware.
@@ -45,37 +49,37 @@ in bad measurement). The guest policy is a 4-byte data structure containing
 several flags that restricts what can be done on a running SEV guest.
 See KM Spec section 3 and 6.2 for more details.
 
-The guest policy can be provided via the 'policy' property (see below)
+The guest policy can be provided via the ``policy`` property::
 
-# ${QEMU} \
-   sev-guest,id=sev0,policy=0x1...\
+  # ${QEMU} \
+     sev-guest,id=sev0,policy=0x1...\
 
 Setting the "SEV-ES required" policy bit (bit 2) will launch the guest as a
-SEV-ES guest (see below)
+SEV-ES guest::
 
-# ${QEMU} \
-   sev-guest,id=sev0,policy=0x5...\
+  # ${QEMU} \
+     sev-guest,id=sev0,policy=0x5...\
 
 The guest owner provided DH certificate and session parameters will be used to
 establish a cryptographic session with the guest owner to negotiate keys used
 for the attestation.
 
-The DH certificate and session blob can be provided via the 'dh-cert-file' and
-'session-file' properties (see below)
+The DH certificate and session blob can be provided via the ``dh-cert-file`` and
+``session-file`` properties::
 
-# ${QEMU} \
-     sev-guest,id=sev0,dh-cert-file=<file1>,session-file=<file2>
+  # ${QEMU} \
+       sev-guest,id=sev0,dh-cert-file=<file1>,session-file=<file2>
 
-LAUNCH_UPDATE_DATA encrypts the memory region using the cryptographic context
-created via the LAUNCH_START command. If required, this command can be called
+``LAUNCH_UPDATE_DATA`` encrypts the memory region using the cryptographic context
+created via the ``LAUNCH_START`` command. If required, this command can be called
 multiple times to encrypt different memory regions. The command also calculates
 the measurement of the memory contents as it encrypts.
 
-LAUNCH_UPDATE_VMSA encrypts all the vCPU VMSAs for a SEV-ES guest using the
-cryptographic context created via the LAUNCH_START command. The command also
+``LAUNCH_UPDATE_VMSA`` encrypts all the vCPU VMSAs for a SEV-ES guest using the
+cryptographic context created via the ``LAUNCH_START`` command. The command also
 calculates the measurement of the VMSAs as it encrypts them.
 
-LAUNCH_MEASURE can be used to retrieve the measurement of encrypted memory and,
+``LAUNCH_MEASURE`` can be used to retrieve the measurement of encrypted memory and,
 for a SEV-ES guest, encrypted VMSAs. This measurement is a signature of the
 memory contents and, for a SEV-ES guest, the VMSA contents, that can be sent
 to the guest owner as an attestation that the memory and VMSAs were encrypted
@@ -85,27 +89,28 @@ Since the guest owner knows the initial contents of the guest at boot, the
 attestation measurement can be verified by comparing it to what the guest owner
 expects.
 
-LAUNCH_FINISH finalizes the guest launch and destroys the cryptographic
+``LAUNCH_FINISH`` finalizes the guest launch and destroys the cryptographic
 context.
 
-See SEV KM API Spec [1] 'Launching a guest' usage flow (Appendix A) for the
+See SEV KM API Spec ([SEVKM]_) 'Launching a guest' usage flow (Appendix A) for the
 complete flow chart.
 
-To launch a SEV guest
+To launch a SEV guest::
 
-# ${QEMU} \
-    -machine ...,confidential-guest-support=sev0 \
-    -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1
+  # ${QEMU} \
+      -machine ...,confidential-guest-support=sev0 \
+      -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1
 
-To launch a SEV-ES guest
+To launch a SEV-ES guest::
 
-# ${QEMU} \
-    -machine ...,confidential-guest-support=sev0 \
-    -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1,policy=0x5
+  # ${QEMU} \
+      -machine ...,confidential-guest-support=sev0 \
+      -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1,policy=0x5
 
 An SEV-ES guest has some restrictions as compared to a SEV guest. Because the
 guest register state is encrypted and cannot be updated by the VMM/hypervisor,
 a SEV-ES guest:
+
  - Does not support SMM - SMM support requires updating the guest register
    state.
  - Does not support reboot - a system reset requires updating the guest register
@@ -114,35 +119,42 @@ a SEV-ES guest:
    manage booting APs.
 
 Debugging
------------
+---------
+
 Since the memory contents of a SEV guest are encrypted, hypervisor access to
 the guest memory will return cipher text. If the guest policy allows debugging,
 then a hypervisor can use the DEBUG_DECRYPT and DEBUG_ENCRYPT commands to access
 the guest memory region for debug purposes.  This is not supported in QEMU yet.
 
 Snapshot/Restore
------------------
+----------------
+
 TODO
 
 Live Migration
-----------------
+---------------
+
 TODO
 
 References
------------------
+----------
 
-AMD Memory Encryption whitepaper:
-https://developer.amd.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf
+`AMD Memory Encryption whitepaper
+<https://developer.amd.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf>`_
 
-Secure Encrypted Virtualization Key Management:
-[1] http://developer.amd.com/wordpress/media/2017/11/55766_SEV-KM-API_Specification.pdf
+.. [SEVKM] `Secure Encrypted Virtualization Key Management
+   <http://developer.amd.com/wordpress/media/2017/11/55766_SEV-KM-API_Specification.pdf>`_
 
 KVM Forum slides:
-http://www.linux-kvm.org/images/7/74/02x08A-Thomas_Lendacky-AMDs_Virtualizatoin_Memory_Encryption_Technology.pdf
-https://www.linux-kvm.org/images/9/94/Extending-Secure-Encrypted-Virtualization-with-SEV-ES-Thomas-Lendacky-AMD.pdf
-
-AMD64 Architecture Programmer's Manual:
-   http://support.amd.com/TechDocs/24593.pdf
-   SME is section 7.10
-   SEV is section 15.34
-   SEV-ES is section 15.35
+
+* `AMD’s Virtualization Memory Encryption (2016)
+  <http://www.linux-kvm.org/images/7/74/02x08A-Thomas_Lendacky-AMDs_Virtualizatoin_Memory_Encryption_Technology.pdf>`_
+* `Extending Secure Encrypted Virtualization With SEV-ES (2018)
+  <https://www.linux-kvm.org/images/9/94/Extending-Secure-Encrypted-Virtualization-with-SEV-ES-Thomas-Lendacky-AMD.pdf>`_
+
+`AMD64 Architecture Programmer's Manual:
+<http://support.amd.com/TechDocs/24593.pdf>`_
+
+* SME is section 7.10
+* SEV is section 15.34
+* SEV-ES is section 15.35
diff --git a/docs/system/index.rst b/docs/system/index.rst
index 73bbedbc22d4..23e30e26e5e6 100644
--- a/docs/system/index.rst
+++ b/docs/system/index.rst
@@ -34,3 +34,4 @@ or Hypervisor.Framework.
    targets
    security
    multi-process
+   confidential-guest-support
diff --git a/docs/system/ppc/pseries.rst b/docs/system/ppc/pseries.rst
index 569237dc0c8b..d9b65ad4e850 100644
--- a/docs/system/ppc/pseries.rst
+++ b/docs/system/ppc/pseries.rst
@@ -224,6 +224,8 @@ nested. Combinations not shown in the table are not available.
 .. [3] Introduced on Power10 machines.
 
 
+.. _power-papr-protected-execution-facility-pef:
+
 POWER (PAPR) Protected Execution Facility (PEF)
 -----------------------------------------------
 
diff --git a/docs/system/target-i386.rst b/docs/system/target-i386.rst
index 4daa53c35d8f..96bf54889a82 100644
--- a/docs/system/target-i386.rst
+++ b/docs/system/target-i386.rst
@@ -28,6 +28,7 @@ Architectural features
    i386/cpu
    i386/kvm-pv
    i386/sgx
+   i386/amd-memory-encryption
 
 .. _pcsys_005freq:
 
-- 
2.34.1



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