xemu/docs
Daniel P. Berrangé 2720ceda05 docs: expand firmware descriptor to allow flash without NVRAM
The current firmware descriptor schema for flash requires that both the
executable to NVRAM template paths be provided. This is fine for the
most common usage of EDK2 builds in virtualization where the separate
_CODE and _VARS files are provided.

With confidential computing technology like AMD SEV, persistent storage
of variables may be completely disabled because the firmware requires a
known clean state on every cold boot. There is no way to express this
in the firmware descriptor today.

Even with regular EDK2 builds it is possible to create a firmware that
has both executable code and variable persistence in a single file. This
hasn't been commonly used, since it would mean every guest bootup would
need to clone the full firmware file, leading to redundant duplicate
storage of the code portion. In some scenarios this may not matter and
might even be beneficial. For example if a public cloud allows users to
bring their own firmware, such that the user can pre-enroll their own
secure boot keys, you're going to have this copied on disk for each
tenant already. At this point the it can be simpler to just deal with
a single file rather than split builds. The firmware descriptor ought
to be able to express this combined firmware model too.

This all points towards expanding the schema for flash with a 'mode'
concept:

 - "split" - the current implicit behaviour with separate files
   for code and variables.

 - "combined" - the alternate behaviour where a single file contains
   both code and variables.

 - "stateless" - the confidential computing use case where storage
   of variables is completely disable, leaving only the code.

Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2022-02-16 18:53:26 +00:00
..
_templates docs: Add QEMU version information to HTML footer 2021-07-18 10:59:47 +01:00
about Deprecate C virtiofsd 2022-02-14 17:11:20 +00:00
config docs: Grammar and spelling fixes 2018-07-13 10:16:04 +01:00
devel docs: remove references to TCG tracing 2022-02-09 12:08:42 +00:00
interop docs: expand firmware descriptor to allow flash without NVRAM 2022-02-16 18:53:26 +00:00
specs Rename ppc-spapr-uv-hcalls.txt to ppc-spapr-uv-hcalls.rst. 2022-01-18 12:56:30 +01:00
sphinx docs/sphinx: fix compatibility with sphinx < 1.8 2022-01-05 11:10:13 +01:00
sphinx-static docs/sphinx: add 's' keyboard binding to focus search 2021-11-08 12:27:23 +04:00
spin docs: create config/, devel/ and spin/ subdirectories 2017-06-07 18:22:03 +02:00
system block: better document SSH host key fingerprint checking 2022-02-16 14:34:15 +00:00
tools qemu-img: Unify [-b [-F]] documentation 2022-02-01 13:49:15 +01:00
user linux-user: Remove the deprecated ppc64abi32 target 2022-02-09 13:29:38 +00:00
block-replication.txt docs/block-replication.txt: Fix replication top-id command demo 2021-12-17 11:35:00 +01:00
bypass-iommu.txt docs: Add documentation for iommu bypass 2021-07-16 11:10:45 -04:00
ccid.txt hw/usb/ccid: remove references to NSS 2021-07-14 14:33:53 +01:00
COLO-FT.txt docs: Use double quotes instead of single quotes for COLO 2021-11-22 15:02:38 +01:00
colo-proxy.txt docs: update to show preferred boolean syntax for -chardev 2021-02-25 14:14:33 +01:00
conf.py Update copyright dates to 2022 2022-01-28 14:29:46 +00:00
defs.rst.inc docs: Fix typo in the default name of the qemu-system-x86_64 binary 2021-04-01 14:28:39 +02:00
hyperv.txt Fix some typos in documentation (found by codespell) 2021-11-22 15:02:38 +01:00
igd-assign.txt vfio/pci: Add IGD documentation 2016-05-26 11:12:05 -06:00
image-fuzzer.txt docs: Render binary names as monospaced text 2021-11-22 15:02:38 +01:00
index.rst docs: standardize book titles to === with overline 2021-09-13 13:56:26 +02:00
memory-hotplug.txt docs: Grammar and spelling fixes 2018-07-13 10:16:04 +01:00
meson.build meson: add "check" argument to run_command 2021-12-18 10:57:36 +01:00
multi-thread-compression.txt Replace '-enable-kvm' with '-accel kvm' in docs and help texts 2018-06-28 19:05:32 +02:00
multiseat.txt docs: Spell QEMU all caps 2021-11-19 10:16:58 +01:00
nvdimm.txt docs/nvdimm: Update nvdimm option value in machine example 2021-09-27 10:57:21 +02:00
pci_expander_bridge.txt pxb: cleanup 2016-03-11 16:59:12 +02:00
pcie_pci_bridge.txt docs: add slot when adding new PCIe root port 2021-07-03 03:12:35 -04:00
pcie.txt docs: pcie: Spell out machine type needs for PCIe features 2018-03-01 16:25:37 +02:00
pvrdma.txt docs: Fix broken links 2020-09-01 09:31:33 +02:00
qcow2-cache.txt qcow2: Document the Extended L2 Entries feature 2020-08-25 08:33:20 +02:00
qdev-device-use.txt hw/ide: remove 'ide-drive' device 2021-03-18 09:22:55 +00:00
qemu_logo.pdf docs: add qemu logo to pdf 2017-01-16 10:11:43 +01:00
qemu-option-trace.rst.inc qemu-option-trace.rst.inc: Don't use option:: markup 2020-11-02 16:52:18 +00:00
qemupciserial.inf docs: Grammar and spelling fixes 2018-07-13 10:16:04 +01:00
rdma.txt migrate: remove QMP/HMP commands for speed, downtime and cache size 2021-03-18 09:22:55 +00:00
replay.txt docs: Fix some typos (found by codespell) 2020-11-18 09:29:41 +01:00
spice-port-fqdn.txt docs: add spice-port-fqdn.txt 2012-12-17 14:01:41 +01:00
throttle.txt docs: Drop deprecated 'props' from object-add 2021-11-22 15:02:38 +01:00
u2f.txt docs: Spell QEMU all caps 2021-11-19 10:16:58 +01:00
xbzrle.txt migrate: remove QMP/HMP commands for speed, downtime and cache size 2021-03-18 09:22:55 +00:00
xen-save-devices-state.txt Fix up dangling references to qmp-commands.* in comment and doc 2018-03-02 13:48:26 -06:00