Re: [PATCH v2 00/22] qga: clean up command source locations and conditionals

["Daniel P. Berrangé" <berrange@redhat.com>]

On Fri, Jun 14, 2024 at 12:34:52PM +0400, Marc-André Lureau wrote:
> Hi
> 
> On Thu, Jun 13, 2024 at 7:02 PM Daniel P. Berrangé <berrange@redhat.com>
> wrote:
> 
> > This series is a side effect of other work I started, to attempt to
> > make the QGA safe to use in confidential VMs by automatically
> > restricting the permitted commands. Since this cleanup stands on
> > its own, I'm sending it now.
> >
> > The QGA codebase has a very complicated maze of #ifdefs to create
> > stubs for the various commands that cannot be implemented on certain
> > platforms. It then has further logic to dynamically disable the stub
> > commands at runtime, except this is not consistently applied, so
> > some commands remain enabled despite being merely stubs.
> >
> > The resulting code is hard to follow, when trying to understand exactly
> > what commands are available under what circumstances, and when changing
> > impls it is easy to get the #ifdefs wrong, resulting in stubs getting
> > missed on platforms without a real impl. In some cases, we have multiple
> > stubs for the same command, due to the maze of #ifdefs.
> >
> > The QAPI schema language has support for many years for expressing
> > conditions against commands when declaring them. This results in the
> > QAPI code generator omitting their implementation entirely at build
> > time. This has mutliple benefits
> >
> >  * The unsupported commands are guaranteed to not exist at runtime
> >  * No stubs need ever be defined in the code
> >  * The generated QAPI reference manual documents the build conditions
> >
> > This series is broadly split into three parts
> >
> >  * Moving tonnes of Linux only commands out of commands-posix.c
> >    into commands-linux.c to remove many #ifdefs.
> >  * Adding 'if' conditions in the QAPI schema to reflect the
> >    build conditions, removing many more #ifdefs
> >  * Sanitizing the logic for disabling/enabling commands at
> >    runtime to guarantee consistency
> >
> > Changed in v2:
> >
> >  - Make FSFreeze error reporting distinguish inability to enable
> >    VSS from user config choice
> >
> >  - Fully remove ga_command_init_blockedrpcs() methods. No more
> >    special case disabling of commands. Either they're disabled
> >    at build time, or disabled by user config, or by well defined
> >    rule ie not permitted during FS freeze.
> >
> >  - Apply rules later in startup to avoid crash from NULL config
> >    pointer
> >
> >  - Document changed error messages in commit messages
> >
> >  - Add -c / --config command line parameter
> >
> >  - Fix mistaken enabling of fsfreeze hooks on win32
> >
> >  - Remove pointless 'blockrpcs_key' variable
> >
> >  - Allow concurrent setting of allow and block lists for
> >    RPC commands
> >
> > Daniel P. Berrangé (22):
> >   qga: drop blocking of guest-get-memory-block-size command
> >   qga: move linux vcpu command impls to commands-linux.c
> >   qga: move linux suspend command impls to commands-linux.c
> >   qga: move linux fs/disk command impls to commands-linux.c
> >   qga: move linux disk/cpu stats command impls to commands-linux.c
> >   qga: move linux memory block command impls to commands-linux.c
> >   qga: move CONFIG_FSFREEZE/TRIM to be meson defined options
> >   qga: conditionalize schema for commands unsupported on Windows
> >   qga: conditionalize schema for commands unsupported on non-Linux POSIX
> >   qga: conditionalize schema for commands requiring getifaddrs
> >   qga: conditionalize schema for commands requiring linux/win32
> >   qga: conditionalize schema for commands only supported on Windows
> >   qga: conditionalize schema for commands requiring fsfreeze
> >   qga: conditionalize schema for commands requiring fstrim
> >   qga: conditionalize schema for commands requiring libudev
> >   qga: conditionalize schema for commands requiring utmpx
> >   qga: conditionalize schema for commands not supported on other UNIX
> >   qga: don't disable fsfreeze commands if vss_init fails
> >   qga: move declare of QGAConfig struct to top of file
> >   qga: remove pointless 'blockrpcs_key' variable
> >   qga: allow configuration file path via the cli
> >   qga: centralize logic for disabling/enabling commands
> >
> >
> Something broke patchew handling:
> https://patchew.org/QEMU/20240613150127.1361931-1-berrange@redhat.com/20240613154406.1365469-1-berrange@redhat.com/

gmail refused further mail delivery from me part way through sending
the series, so I had to send the 2nd half of it separately.

With regards,
Daniel
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