Re: [RFC PATCH v2 1/9] Add Rust SEV library as subproject

[Tyler Fanelli <tfanelli@redhat.com>]

Hi Manos,

Thanks for the heads up, I was using rust 1.71.1. Will update the series 
with 1.72.1

Stefan, Philippe, or Daniel: is there a specific policy for the Rust 
version we should be developing on for crates in qemu?

Tyler

On 10/13/23 2:09 PM, Manos Pitsidianakis wrote:
> Hello Tyler!
>
> With Rust stable 1.72.1, I get:
>
> error: unneeded `return` statement
>     --> tests/launch.rs:103:26
>      |
> 103 |         VcpuExit::Hlt => return,
>      |                          ^^^^^^
>      |
>      = help: for further information visit
> https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
>      = note: `-D clippy::needless-return` implied by `-D warnings`
> help: replace `return` with a unit value
>      |
> 103 |         VcpuExit::Hlt => (),
>      |                          ~~
>
> error: could not compile `sev` (test "launch") due to previous error
> warning: build failed, waiting for other jobs to finish...
>
>
> When doing make.
>
> --
> Manos
>
> On Wed, 11 Oct 2023 at 06:11, Tyler Fanelli <tfanelli@redhat.com> wrote:
>> On 10/5/23 11:54 AM, Stefan Hajnoczi wrote:
>>> On Wed, Oct 04, 2023 at 04:34:10PM -0400, Tyler Fanelli wrote:
>>>> The Rust sev library provides a C API for the AMD SEV launch ioctls, as
>>>> well as the ability to build with meson. Add the Rust sev library as a
>>>> QEMU subproject with the goal of outsourcing all SEV launch ioctls to C
>>>> APIs provided by it.
>>>>
>>>> Signed-off-by: Tyler Fanelli <tfanelli@redhat.com>
>>>> ---
>>>>    meson.build                   | 8 ++++++++
>>>>    meson_options.txt             | 2 ++
>>>>    scripts/meson-buildoptions.sh | 3 +++
>>>>    subprojects/sev.wrap          | 6 ++++++
>>>>    target/i386/meson.build       | 2 +-
>>>>    5 files changed, 20 insertions(+), 1 deletion(-)
>>>>    create mode 100644 subprojects/sev.wrap
>>>>
>>>> diff --git a/meson.build b/meson.build
>>>> index 20ceeb8158..8a17c29de8 100644
>>>> --- a/meson.build
>>>> +++ b/meson.build
>>>> @@ -960,6 +960,13 @@ if not get_option('slirp').auto() or have_system
>>>>      endif
>>>>    endif
>>>>
>>>> +sev = not_found
>>>> +if not get_option('sev').auto()
>>> When 'sev' is auto, then it won't be built. That seems strange. The
>>> auto-detection part is missing! I did you test this on a system that
>>> doesn't have libsev installed system-wide?
>> My testing environment had libsev installed system-wide. Thanks for
>> pointing this out.
>>
>>> I guess the auto-detection would look something like:
>>>
>>>     cargo = find_program('cargo', required: true)
>>>
>>>     if not get_option('sev').auto() or cargo.found()
>>>         ...
>>>
>>> That way 'sev' is only built automatically on systems that have cargo
>>> installed.
>>>
>>>> +  sev = dependency('sev',
>>>> +                   method: 'pkg-config',
>>>> +                   required: get_option('sev'))
>>>> +endif
>>> If you update the auto logic, see the documentation about fallbacks to
>>> subprojects for optional dependencies:
>>> https://mesonbuild.com/Wrap-dependency-system-manual.html#provide-section
>>>
>>> It might be necessary to add dependency(..., fallback='sev').
>> Noted. Thanks!
>>
>>>> +
>>>>    vde = not_found
>>>>    if not get_option('vde').auto() or have_system or have_tools
>>>>      vde = cc.find_library('vdeplug', has_headers: ['libvdeplug.h'],
>>>> @@ -4331,6 +4338,7 @@ summary_info += {'libudev':           libudev}
>>>>    # Dummy dependency, keep .found()
>>>>    summary_info += {'FUSE lseek':        fuse_lseek.found()}
>>>>    summary_info += {'selinux':           selinux}
>>>> +summary_info += {'sev':               sev}
>>>>    summary_info += {'libdw':             libdw}
>>>>    summary(summary_info, bool_yn: true, section: 'Dependencies')
>>>>
>>>> diff --git a/meson_options.txt b/meson_options.txt
>>>> index 57e265c871..5b8d283717 100644
>>>> --- a/meson_options.txt
>>>> +++ b/meson_options.txt
>>>> @@ -204,6 +204,8 @@ option('sdl_image', type : 'feature', value : 'auto',
>>>>           description: 'SDL Image support for icons')
>>>>    option('seccomp', type : 'feature', value : 'auto',
>>>>           description: 'seccomp support')
>>>> +option('sev', type : 'feature', value : 'auto',
>>>> +        description: 'Rust AMD SEV library')
>>>>    option('smartcard', type : 'feature', value : 'auto',
>>>>           description: 'CA smartcard emulation support')
>>>>    option('snappy', type : 'feature', value : 'auto',
>>>> diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh
>>>> index e4b46d5715..e585a548fa 100644
>>>> --- a/scripts/meson-buildoptions.sh
>>>> +++ b/scripts/meson-buildoptions.sh
>>>> @@ -161,6 +161,7 @@ meson_options_help() {
>>>>      printf "%s\n" '  sdl-image       SDL Image support for icons'
>>>>      printf "%s\n" '  seccomp         seccomp support'
>>>>      printf "%s\n" '  selinux         SELinux support in qemu-nbd'
>>>> +  printf "%s\n" '  sev             SEV library support'
>>>>      printf "%s\n" '  slirp           libslirp user mode network backend support'
>>>>      printf "%s\n" '  slirp-smbd      use smbd (at path --smbd=*) in slirp networking'
>>>>      printf "%s\n" '  smartcard       CA smartcard emulation support'
>>>> @@ -440,6 +441,8 @@ _meson_option_parse() {
>>>>        --disable-seccomp) printf "%s" -Dseccomp=disabled ;;
>>>>        --enable-selinux) printf "%s" -Dselinux=enabled ;;
>>>>        --disable-selinux) printf "%s" -Dselinux=disabled ;;
>>>> +    --enable-sev) printf "%s" -Dsev=enabled ;;
>>>> +    --disable-sev) printf "%s" -Dsev=disabled ;;
>>>>        --enable-slirp) printf "%s" -Dslirp=enabled ;;
>>>>        --disable-slirp) printf "%s" -Dslirp=disabled ;;
>>>>        --enable-slirp-smbd) printf "%s" -Dslirp_smbd=enabled ;;
>>>> diff --git a/subprojects/sev.wrap b/subprojects/sev.wrap
>>>> new file mode 100644
>>>> index 0000000000..5be1faccf6
>>>> --- /dev/null
>>>> +++ b/subprojects/sev.wrap
>>>> @@ -0,0 +1,6 @@
>>>> +[wrap-git]
>>>> +url = https://github.com/tylerfanelli/sev
>>>> +revision = b81b1da5df50055600a5b0349b0c4afda677cccb
>>>> +
>>>> +[provide]
>>>> +sev = sev_dep
>>>> diff --git a/target/i386/meson.build b/target/i386/meson.build
>>>> index 6f1036d469..8972a4fb17 100644
>>>> --- a/target/i386/meson.build
>>>> +++ b/target/i386/meson.build
>>>> @@ -20,7 +20,7 @@ i386_system_ss.add(files(
>>>>      'monitor.c',
>>>>      'cpu-sysemu.c',
>>>>    ))
>>>> -i386_system_ss.add(when: 'CONFIG_SEV', if_true: files('sev.c'), if_false: files('sev-sysemu-stub.c'))
>>>> +i386_system_ss.add(when: 'CONFIG_SEV', if_true: [sev, files('sev.c')], if_false: files('sev-sysemu-stub.c'))
>>>>
>>>>    i386_user_ss = ss.source_set()
>>>>
>>>> --
>>>> 2.40.1
>>>>
>> Tyler
>>
>>