[PATCH] qemu: Report sev measurement value and nonce explicitly

Cole Robinson crobinso at redhat.com
Tue Oct 25 19:03:46 UTC 2022

On 10/17/22 3:42 AM, Michal Prívozník wrote:
> On 10/16/22 22:06, Cole Robinson wrote:
>> The value returned by qemu's query-sev-launch-measure comes
>> straight from the LAUNCH_MEASURE SEV firmware command. It's two
>> values packed together: first 32 bytes is the launch measurement,
>> last 16 bytes is the nonce.
>> This combined value is really just an artifact of the return value
>> of the firmware command, it has no direct usage. Users want the two
>> individual values. But because qemu and libvirt do not separate them
>> apart, every app that wants to process this value will have to do
>> it manually.
>> This performs the split for the user, and delivers the values in two
>> new TYPED_PARAM fields: sev-measurement-value, sev-measurement-nonce
>> Signed-off-by: Cole Robinson <crobinso at redhat.com>
>> ---
>>  include/libvirt/libvirt-domain.h | 22 ++++++++++++++++++++++
>>  src/qemu/qemu_driver.c           | 23 +++++++++++++++++++++++
>>  2 files changed, 45 insertions(+)
> Reviewed-by: Michal Privoznik <mprivozn at redhat.com>

Thanks, but thinking more, I'll propose this at the qemu layer and make
sure it's acceptable there first. Otherwise long term tools will may
still need to handle the sev-measurement format to cover both qemu and
libvirt cases.

- Cole

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