Re: [PATCH] x86/kvm/tdx: Save %rbp in TDX_MODULE_CALL

Jürgen Groß
2024-05-23T05:56:42Z

On 20.05.24 13:54, Huang, Kai wrote:
> On Fri, 2024-05-17 at 09:48 -0700, Dave Hansen wrote:
>> On 5/17/24 08:58, Juergen Gross wrote:
>>> On 17.05.24 17:52, Dave Hansen wrote:
>> ..
>>>> Once we have the specific TDX module version, we can go ask the folks
>>>> who write it if there were any RBP clobbering bugs.
>>>
>>> Okay, how to get the TDX module version?
>>
>> You need something like this:
>>
>>> https://lore.kernel.org/all/20231012134136.1310650-1-yi.sun@intel.com/
>
> This one prints TDX version info in the TDX guest, but not host.
>
> The attached diff prints the TDX version (something like below) during
> module initialization, and should meet Juergen's needs for temporary use:
>
> [ 113.543538] virt/tdx: module verson: major 1, minor 5, internal 0
>
>>
>> .. and yeah, this needs to be upstream.
>>
>
> From this thread I think it makes sense to add code to the TDX host code
> to print the TDX version during module initialization. I'll start to work
> on this.
>
> One thing is from the spec TDX has "4 versions": major, minor, update,
> internal. They are all 16-bit, and the overall version can be written in:
>
> <Major>.<Minor>.<Update>.<Internal>, e.g., 1.5.05.01
>
> (see TDX module 1.5 API spec, section 3.3.2 "TDX Module Version".)
>
> The attached diff only prints major, minor and internal, but leaves the
> update out because I believe it is for module runtime update (yet to
> confirm).
>
> Given there are 4 versions, I think it makes sense to implement reading
> them based on this patchset ...
>
> https://lore.kernel.org/kvm/6940c326-bfca-4c67-badf-ab5c086bf492@intel.com/T/
>
> ... which extends the global metadata reading code to support any
> arbitrary struct and all element sizes (although all 4 versions are 16-
> bit)?

With that I got:

[ 29.328484] virt/tdx: module verson: major 1, minor 5, internal 0

Juergen