On 02/25/25 at 10:35am, steven chen wrote:

On 2/24/2025 4:18 PM, Baoquan He wrote:

quoted

On 02/24/25 at 03:05pm, steven chen wrote:

quoted

On 2/23/2025 10:14 PM, Baoquan He wrote:

quoted

Hi Steve, Mimi,

On 02/18/25 at 02:54pm, steven chen wrote:

quoted

Currently, the mechanism to map and unmap segments to the kimage
structure is not available to the subsystems outside of kexec.  This
functionality is needed when IMA is allocating the memory segments
during kexec 'load' operation.  Implement functions to map and unmap
segments to kimage.

I am done with the whole patchset understanding. My concern is if this
TPM PCRs content can be carried over through newly introduced KHO. I can
see that these patchset doesn't introduce too much new code changes,
while if many conponents need do this, kexec reboot will be patched all
over its body and become ugly and hard to maintain.

Please check Mike Rapoport's v4 patchset to see if IMA can register
itself to KHO and do somthing during 2nd kernel init to restore those
TPM PCRs content to make sure all measurement logs are read correctly.
[PATCH v4 00/14] kexec: introduce Kexec HandOver (KHO)

Thanks
Baoquan

Hi Baoquan,

For IMA, it appears that there are no current issues with TPM PCRs after a
kernel soft reboot.

I mean using KHO to hold in 1st kernel and restore the IMA log in 2nd
kernel.

quoted

This patches is used to get currently missed IMA measurements during the
kexec process copied to new kernel after the kernel soft reboot. I think
it's ok to leave it at current location: it will be easy to maintain for
IMA.

Yeah, but I am saying this patchset increase unnecessary code
complexity in kexec code maintaining.

quoted

Overall, for these patches, do you see any major blockers for kexec?

If you have any specific concerns or need further details, please let me
know.

I have no concerns for this patchset implementation itself, I saw you using
vmap to maping the possible scattered source pages smartly and taking
the mapped buffer pointers to update later duing kexec jumping. That's very
great and clever method. BUT I am concerned about the solution, if we
can make use of the existed way of KHO to implement it more simply. Could
you please do investigation?

Hi Baoquan,

I will conduct an investigation. Thank you for your comments.

Thanks a lot, Steven.