On Wed, Jun 05, 2024 at 03:21:42PM +0300, Kirill A. Shutemov wrote:
> If a page can be accessed via private mapping is determined by the
> presence in Secure EPT. This state persist across kexec.
I just love it how I tickle out details each time I touch this comment
because we three can't write a single concise and self-contained
explanation. :-(
Ok, next version:
"Private mappings persist across kexec. If tdx_enc_status_changed() fails
in the first kernel, it leaves memory in an unknown state.
If that memory remains shared, accessing it in the *next* kernel through
a private mapping will result in an unrecoverable guest shutdown.
The kdump kernel boot is not impacted as it uses a pre-reserved memory
range that is always private. However, gathering crash information
could lead to a crash if it accesses unconverted memory through
a private mapping which is possible when accessing that memory through
/proc/vmcore, for example.
In all cases, print error info in order to leave enough bread crumbs for
debugging."
I think this is getting in the right direction as it actually makes
sense now.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
