Messages in this thread | | | Date | Wed, 8 May 2024 14:04:22 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCHv10 10/18] x86/tdx: Convert shared memory back to private on kexec |
| |
On Mon, May 06, 2024 at 06:37:19PM +0300, Kirill A. Shutemov wrote: > "second kernel" is nomenclature kexec folks are using, but okay.
And the "third kernel" is the one which got kexec-ed the second time?
You can make it: "The second, kexec-ed kernel" and then it is perfectly clear.
> > > + /* > > > + * Crash kernel reaches here with interrupts disabled: can't wait for > > > + * conversions to finish. > > > + * > > > + * If race happened, just report and proceed. > > > + */ > > > + bool wait_for_lock = !crash; > > > > You don't need that bool - use crash. > > Dave suggested the variable for documentation purposes. > > https://lore.kernel.org/all/0b70ee1e-4bb5-4867-9378-f5723ca091d5@intel.com > > I'm fine either way.
But you have the comment above it which already explains what's going on...
> > Why are we printing something here if we're not really acting up on it? > > > > Who should care here? > > The only thing we can do at this point on failure is panic. It think > it is reasonable to proceed, especially for crash case. > > The print leaves a trace in the log to give a clue for debug.
Sure but you'll leave a trace if you panic right then and there, on the first failure. Why noodle through the pages if the first failure is already fatal?
> One possible reason for the failure is if kdump raced with memory > conversion. In this case shared bit in page table got set (or not cleared > form shared->private conversion), but the page is actually private. So > this failure is not going to affect the kexec'ed kernel.
Lemme make sure I understand what you're saying here:
1. This is a fatal failure and we should panic
However,
2. the kexec-ed kernel is using a different page table so there won't be a mismatch between shared/private marking of the page so it doesn't matter
Close?
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
| |