Re: [PATCH 1/3] proc/vmcore: Do not map unaccepted memory

[Kirill A. Shutemov]

On Mon, Sep 11, 2023 at 10:03:36AM +0200, David Hildenbrand wrote:
> On 06.09.23 09:39, Adrian Hunter wrote:
> > Support for unaccepted memory was added recently, refer commit
> > dcdfdd40fa82 ("mm: Add support for unaccepted memory"), whereby
> > a virtual machine may need to accept memory before it can be used.
> > 
> > Do not map unaccepted memory because it can cause the guest to fail.
> > 
> > For /proc/vmcore, which is read-only, this means a read or mmap of
> > unaccepted memory will return zeros.
> 
> Does a second (kdump) kernel that exposes /proc/vmcore reliably get access
> to the information whether memory of the first kernel is unaccepted (IOW,
> not its memory, but the memory of the first kernel it is supposed to expose
> via /proc/vmcore)?

There are few patches in my queue to few related issue, but generally,
yes, the information is available to the target kernel via EFI
configuration table.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov