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)?
I recall there might be other kdump-related issues for TDX and friends
to solve. Especially, which information the second kernel gets provided
by the first kernel.
So can this patch even be tested reasonably (IOW, get into a kdump
kernel in an environment where the first kernel has unaccepted memory,
and verify that unaccepted memory is handled accordingly? ... while
kdump doing anything reasonable in such an environment at all?)
--
Cheers,
David / dhildenb
