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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 11.09.23 12:05, Kirill A. Shutemov wrote:
On Mon, Sep 11, 2023 at 11:50:31AM +0200, David Hildenbrand wrote:
On 11.09.23 11:27, Kirill A. Shutemov wrote:
On Mon, Sep 11, 2023 at 10:42:51AM +0200, David Hildenbrand wrote:
On 11.09.23 10:41, Kirill A. Shutemov wrote:
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.

I assume that table provided by the first kernel, and not read directly from
HW, correct?

The table is constructed by the EFI stub in the first kernel based on EFI
memory map.


Okay, should work then once that's done by the first kernel.

Maybe include this patch in your series?

Can do. But the other two patches are not related to kexec. Hm.

Yes, the others can go in separately. But this here really needs other kexec/kdump changes.

--
Cheers,

David / dhildenb


_______________________________________________
kexec mailing list
kexec@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/kexec



[Index of Archives]     [LM Sensors]     [Linux Sound]     [ALSA Users]     [ALSA Devel]     [Linux Audio Users]     [Linux Media]     [Kernel]     [Gimp]     [Yosemite News]     [Linux Media]

  Powered by Linux