Messages in this thread | | | Date | Mon, 11 Sep 2023 11:50:31 +0200 | Subject | Re: [PATCH 1/3] proc/vmcore: Do not map unaccepted memory | From | David Hildenbrand <> |
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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?
-- Cheers,
David / dhildenb
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