Messages in this thread | | | Date | Mon, 11 Sep 2023 16:33:48 +0200 | Subject | Re: [PATCH 1/3] proc/vmcore: Do not map unaccepted memory | From | David Hildenbrand <> |
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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
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