Re: kexec_file overwrites reserved EFI ESRT memory
On 11/22/19 at 10:07pm, Michael Weiser wrote:
> Hi Eric,
>
> On Fri, Nov 22, 2019 at 02:00:22PM -0600, Eric W. Biederman wrote:
>
> > > esrt: Unsupported ESRT version 2904149718861218184.
> > >
> > > (The image is rather large at 18MiB as it has a built-in initrd.)
> > When did x86_64 get support for ARCH_KEEP_MEMBLOCK? I can't find it
> > anywhere.
>
> No, is hasn't. I temporarily hacked that in to see if it'd change
> anything and it did. Sorry to not be more clear about that.
>
> > Fundamentally when deciding where to place a new kernel kexec (either
> > user space or the in kernel kexec_file implementation) needs to be able
> > to ask the question which memory ares are reserved.
> > What the buddy
> > allocator does is unimportant as kexec copies memory from all over
> > the place and places it in the destined memory addresses at the
> > time of the kexec operation.
>
> > So my question is why doesn't the ESRT reservation wind up in
> > /proc/iomem?
>
> My guess is that the focus was that some EFI structures need to be kept
> around accross the life cycle of *one* running kernel and
> memblock_reserve() was enough for that. Marking them so they survive
> kexecing another kernel might just never have cropped up thus far. Ard
> or Matt would know.
Can you check your un-reserved memory, if your memory falls into EFI
BOOT* then in X86 you can use something like below if it is not covered:
void __init efi_esrt_init(void)
{
...
pr_info("Reserving ESRT space from %pa to %pa.\n", &esrt_data, &end);
if (md.type == EFI_BOOT_SERVICES_DATA)
efi_mem_reserve(esrt_data, esrt_data_size);
...
}
Unfortunately I noticed there are different requirements/ways for
different types of "reserved" memory. But that is another topic..
Thanks
Dave
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Venture Capital & Private Investors
Attention: I am an investor that can provide funding for any viable business idea or venture. Please do let me know if you have fund management abilities, credible projects in need of funding or advanced stage projects requiring Bank Guarantees, Loans or Partnership, Joint Venture, Equity, we would be delighted to work with you. Best Regards, Mr. Joon-Kyu Lim Al Faisaliah Group (AFG) Venture Capital & Private Investors -- *This email and any attachments are intended for the named recipients only and contain confidential materials. Any unauthorized copying, reviewing, dissemination or other use by anyone other than the named recipients of this communication is strictly prohibited. If you received this email in error and/or are not a named recipient, please notify the sender (Al Faisaliah Group) and delete all copies of this email. Thank you. ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
