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    SubjectRe: [PATCHv7 11/14] x86: Disable kexec if system has unaccepted memory
    On Wed, 29 Jun 2022 at 08:59, Kirill A. Shutemov
    <kirill.shutemov@linux.intel.com> wrote:
    >
    > On Tue, Jun 28, 2022 at 05:10:56PM -0700, Dave Hansen wrote:
    > > On 6/28/22 16:51, Kirill A. Shutemov wrote:
    > > > On Fri, Jun 24, 2022 at 05:00:05AM +0300, Kirill A. Shutemov wrote:
    > > >>> If there is some deep and fundamental why this can not be supported
    > > >>> then it probably makes sense to put some code in the arch_kexec_load
    > > >>> hook that verifies that deep and fundamental reason is present.
    > > ...
    > > > + /*
    > > > + * TODO: Information on memory acceptance status has to be communicated
    > > > + * between kernel.
    > > > + */
    > >
    > > So, the deep and fundamental reason is... drum roll... you haven't
    > > gotten around to implementing bitmap passing yet?!?!? I have the
    > > feeling that wasn't what Eric was looking for.
    >
    > The deep fundamental reason is that everything cannot be implemented and
    > upstreamed at once.

    If the only thing is to pass bitmap to kexec kernel, since you have
    reserved the bitmap memory I guess it is straightforward to set the
    kexec bootparams.unaccepted_memory as the old value. Not sure if
    there are problems when the decompress code accepts memory again
    though.
    for kernel kexec_file_load, refer to function setup_boot_parameters()
    in arch/x86/kernel/kexec-bzimage64.c for kexec_file_load,
    for kexec-tools kexec_load code refer to
    setup_linux_system_parameters() kexec/arch/i386/x86-linux-setup.c

    Thanks
    Dave

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