[PATCH 0/3 v11] add reserved e820 ranges to the kdump kernel e820 table

Baoquan He bhe at redhat.com
Fri Jun 7 20:54:51 PDT 2019

On 06/07/19 at 07:42pm, Borislav Petkov wrote:
> On Tue, May 28, 2019 at 03:30:21PM +0800, lijiang wrote:
> > Hi, Boris and Thomas
> > 
> > Could you give me any suggestions about this patch series? Other reviewers?
> So I'm testing this on a box with SME enabled but after loading the
> crash kernel, it freezes instead of rebooting. My cmdline is:
>  kexec -s -p /boot/vmlinuz-5.2.0-rc3+ --initrd=/boot/initrd.img-5.2.0-rc3+ --command-line="maxcpus=1 root=/dev/sda5 ro debug ignore_loglevel log_buf_len=16M no_console_suspend net.ifnames=0 systemd.log_target=null mem_encrypt=on kvm_amd.sev=1 nr_cpus=1 irqpoll reset_devices vga=normal LANG=en_US.UTF-8 earlyprintk=serial cgroup_disable=memory mce=off numa=off udev.children-max=2 panic=10 rootflags=nofail acpi_no_memhotplug transparent_hugepage=never disable_cpu_apicid=0"
> and the reserved range is:
> [    0.000000] Reserving 256MB of memory at 3392MB for crashkernel (System RAM: 16271MB)

Is it a UEFI box? If it's uefi machine, it should relate to below issue.
Because kexec always fails to randomly choose a new position for kernel.

The current kexec code fills boot_params->efi_info->efi_loader_signature,
but doesn't contruct efi_memmap table. The kexec/kdump kernel will always
fail to find available slot for KASLR in process_efi_entries.

> I'm wondering if it is related to
> https://lkml.kernel.org/r/20190604134952.GC26891@MiWiFi-R3L-srv
> Thx.
> -- 
> Regards/Gruss,
>     Boris.
> Good mailing practices for 400: avoid top-posting and trim the reply.

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