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

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Message-ID: <20190608035451.GB26148@MiWiFi-R3L-srv>
Date:   Sat, 8 Jun 2019 11:54:51 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     lijiang <lijiang@...hat.com>, linux-kernel@...r.kernel.org,
        kexec@...ts.infradead.org, tglx@...utronix.de, mingo@...hat.com,
        akpm@...ux-foundation.org, dave.hansen@...ux.intel.com,
        luto@...nel.org, peterz@...radead.org, x86@...nel.org,
        hpa@...or.com, dyoung@...hat.com, Thomas.Lendacky@....com
Subject: Re: [PATCH 0/3 v11] add reserved e820 ranges to the kdump kernel
 e820 table

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.