Re: [PATCH] efi/memreserve: register reservations as 'reserved' in /proc/iomem

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On Wed, 4 Dec 2019 at 20:13, Bhupesh SHARMA <bhupesh.linux@gmail.com> wrote:
>
> Hello Masa,
>
> (+Cc Simon)
>
> On Thu, Dec 5, 2019 at 12:27 AM Masayoshi Mizuma <msys.mizuma@gmail.com> wrote:
> >
> > On Wed, Dec 04, 2019 at 06:17:59PM +0000, James Morse wrote:
> > > Hi Masa,
> > >
> > > On 04/12/2019 17:17, Masayoshi Mizuma wrote:
> > > > Thank you for sending the patch, but unfortunately it doesn't work for the issue...
> > > >
> > > > After applied your patch, the LPI tables are marked as reserved in
> > > > /proc/iomem like as:
> > > >
> > > > 80300000-a1fdffff : System RAM
> > > >   80480000-8134ffff : Kernel code
> > > >   81350000-817bffff : reserved
> > > >   817c0000-82acffff : Kernel data
> > > >   830f0000-830fffff : reserved # Property table
> > > >   83480000-83480fff : reserved # Pending table
> > > >   83490000-8349ffff : reserved # Pending table
> > > >
> > > > However, kexec tries to allocate memory from System RAM, it doesn't care
> > > > the reserved in System RAM.
> > >
> > > > I'm not sure why kexec doesn't care the reserved in System RAM, however,
> > >
> > > Hmm, we added these to fix a problem with the UEFI memory map, and more recently ACPI
> > > tables being overwritten by kexec.
> > >
> > > Which version of kexec-tools are you using? Could you try:
> > > https://git.linaro.org/people/takahiro.akashi/kexec-tools.git/commit/?h=arm64/resv_mem
> >
> > Thanks a lot! It worked and the issue is gone with Ard's patch and
> > the linaro kexec (arm64/resv_mem branch).
> >
> > Ard, please feel free to add:
> >
> >         Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
>
> Same results at my side, so:
> Tested-and-Reviewed-by: Bhipesh Sharma <bhsharma@redhat.com>
>

Thank you all. I'll get this queued as a fix with cc:stable for v5.4


> > >
> > > > if the kexec behaivor is right, the LPI tables should not belong to
> > > > System RAM.
> > >
> > > > Like as:
> > > >
> > > > 80300000-830effff : System RAM
> > > >   80480000-8134ffff : Kernel code
> > > >   81350000-817bffff : reserved
> > > >   817c0000-82acffff : Kernel data
> > > > 830f0000-830fffff : reserved # Property table
> > > > 83480000-83480fff : reserved # Pending table
> > > > 83490000-8349ffff : reserved # Pending table
> > > > 834a0000-a1fdffff : System RAM
> > > >
> > > > I don't have ideas to separete LPI tables from System RAM... so I tried
> > > > to add a new file to inform the LPI tables to userspace.
> > >
> > > This is how 'nomap' memory appears, we carve it out of System RAM. A side effect of this
> > > is kdump can't touch it, as you've told it this isn't memory.
> > >
> > > As these tables are memory, mapped by the linear map, I think Ard's patch is the right
> > > thing to do ... I suspect your kexec-tools doesn't have those patches from Akashi to make
> > > it honour all second level entries.
> >
> > I used the kexec on the top of master branch:
> > git://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git
> >
> > Should we use the linaro kexec for aarch64 machine?
> > Or will the arm64/resv_mem branch be merged to the kexec on
> > git.kernel.org...?
>
> Glad that Ard's patch fixes the issue for you.
> Regarding Akashi's patch, I think it was sent to upstream kexec-tools
> some time ago (see [0}) but  seems not integrated in upstream
> kexec-tools (now I noticed my Tested-by email for the same got bounced
> off due to some gmail msmtp setting issues at my end - sorry for
> that). I have added Simon in Cc list.
>
> Hi Simon,
>
> Can you please help pick [0] in upstream kexec-tools with Tested-by
> from Masa and myself? Thanks a lot for your help.
>
> [0]. http://lists.infradead.org/pipermail/kexec/2019-January/022201.html
>
> Thanks,
> Bhupesh