Xen project Mailing List

Dear all,

Andrii, thanks for the remark - I'll rework this patch.

Julien, I have updated yocto layer [1] to use the most recent stable Xen version - Xen 4.8-rc6

Looks like used patches for Xen should be described more briefly:

1. 0001-arm64-renesas-Introduce-early-console-for-Salvator-X.patch - Early console introduction for Salvator-X board

2. 0002-libxl-Hack-fix-compilation-on-arm64.patch - required by to fix build issue, described here [2]. I haven't found any better solution except this one.

3. 0003-HACK-Fix-compilation-issues.patch - is a hack to avoid acpi compilation issue on arm64 platform. Looks like Andrii faces same problem [3] [4].

4. 0004-Enable-XSM.patch - enable XSM for arm64 build - this patch is not essential, but xsm might be usefull for some use-cases.

5. 0005-xen-arm-domain_build-allocate-lowmem-for-dom0-as-muc.patch - Salvator-X board has 4GB RAM, but has only 32bit DMA controller - so, if Dom0 will be allocated at over 4GB space - DMA operation will fail.

According to xen-devel list [5], this patch planned to be included in Xen 4.9.

6. 0006-Do-no-trap-smc-instructions.patch - Renesas use OP-TEE out of box, but by default Xen traps such calls, so we have to allow such actions.

[1] https://github.com/qbeeukraine/meta-platform-xen

[2] https://lists.xen.org/archives/html/xen-devel/2015-12/msg00137.html

[3] https://lists.xen.org/archives/html/xen-devel/2016-11/msg01903.html

[4] https://lists.xen.org/archives/html/xen-devel/2016-11/msg01930.html

[5] https://lists.xen.org/archives/html/xen-devel/2016-09/msg02561.html

In last email you have written:

> Also, it is not clear to me why you need a specific device tree and hacked DOM0 linux (see [2]) on this board for Xen. This would need some documentation on the wiki.

Yes, this need some explanation. I'll update related wiki page in few hours.

Thanks for all of your comments.

With the best regards,

Iurii Mykhalskyi

On Tue, Nov 22, 2016 at 1:20 PM, Andrii Anisov <andrii.anisov@xxxxxxxxx> wrote:

Well,

> This patch https://github.com/qbeeukraine/meta-platform-xen/blob/2.12/minimal/meta-rcar-gen3-xen/recipes-bsp/u-boot/u-boot/0002-arm-fdt-Don-t-touch-memory-node-from-full-U-Boot-in-.patch
> Is a total mess.
It seems you've lost some code and related history during porting the original patch.

Sincerely,
Andrii Anisov.

On Tue, Nov 22, 2016 at 12:59 PM, Andrii Anisov <andrii.anisov@xxxxxxxxx> wrote:
Dear Iurii,

This patch https://github.com/qbeeukraine/meta-platform-xen/blob/2.12/minimal/meta-rcar-gen3-xen/recipes-bsp/u-boot/u-boot/0002-arm-fdt-Don-t-touch-memory-node-from-full-U-Boot-in-.patch
Is a total mess. Somewhy you check defined CONFIG_XEN to introduce the arch_fixup_fdt() function, which, as per you idea, is not needed to be built for the XEN boot. You have no patch lines to introduce CONFIG_XEN so the code works.
Also arch_fixup_fdt() not only mangles memory nodes, so it is not right to drop whole the function.

But the problem in that piece of code still exists:
u-boot updates the first memory node in the dtb with all memory banks it found in the board code, does not take into consideration other memory nodes
as a result memory banks in device tree are duplicated
unlike the kernel which tolerates that mess from u-boot, XEN does not accept memory banks are duplicated and crashes.
Putting all memory banks into one memory node in the device tree is the simplest workaround.
I'm not really sure where should be a proper fix. Should it be on u-boot or XEN side?

Sincerely,
Andrii Anisov.

Iurii Mykhalskyi | Senior Software Engineer
GlobalLogic
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Re: [Xen-devel] [PATCH] arm64:renesas: Introduce early console for Salvator-X board