Re: [Xen-devel] [GSoC] Xen on ARM: create multiple guests from device tree

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 23 Mar 2017, Luca Miccio wrote:
> Hi Stefano and Julien,
> 
> > Il giorno 22 mar 2017, alle ore 22:38, Stefano Stabellini 
> > <sstabellini@xxxxxxxxxx> ha scritto:
> > 
> > Hi Luca,
> > 
> > please don't use HTML emails.
> > 
> > 
> Sorry for that.
> 
> > On Wed, 22 Mar 2017, Julien Grall wrote:
> >> On 22/03/2017 19:45, Luca Miccio wrote:
> >>> Hi Stefano,
> >> 
> >> Hello Luca,
> >> 
> >>> aarch64-linux-gnu-gcc  -DCNTFRQ=0x01800000-DUART_BASE=0x1c090000
> >>> -DSYSREGS_BASE=0x1c010000 -DGIC_DIST_BASE=0x2c001000
> >>> -DGIC_CPU_BASE=0x2c002000 -c -o boot.xen.o boot.S -DXEN
> >>> aarch64-linux-gnu-gcc  -DPHYS_OFFSET=0x80000000 -DMBOX_OFFSET=0xfff8
> >>> -DBOOT=boot.xen.o -DXEN_OFFSET=0xA00000 -DKERNEL_OFFSET=0x80000
> >>> -DFDT_OFFSET=0x08000000 -DFS_OFFSET=0x10000000 -DXEN=Xen -DKERNEL=Image
> >>> -DFILESYSTEM=filesystem.cpio.gz -E -P -C -o model.xen.lds model.lds.S
> >>> aarch64-linux-gnu-gcc  -DCNTFRQ=0x01800000-DUART_BASE=0x1c090000
> >>> -DSYSREGS_BASE=0x1c010000 -DGIC_DIST_BASE=0x2c001000
> >>> -DGIC_CPU_BASE=0x2c002000 -c -o boot.o boot.S
> >>> aarch64-linux-gnu-gcc  -DPHYS_OFFSET=0x80000000 -DMBOX_OFFSET=0xfff8
> >>> -DBOOT=boot.o -DKERNEL_OFFSET=0x80000 -DFDT_OFFSET=0x08000000
> >>> -DFS_OFFSET=0x10000000 -DKERNEL=Image -DFILESYSTEM=filesystem.cpio.gz -E
> >>> -P -C -o model.lds model.lds.S
> >>> aarch64-linux-gnu-ld -o xen-system.axf --script=model.xen.lds
> >>> aarch64-linux-gnu-ld: section .xen LMA
> >>> [0000000080a00000,0000000080ac814f] overlaps section .kernel LMA
> >>> [0000000080080000,0000000080f009ff]
> >>> Makefile:78: set di istruzioni per l'obiettivo "xen-system.axf" non 
> >>> riuscito
> >>> make: *** [xen-system.axf] Errore 1\
> >>> 
> >>> Clearly there is a problem with the offset of xen section but i can't
> >>> figure out how to solve it.
> >> 
> >> I would recommend to use the latest version of bootwrapper which is now
> >> including support for Xen. I haven't yet updated the wiki with the runes
> >> but here a quick summary of the step I am using:
> >> 
> >> * Building bootwrapper
> >> 
> >> 42sh> git clone 
> >> git://git.kernel.org/pub/scm/linux/kernel/git/mark/boot-wrapper-aarch64.git
> >> 42sh> autoreconf -i
> >> 42sh> ./configure --host=aarch64-linux-gnu --with-kernel-dir=<kernel-dir> 
> >> --with-dtb=<dtb> \
> >> --with-cmdline="console=hvc0 earlycon=pl011,0x1c090000 root=/dev/vda rw" 
> >> --enable-psci \
> >> --with-xen-cmdline="dtuart=serial0 console=dtuart no-bootscrub 
> >> dom0_mem=512M" \
> >> --with-xen=<xen-bin> --with-cpu-ids=0,1,2,3
> >> 42sh> make
> >> 
> >> Where:
> >>  * <kernel-dir> is the path to the kernel repository
> >>  * <dtb> is the path to the device-tree. I am using the one shipped with 
> >> Linux
> >>    in arch/arm64/boot/dts/arm/foundation-armv8.dtbs
> >>    It will be built if you did make all in Linux
> >>  * <xen-bin> is the path to Xen binary (xen/xen in the repo)
> >> 
> >> * Command line for the foundation model
> >> 42sh> Foundation_Platform --image=<image> --block-device=<rootfs> --cores=4
> >> 
> >> Where:
> >>  * <image> is the path to xen-system.axf produced by bootwrapper
> >>  * <rootfs> is the patch to your rootfs
> >> 
> >> Let me know if you need more details.
> > 
> > Thanks Julien, I successfully booted Xen and Linux following these
> > steps. I quickly updated the wiki.
> > 
> > Luca, I took me a while to figure out that for root=/dev/vda to work
> > properly, Linux requires not just all the filesystem and virtio options
> > enabled in the kernel config, but also CONFIG_VIRTIO_MMIO=y. With that,
> > you should be able to boot Xen, Linux and mount the root filesystem. If
> > you download one of the Ubuntu arm64 cloud images, the root device will
> > be /dev/vda1.
> 
> First of all, thank you for your help.
> 
> I think that i keep on doing somenthing wrong because now the bootwrapper 
> produces
> with no errors the xen-system.axf  with the configuration that Julien 
> provided. 
> But when i launch the emulator it simply stops at:
> (XEN) Bringing up CPU1
> 
> To help you understand, this is what i have done:
> - First i compiled the xen source with the following command:
> $ make dist-xen XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- 
> CONFIG_EARLY_PRINT=fastmodel
> ( I am using the staging branch)
> 
> - Get the linux source with git: 
> $ git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> 
> -Checkout on the v4.4 branch 
> 
> - Follow the steps described in the blog and, as you said, i set in my 
> .config file:
>  CONFIG_VIRTIO=y
>  CONFIG_VIRTIO_MMIO=y
>  CONFIG_VIRTIO_BLK=y
> I also checked all the filesystem and virtio options. 
> 
> - Compile the linux kernel with the toolchain:
> $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- all (to get also the .dtb 
> file)
> 
> - Configured the bootwrapper with the command that Julian wrote and then 
> launched the 
> foundation model with the simple command:
> $ Foundation_Platform --image=/path/to/the/xen-system.axf 
> --block-device=xenial-server-cloudimg-arm64.img --cores=4

Try removing --cores=4, does it work?


> The image was downloaded at : 
> https://cloud-images.ubuntu.com/releases/16.04/release/
> 
> But, as I said, the emulator blocks at boot. I tried different rootfs images 
> and i have configured the root device
> properly to /dev/vda1.
> 
> Maybe my kernel configuration is wrong?
> 
> Thank you,
> Luca
> 

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