Re: [Xen-devel] [PATCH v3 00/18] xen: add pvh guest support

[Hans van Kranenburg <hans@xxxxxxxxxxx>]

Hi,

On 10/24/2018 04:54 PM, Juergen Gross wrote:
> This patch series adds support for booting Linux as PVH guest.
> 
> Similar to i386/xen and x86_64/xen platforms the new i386/xenpvh
> platform grub is booted as a standalone image directly by Xen.
> 
> For booting Linux kernel it is using the standard linux kernel
> loader. The only modification of the linux loader is to pass the
> ACPI RSDP address via boot parameters to the kernel, as that table
> might not be located at the usual physical address just below 1MB.
> 
> The related Linux kernel patches have been accepted in the merge
> window for post 4.19 (4.20 or 5.0, whatever it will be called).
> 
> Changes in V3:
> - addressed lots of comments, most by Daniel and some by Roger,
>   details are mentioned in the individual patches
> 
> [...]

Thanks for the hard work.

FWIW, a test report from an end user.

I used the following for testing, which is derived from the instructions
Juergen provided earlier this year. Maybe it's useful for someone else
who wants to test.

git clone https://git.savannah.gnu.org/git/grub.git
git checkout -b xen_pvh
[apply patches from emails]
./autogen.sh
rm -rf knorrie/build
mkdir -p knorrie/build
cd knorrie/build
../../configure TARGET_LDFLAGS=-static --target=i386 --with-platform=xen_pvh
make

I just symlinked the test-kernel to vmlinuz-pvh here, so that I could
easily boot back into the regular kernel with pvgrub2, which is
hardcoded to look at /vmlinuz in my case (no grub with menu in the domU
etc).

cat <<EOF >grub.cfg
root='(xen/xvda)'
insmod xzio
insmod gzio
insmod btrfs
insmod ext2
echo 'Loading Linux ...'
linux /vmlinuz-pvh root=/dev/xvda ro elevator=noop console=hvc0
echo 'Loading initial ramdisk ...'
initrd /initrd.img-pvh
echo 'There we go! ...'
boot
EOF

./grub-mkstandalone --grub-mkimage=./grub-mkimage -o
grub-i386-xen_pvh-fire-ze-missile -O i386-xen_pvh -d grub-core/
"/boot/grub/grub.cfg=./grub.cfg"

On the dom0, I have a copy of the config file, changed with:

type = 'pvh'
kernel = "/test/grub-i386-xen_pvh-fire-ze-missile"
[...]

Now xl create -c, and it greets me with things like

Welcome to GRUB!

Loading Linux ...
Loading initial ramdisk ...
There we go! ...

And in the startup-sequence of the domU kernel:
[    0.204361] Booting paravirtualized kernel on Xen PVH

I can see all 4 configured cpus, and I can see 8GiB of memory inside,
which was not possible with the first series of the patches.

So, great success!

Hans

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