Pkg xen devel - Jan 2019 - Bug#776450: Xen PVH support for grub-xen in Buster

On 1/7/19 2:13 PM, Hans van Kranenburg wrote:
> On 1/7/19 12:48 PM, Colin Watson wrote:
>> [...]
> 
>> Would you mind trying out the temporary pvh branch of
>> https://salsa.debian.org/grub-team/grub ?  I'd like to know whether
the
>> resulting grub-xen-host binary package does the right thing, when built
>> in the ordinary way (I've test-built this branch using sbuild).
> 
> Sure. I'll have a look at it today.
Ok, I've built it in sid pbuilder.

On dom0 (this is actually a buster one):

-# dpkg -L grub-xen-host |grep bin
/usr/lib/grub-xen/grub-i386-xen.bin
/usr/lib/grub-xen/grub-i386-xen_pvh.bin
/usr/lib/grub-xen/grub-x86_64-xen.bin

In domU I installed grub-xen-bin grub-xen grub2-common grub-common.

Note that:

Installing for x86_64-xen platform.
grub-install: warning: no hints available for your platform. Expect
reduced performance.
Installation finished. No error reported.

...which means that it only has /boot/grub/x86_64-xen with a copy of the
modules. Maybe that's something to think about for the part of the story
that actually expects those modules to be there? Maybe just always throw
all of the three different types in there?

Anyway, the first thing we're testing doesn't rely on that, so let's
continue. In the xen config file, I use...

---- >8 ----
kernel = "/usr/lib/grub-xen/grub-i386-xen_pvh.bin"
type = "pvh"
---- >8 ----

...and yes, blue grub screen and it boots.

Suggestion:
>From usability point of view, it would actually also be nice if
console=hvc0 would be added by default in the GRUB_CMDLINE_LINUX_DEFAULT
for inside the Xen domU.

The default is now "quiet", but if you remove "quiet", it
stays as
quiet, and for a new user, it doesn't have to be super obvious what to
do in this case.

Hans

On Mon, Jan 07, 2019 at 09:53:36PM +0100, Hans van Kranenburg
wrote:
> Note that:
> 
> Installing for x86_64-xen platform.
> grub-install: warning: no hints available for your platform. Expect
> reduced performance.
> Installation finished. No error reported.
> 
> ...which means that it only has /boot/grub/x86_64-xen with a copy of the
> modules. Maybe that's something to think about for the part of the
story
> that actually expects those modules to be there? Maybe just always throw
> all of the three different types in there?
Oh right, I indeed forgot that bit.  I've pushed a fix (though no need
to retest).  i386-xen can only boot a 32-bit kernel and so isn't usable
with an amd64 userspace, but i386-xen_pvh can be used either way.
> Anyway, the first thing we're testing doesn't rely on that, so
let's
> continue. In the xen config file, I use...
> 
> ---- >8 ----
> kernel = "/usr/lib/grub-xen/grub-i386-xen_pvh.bin"
> type = "pvh"
> ---- >8 ----
> 
> ...and yes, blue grub screen and it boots.
Excellent; thanks a lot for the test!
> Suggestion:
> 
> From usability point of view, it would actually also be nice if
> console=hvc0 would be added by default in the GRUB_CMDLINE_LINUX_DEFAULT
> for inside the Xen domU.
> 
> The default is now "quiet", but if you remove "quiet",
it stays as
> quiet, and for a new user, it doesn't have to be super obvious what to
> do in this case.
It would be helpful not to collect too many not-very-closely-related
issues into this single bug.  In any case, if you install via the Debian
installer then it arranges for this to happen; we could look into doing
it somewhere else if there were a compelling reason to do so, but I'm a
little wary of shuffling all that fairly delicate machinery around as we
approach release, and d-i already sets up a number of other similar
things so is in a good position to do this.

-- 
Colin Watson                                       [cjwatson at debian.org]

On 1/7/19 10:17 PM, Colin Watson wrote:
> On Mon, Jan 07, 2019 at 09:53:36PM +0100, Hans van Kranenburg wrote:
>> Note that:
>>
>> Installing for x86_64-xen platform.
>> grub-install: warning: no hints available for your platform. Expect
>> reduced performance.
>> Installation finished. No error reported.
>>
>> ...which means that it only has /boot/grub/x86_64-xen with a copy of
the
>> modules. Maybe that's something to think about for the part of the
story
>> that actually expects those modules to be there? Maybe just always
throw
>> all of the three different types in there?
> 
> Oh right, I indeed forgot that bit.  I've pushed a fix (though no need
> to retest).  i386-xen can only boot a 32-bit kernel and so isn't usable
> with an amd64 userspace, but i386-xen_pvh can be used either way.
> 
>> Anyway, the first thing we're testing doesn't rely on that, so
let's
>> continue. In the xen config file, I use...
>>
>> ---- >8 ----
>> kernel = "/usr/lib/grub-xen/grub-i386-xen_pvh.bin"
>> type = "pvh"
>> ---- >8 ----
>>
>> ...and yes, blue grub screen and it boots.
> 
> Excellent; thanks a lot for the test!
And thanks for picking the whole issue up so quickly. ;] I'm really
happy the completed puzzle is going to be in Buster now.
>> Suggestion:
>>
>> From usability point of view, it would actually also be nice if
>> console=hvc0 would be added by default in the
GRUB_CMDLINE_LINUX_DEFAULT
>> for inside the Xen domU.
>>
>> The default is now "quiet", but if you remove
"quiet", it stays as
>> quiet, and for a new user, it doesn't have to be super obvious what
to
>> do in this case.
> 
> It would be helpful not to collect too many not-very-closely-related
> issues into this single bug.  In any case, if you install via the Debian
> installer then it arranges for this to happen; we could look into doing
> it somewhere else if there were a compelling reason to do so, but I'm a
> little wary of shuffling all that fairly delicate machinery around as we
> approach release, and d-i already sets up a number of other similar
> things so is in a good position to do this.
Yes, you're right.

Hans