Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-07-03 Thread Tim Deegan
At 07:52 -0400 on 24 Jun (1435132373), Boris Ostrovsky wrote:
 On 06/24/2015 06:14 AM, Roger Pau Monné wrote:
  El 24/06/15 a les 12.05, Jan Beulich ha escrit:
  On 24.06.15 at 11:47, roger@citrix.com wrote:
  What needs to be done (ordered by priority):
 
- Clean up the patches, this patch series was done in less than a week.
- Finish the boot ABI (this would also be needed for PVH anyway).
- Convert the rest of xc_dom_*loaders in order to use the physical
  entry point when present, right now xc_dom_elfloader is the only one
  usable with HVMlite. This is quite trivial (see patch 10, it's a 4
  LOC change).
- Dom0 support.
- Migration.
- PCI pass-through.
 
  IMHO this is what we agreed to do with PVH, make it an HVM guest without
  a device model and without the emulated devices inside of Xen. Sooner or
  later we would need to make that change anyway in order to properly
  integrate PVH into Xen, and we get a bunch of new features for free as
  compared to PVH.
 
  I don't think of this as throw PVH out of the window and start
  something completely new from scratch, we are going to reuse some of
  the code paths used by PVH inside of Xen. From a guest POV the changes
  needed to move from PVH into HVMlite are regarding the boot ABI only,
  which we already agreed that should be changed anyway.
  I have to admit that I'm having a hard time making myself a clear
  picture of what the intention now is, namely with feature freeze
  being in about 2.5 weeks: If we assume that this series gets ready
  in time, should we drop Boris' 32-bit support patches? Would then
  be unfortunate if the series here didn't get ready.
  TBH I'm not going to make any promises of this being ready before the
  4.6 feature freeze, not until I get some feedback from the tools
  maintainers regarding the libxc changes to unify the PV and HVM domain
  creation paths.
 
 FWIW, I gave this a quick spin on Monday and crashed the hypervisor on a 
 NULL pointer right away in vapic code. Which, I assume, is not 
 surprising since we are not supposed to be there in the first place.
 
 I'll try it again later today (I was out yesterday), maybe I messed 
 something up.
 
 
  Otoh I don't think this and Boris' code conflict, and what we got in
  the tree PVH-wise is kind of a mess right now anyway, so adding to
  it just a few more bits (actually getting rid of some fixme-s, i.e.
  reducing messiness), so I'd be inclined to take the rest of Boris'
  series once ready, and if the series here gets ready too it could
  then also go in. Which would then mean for someone (perhaps
  after 4.6 was branched) to clean up any no longer necessary
  PVH special cases, unifying things towards what we seem to now
  call HVMlite.
  I'm not against merging the 32bit support series for PVH, but I'm
  certainly not going to invest time in adding 32bit PVH entry points to
  any OSes.
 
 What about Tim's proposal 
 (http://lists.xen.org/archives/html/xen-devel/2014-12/msg00596.html)? 
 Can this work be made part of it? At least, make it extendable to that?

FWIW, I think this new scheme (start at HVM and remove things) is
approaching the same end result from the other direction: Xen itself
no longer needs to have a concept of PVH, and the guests get to keep
their useful new interface.  As such, I heartily approve. :)

Cheers,

Tim.

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-24 Thread Boris Ostrovsky

On 06/24/2015 06:14 AM, Roger Pau Monné wrote:

El 24/06/15 a les 12.05, Jan Beulich ha escrit:

On 24.06.15 at 11:47, roger@citrix.com wrote:

What needs to be done (ordered by priority):

  - Clean up the patches, this patch series was done in less than a week.
  - Finish the boot ABI (this would also be needed for PVH anyway).
  - Convert the rest of xc_dom_*loaders in order to use the physical
entry point when present, right now xc_dom_elfloader is the only one
usable with HVMlite. This is quite trivial (see patch 10, it's a 4
LOC change).
  - Dom0 support.
  - Migration.
  - PCI pass-through.

IMHO this is what we agreed to do with PVH, make it an HVM guest without
a device model and without the emulated devices inside of Xen. Sooner or
later we would need to make that change anyway in order to properly
integrate PVH into Xen, and we get a bunch of new features for free as
compared to PVH.

I don't think of this as throw PVH out of the window and start
something completely new from scratch, we are going to reuse some of
the code paths used by PVH inside of Xen. From a guest POV the changes
needed to move from PVH into HVMlite are regarding the boot ABI only,
which we already agreed that should be changed anyway.

I have to admit that I'm having a hard time making myself a clear
picture of what the intention now is, namely with feature freeze
being in about 2.5 weeks: If we assume that this series gets ready
in time, should we drop Boris' 32-bit support patches? Would then
be unfortunate if the series here didn't get ready.

TBH I'm not going to make any promises of this being ready before the
4.6 feature freeze, not until I get some feedback from the tools
maintainers regarding the libxc changes to unify the PV and HVM domain
creation paths.


FWIW, I gave this a quick spin on Monday and crashed the hypervisor on a 
NULL pointer right away in vapic code. Which, I assume, is not 
surprising since we are not supposed to be there in the first place.


I'll try it again later today (I was out yesterday), maybe I messed 
something up.





Otoh I don't think this and Boris' code conflict, and what we got in
the tree PVH-wise is kind of a mess right now anyway, so adding to
it just a few more bits (actually getting rid of some fixme-s, i.e.
reducing messiness), so I'd be inclined to take the rest of Boris'
series once ready, and if the series here gets ready too it could
then also go in. Which would then mean for someone (perhaps
after 4.6 was branched) to clean up any no longer necessary
PVH special cases, unifying things towards what we seem to now
call HVMlite.

I'm not against merging the 32bit support series for PVH, but I'm
certainly not going to invest time in adding 32bit PVH entry points to
any OSes.


What about Tim's proposal 
(http://lists.xen.org/archives/html/xen-devel/2014-12/msg00596.html)? 
Can this work be made part of it? At least, make it extendable to that?


-boris

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-24 Thread Roger Pau Monné
El 24/06/15 a les 12.05, Jan Beulich ha escrit:
 On 24.06.15 at 11:47, roger@citrix.com wrote:
 What needs to be done (ordered by priority):

  - Clean up the patches, this patch series was done in less than a week.
  - Finish the boot ABI (this would also be needed for PVH anyway).
  - Convert the rest of xc_dom_*loaders in order to use the physical
entry point when present, right now xc_dom_elfloader is the only one
usable with HVMlite. This is quite trivial (see patch 10, it's a 4
LOC change).
  - Dom0 support.
  - Migration.
  - PCI pass-through.

 IMHO this is what we agreed to do with PVH, make it an HVM guest without
 a device model and without the emulated devices inside of Xen. Sooner or
 later we would need to make that change anyway in order to properly
 integrate PVH into Xen, and we get a bunch of new features for free as
 compared to PVH.

 I don't think of this as throw PVH out of the window and start
 something completely new from scratch, we are going to reuse some of
 the code paths used by PVH inside of Xen. From a guest POV the changes
 needed to move from PVH into HVMlite are regarding the boot ABI only,
 which we already agreed that should be changed anyway.
 
 I have to admit that I'm having a hard time making myself a clear
 picture of what the intention now is, namely with feature freeze
 being in about 2.5 weeks: If we assume that this series gets ready
 in time, should we drop Boris' 32-bit support patches? Would then
 be unfortunate if the series here didn't get ready.

TBH I'm not going to make any promises of this being ready before the
4.6 feature freeze, not until I get some feedback from the tools
maintainers regarding the libxc changes to unify the PV and HVM domain
creation paths.

 Otoh I don't think this and Boris' code conflict, and what we got in
 the tree PVH-wise is kind of a mess right now anyway, so adding to
 it just a few more bits (actually getting rid of some fixme-s, i.e.
 reducing messiness), so I'd be inclined to take the rest of Boris'
 series once ready, and if the series here gets ready too it could
 then also go in. Which would then mean for someone (perhaps
 after 4.6 was branched) to clean up any no longer necessary
 PVH special cases, unifying things towards what we seem to now
 call HVMlite.

I'm not against merging the 32bit support series for PVH, but I'm
certainly not going to invest time in adding 32bit PVH entry points to
any OSes.

Roger.


___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-24 Thread Konrad Rzeszutek Wilk
On Wed, Jun 24, 2015 at 02:04:45PM +0200, Roger Pau Monné wrote:
 El 24/06/15 a les 13.52, Boris Ostrovsky ha escrit:
  On 06/24/2015 06:14 AM, Roger Pau Monné wrote:
  El 24/06/15 a les 12.05, Jan Beulich ha escrit:
  On 24.06.15 at 11:47, roger@citrix.com wrote:
  What needs to be done (ordered by priority):
 
- Clean up the patches, this patch series was done in less than a
  week.
- Finish the boot ABI (this would also be needed for PVH anyway).
- Convert the rest of xc_dom_*loaders in order to use the physical
  entry point when present, right now xc_dom_elfloader is the only
  one
  usable with HVMlite. This is quite trivial (see patch 10, it's a 4
  LOC change).
- Dom0 support.
- Migration.
- PCI pass-through.
 
  IMHO this is what we agreed to do with PVH, make it an HVM guest
  without
  a device model and without the emulated devices inside of Xen.
  Sooner or
  later we would need to make that change anyway in order to properly
  integrate PVH into Xen, and we get a bunch of new features for free as
  compared to PVH.
 
  I don't think of this as throw PVH out of the window and start
  something completely new from scratch, we are going to reuse some of
  the code paths used by PVH inside of Xen. From a guest POV the changes
  needed to move from PVH into HVMlite are regarding the boot ABI only,
  which we already agreed that should be changed anyway.
  I have to admit that I'm having a hard time making myself a clear
  picture of what the intention now is, namely with feature freeze
  being in about 2.5 weeks: If we assume that this series gets ready
  in time, should we drop Boris' 32-bit support patches? Would then
  be unfortunate if the series here didn't get ready.
  TBH I'm not going to make any promises of this being ready before the
  4.6 feature freeze, not until I get some feedback from the tools
  maintainers regarding the libxc changes to unify the PV and HVM domain
  creation paths.
  
  FWIW, I gave this a quick spin on Monday and crashed the hypervisor on a
  NULL pointer right away in vapic code. Which, I assume, is not
  surprising since we are not supposed to be there in the first place.
  
  I'll try it again later today (I was out yesterday), maybe I messed
  something up.
 
 Yes, feature disabling is still not 100% done I'm afraid. For example if
 your hw supports vAPIC it will be enabled anyway, which can then lead to
 all kinds of trouble. As said, this is very initial and I've only tested
 it on one Nehalem box which doesn't have vAPIC.
 
 
  Otoh I don't think this and Boris' code conflict, and what we got in
  the tree PVH-wise is kind of a mess right now anyway, so adding to
  it just a few more bits (actually getting rid of some fixme-s, i.e.
  reducing messiness), so I'd be inclined to take the rest of Boris'
  series once ready, and if the series here gets ready too it could
  then also go in. Which would then mean for someone (perhaps
  after 4.6 was branched) to clean up any no longer necessary
  PVH special cases, unifying things towards what we seem to now
  call HVMlite.
  I'm not against merging the 32bit support series for PVH, but I'm
  certainly not going to invest time in adding 32bit PVH entry points to
  any OSes.
  
  What about Tim's proposal
  (http://lists.xen.org/archives/html/xen-devel/2014-12/msg00596.html)?
  Can this work be made part of it? At least, make it extendable to that?
 
 Yes, the aim of this work is to address some of the points expressed in
 that email, mainly merge PVH into HVM. But as we have already spoken,
 the entry point of HVMlite or whatever we call it is going to be
 different from the traditional PV/PVH entry point.

Right. If you were to take a sharpie where would you put in the 
list that Tim had written out?

And to my eye - it looks as the HVMLIte boot entry and the old PVH
bootpaths can co-exist for some time until they get merged together?

This would have the nice benefit of being able to troubleshoot
issues easier as you have an existing codepath for 'old-PVH' 
and new bootup path and can figure out what is missing to make it work
(with the Linux kernel at least).

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-24 Thread Stefano Stabellini
On Wed, 24 Jun 2015, Boris Ostrovsky wrote:
 On 06/24/2015 09:26 AM, Stefano Stabellini wrote:
  On Wed, 24 Jun 2015, Roger Pau Monné wrote:
 
 - PCI pass-through.
  Do we really need PCI pass-through? I see HVMlite mostly useful for
  Dom0, but also for higher security Linux and BSD guests. If a user wants
  PCI pass-through, she can always use PV on HVM.

 Why is this model not useful for a generic domU? I thought that it should
 eventually become a replacement for what we now have as PVH?

It is useful as generic DomU because it provides a smaller surface of
attack compared to PV on HVM guests. At the same time using PCI
pass-through increases that surface of attack again, decreasing the
value of HVMLite/PVH, at least in my view. But you are right that it
might be nice to have it for feature completeness, if nothing else.___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-23 Thread Ian Campbell
On Tue, 2015-06-23 at 11:55 +0100, Stefano Stabellini wrote:
 I don't know if we should introduce a new name for this, but I wanted to
 point out that this is different from PVH from Xen point of view. In
 particular most of the outstanding PVH work items (32bit, AMD) on the
 hypervisor would be redudant if we get this to work, right? If that is
 the case, then I think it is best we agree on which road we want to take
 going forward as soon as possible to avoid duplicated or wasted efforts.

I think what you are saying is we either want to pursue this path _or_
PVH, but not both, and I would be inclined to agree, it seems to me like
duplication of both effort and functionality to do both.

Ian.


___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-23 Thread Stefano Stabellini
On Tue, 23 Jun 2015, Ian Campbell wrote:
 On Tue, 2015-06-23 at 11:55 +0100, Stefano Stabellini wrote:
  I don't know if we should introduce a new name for this, but I wanted to
  point out that this is different from PVH from Xen point of view. In
  particular most of the outstanding PVH work items (32bit, AMD) on the
  hypervisor would be redudant if we get this to work, right? If that is
  the case, then I think it is best we agree on which road we want to take
  going forward as soon as possible to avoid duplicated or wasted efforts.
 
 I think what you are saying is we either want to pursue this path _or_
 PVH, but not both, and I would be inclined to agree, it seems to me like
 duplication of both effort and functionality to do both.

Right, especially given that they both seem to provide similar
functionalities.

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-23 Thread Stefano Stabellini
On Mon, 22 Jun 2015, Konrad Rzeszutek Wilk wrote:
 On Mon, Jun 22, 2015 at 06:55:12PM +0100, Stefano Stabellini wrote:
  Hi Roger,
  
  given that this patch series is actually using the Xen hvm builder, I
  take that all the PVH code paths in Xen or the guest kernel are not
  actually used, correct? This is more like PV on HVM without QEMU, right?
 
 Are you saying it should be called now 'HVM-diet' ? Or 'HVMlite' instead
 of PVH since it is looking at this from the HVM perspective instead of PVH?

HVMlite doesn't sound bad :-)

I don't know if we should introduce a new name for this, but I wanted to
point out that this is different from PVH from Xen point of view. In
particular most of the outstanding PVH work items (32bit, AMD) on the
hypervisor would be redudant if we get this to work, right? If that is
the case, then I think it is best we agree on which road we want to take
going forward as soon as possible to avoid duplicated or wasted efforts.

In fact it is not clear to me if/when we get this to work, what would be
the remaining open issues to complete HVMlite. Roger?


  Do you think think this can work for Dom0 too?
  
  Would that make all the PVH stuff in Xen and Linux effectively useless?
 
 No. The AP bootup is still the same. So would all the hypercalls I think.
  
  Thanks,
  
  Stefano
  
  On Mon, 22 Jun 2015, Roger Pau Monne wrote:
   Before reading any further, keep in mind this is a VERY inital RFC 
   prototype series. Many things are not finished, and those that are done 
   make heavy use of duck tape in order to keep things into place.
   
   Now that you are warned, this series is split in the following order:
   
- Patches from 1 to 7 switch HVM domain contruction to use the xc_dom_* 
  family of functions, like they are used to build PV domains. 
- Patches from 8 to 13 introduce the creation of HVM domains without 
  firmware, which is replaced by directly loading a kernel like it's 
   done 
  for PV guests. A new boot ABI based on the discussion in the thread 
   RFC: 
  making the PVH 64bit ABI as stable is also introduced, although it's 
   not 
  finished.
   
   Some things that are missing from the new boot ABI:
   
- Although it supports loading a ramdisk, there's still now defined way 
  into how to pass this ramdisk to the guest. I'm thinking of using a 
  HVMPARAM or simply setting a GP register to contain the address of the 
  ramdisk. Ideally I would like to support loading more than one ramdisk.
   
   Some patches contain comments after the SoB, which in general describe 
   the 
   shortcommings of the implementation. The aim of those is to initiate 
   discussion about whether the aproach taken is TRTTD.
   
   I've only tested this on Intel hw, but I see no reason why it shouldn't 
   work 
   on AMD. I've managed to boot FreeBSD up to the point were it should 
   jump into user-space (I just didn't have a VBD attached to the VM so it 
   just 
   sits waiting for a valid disk). I have not tried to boot it any further 
   since I think that's fine for the purpose of this series. 
   
   The series can also be found in the following git repo:
   
   git://xenbits.xen.org/people/royger/xen.git branch hvm_without_dm_v1
   
   And for the FreeBSD part:
   
   git://xenbits.xen.org/people/royger/freebsd.git branch new_entry_point_v1
   
   In case someone wants to give it a try, I've uploaded a FreeBSD kernel 
   that 
   should work when booted into this mode:
   
   https://people.freebsd.org/~royger/kernel_no_dm
   
   The config file that I've used is:
   
   config
   kernel=/path/to/kernel_no_dm
   
   builder=hvm
   device_model_version=none
   
   memory=128
   vcpus=1
   name = freebsd
   /config
   
   Thanks, Roger.
   
   ___
   Xen-devel mailing list
   Xen-devel@lists.xen.org
   http://lists.xen.org/xen-devel
   
 

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-23 Thread Boris Ostrovsky

On 06/23/2015 09:12 AM, Stefano Stabellini wrote:

On Tue, 23 Jun 2015, Ian Campbell wrote:

On Tue, 2015-06-23 at 11:55 +0100, Stefano Stabellini wrote:

I don't know if we should introduce a new name for this, but I wanted to
point out that this is different from PVH from Xen point of view. In
particular most of the outstanding PVH work items (32bit, AMD) on the
hypervisor would be redudant if we get this to work, right? If that is
the case, then I think it is best we agree on which road we want to take
going forward as soon as possible to avoid duplicated or wasted efforts.

I think what you are saying is we either want to pursue this path _or_
PVH, but not both, and I would be inclined to agree, it seems to me like
duplication of both effort and functionality to do both.

Right, especially given that they both seem to provide similar
functionalities.


Given that 32-bit support of existing PVH model looks pretty simple and 
required AMD changes are also well understood (right?) and do not appear 
particularly invasive I would argue for finishing those two while 
continuing to work on unified boot model.


-boris

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


[Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-22 Thread Roger Pau Monne
Before reading any further, keep in mind this is a VERY inital RFC 
prototype series. Many things are not finished, and those that are done 
make heavy use of duck tape in order to keep things into place.

Now that you are warned, this series is split in the following order:

 - Patches from 1 to 7 switch HVM domain contruction to use the xc_dom_* 
   family of functions, like they are used to build PV domains. 
 - Patches from 8 to 13 introduce the creation of HVM domains without 
   firmware, which is replaced by directly loading a kernel like it's done 
   for PV guests. A new boot ABI based on the discussion in the thread RFC: 
   making the PVH 64bit ABI as stable is also introduced, although it's not 
   finished.

Some things that are missing from the new boot ABI:

 - Although it supports loading a ramdisk, there's still now defined way 
   into how to pass this ramdisk to the guest. I'm thinking of using a 
   HVMPARAM or simply setting a GP register to contain the address of the 
   ramdisk. Ideally I would like to support loading more than one ramdisk.

Some patches contain comments after the SoB, which in general describe the 
shortcommings of the implementation. The aim of those is to initiate 
discussion about whether the aproach taken is TRTTD.

I've only tested this on Intel hw, but I see no reason why it shouldn't work 
on AMD. I've managed to boot FreeBSD up to the point were it should 
jump into user-space (I just didn't have a VBD attached to the VM so it just 
sits waiting for a valid disk). I have not tried to boot it any further 
since I think that's fine for the purpose of this series. 

The series can also be found in the following git repo:

git://xenbits.xen.org/people/royger/xen.git branch hvm_without_dm_v1

And for the FreeBSD part:

git://xenbits.xen.org/people/royger/freebsd.git branch new_entry_point_v1

In case someone wants to give it a try, I've uploaded a FreeBSD kernel that 
should work when booted into this mode:

https://people.freebsd.org/~royger/kernel_no_dm

The config file that I've used is:

config
kernel=/path/to/kernel_no_dm

builder=hvm
device_model_version=none

memory=128
vcpus=1
name = freebsd
/config

Thanks, Roger.

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-22 Thread Stefano Stabellini
Hi Roger,

given that this patch series is actually using the Xen hvm builder, I
take that all the PVH code paths in Xen or the guest kernel are not
actually used, correct? This is more like PV on HVM without QEMU, right?

Do you think think this can work for Dom0 too?

Would that make all the PVH stuff in Xen and Linux effectively useless?

Thanks,

Stefano

On Mon, 22 Jun 2015, Roger Pau Monne wrote:
 Before reading any further, keep in mind this is a VERY inital RFC 
 prototype series. Many things are not finished, and those that are done 
 make heavy use of duck tape in order to keep things into place.
 
 Now that you are warned, this series is split in the following order:
 
  - Patches from 1 to 7 switch HVM domain contruction to use the xc_dom_* 
family of functions, like they are used to build PV domains. 
  - Patches from 8 to 13 introduce the creation of HVM domains without 
firmware, which is replaced by directly loading a kernel like it's done 
for PV guests. A new boot ABI based on the discussion in the thread RFC: 
making the PVH 64bit ABI as stable is also introduced, although it's not 
finished.
 
 Some things that are missing from the new boot ABI:
 
  - Although it supports loading a ramdisk, there's still now defined way 
into how to pass this ramdisk to the guest. I'm thinking of using a 
HVMPARAM or simply setting a GP register to contain the address of the 
ramdisk. Ideally I would like to support loading more than one ramdisk.
 
 Some patches contain comments after the SoB, which in general describe the 
 shortcommings of the implementation. The aim of those is to initiate 
 discussion about whether the aproach taken is TRTTD.
 
 I've only tested this on Intel hw, but I see no reason why it shouldn't work 
 on AMD. I've managed to boot FreeBSD up to the point were it should 
 jump into user-space (I just didn't have a VBD attached to the VM so it just 
 sits waiting for a valid disk). I have not tried to boot it any further 
 since I think that's fine for the purpose of this series. 
 
 The series can also be found in the following git repo:
 
 git://xenbits.xen.org/people/royger/xen.git branch hvm_without_dm_v1
 
 And for the FreeBSD part:
 
 git://xenbits.xen.org/people/royger/freebsd.git branch new_entry_point_v1
 
 In case someone wants to give it a try, I've uploaded a FreeBSD kernel that 
 should work when booted into this mode:
 
 https://people.freebsd.org/~royger/kernel_no_dm
 
 The config file that I've used is:
 
 config
 kernel=/path/to/kernel_no_dm
 
 builder=hvm
 device_model_version=none
 
 memory=128
 vcpus=1
 name = freebsd
 /config
 
 Thanks, Roger.
 
 ___
 Xen-devel mailing list
 Xen-devel@lists.xen.org
 http://lists.xen.org/xen-devel
 

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel


Re: [Xen-devel] [PATCH RFC v1 00/13] Introduce HMV without dm and new boot ABI

2015-06-22 Thread Konrad Rzeszutek Wilk
On Mon, Jun 22, 2015 at 06:55:12PM +0100, Stefano Stabellini wrote:
 Hi Roger,
 
 given that this patch series is actually using the Xen hvm builder, I
 take that all the PVH code paths in Xen or the guest kernel are not
 actually used, correct? This is more like PV on HVM without QEMU, right?

Are you saying it should be called now 'HVM-diet' ? Or 'HVMlite' instead
of PVH since it is looking at this from the HVM perspective instead of PVH?


 
 Do you think think this can work for Dom0 too?
 
 Would that make all the PVH stuff in Xen and Linux effectively useless?

No. The AP bootup is still the same. So would all the hypercalls I think.
 
 Thanks,
 
 Stefano
 
 On Mon, 22 Jun 2015, Roger Pau Monne wrote:
  Before reading any further, keep in mind this is a VERY inital RFC 
  prototype series. Many things are not finished, and those that are done 
  make heavy use of duck tape in order to keep things into place.
  
  Now that you are warned, this series is split in the following order:
  
   - Patches from 1 to 7 switch HVM domain contruction to use the xc_dom_* 
 family of functions, like they are used to build PV domains. 
   - Patches from 8 to 13 introduce the creation of HVM domains without 
 firmware, which is replaced by directly loading a kernel like it's done 
 for PV guests. A new boot ABI based on the discussion in the thread 
  RFC: 
 making the PVH 64bit ABI as stable is also introduced, although it's 
  not 
 finished.
  
  Some things that are missing from the new boot ABI:
  
   - Although it supports loading a ramdisk, there's still now defined way 
 into how to pass this ramdisk to the guest. I'm thinking of using a 
 HVMPARAM or simply setting a GP register to contain the address of the 
 ramdisk. Ideally I would like to support loading more than one ramdisk.
  
  Some patches contain comments after the SoB, which in general describe the 
  shortcommings of the implementation. The aim of those is to initiate 
  discussion about whether the aproach taken is TRTTD.
  
  I've only tested this on Intel hw, but I see no reason why it shouldn't 
  work 
  on AMD. I've managed to boot FreeBSD up to the point were it should 
  jump into user-space (I just didn't have a VBD attached to the VM so it 
  just 
  sits waiting for a valid disk). I have not tried to boot it any further 
  since I think that's fine for the purpose of this series. 
  
  The series can also be found in the following git repo:
  
  git://xenbits.xen.org/people/royger/xen.git branch hvm_without_dm_v1
  
  And for the FreeBSD part:
  
  git://xenbits.xen.org/people/royger/freebsd.git branch new_entry_point_v1
  
  In case someone wants to give it a try, I've uploaded a FreeBSD kernel that 
  should work when booted into this mode:
  
  https://people.freebsd.org/~royger/kernel_no_dm
  
  The config file that I've used is:
  
  config
  kernel=/path/to/kernel_no_dm
  
  builder=hvm
  device_model_version=none
  
  memory=128
  vcpus=1
  name = freebsd
  /config
  
  Thanks, Roger.
  
  ___
  Xen-devel mailing list
  Xen-devel@lists.xen.org
  http://lists.xen.org/xen-devel
  

___
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel