Re: [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest

From	Boris Ostrovsky <boris.ostrovsky@oracle.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest
Date	2016-01-26 20:10 +0100
Message-ID	<qVha3-8N-43@gated-at.bofh.it> (permalink)
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On 01/26/2016 01:46 PM, Andy Lutomirski wrote:
> On Tue, Jan 26, 2016 at 10:34 AM, Luis R. Rodriguez <mcgrof@suse.com> wrote:
>> On Mon, Jan 25, 2016 at 05:28:08PM -0500, Boris Ostrovsky wrote:
>>> On 01/25/2016 04:21 PM, H. Peter Anvin wrote:
>>>> On 01/25/16 13:12, Luis R. Rodriguez wrote:
>>>>>> Perhaps, but someone would still have to set hardware_subarch. And
>>>>>> it's hvmlite_bootparams() that does it.
>>>>> No, Xen would do it as well, essentially all of hvmlite_bootparams() could be
>>>>> done in Xen.
>>>>>
>>>> Or a stub code.
>>> This patch in fact is the stub for Xen HVMlite guests, after we are
>>> done with it we jump to bare-metal startup code (i.e startup_32|64)
>> Right the point is the stub need not be in Linux, I'll explain in the other
>> thread where I provided more details on the different known approaches.
>>
> ISTM if the Xen ABI-specified entry point has a different convention
> than the Linux native entry, then the stub should live in Linux.  It
> would be just a couple if lines of code, right?

It's not exactly a couple of lines but it's not large neither. It mainly 
sets up boot_params (similar to what make_boot_params() does for EFI). 
Plus, for 64-bit, it loads identity page tables and switches to long 
mode. And then jumps to bare-meta startup code.


>
> The issue that caused headaches in the past isn't that there's code
> that's executed only on native, it's that there are whole big
> functions that are executed only on native for no good reason and that
> aren't clearly marked.

This won't happen with HVMlite.

>
> If we had native_start_kernel and xen_start_kernel, and they both
> called very quickly in to common_start_kernel, it would be very clear
> what's going on.

What is now xen_start_kernel() is no longer the entry point for HVMlite. 
It is called as x86_init.oem.arch_setup() (or I may even move it to 
x86_hyper_xen.init_platform() or something like that).

-boris

Thread

[PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-01-22 22:40 +0100
  Re: [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-01-23 00:40 +0100
    Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Andrew Cooper <andrew.cooper3@citrix.com> - 2016-01-23 01:40 +0100
      Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-01-23 01:50 +0100
      Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-01-23 02:00 +0100
        Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Andrew Cooper <andrew.cooper3@citrix.com> - 2016-01-23 15:50 +0100
          Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "H. Peter Anvin" <hpa@zytor.com> - 2016-01-23 17:10 +0100
            Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2016-01-23 17:20 +0100
              Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "H. Peter Anvin" <hpa@zytor.com> - 2016-01-23 19:30 +0100
              Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Roger Pau Monné <royger@FreeBSD.org> - 2016-01-25 11:40 +0100
          Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-01-25 23:20 +0100
            Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-01-26 00:00 +0100
              Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-01-26 21:40 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-01-26 23:00 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-01-27 01:10 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-01-27 03:20 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest David Vrabel <david.vrabel@citrix.com> - 2016-01-27 16:00 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-01-27 16:10 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest David Vrabel <david.vrabel@citrix.com> - 2016-01-27 16:10 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-01-27 16:20 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-01-27 17:20 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-01-27 19:50 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-01-27 20:10 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Borislav Petkov <bp@suse.de> - 2016-01-27 17:20 +0100
          Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2016-01-26 17:20 +0100
      Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-01-25 16:10 +0100
    Re: [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-01-25 17:10 +0100
      Re: [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-01-25 22:20 +0100
        Re: [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "H. Peter Anvin" <hpa@zytor.com> - 2016-01-25 22:30 +0100
          Re: [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-01-25 23:30 +0100
            Re: [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-01-26 19:40 +0100
              Re: [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Andy Lutomirski <luto@amacapital.net> - 2016-01-26 19:50 +0100
                Re: [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-01-26 20:10 +0100
                Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-01-26 20:20 +0100

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