[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH 2/2] arm/efi: Use dom0less configuration when using EFI boot

  • To: Stefano Stabellini <sstabellini@xxxxxxxxxx>
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Fri, 17 Sep 2021 08:44:11 +0200
  • Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=suse.com; dmarc=pass action=none header.from=suse.com; dkim=pass header.d=suse.com; arc=none
  • Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version; bh=6yWu6BQ5ivwsWsLLZFhrPujMJy9qa1cwJD3Vnzeo0Kc=; b=cAsJkJePV3+MuVKGCMDyhSTlHooR+Dh9FpBj/2gQOJD0fZaP2fG2ocIB0kSXFJLmFXnxZ1LpnBUQRnFLjQTuI+Xcv9PZkdWwtHZGEgZhRd+oxDscvLCykALV0tFsMa+6BlVDyHziNW+k7Oyez2F41+sKpxuFzsQaDC0wqa/P0u3ixcbw65A1grHLf/1Npu8IhjVw4Hp6DudxqZWjEyJAwqSn+OYZ0iAB8aeAaSm3nD8mncCWDn671h2mJfHcuKp31a2ayhePaSwZpMmzKujhCSVt5DrSf3PN40JRi0lDsQPGvEoyk+s3VNLkdOJ8ezch8V5JvqXXyDbZWYXhnqog9g==
  • Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=EYvylNVfEkYIDWQtKwtDSWTnG0C5OAknOGoxtatZPJ7uzen48rCGomCkLK4p6pTZzqwM28sGnXG5VoJuNz7dzyBnhJy0UOktWAwlaQRVNZiUS7YaJr+JqkVjIXesoxnrSJsx/zz5NxuYZrrOmk45bWTxxYThSMgZRoieTYsmdOtgDRHA42U5AooAU1Yv8jbevwtwJyuCnQP2TG36gslWGHRyuqYrpxkSNxz+KAKaennvxOoMariofx95WhoyiKiBRixFMj8rhyEkhRrt54ipaMRWW541xRK9fsfKXmbxHQVlsg2o2j4zeq+pRr4BOhnSNH/NWHDQ0s3dqnlDd7ZL0Q==
  • Authentication-results: lists.xenproject.org; dkim=none (message not signed) header.d=none;lists.xenproject.org; dmarc=none action=none header.from=suse.com;
  • Cc: Luca Fancellu <luca.fancellu@xxxxxxx>, Bertrand Marquis <bertrand.marquis@xxxxxxx>, wei.chen@xxxxxxx, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, George Dunlap <george.dunlap@xxxxxxxxxx>, Ian Jackson <iwj@xxxxxxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, Wei Liu <wl@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
  • Delivery-date: Fri, 17 Sep 2021 06:44:21 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 16.09.2021 22:16, Stefano Stabellini wrote:
> On Thu, 16 Sep 2021, Jan Beulich wrote:
>> On 16.09.2021 17:07, Luca Fancellu wrote:
>>> I explain here my understanding on dom0less, this feature is used to start 
>>> domUs at
>>> Xen boot in parallel, the name is misleading but it doesn’t require dom0 to 
>>> be absent.
>>> So if you have a dom0 kernel embed in the image, it's completely fine to 
>>> start it and it 
>>> doesn’t have to be skipped.
>>> Here the possible user cases:
>>> 1) start only dom0 [dom0 modules on xen.cfg or embedded in Xen image]
>>> 2) start only domUs, true dom0less [no dom0 modules on xen.cfg or embedded 
>>> in Xen image, domUs on DT]
>>> 3) start dom0 and domUs [(dom0 modules on xen.cfg or embedded in Xen image) 
>>> and domUs on DT]
>> If that's the intention - fine. Stefano?
> What do you mean by dom0 modules embedded in the Xen image? I am not
> familiar with it, but I imagine it doesn't involve any multiboot,module
> nodes in device tree, right?

There's no DT interaction there afaict. See commit 8a71d50ed40b
("efi: Enable booting unified hypervisor/kernel/initrd images").

> Putting aside "dom0 modules embedded in Xen image" that I didn't fully
> understand, there are three ways to load Dom0:
> - dom0 kernel (and ramdisk, optional) on xen.cfg
> - dom0 kernel (and ramdisk, optional) on device tree using the "reg" property
> - dom0 kernel (and ramdisk, optional) on device tree using the "uefi,binary" 
> property
> Then, the other use cases are:
> - true dom0less, domUs on device tree using the "reg" property
> - true dom0less, domUs on device tree using the "uefi,binary" property
> And of course all the possible combinations between Dom0 and DomU
> loading.

Okay, so as Luca says "dom0less" is a misnomer really. I wasn't
aware of this.




Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.