From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH 3/4] x86-64: EFI runtime code Date: Wed, 13 Jul 2011 09:42:42 -0400 Message-ID: <20110713134242.GA8466@dumpdata.com> References: <4E099AA6020000780004A4C6@nat28.tlf.novell.com> <4E09A533020000780004A535@nat28.tlf.novell.com> <20110628160503.GD30413@dumpdata.com> <4E0A1F20020000780004A9CA@nat28.tlf.novell.com> <20110628170331.GA30761@dumpdata.com> <4E0AE75E020000780004ABE2@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4E0AE75E020000780004ABE2@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jan Beulich Cc: Keir Fraser , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On Wed, Jun 29, 2011 at 07:50:38AM +0100, Jan Beulich wrote: > >>> On 28.06.11 at 19:03, Konrad Rzeszutek Wilk wrote: > > Ah, here it is: "acpi_os_get_root_pointer" uses the efi.acpi20 or > > efi.acpi and the DMI scan uses efi.smbios. > > > > And those physical addresses reside within a reserved E820 region or > > a gap I hope. > > That's how it's supposed to be. If we find systems where it lives > elsewhere, we'll have to add workarounds (in Xen). > > >> Yes, it needs to, due to the table pointer retrieval differences. And > >> then there's the runtime services (RTC access, EFI variables) that > >> the OS ought to use. On the RTC side of things, a legacy free system > > > > I am just looking at the minimal to understand it. > >> might not have a CMOS clock, and hence even native Linux is currently > >> broken in that respect (because the driver can be built only for IA64). > > > > We do switch to the Xen clock (which is to say that the hypervisor is > > responsible for it) ... so I think we could skip the RTC in the Linux > > kernel. > > No, Dom0 has to manage the RTC (and so it does today, at least > in all non-pvops kernels I know of). And it looks that the efi set/get vars are important for the efibootmgr, so that, RTC, and ACPI RSDT pointer must be implemented somehow. The ACPI RSDT can be potentially piggybacked http://marc.info/?i=E8CC3FDD41FF9Findou.takao@jp.fujitsu.com by making that variable global. But for the RTC and set/get vars I am not sure. The good thing is that I finally got an EFI box so let me play with this. On another topic - I saw you posted some patches upstream for EFI cleanup - were you by any chance looking at implementing this in paravirt?