From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH v2 3/3] x86/xen: supply rsdp address in boot params for pvh guests Date: Fri, 8 Dec 2017 08:22:16 +0100 Message-ID: <20171208072216.nkexmwnbzin4iwmf@gmail.com> References: <20171207122821.30158-1-jgross@suse.com> <20171207122821.30158-4-jgross@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Received: from mail-wr0-f194.google.com ([209.85.128.194]:47082 "EHLO mail-wr0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751116AbdLHHWU (ORCPT ); Fri, 8 Dec 2017 02:22:20 -0500 Content-Disposition: inline In-Reply-To: <20171207122821.30158-4-jgross@suse.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Juergen Gross Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, boris.ostrovsky@oracle.com, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, corbet@lwn.net, rjw@rjwysocki.net, lenb@kernel.org, linux-acpi@vger.kernel.org * Juergen Gross wrote: > When booted via the special PVH entry save the RSDP address set in the > boot information block in struct boot_params. This will enable Xen to > locate the RSDP at an arbitrary address. > > Set the boot loader version to 2.14 (0x020e) replacing the wrong 0x0212 > which should have been 0x020c. > > Signed-off-by: Juergen Gross > --- > V2: set bootloader version to 2.14 (Roger Pau Monné) > --- > arch/x86/xen/enlighten_pvh.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c > index 436c4f003e17..036e3a5f284a 100644 > --- a/arch/x86/xen/enlighten_pvh.c > +++ b/arch/x86/xen/enlighten_pvh.c > @@ -68,9 +68,12 @@ static void __init init_pvh_bootparams(void) > * > * Version 2.12 supports Xen entry point but we will use default x86/PC > * environment (i.e. hardware_subarch 0). > + * The RSDP address is available from version 2.14 on. > */ > - pvh_bootparams.hdr.version = 0x212; > + pvh_bootparams.hdr.version = 0x20e; While 0x212 was "obvious" to read but totally wrong, it would be less fragile and more readable if the version was generated as something like: pvh_bootparams.hdr.version = (2 << 8) | 14; similar to how it's written in other cases: > pvh_bootparams.hdr.type_of_loader = (9 << 4) | 0; /* Xen loader */ Also, shouldn't the 0x212 fix be a separate patch, Cc: stable? The bug appears to have been introduced at around v4.12. Thanks, Ingo