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[46.139.12.213]) by smtp.gmail.com with ESMTPSA id c24-v6sm12274183wre.44.2018.10.09.23.23.54 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 09 Oct 2018 23:23:54 -0700 (PDT) Date: Wed, 10 Oct 2018 08:23:52 +0200 From: Ingo Molnar To: Juergen Gross Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, linux-doc@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, corbet@lwn.net, boris.ostrovsky@oracle.com, Peter Zijlstra , Kees Cook Subject: Re: [PATCH v5 0/3] x86: make rsdp address accessible via boot params Message-ID: <20181010062352.GC37224@gmail.com> References: <20181010061456.22238-1-jgross@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181010061456.22238-1-jgross@suse.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org * Juergen Gross wrote: > In the non-EFI boot path the ACPI RSDP table is currently found via > either EBDA or by searching through low memory for the RSDP magic. > This requires the RSDP to be located in the first 1MB of physical > memory. Xen PVH guests, however, get the RSDP address via the start of > day information block. > > In order to support an arbitrary RSDP address this patch series adds > the physical address of the RSDP to the boot params structure filled > by the boot loader. > > Juergen Gross (3): > x86/xen: fix boot loader version reported for pvh guests > x86/boot: add acpi rsdp address to setup_header > x86/acpi: take rsdp address for boot params if available > > Documentation/x86/boot.txt | 32 +++++++++++++++++++++++++++++++- > arch/x86/boot/header.S | 6 +++++- > arch/x86/include/asm/acpi.h | 7 +++++++ > arch/x86/include/asm/x86_init.h | 2 ++ > arch/x86/include/uapi/asm/bootparam.h | 4 ++++ > arch/x86/kernel/acpi/boot.c | 6 ++++++ > arch/x86/kernel/head32.c | 1 + > arch/x86/kernel/head64.c | 2 ++ > arch/x86/kernel/setup.c | 17 +++++++++++++++++ > arch/x86/kernel/x86_init.c | 3 +-- > arch/x86/xen/enlighten_pvh.c | 2 +- > 11 files changed, 77 insertions(+), 5 deletions(-) I have some vague memories of an older variant of this feature breaking stuff and resulting in me involuntarily participating in an overly long bisection session. If that memory is right and I'm not confusing it with some other patchset, could you please provide some more context, what that old problem was, how it was resolved, whether it is expected to trigger on any machines, etc., to create some warm fuzzy feelings about this patch-set and to reduce my bisectofobia? ;-) Thanks, Ingo