linux-kernel - Re: [PATCH v2 7/7] xen: tolerate ACPI NVS memory overlapping with Xen allocated memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <a3494824-a976-4256-b056-97fee841de6c@suse.com>
Date: Tue, 10 Sep 2024 10:16:15 +0200
From: Jürgen Groß <jgross@...e.com>
To: Jan Beulich <jbeulich@...e.com>
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
 "H. Peter Anvin" <hpa@...or.com>, xen-devel@...ts.xenproject.org,
 Marek Marczykowski-Górecki
 <marmarek@...isiblethingslab.com>, linux-kernel@...r.kernel.org,
 x86@...nel.org
Subject: Re: [PATCH v2 7/7] xen: tolerate ACPI NVS memory overlapping with Xen
 allocated memory

On 20.08.24 12:23, Jan Beulich wrote:
> On 20.08.2024 10:20, Juergen Gross wrote:
>> In order to minimize required special handling for running as Xen PV
>> dom0, the memory layout is modified to match that of the host. This
>> requires to have only RAM at the locations where Xen allocated memory
>> is living. Unfortunately there seem to be some machines, where ACPI
>> NVS is located at 64 MB, resulting in a conflict with the loaded
>> kernel or the initial page tables built by Xen.
>>
>> As ACPI NVS needs to be accessed by the kernel only for saving and
>> restoring it across suspend operations, it can be relocated in the
>> dom0's memory map by swapping it with unused RAM (this is possible
>> via modification of the dom0 P2M map).
> 
> Shouldn't this paragraph be amended / re-written, as this was what made
> me ask for what is now patch 6?

Oh, indeed.

Juergen

Download attachment "OpenPGP_0xB0DE9DD628BF132F.asc" of type "application/pgp-keys" (3684 bytes)

Download attachment "OpenPGP_signature.asc" of type "application/pgp-signature" (496 bytes)