From: Borislav Petkov <bp@alien8.de>
To: Juergen Gross <jgross@suse.com>
Cc: xen-devel@lists.xenproject.org, x86@kernel.org,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v2 01/10] x86/mtrr: fix MTRR fixup on APs
Date: Mon, 22 Aug 2022 10:28:08 +0200 [thread overview]
Message-ID: <YwM+GPu8hFowl2R7@zn.tnic> (raw)
In-Reply-To: <f205da1c-db33-299c-5fc6-922a8ebd1983@suse.com>
On Mon, Aug 22, 2022 at 07:17:40AM +0200, Juergen Gross wrote:
> And then there is mtrr_state_warn() in arch/x86/kernel/cpu/mtrr/generic.c
> which has a comment saying:
>
> /* Some BIOS's are messed up and don't set all MTRRs the same! */
That thing also says:
pr_info("mtrr: probably your BIOS does not setup all CPUs.\n");
pr_info("mtrr: corrected configuration.\n");
because it'll go and force on all CPUs the MTRR state it read from the
BSP in mtrr_bp_init->get_mtrr_state.
> Yes, the chances are slim to hit such a box,
Well, my workstation says:
$ dmesg | grep -i mtrr
[ 0.391514] mtrr: your CPUs had inconsistent variable MTRR settings
[ 0.395199] mtrr: probably your BIOS does not setup all CPUs.
[ 0.399199] mtrr: corrected configuration.
but that's the variable MTRRs.
> but your reasoning suggests I should remove the related code?
My reasoning says you should not do anything at all here - works as
advertized. :-)
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-08-22 8:28 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-20 9:25 [PATCH v2 00/10] x86: make pat and mtrr independent from each other Juergen Gross
2022-08-20 9:25 ` [PATCH v2 01/10] x86/mtrr: fix MTRR fixup on APs Juergen Gross
2022-08-20 10:28 ` Greg KH
2022-08-21 12:25 ` Borislav Petkov
2022-08-21 21:41 ` Borislav Petkov
2022-08-22 5:17 ` Juergen Gross
2022-08-22 8:28 ` Borislav Petkov [this message]
2022-08-22 8:32 ` Juergen Gross
2022-10-19 18:45 ` [tip: x86/cpu] x86/mtrr: Add comment for set_mtrr_state() serialization tip-bot2 for Juergen Gross
2022-08-20 9:25 ` [PATCH v2 02/10] x86/mtrr: remove unused cyrix_set_all() function Juergen Gross
2022-08-25 10:31 ` Borislav Petkov
2022-08-25 10:38 ` Juergen Gross
2022-08-25 10:41 ` Juergen Gross
2022-08-25 11:42 ` Borislav Petkov
2022-08-25 12:13 ` Juergen Gross
2022-08-20 9:25 ` [PATCH v2 03/10] x86/mtrr: replace use_intel() with a local flag Juergen Gross
2022-08-20 9:25 ` [PATCH v2 04/10] x86: move some code out of arch/x86/kernel/cpu/mtrr Juergen Gross
2022-08-20 9:25 ` [PATCH v2 05/10] x86/mtrr: split generic_set_all() Juergen Gross
2022-08-20 9:25 ` [PATCH v2 06/10] x86/mtrr: remove set_all callback from struct mtrr_ops Juergen Gross
2022-08-20 9:25 ` [PATCH v2 07/10] x86/mtrr: simplify mtrr_bp_init() Juergen Gross
2022-08-20 9:25 ` [PATCH v2 08/10] x86/mtrr: let cache_aps_delayed_init replace mtrr_aps_delayed_init Juergen Gross
2022-08-20 9:25 ` [PATCH v2 09/10] x86/mtrr: add a stop_machine() handler calling only cache_cpu_init() Juergen Gross
2022-08-20 9:25 ` [PATCH v2 10/10] x86: decouple pat and mtrr handling Juergen Gross
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