From: Borislav Petkov <bp@alien8.de>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Tom Lendacky <thomas.lendacky@amd.com>,
x86@kernel.org, Kim Phillips <kim.phillips@amd.com>,
Yazen Ghannam <yazen.ghannam@amd.com>, Pu Wen <puwen@hygon.cn>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/cpu/amd: Remove dead code for TSEG region remapping
Date: Thu, 3 Dec 2020 17:44:11 +0100 [thread overview]
Message-ID: <20201203164411.GK3059@zn.tnic> (raw)
In-Reply-To: <X8kOzpXyDXNo2PE7@rani.riverdale.lan>
On Thu, Dec 03, 2020 at 11:14:06AM -0500, Arvind Sankar wrote:
> Do any of them have it mapped at all, regardless of the alignment? There
> seems to be nothing else in the kernel that ever looks at the TSEG MSR,
> so I would guess that it has to be non-RAM in the E820 map, otherwise
> nothing would prevent the kernel from allocating and using that space.
Ha, that's a very good question. If all those BIOSes from K8 onwards
would put the TSEG in a non-RAM area and after
66520ebc2df3 ("x86, mm: Only direct map addresses that are marked as E820_RAM")
(great investigative work, btw, thanks for that!) then we can simply say
that that splitting is not needed anymore.
Maybe Tom can ask BIOS people whether they always did that - that being
to put the TSEG into a non-RAM area. I can boot my debug patch on my
boxes here but that doesn't mean a whole lot...
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-12-03 16:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-27 17:13 [PATCH] x86/cpu/amd: Remove dead code for TSEG region remapping Arvind Sankar
2020-11-27 17:27 ` Borislav Petkov
2020-12-02 17:58 ` Tom Lendacky
2020-12-02 18:10 ` Borislav Petkov
2020-12-02 22:32 ` Arvind Sankar
2020-12-03 8:48 ` Borislav Petkov
2020-12-03 16:14 ` Arvind Sankar
2020-12-03 16:44 ` Borislav Petkov [this message]
2020-12-08 18:12 ` [tip: x86/cpu] " tip-bot2 for Arvind Sankar
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