From: Juergen Gross <jgross@suse.com>
To: Borislav Petkov <bp@alien8.de>
Cc: "Janusz Krzysztofik" <janusz.krzysztofik@linux.intel.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"David Hildenbrand" <david@redhat.com>,
"Yu Zhao" <yuzhao@google.com>,
linux-kernel@vger.kernel.org,
"Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>,
"Andi Shyti" <andi.shyti@linux.intel.com>,
drm-intel@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Subject: Re: [RESUBMIT][PATCH] x86/mm: Fix PAT bit missing from page protection modify mask
Date: Fri, 2 Jun 2023 16:48:11 +0200 [thread overview]
Message-ID: <bd70e7b8-1971-6982-979a-ce1eb4c93465@suse.com> (raw)
In-Reply-To: <20230602144357.GCZHoALQjO+xx3YxAz@fat_crate.local>
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On 02.06.23 16:43, Borislav Petkov wrote:
> On Thu, Jun 01, 2023 at 10:47:39AM +0200, Juergen Gross wrote:
>> As described in the commit message, this only works on bare metal due to the
>> PAT bit not being needed for WC mappings.
>>
>> Making this patch Xen specific would try to cure the symptoms without fixing
>> the underlying problem: _PAGE_PAT should be regarded the same way as the bits
>> for caching mode (_PAGE_CHG_MASK).
>
> So why isn't _PAGE_PAT part of _PAGE_CHG_MASK?
This would result in problems for large pages: _PAGE_PSE is at the same
position as _PAGE_PAT (large pages are using _PAGE_PAT_LARGE instead).
Yes, x86 ABI is a mess.
Juergen
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next prev parent reply other threads:[~2023-06-02 14:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-19 18:36 Janusz Krzysztofik
2023-05-31 9:35 ` Andi Shyti
[not found] ` <20230531181412.GFZHeOdMHIGOXB2hwL@fat_crate.local>
2023-06-01 8:47 ` Juergen Gross
2023-06-02 14:43 ` Borislav Petkov
2023-06-02 14:48 ` Juergen Gross [this message]
2023-06-02 14:53 ` Juergen Gross
2023-06-05 15:51 ` Janusz Krzysztofik
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